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Reserves definitions

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Glossary of terms used in petroleum reserves or resources definitions

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1C

Denotes low estimate of contingent resources. Glossary of Petroleum Resources Management System - June 2018 (revised version)

2C

Denotes best estimate of contingent resources. Glossary of Petroleum Resources Management System - June 2018 (revised version)

3C

Denotes high estimate of contingent resources. Glossary of Petroleum Resources Management System - June 2018 (revised version)

1P

Denotes low estimate of Reserves (i.e., Proved Reserves). Equal to P1. Glossary of Petroleum Resources Management System - June 2018 (revised version)

2P

Denotes the best estimate of Reserves. The sum of Proved plus Probable Reserves. Glossary of Petroleum Resources Management System - June 2018 (revised version)

3P

Denotes high estimate of reserves. The sum of Proved plus Probable plus Possible Reserves. Glossary of Petroleum Resources Management System - June 2018 (revised version)

1U

Denotes the unrisked low estimate qualifying as Prospective Resources. Glossary of Petroleum Resources Management System - June 2018 (revised version)

2U

Denotes the unrisked best estimate qualifying as Prospective Resources. Glossary of Petroleum Resources Management System - June 2018 (revised version)

3U

Denotes the unrisked high estimate qualifying as Prospective Resources. Glossary of Petroleum Resources Management System - June 2018 (revised version)

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A

Abandoning, Decommissioning, and Restoration (ADR)

The process (and associated costs) of returning part or all of a project to a safe and environmentally compliant condition when operations cease. Examples include, but are not limited to, the removal of surface facilities, wellbore plugging procedures, and environmental remediation. In some instances, there may be salvage value associated with the equipment removed from the project. ADR costs are presumed to be without consideration of any salvage value, unless presented as “ADR net of salvage.” Glossary of Petroleum Resources Management System - June 2018 (revised version)

Accumulation

An individual body of naturally occurring petroleum in a reservoir. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Aggregation

The process of summing well, reservoir, or project-level estimates of resources quantities to higher levels or combinations, such as field, country or company totals. Arithmetic summation of incremental categories may yield different results from probabilistic aggregation of distributions. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Analog

Method used in resources estimation in the exploration and early development stages (including improved recovery projects) when direct measurement is limited. Based on evaluator’s assessment of similarities of the analogous reservoir(s) together with the development plan. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Analogous Reservoir

Reservoirs that have similar rock properties (e.g., petrophysical, lithological, depositional, diagenetic, and structural), fluid properties (e.g., type, composition, density, and viscosity), reservoir conditions (e.g., depth, temperature, and pressure) and drive mechanisms, but are typically at a more advanced stage of development than the reservoir of interest and thus may provide insight and comparative data to assist in estimation of recoverable resources. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Appraisal

The phase that may follow successful exploratory drilling. Activities to further evaluate the discovery, such as seismic acquisition, geological studies, and drilling additional wells may be conducted to reduce technical uncertainties and commercial contingencies. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Approved for Development

All necessary approvals have been obtained, capital funds have been committed, and implementation of the development project is underway. A project maturity sub-class of Reserves. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Assessment

See Evaluation. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Associated Gas

A natural gas found in contact with or dissolved in crude oil in the reservoir. It can be further categorized as gas cap gas or solution gas. Glossary of Petroleum Resources Management System - June 2018 (revised version)

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B

Barrel of Oil Equivalent (BOE)

The term allows for a single value to represent the sum of all the hydrocarbon products that are forecast as resources. Typically, condensate, oil, bitumen, and synthetic crude barrels are taken to be equal (1 bbl = 1 BOE). Gas and NGL quantities are converted to an oil equivalent based on a conversion factor that is recommended to be based on a nominal heating content or calorific value equivalent to a barrel of oil. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Basin-centered gas

An unconventional natural gas accumulation that is regionally pervasive and characterized by low permeability, abnormal pressure, gas-saturated reservoirs, and lack of a down dip water leg. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Basis for Estimate

The methodology (or methodologies) and supporting data on which the estimated quantities are based. (Also referenced as basis for the estimation.) Glossary of Petroleum Resources Management System - June 2018 (revised version)

Behind-Pipe Reserves

Reserves that are expected to be recovered from zones in existing wells, which will require additional completion work or future re-completion before the start of production. In all cases, production can be initiated or restored with relatively low expenditure compared to the cost of drilling and completing a new well including hook-up to allow production. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Best Estimate

With respect to resources categorization, the most realistic assessment of recoverable quantities if only a single result were reported. If probabilistic methods are used, there should be at least a 50% probability (P50) that the quantities actually recovered will equal or exceed the best estimate. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Bitumen 

See Natural bitumen Appendix A: Glossary of Terms Used in Resources Evaluations - 2007 - 2.4.

Buy back agreement 

An agreement between a host government and a contractor under which the host pays the contractor an agreed price for all volumes of hydrocarbons produced by the contractor. Pricing mechanisms typically provide the contractor with an opportunity to recover investment at an agreed level of profit. Glossary of Reserves/Resources Terminology - 2005 & Appendix A: Glossary of Terms Used in Resources Evaluations - 2007.

These agreements may include financial incentives for more efficient, lower cost developments and production levels higher than the minimum level agreed. These agreements may give rights to oil volumes and generally carry a risk for the contractor. They may allow booking of reserves Glossary of Reserves/Resources Terminology - 2005.

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C

C1

Denotes low estimate of Contingent Resources. C1 is equal to 1C. Glossary of Petroleum Resources Management System - June 2018 (revised version)

C2

Denotes Contingent Resources of same technical confidence as Probable, but not commercially matured to Reserves. Glossary of Petroleum Resources Management System - June 2018 (revised version)

C3

Denotes Contingent Resources of same technical confidence as Possible, but not commercially matured to Reserves. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Carried interest 

A carried interest is an agreement under which one party (the carrying party) agrees to pay for a portion or all of the pre-production costs of another party (the carried party) on a license in which both own a portion of the working interest Glossary of Reserves/Resources Terminology - 2005 & Appendix A: Glossary of Terms Used in Resources Evaluations - 2007 - 2001 - 9.6.7.

This arises when the carried party is either unwilling to bear the risk of exploration or is unable to fund the cost of exploration or development directly. Owners may enter into carried interest arrangements with existing or incoming joint venture partners at the exploration stage, the development stage, or both Glossary of Reserves/Resources Terminology - 2005.

Chance

Chance equals 1-risk. Generally synonymous with likelihood. (See Risk) Glossary of Petroleum Resources Management System - June 2018 (revised version)

Chance of Commerciality

The estimated probability that the project will achieve commercial maturity to be developed. For Prospective Resources, this is the product of the chance of geologic discovery and the chance of development. For Contingent Resources and Reserves, it is equal to the chance of development. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Chance of Development

The estimated probability that a known accumulation, once discovered, will be commercially developed. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Chance of Geologic Discovery

The estimated probability that exploration activities will confirm the existence of a significant accumulation of potentially recoverable petroleum. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Coalbed Methane (CBM)

Natural gas contained in coal deposits. Coalbed gas, although usually mostly methane, may be produced with variable amounts of inert or even non-inert gases. [Also called coal-seam gas (CSG) or natural gas from coal (NGC).] Glossary of Petroleum Resources Management System - June 2018 (revised version)

Commercial

A project is commercial when there is evidence of a firm intention to proceed with development within a reasonable time-frame. Typically, this requires that the best estimate case meet or exceed the minimum evaluation decision criteria (e.g., rate of return, investment payout time). There must be a reasonable expectation that all required internal and external approvals will be forthcoming. Also, there must be evidence of a technically mature, feasible development plan and the essential social, environmental, economic, political, legal, regulatory, decision criteria, and contractual conditions are met. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Committed Project

Project that the entity has a firm intention to develop in a reasonable time-frame. Intent is demonstrated with funding/financial plans, but FID has not yet been declared (See also Final Investment Decision.) Glossary of Petroleum Resources Management System - June 2018 (revised version)

Completion

Completion of a well. The process by which a well is brought to its operating status (e.g., producer, injector, or monitor well). A well deemed to be capable of producing petroleum, or used as an injector, is completed by establishing a connection between the reservoir(s) and the surface so that fluids can be produced from, or injected into, the reservoir. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Completion Interval

The specific reservoir interval(s) that is (are) open to the borehole and connected to the surface facilities for production or injection, or reservoir intervals open to the wellbore and each other for injection purposes. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Concession

A grant of access for a defined area and time period that transfers certain entitlements to produced hydrocarbons from the host country to an entity. The entity is generally responsible for exploration, development, production, and sale of hydrocarbons that may be discovered. Typically granted under a legislated fiscal system where the host country collects taxes, fees, and sometimes royalty on profits earned. (Also called a license.) Glossary of Petroleum Resources Management System - June 2018 (revised version)

Condensate

A mixture of hydrocarbons (mainly pentanes and heavier) that exist in the gaseous phase at original temperature and pressure of the reservoir, but when produced, are in the liquid phase at surface pressure and temperature conditions. Condensate differs from NGLs in two respects: (1) NGL is extracted and recovered in gas plants rather than lease separators or other lease facilities, and (2) NGL includes very light hydrocarbons (ethane, propane, or butanes) as well as the pentanes-plus that are the main constituents of condensate. Glossary of Petroleum Resources Management System - June 2018 (revised version)

=== Conditions ===

The economic, marketing, legal, environmental, social, and governmental factors forecast to exist and impact the project during the time period being evaluated (also termed Contingencies) Appendix A: Glossary of Terms Used in Resources Evaluations - 2007 - 2001 - 3.1.

Confidence Level

A measure of the estimated reliability of a result. As used in the deterministic incremental method, the evaluator assigns a relative level of confidence (high/ moderate/low) to areas/segments of an accumulation based on the information available (e.g., well control and seismic coverage). Probabilistic and statistical methods use the 90% (P90) for the high confidence (low value case), 50% (P50) for the best estimate (moderate value case), and 10% (P10) for the low (high value case) estimate to represent the chances that the actual value will equal or exceed the estimate. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Constant Case

A descriptor applied to the economic evaluation of resources estimates. Constantcase estimates are based on current economic conditions being those conditions (including costs and product prices) that are fixed at the evaluation date and held constant, with no inflation or deflation made to costs or prices throughout the remainder of the project life other than those permitted contractually. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Consumed In Operations (CIO)

That portion of produced petroleum consumed as fuel in production or lease plant operations before delivery to the market at the reference point. (Also called lease fuel.) Glossary of Petroleum Resources Management System - June 2018 (revised version)

Contingency

A condition that must be satisfied for a project in Contingent Resources to be reclassified as Reserves. Resolution of contingencies for projects in Development Pending is expected to be achieved within a reasonable time period. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Contingent Project

A project that is not yet commercial owing to one or more contingencies that have not been resolved. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Contingent Resources

Those quantities of petroleum estimated, as of a given date, to be potentially recoverable from known accumulations by application of development projects, but which are not currently considered to be commercially recoverable owing to one or more contingencies. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Continuous-Type Deposit

A petroleum accumulation that is pervasive throughout a large area and that generally lacks well-defined OWC or GWC. Such accumulations are included in unconventional resources. Examples of such deposits include “basin-centered” gas, tight gas, tight oil, gas hydrates, natural bitumen, and oil shale (kerogen) accumulations. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Conventional crude oil 

Petroleum found in liquid form, flowing naturally or capable of being pumped without further processing or dilution. See Crude Oil. Glossary of Reserves/Resources Terminology - 2005.

Crude oil flowing naturally or capable of being pumped without further processing or dilution See Crude Oil Appendix A: Glossary of Terms Used in Resources Evaluations - 2007 - 2.4.

Conventional deposit 

A discrete accumulation related to a localized geological structural feature and/or stratigraphic condition, typically with each accumulation bounded by a down-dip contact with an aquifer, and which is significantly affected by hydrodynamic influences, such as the buoyancy of petroleum in water Glossary of Reserves/Resources Terminology - 2005.

Conventional gas 

Conventional Gas is a natural gas occurring in a normal porous and per- meable reservoir rock, either in the gaseous phase or dissolved in crude oil, and which technically can be produced by normal production practices Glossary of Reserves/Resources Terminology - 2005.

Conventional Gas is a natural gas occurring in a normal porous and permeable reservoir rock, either in the gaseous phase or dissolved in crude oil, and which technically can be produced by normal production practices Appendix A: Glossary of Terms Used in Resources Evaluations - 2007 - 2.4.

Conventional Resources

A petroleum accumulation that is pervasive throughout a large area and that generally lacks well-defined OWC or GWC. Such accumulations are included in unconventional resources. Examples of such deposits include “basin-centered” gas, tight gas, tight oil, gas hydrates, natural bitumen, and oil shale (kerogen) accumulations. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Conveyance 

Certain transactions that are in substance borrowings repayable in cash or its equivalent and shall be accounted for as borrowings and may not qualify for the recognition and reporting of oil and gas reserves. These include: 1) a) Cash advances to operators to finance exploration in return for the right to purchase oil or gas discovered. b) Funds advanced for exploration that is repayable by offset against purchases of oil or gas discovered, or in cash if insufficient oil or gas is produced by a specified date. 2) Funds advanced to an operator that are repayable in cash out of the proceeds from a specified share of future production of a producing property, until the amount advanced plus interest at a specified or determinable rate is paid in full, shall be accounted for as a borrowing and do not qualify for the recognition of reserves. The advance is a payable for the recipient of the cash and receivable for the party making the advance. Such transactions fall into a category commonly referred to as production payments Glossary of Reserves/Resources Terminology - 2005.

Certain transactions that are in substance borrowings repayable in cash or its equivalent and shall be accounted for as borrowings and may not qualify for the recognition and reporting of oil and gas reserves Appendix A: Glossary of Terms Used in Resources Evaluations - 2007 - 9.6.9.

Cost Recovery

Under a typical production-sharing agreement, the contractor is responsible for the field development and all exploration and development expenses. In return, the contractor recovers costs (investments and operating expenses) out of the production stream. The contractor normally receives an entitlement interest share in the petroleum production and is exposed to both technical and market risks. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Crude Oil

Crude oil is the portion of petroleum that exists in the liquid phase in natural underground reservoirs and remains liquid at atmospheric conditions of pressure and temperature (excludes retrograde condensate). Crude oil may include small amounts of non-hydrocarbons produced with the liquids but does not include liquids obtained from the processing of natural gas. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Crude oil equivalent

 

Converting gas volumes to the oil equivalent is customarily done on the basis of the heating content or calorific value of the fuel. There are a number of methodologies in common use. Before aggregating, the gas volumes first must be converted to the same temperature and pressure. Common industry gas conversion factors usually range between 1.0 barrel of oil equivalent (boe) = 5.6 thousand standard cubic feet of gas (mscf) to 1.0 boe = 6.0 mscf Glossary of Reserves/Resources Terminology - 2005.

Converting gas volumes to the oil equivalent is customarily done on the basis of the nominal heating content or calorific value of the fuel. There are a number of methodologies in common use. Before aggregating, the gas volumes first must be converted to the same temperature and pressure. Common industry gas conversion factors usually range between 1 barrel of oil equivalent (BOE) = 5,600 standard cubic feet (scf) of gas to 1 BOE = 6,000 scf. (Many operators use 1 BOE = 5,620 scf derived from the metric unit equivalent 1 m³ crude oil = 1,000 m³ natural gas ). (Also termed Barrels of Oil Equivalent.) Appendix A: Glossary of Terms Used in Resources Evaluations - 2007 - 2001 - 3.7.

Cumulative Production

The sum of petroleum quantities that have been produced at a given date. (See also Production). Production is measured under defined conditions to allow for the computation of both reservoir voidage and sales quantities and for the purpose of voidage also includes non-petroleum quantities. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Current Economic Conditions

Economic conditions based on relevant historical petroleum prices and associated costs averaged over a specified period. The default period is 12 months. However, in the event that a step change has occurred within the previous 12-month period, the use of a shorter period reflecting the step change must be justified and used as the basis of constant-case resources estimates and associated project cash flows. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Cushion gas volume 

With respect to underground natural gas storage, Cushion Gas Volume (CGV) is the gas volume required in a storage field for reservoir management purposes and to maintain adequate minimum storage pressure for meeting working gas volume delivery with the required withdrawal profile. In caverns, the cushion gas volume is also required for stability reasons. The cushion gas volume may consist of recoverable and non-recoverable in-situ gas volumes and injected gas volumes Appendix A: Glossary of Terms Used in Resources Evaluations - 2007.

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D

Defined Conditions

Forecast of conditions to exist and impact the project during the time period being evaluated. Forecasts should account for issues that impact the commerciality, such as economics (e.g., hurdle rates and commodity price); operating and capital costs; and technical, marketing, sales route, legal, environmental, social, and governmental factors. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Deposit

Material laid down by a natural process. In resources evaluations, it identifies an accumulation of hydrocarbons in a reservoir. (See Accumulation.) Glossary of Petroleum Resources Management System - June 2018 (revised version)

Deterministic estimate 

The method of estimation of reserves or resources is called deterministic if a single best estimate is made based on known geological, engineering, and economic data Glossary of Reserves/Resources Terminology - 2005.

Deterministic Incremental Method

An assessment method based on defining discrete parts or segments of the accumulation that reflect high, moderate, and low confidence regarding the estimates of recoverable quantities under the defined development plan. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Deterministic Method

An assessment method based on discrete estimate(s) made based on available geoscience, engineering, and economic data and corresponds to a given level of certainty. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Deterministic Scenario Method

Method where the evaluator provides three deterministic estimates of the quantities to be recovered from the project being applied to the accumulation. Estimates consider the full range of values for each input parameter based on available engineering and geoscience data, but one set is selected that is most appropriate for the corresponding resources confidence category. A single outcome of recoverable quantities is derived for each scenario. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Developed Non-Producing Reserves

Developed Reserves that are either shut-in or behind-pipe. (See also Shut-In Resources and Behind-Pipe Reserves.)  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Developed Producing Reserves

Developed Reserves that are expected to be recovered from completion intervals that are open and producing at the effective date. Improved recovery reserves are considered producing only after the improved recovery project is in operation. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Developed Reserves

Reserves that are expected to be recovered from existing wells and facilities. Developed Reserves may be further sub-classified as Producing or Non-Producing. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Development Not Viable

A discovered accumulation for which there are contingencies resulting in there being no current plans to develop or to acquire additional data at the time due to limited commercial potential. A project maturity sub-class of Contingent Resources.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Development On Hold

A discovered accumulation where project activities are on hold and/or where justification as a commercial development may be subject to significant delay. A project maturity sub-class of Contingent Resources.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Development Pending

A discovered accumulation where project activities are ongoing to justify commercial development in the foreseeable future. A project maturity sub-class of Contingent Resources.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Development Plan

The design specifications, timing, and cost estimates of the appraisal and development project(s) that are planned in a field or group of fields. The plan will include, but is not limited to, well locations, completion techniques, drilling methods, processing facilities, transportation, regulations, and marketing. The plan is often executed in phases when involving large, complex, sequential recovery and/or extensive areas.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Development Unclarified

A discovered accumulation where project activities are under evaluation and where justification as a commercial development is unknown based on available information. This sub-class requires appraisal or study and should not be maintained without a plan for future evaluation. The sub-class should reflect the actions required to move a project toward commercial maturity. A project maturity sub-class of Contingent Resources.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Discovered

A petroleum accumulation where one or several exploratory wells through testing, sampling, and/or logging have demonstrated the existence of a significant quantity of potentially recoverable hydrocarbons and thus have established a known accumulation. In this context, “significant” implies that there is evidence of a sufficient quantity of petroleum to justify estimating the in-place volume demonstrated by the well(s) and for evaluating the potential for commercial recovery. (See also Known Accumulation.)  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Discovered Petroleum Initially In-Place (PIIP)

Quantity of petroleum that is estimated, as of a given date, to be contained in known accumulations before production. Discovered PIIP may be subdivided into commercial, sub-commercial, and the portion remaining in the reservoir as Unrecoverable.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Discovered Unrecoverable

Discovered petroleum in-place resources that are evaluated, as of a given date, as not able to be recovered by the commercial and sub-commercial projects envisioned.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Dry Gas

Natural gas remaining after hydrocarbon liquids have been removed before the reference point. It should be recognized that this is a resources assessment definition and not a phase behavior definition. (Also called lean gas.)  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Dry hole 

A well found to be incapable of producing either oil or gas in sufficient quantities to justify completion as an oil or gas well Glossary of Reserves/Resources Terminology - 2005.

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E

Economic

A project is economic when it has a positive undiscounted cumulative cash flow from the effective date of the evaluation, the net revenue exceeds the net cost of operation (i.e., positive cumulative net cash flow at discount rate greater than or equal to zero percent).  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Economic Interest

Interest that is possessed when an entity has acquired an interest in the minerals in-place or a license and secures, by any form of legal relationship, revenue derived from the extraction of the mineral to which he must look for a return.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Economic Limit

Defined as the time when the maximum cumulative net cash flow (see Net Entitlement) occurs for a project.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Economically Not Viable Contingent Resources

Those quantities for which development projects are not expected to yield positive cash flows under reasonable forecast conditions. May also be subject to additional unsatisfied contingencies.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Economically Producible

Refers to the situation where the net revenue from an ongoing producing project exceeds the net expenses attributable to a certain entity’s interest. The ADR costs are excluded from the determination.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Economically Viable Contingent Resources

Those quantities associated with technically feasible projects where cash flows are positive under reasonable forecast conditions but are not Reserves because it does not meet the other commercial criteria.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Effective Date

Resource estimates of remaining quantities are “as of the given date” (effective date) of the evaluation. The evaluation must take into account all data related to the period before the “as of date.”  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Entitlement

That portion of future production (and thus resources) legally accruing to an entity under the terms of the development and production contract or license.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Entity

A legal construct capable of bearing legal rights and obligations. In resources evaluations, this typically refers to the lessee or contractor, which is some form of legal corporation (or consortium of corporations). In a broader sense, an entity can be an organization of any form and may include governments or their agencies.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Established Technology

Methods of recovery or processing that have proved to be successful in commercial applications.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Estimated Ultimate Recovery (EUR)

Those quantities of petroleum estimated, as of a given date, to be potentially recoverable plus those quantities that have been already produced. For clarity, EUR must reference the associated technical and commercial conditions for the resources; for example, proved EUR is Proved Reserves plus prior production.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Evaluation

The geosciences, engineering, and associated studies, including economic analyses, conducted on a petroleum exploration, development, or producing project resulting in estimates of the quantities that can be recovered and sold and the associated cash flow under defined forward conditions. (Also called assessment.)  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Evaluator

The person or group of persons responsible for performing an evaluation of a project. These may be employees of the entities that have an economic interest in the project or independent consultants contracted for reviews and audits. In all cases, the entity accepting the evaluation takes responsibility for the results, including its resources and attributed value estimates. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Exploration

Prospecting for undiscovered petroleum using various techniques, such as seismic surveys, geological studies, and exploratory drilling. Glossary of Petroleum Resources Management System - June 2018 (revised version)

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F

Field

In conventional reservoirs, a field is typically an area consisting of a single reservoir or multiple reservoirs all grouped on, or related to, the same individual geological structural feature and/or stratigraphic condition. There may be two or more reservoirs in a field that are separated vertically by intervening impermeable rock, laterally by local geologic barriers, or both. The term may be defined differently by individual regulatory authorities. For unconventional reservoirs without hydrodynamic influences, a field is often defined by regulatory or ownership boundaries as necessary. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Final Investment Decision (FID)

Project approval stage when the participating companies have firmly agreed to the project and the required capital funding.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Flare Gas

The total quantity of gas vented and/or burned as part of production and processing operations (but not as fuel).  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Flow Test

An operation on a well designed to demonstrate the existence of recoverable petroleum in a reservoir by establishing flow to the surface and/or to provide an indication of the potential productivity of that reservoir (such as a wireline formation test). May also demonstrate the potential of certain completion techniques, particularly in unconventional reservoirs.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Fluid Contacts

The surface or interface in a reservoir separating two regions characterized by predominant differences in fluid saturations. Because of capillary and other phenomena, fluid saturation change is not necessarily abrupt or complete, nor is the surface necessarily horizontal.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Forecast Case

A descriptor applied to a scenario when production and associated cash-flow estimates are based on those conditions (including costs and product price schedules, inflation indexes, and market factors) forecast by the evaluator to reasonably exist throughout the evaluation life (i.e., defined conditions). Inflation or deflation adjustments are made to costs and revenues over the evaluation period.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Forward sales 

There are a variety of forms of transactions that involve the advance of funds to the owner of an interest in an oil and gas property in exchange for the right to receive the cash proceeds of production, or the production itself, arising from the future operation of the property. In such transactions, the owner almost invariably has a future performance obligation, the outcome of which is uncertain to some degree. Determination as to whether the transaction represents a sale or financing rests on the particular circumstances of each case Glossary of Reserves/Resources Terminology - 2005.

Fuel gas 

Gas used for field and plant operations. Substantial savings can be achieved to the operating cost of a project by avoiding the purchase of alternative supplies of gas or refined fuels such as diesel. SPE guidance allows the option to include fuel gas as part of the reserves estimate as long as an appropriate expense for the gas is included in the cash flow analysis Glossary of Reserves/Resources Terminology - 2005.

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G

Gas Balance

In gas production operations involving multiple working interest owners, maintaining a statement of volumes attributed to each, depending on each owner’s portion received. Imbalances may occur that must be monitored over time and eventually balanced in accordance with accepted accounting procedures.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Gas Cap Gas

Free natural gas that overlies and is in contact with crude oil in the reservoir. It is a subset of associated gas.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Gas Hydrates

Naturally occurring crystalline substances composed of water and gas, in which a solid water lattice accommodates gas molecules in a cage-like structure or clathrate. At conditions of standard temperature and pressure, one volume of saturated methane hydrate will contain as much as 164 volumes of methane gas. Gas hydrates are included in unconventional resources, but the technology to support commercial maturity has yet to be developed.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Gas plant products 

Gas Plant Products are natural gas liquids recovered from natural gas in gas processing plants and, in some situations, from field facilities. Gas Plant Products include ethane, propane, butanes, butanes-propane mixtures, natural gasoline and plant condensates, sulphur, carbon dioxide, nitrogen and helium Glossary of Reserves/Resources Terminology - 2005.

Gas-Oil Ratio

Ratio that is calculated using measured natural gas and crude oil volumes at stated conditions. The gas/oil ratio may be the solution gas/oil ratio, Rs; produced gas/oil ratio, Rp; or another suitably defined ratio of gas production to oil production.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Geostatistical Methods

A variety of mathematical techniques and processes dealing with the collection, methods, analysis, interpretation, and presentation of large quantities of geoscience and engineering data to (mathematically) describe the variability and uncertainties within any reservoir unit or pool, specifically related here to resources estimates.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

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H

High Estimate

With respect to resources categorization, this is considered to be an optimistic estimate of the quantity that will actually be recovered from an accumulation by a project. If probabilistic methods are used, there should be at least a 10% probability (P10) that the quantities actually recovered will equal or exceed the high estimate.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Hydrates

See Gas Hydrates.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Hydrocarbons

Hydrocarbons are chemical compounds consisting wholly of hydrogen and carbon molecules.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

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I

Improved Recovery

The extraction of additional petroleum, beyond primary recovery, from naturally occurring reservoirs by supplementing the natural forces in the reservoir. It includes waterflooding and gas injection for pressure maintenance, secondary processes, tertiary processes, and any other means of supplementing natural reservoir recovery processes. Improved recovery also includes thermal and chemical processes to improve the in-situ mobility of viscous forms of petroleum. (Also called enhanced recovery.)  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Injection

The forcing, pumping, or natural flow of substances into a porous and permeable subsurface rock formation. Injected substances can include either gases or liquids.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

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J

Justified for Development

A development project that has reasonable forecast commercial conditions at the time of reporting and there are reasonable expectation that all necessary approvals/ contracts will be obtained. A project maturity sub-class of Reserves.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

K

Kerogen

The naturally occurring, solid, insoluble organic material that occurs in source rocks and can yield oil upon heating. Kerogen is also defined as the fraction of large chemical aggregates in sedimentary organic matter that is insoluble in solvents (in contrast, the fraction that is soluble in organic solvents is called bitumen). (See also Oil Shales.)  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Known Accumulation

An accumulation that has been discovered.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

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L

Lead

A project associated with a potential accumulation that is currently poorly defined and requires more data acquisition and/or evaluation to be classified as a Prospect. A project maturity sub-class of Prospective Resources.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Learning Curve

Demonstrated improvements over time in performance of a repetitive task that results in efficiencies in tasks to be realized and/or in reduced time to perform and ultimately in cost reductions.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Lease condensates 

Lease Condensate is natural gas liquids recovered from produced gas (associated and non-associated), in gas-liquid separators or field facilities Glossary of Reserves/Resources Terminology - 2005.

Likelihood

Likelihood (the estimated probability or chance) is equal (1- risk). (See Probability and Risk.)  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Loan agreement 

A loan agreement is typically used by a bank, other financial investor, or partner to finance all or part of an oil and gas project. Compensation for funds advanced is limited to a specified interest rate. The lender does not participate in profits earned by the project above this interest rate. There is normally a fixed repayment schedule for the amount advanced, and repayment of the obligation is made before any return to equity investors. Risk is limited to default of the borrower or failure of the project. Variations in production, market prices, and sales do not normally affect compensation. Reserves are not recognized under this type of agreement Glossary of Reserves/Resources Terminology - 2005.

Low Estimate

With respect to resources categorization, this is a conservative estimate of the quantity that will actually be recovered from the accumulation by a project. If probabilistic methods are used, there should be at least a 90% probability (P90) that the quantities actually recovered will equal or exceed the low estimate.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Low/Best/High Estimates

Reflects the range of uncertainty as a reasonable range of estimated potentially recoverable quantities.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Lowest Known Hydrocarbons (LKH)

The deepest documented occurrence of a producible hydrocarbon accumulation as interpreted from well log, flow test, pressure measurement, core data, or other conclusive and reliable evidence.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

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M

Markets

A consumer or group of consumers of a product that has been obtained through purchase, barter, or contractual terms.  Glossary of Petroleum Resources Management System - June 2018 (revised version)

Marketable Quantities

Those quantities of hydrocarbons that are estimated to be producible from petroleum accumulations and that will be consumed by the market. (Also referred to as marketable products.) Glossary of Petroleum Resources Management System - June 2018 (revised version)

Mean

The sum of a set of numerical values divided by the number of values in the set. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Measurement

The process of establishing quantity (volume, mass, or energy content) and quality of petroleum products delivered to a reference point under conditions defined by delivery contract or regulatory authorities. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Mineral Interest

An agreement in which a mineral owner (lessor) grants an entity (lessee) rights. Such rights can include (1) a fee ownership or lease, concession, or other interest representing the right to extract oil or gas subject to such terms as may be imposed by the conveyance of the lease; (2) royalty interests, production payments payable in oil or gas, and other non-operating interests in properties operated by others; and/or (3) those agreements with foreign governments or authorities under which a reporting entity participates in the operation of the related properties or otherwise serves as producer of the underlying reserves (as opposed to being an independent purchaser, broker, dealer, or importer). Glossary of Petroleum Resources Management System - June 2018 (revised version)

Mineral Lease

An agreement in which a mineral owner (lessor) grants an entity (lessee) rights. Such rights can include (1) a fee ownership or lease, concession, or other interest representing the right to extract oil or gas subject to such terms as may be imposed by the conveyance of the lease; (2) royalty interests, production payments payable in oil or gas, and other non-operating interests in properties operated by others; and/or (3) those agreements with foreign governments or authorities under which

a reporting entity participates in the operation of the related properties or otherwise serves as producer of the underlying reserves (as opposed to being an independent purchaser, broker, dealer, or importer).

Monte Carlo Simulation

A type of stochastic mathematical simulation that randomly and repeatedly samples input distributions (e.g., reservoir properties) to generate a resulting distribution (e.g., recoverable petroleum quantities). Glossary of Petroleum Resources Management System - June 2018 (revised version)

Multi-Scenario Method

An extension of the deterministic scenario method. In this case, a significant number of discrete deterministic scenarios are developed by the evaluator, with each scenario leading to a single deterministic outcome. Probabilities may be assigned to each discrete input assumption from which the probability of the scenario can be obtained; alternatively, each outcome may be assumed to be equally likely. Glossary of Petroleum Resources Management System - June 2018 (revised version)

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N

Natural Bitumen

The portion of petroleum that exists in the semi-solid or solid phase in natural deposits. In its natural state, it usually contains sulfur, metals, and other nonhydrocarbons. Natural bitumen has a viscosity greater than 10,000 mPa·s (or 10,000 cp) measured at original temperature in the deposit and atmospheric pressure, on a gas free basis. In its natural viscous state, it is not normally recoverable at commercial rates through a well and requires the implementation of improved recovery methods such as steam injection. Natural bitumen generally requires upgrading before normal refining. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Natural Gas

Portion of petroleum that exists either in the gaseous phase or is in solution in crude oil in a reservoir, and which is gaseous at atmospheric conditions of pressure and temperature. Natural gas may include some amount of non-hydrocarbons. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Natural Gas Liquids (NGL's)

A mixture of light hydrocarbons that exist in the gaseous phase in the reservoir and are recovered as liquids in gas processing plants. NGLs differ from condensate in two principal respects: (1) NGLs are extracted and recovered in gas plants rather than lease separators or other lease facilities, and (2) NGLs include very light hydrocarbons (ethane, propane, or butanes) as well as the pentanes-plus that are the main constituents of condensates.Glossary of Petroleum Resources Management System - June 2018 (revised version)

Natural gas liquids to gas ratio 

Ratio of natural gas liquids to gas (in barrels/million cubic feet) in an oil field, calculated using measured natural gas liquids and gas volumes at stated conditions Glossary of Reserves/Resources Terminology - 2005.

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Net Entitlement

That portion of future production (and thus resources) legally accruing to an entity under the terms of the development and production contract or license. Under the terms of PSCs, the producers have an entitlement to a portion of the production. This entitlement, often referred to as “net entitlement” or “net economic interest,” is estimated using a formula based on the contract terms incorporating costs and profits.Glossary of Petroleum Resources Management System - June 2018 (revised version)

Net Pay

The portion (after applying cutoffs) of the thickness of a reservoir from which petroleum can be produced or extracted. Value is referenced to a true vertical thickness measured.Glossary of Petroleum Resources Management System - June 2018 (revised version)

Net profits interest 

An interest that receives a portion of the net proceeds from a well, typically after all costs have been paid Glossary of Reserves/Resources Terminology - 2005.

Net Revenue Interest

An entity’s revenue share of petroleum sales after deduction of royalties or share of production owing to others under applicable lease and fiscal terms. (See also Entitlement and Net Entitlement) Glossary of Petroleum Resources Management System - June 2018 (revised version)

Net working interest 

A company’s working interest reduced by royalties or share of production owing to others under applicable lease and fiscal terms Glossary of Reserves/Resources Terminology - 2005.

Netback Calculation

Term used in the hydrocarbon product price determination at reference point to reflect the revenue of one unit of sales after the costs associated with bringing the product to a market (e.g., transportation and processing) are removed. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Non hydrocarbon gas 

In the event that non-hydrocarbon gases are present, the reported volumes should reflect the condition of the gas at the point of sale. Correspondingly, the accounts will reflect the value of the gas product at the point of sale. Hence, if gas sold as produced includes a proportion of carbon dioxide, for example, the reserves and production should also include that CO2. In the case of the CO2 being extracted before sale and the sales gas containing only hydrocarbon gases, the reserves and production should reflect only the hydrocarbon gases that will be sold Glossary of Reserves/Resources Terminology - 2005.

Non-associated gas 

Non-Associated Gas is a natural gas found in a natural reservoir that does not contain crude oil Glossary of Reserves/Resources Terminology - 2005.

Non-conventional gas 

Non-Conventional Gas is a natural gas found in unusual underground situations such as very impermeable reservoirs, hydrates, and coal deposits Glossary of Reserves/Resources Terminology - 2005.

Non-Hydrocarbon Gas

Associated gases such as nitrogen, carbon dioxide, hydrogen sulfide, and helium that are present in naturally occurring petroleum accumulations. Glossary of Petroleum Resources Management System - June 2018 (revised version)


Non-producing reserves 

Reserves subcategorized as non-producing include shut-in and behind-pipe reserves. Shut-in reserves are expected to be recovered from (1) completion intervals which are open at the time of the estimate, but which have not started producing, (2) wells which were shut-in for market conditions or pipeline connections, or (3) wells not capable of production for mechanical reasons. Behind-pipe reserves are expected to be recovered from zones in existing wells, which will require additional completion work or future recompletion prior to the start of production Glossary of Reserves/Resources Terminology - 2005.

Non-Sales

That portion of estimated recoverable or produced quantities that will not be included in sales as contractually defined at the reference point. Non-sales include quantities CiO, flare, and surface losses, and may include non-hydrocarbons. Glossary of Petroleum Resources Management System - June 2018 (revised version)

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O

Offset well location 

Potential drill location adjacent to an existing well. The offset distance may be governed by well spacing regulations. Proved volumes on the existing well are indicated by either conclusive formation test or production. For proved volumes to be assigned to an offset well location there must be conclusive, unambiguous technical data which supports the reasonable certainty of production of hydrocarbon volumes and sufficient legal acreage to economically justify the development without going below the shallower of the fluid contact or the lowest known hydrocarbon Glossary of Reserves/Resources Terminology - 2005.

Oil Sands

Sand deposits highly saturated with natural bitumen. Also called “tar sands.” Note that in deposits such as the western Canada oil sands, significant quantities of natural bitumen may be hosted in a range of lithologies, including siltstones and carbonates. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Oil Shales

Shale, siltstone, and marl deposits highly saturated with kerogen. Whether extracted by mining or in-situ processes, the material must be extensively processed to yield a marketable product (synthetic crude oil). (Often called kerogen shale.) Glossary of Petroleum Resources Management System - June 2018 (revised version)

On Production

A project maturity sub-class of Reserves that reflects the operational execution phase of one or multiple development projects with the Reserves currently producing or capable of producing. Includes Developed Producing and Developed Non-Producing Reserves. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Operator 

The company or individual responsible for managing an exploration, development, or production operation Glossary of Reserves/Resources Terminology - 2005.

Overlift/Underlift

Production entitlements received that vary from contractual terms resulting in overlift or underlift positions. This can occur in annual records because of the necessity for companies to lift their entitlement in parcel sizes to suit the available shipping schedules as agreed upon by the parties. At any given financial year-end, a company may be in overlift or underlift. Based on the production matching the company’s accounts, production should be reported in accord with and equal to the liftings actually made by the company during the year and not on the production entitlement for the year. Glossary of Petroleum Resources Management System - June 2018 (revised version)

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P

P1

Denotes Proved Reserves. P1 is equal to 1P. Glossary of Petroleum Resources Management System - June 2018 (revised version)

P2

Denotes Probable Reserves. Glossary of Petroleum Resources Management System - June 2018 (revised version)

P3

Denotes Possible Reserves. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Penetration

The intersection of a wellbore with a reservoir. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Petroleum

Defined as a naturally occurring mixture consisting of hydrocarbons in the gaseous, liquid, or solid phase. Petroleum may also contain non-hydrocarbon compounds, common examples of which are carbon dioxide, nitrogen, hydrogen sulfide, and sulfur. In rare cases, non-hydrocarbon content of petroleum can be greater than 50%. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Petroleum Initially In Place (PIIP)

The total quantity of petroleum that is estimated to exist originally in naturally occurring reservoirs, as of a given date. Crude oil in-place, natural gas in-place, and natural bitumen in-place are defined in the same manner. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Pilot Project

A small-scale test or trial operation used to assess technology, including recovery processes, for commercial application in a specific reservoir. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Planned for development 

Satisfies all the criteria for reserves, and there is a firm intent to develop, but detailed development planning and/or necessary approvals/contracts have yet to be finalized Glossary of Reserves/Resources Terminology - 2005.

Play

A project associated with a prospective trend of potential prospects, but which requires more data acquisition and/or evaluation to define specific Leads or Prospects. A project maturity sub-class of Prospective Resources. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Pool

An individual and separate accumulation of petroleum in a reservoir within a field. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Possible Reserves 

An incremental category of estimated recoverable quantities associated with a defined degree of uncertainty. Possible Reserves are those additional reserves that analysis of geoscience and engineering data suggest are less likely to be recoverable than Probable Reserves. The total quantities ultimately recovered from the project have a low probability to exceed the sum of Proved plus Probable plus Possible (3P), which is equivalent to the high estimate scenario. When probabilistic methods are used, there should be at least a 10% probability that the actual quantities recovered will equal or exceed the 3P estimate. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Primary Recovery

The extraction of petroleum from reservoirs using only the natural energy available in the reservoirs to move fluids through the reservoir rock to other points of recovery. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Probability

The extent to which an event is likely to occur, measured by the ratio of the favorable cases to the whole number of cases possible. PRMS convention is to quote cumulative probability of exceeding or equaling a quantity where P90 is the small estimate and P10 is the large estimate. (See also Uncertainty.) Glossary of Petroleum Resources Management System - June 2018 (revised version)

Probabilistic estimate 

The method of estimation is called probabilistic when the known geological, engineering, and economic data are used to generate a range of estimates and their associated probabilities Glossary of Reserves/Resources Terminology - 2005.

Probabilistic Method

The method of estimation of resources is called probabilistic when the known geoscience, engineering, and economic data are used to generate a continuous range of estimates and their associated probabilities. Glossary of Petroleum Resources Management System - June 2018 (revised version)

=== Probable and possible reserves ===

See criteria for Probable reserves and Possible reserves Table 3: Reserves Category Definitions and Guidelines - 2007.

'The 2P and 3P estimates may be based on reasonable alternative technical and commercial interpretations within the reservoir and/or subject project that are clearly documented, including comparisons to results in successful similar projects Table 3: Reserves Category Definitions and Guidelines - 2007.

In conventional accumulations, Probable and/or Possible Reserves may be assigned where geoscience and engineering data identify directly adjacent portions of a reservoir within the same accumulation that may be separated from Proved areas by minor faulting or other geological discontinuities and have not been penetrated by a wellbore but are interpreted to be in communication with the known (Proved) reservoir. Probable or Possible Reserves may be assigned to areas that are structurally higher than the Proved area. Possible (and in some cases, Probable) Reserves may be assigned to areas that are structurally lower than the adjacent Proved or 2P area Table 3: Reserves Category Definitions and Guidelines - 2007.

Caution should be exercised in assigning Reserves to adjacent reservoirs isolated by major, potentially sealing, faults until this reservoir is penetrated and evaluated as commercially productive. Justification for assigning Reserves in such cases should be clearly documented. Reserves should not be assigned to areas that are clearly separated from a known accumulation by non-productive reservoir (i.e., absence of reservoir, structurally low reservoir, or negative test results); such areas may contain Prospective Resources Table 3: Reserves Category Definitions and Guidelines - 2007.

In conventional accumulations, where drilling has defined a highest known oil (HKO) elevation and there exists the potential for an associated gas cap, Proved oil Reserves should only be assigned in the structurally higher portions of the reservoir if there is reasonable certainty that such portions are initially above bubble point pressure based on documented engineering analyses. Reservoir portions that do not meet this certainty may be assigned as Probable and Possible oil and/or gas based on reservoir fluid properties and pressure gradient interpretations Table 3: Reserves Category Definitions and Guidelines - 2007.

Probable Reserves

An incremental category of estimated recoverable quantities associated with a defined degree of uncertainty. Probable Reserves are those additional Reserves that are less likely to be recovered than Proved Reserves but more certain to be recovered than Possible Reserves. It is equally likely that actual remaining quantities recovered will be greater than or less than the sum of the estimated Proved plus Probable Reserves (2P). In this context, when probabilistic methods are used, there should be at least a 50% probability that the actual quantities recovered will equal or exceed the 2P estimate. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Producing reserves 

Reserves subcategorized as producing are expected to be recovered from intervals which are open and producing at the time of the estimate. Improved recovery is considered producing only after the improved recovery project is in operation Glossary of Reserves/Resources Terminology - 2005.

Production 

The cumulative quantities of petroleum that have been recovered at a given date. Production can be reported in terms of the sales product specifications, but project evaluation requires that all production quantities (sales and non-sales), as measured to support engineering analyses requiring reservoir voidage calculations, are recognized. Glossary of Petroleum Resources Management System - June 2018 (revised version)

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Production Forecast

A forecasted schedule of production over time. For Reserves, the production forecast reflects a specific development scenario under a specific recovery process, a certain number and type of wells and particular facilities and infrastructure. When forecasting Contingent or Prospective Resources, more than one project scope (e.g., wells and facilities) is frequently carried to determine the range of the potential project and its uncertainty together with the associated resources defining the low, best, and high production forecasts. The uncertainty in resources estimates associated with a production forecast is usually quantified by using at least three scenarios or cases of low, best, and high, which lead to the resources classifications of, respectively, 1P, 2P, 3P and 1C, 2C, 3C or 1U,2U and 3U. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Production Sharing Contract (PSC)

A contract between a contractor and a host government in which the contractor typically bears the risk and costs for exploration, development, and production. In return, if exploration is successful, the contractor is given the opportunity to recover the incurred investment from production, subject to specific limits and terms. Ownership of petroleum in the ground is retained by the host government; however, the contractor normally receives title to the prescribed share of the quantities as they are produced. (Also termed production-sharing agreement (PSA). Glossary of Petroleum Resources Management System - June 2018 (revised version)

Profit split 

Under a typical production-sharing agreement, the contractor is responsible for the field development and all exploration and development expenses. In return, the contractor is entitled to a share of the remaining profit oil or gas. The contractor receives payment in oil or gas production and is exposed to both technical and market risks Glossary of Reserves/Resources Terminology - 2005.

Project

A defined activity or set of activities that provides the link between the petroleum accumulation’s resources sub-class and the decision-making process, including budget allocation. A project may, for example, constitute the development of a single reservoir or field, an incremental development in a larger producing field, or the integrated development of a group of several fields and associated facilities (e.g. compression) with a common ownership. In general, an individual project will represent a specific maturity level (sub-class) at which a decision is made on whether or not to proceed (i.e., spend money), suspend, or remove. There should be an associated range of estimated recoverable resources for that project. (See also Development Plan.) Glossary of Petroleum Resources Management System - June 2018 (revised version)

Property

A defined portion of the Earth’s crust wherein an entity has contractual rights to extract, process, and market specified in-place minerals (including petroleum). In general, defined as an area but may have depth and/or stratigraphic constraints. May also be termed a lease, concession, or license. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Prorationing 

The allocation of production among reservoirs and wells or pipeline allocation of capacity among shippers, etc Glossary of Reserves/Resources Terminology - 2005.

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Prospect

A project associated with an undrilled potential accumulation that is sufficiently well defined to represent a viable drilling target. A project maturity sub-class of Prospective Resources. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Prospective Resources

Those quantities of petroleum estimated, as of a given date, to be potentially recoverable from undiscovered accumulations by application of future development projects. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Proved developed reserves 

Proved Developed Reserves are those Proved Reserves that can be expected to be recovered through existing wells and facilities and by existing operating methods. Improved recovery reserves can be considered as Proved Developed Reserves only after an improved recovery project has been installed and favorable response has occurred or is expected with a reasonable degree of certainty. (See Developed Reserves)

Behind-pipe reserves are expected to be recovered from zones in existing wells, which will require additional completion work or future re-completion prior to the start of production Glossary of Reserves/Resources Terminology - 2005.

Proved Reserves

An incremental category of estimated recoverable quantities associated with a defined degree of uncertainty. Proved Reserves are those quantities of petroleum that, by analysis of geoscience and engineering data, can be estimated with reasonable certainty to be commercially recoverable, from a given date forward, from known reservoirs and under defined economic conditions, operating methods, and government regulations. If deterministic methods are used, the term “reasonable certainty” is intended to express a high degree of confidence that the quantities will be recovered. If probabilistic methods are used, there should be at least a 90% probability that the quantities actually recovered will equal or exceed the estimate. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Proved undeveloped reserves

Proved Undeveloped Reserves are those Proved Reserves that are expected to be recovered from future wells and facilities, including future improved recovery projects which are anticipated with a high degree of certainty in reservoirs which have previously shown favorable response to improved recovery projects. [See Undeveloped] Glossary of Reserves/Resources Terminology - 2005.

Purchase contracts 

A contract to purchase oil and gas provides the right to purchase a specified volume at an agreed price for a defined term. Under purchase contracts, exposure to technical and market risks are borne by the seller. While a purchase or supply contract can provide long-term access to reserves through production, it does not convey the right to extract, nor does it convey a financial interest in the reserves. Consequently, reserves would not be recognized by the buyer under this type of agreement Glossary of Reserves/Resources Terminology - 2005.

Pure Service Contract

Agreement between a contractor and a host government that typically covers a defined technical service to be provided or completed during a specific time period. The service company investment is typically limited to the value of equipment, tools, and expenses for personnel used to perform the service. In most cases, the service contractor’s reimbursement is fixed by the contract’s terms with little exposure to either project performance or market factors. No Reserves or Resources can be attributed to these activities. Glossary of Petroleum Resources Management System - June 2018 (revised version)

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Q

Qualified Reserves Auditor

A reserves evaluator who (1) has a minimum of ten years of practical experience in petroleum engineering or petroleum production geology, with at least five years of such experience being in responsible charge of the estimation and evaluation of Reserves information; and (2) either (a) has obtained from a college or university of recognized stature a bachelor’s or advanced degree in petroleum engineering, geology, or other discipline of engineering or physical science or (b) hasreceived, and is maintaining in good standing, a registered or certified professional engineer’s license or a registered or certified professional geologist’s license, or the equivalent, from an appropriate governmental authority or professional organization. (see SPE 2007 “Standards Pertaining to the Estimating and Auditing of Oil and Gas Reserves Information”) Glossary of Petroleum Resources Management System - June 2018 (revised version)

Qualified Reserves Evaluator

A reserves evaluator who (1) has a minimum of five years of practical experience in petroleum engineering or petroleum production geology, with at least three years of such experience being in the estimation and evaluation of Reserves information; and (2) either (a) has obtained from a college or university of recognized stature a bachelor’s or advanced degree in petroleum engineering, geology, or other discipline of engineering or physical science or (b) has received, and is maintaining in good standing, a registered or certified professional engineer’s license or a registered or certified professional geologist’s license, or the equivalent, from an appropriate governmental authority or professional organization. (modified from SPE 2007 “Standards Pertaining to the Estimating and Auditing of Oil and Gas Reserves Information”) Glossary of Petroleum Resources Management System - June 2018 (revised version)

R

Range of uncertainty of recoverable hydrocarbon quantities 

See [Resource Uncertainty Categories] Glossary of Reserves/Resources Terminology - 2005.

Range of Uncertainty

The range of uncertainty of the in-place, recoverable, and/or potentially recoverable quantities; may be represented by either deterministic estimates or by a probability distribution. (See Resources Categories.) Glossary of Petroleum Resources Management System - June 2018 (revised version)

Raw natural gas 

Raw Natural Gas is natural gas as it is produced from the reservoir. It includes varying amounts of the heavier hydrocarbons which liquefy at atmospheric conditions, and water vapor; and may also contain sulphur compounds such as hydrogen sulphide, and other non-hydrocarbon gases such as carbon dioxide, nitrogen or helium, but which, nevertheless, is exploitable for its hydrocarbon content. Raw Natural Gas is often not suitable for direct utilization by most types of consumers Glossary of Reserves/Resources Terminology - 2005.

Raw Production

All components, whether hydrocarbon or other, produced from the well or extracted from the mine (hydrocarbons, water, impurities such as non-hydrocarbon gases, etc.). Glossary of Petroleum Resources Management System - June 2018 (revised version)

Reasonable Certainty

If deterministic methods for estimating recoverable resources quantities are used, then reasonable certainty is intended to express a high degree of confidence that the estimated quantities will be recovered. Typically attributed to Proved Reserves or 1C Resources quantities. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Reasonable Expectation

Indicates a high degree of confidence (low risk of failure) that the project will proceed with commercial development or the referenced event will occur. (Differs from reasonable certainty, which applies to resources quantity technical confidence, while reasonable expectation relates to commercial confidence.). Glossary of Petroleum Resources Management System - June 2018 (revised version)

Recoverable resources 

Those quantities of hydrocarbons that are estimated to be producible by the project from either discovered or undiscovered accumulations. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Recovery Efficiency

A numeric expression of that portion (expressed as a percentage) of in-place quantities of petroleum estimated to be recoverable by specific processes or projects, most often represented as a percentage. It is estimated using the recoverable resources divided by the hydrocarbons initially in-place. It is also referenced to timing; current and ultimate (or estimated ultimate) are descriptors applied to reference the stage of the recovery. (Also called recovery factor.) Glossary of Petroleum Resources Management System - June 2018 (revised version)

Reference Point

A defined location within a petroleum extraction and processing operation where quantities of produced product are measured under defined conditions before custody transfer (or consumption). Also called point of sale, terminal point, or custody transfer point. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Report

The presentation of evaluation results within the entity conducting the assessment. Should not be construed as replacing requirements for public disclosures under guidelines established by regulatory and/or other government agencies. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Reserves

Those quantities of petroleum anticipated to be commercially recoverable by application of development projects to known accumulations from a given date forward under defined conditions. Reserves must satisfy four criteria: they must be discovered, recoverable, commercial, and remaining (as of a given date) based on the development project(s) applied. Glossary of Petroleum Resources Management System - June 2018 (revised version)

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Reservoir

A subsurface rock formation that contains an individual and separate natural accumulation of petroleum that is confined by impermeable barriers, pressure systems, or fluid regimes (conventional reservoirs), or is confined by hydraulic fracture barriers or fluid regimes (unconventional reservoirs). Glossary of Petroleum Resources Management System - June 2018 (revised version)

Resource uncertainty categories 

Any estimation of resource quantities for an accumulation or group of accumulations is subject to uncertainty and should, in general, be expressed as a range. The function of the three primary categories of reserves (proved, probable, possible) is to illustrate the range of uncertainty in the estimate of the potentially recoverable volume of petroleum from a known accumulation. Such estimates, which are done initially for each well or reservoir, may be made deterministically or probabilistically and are then aggregated for the accumulation/project as a whole. Provided a similar logic is applied for all volumetric estimates (including contingent and prospective resources), the estimate of uncertainty for each accumulation can be tracked over time from exploration through discovery, development, and production. This approach provides an extremely effective basis for evaluating the validity of the methodology used for the estimate of potentially recoverable volumes. The range of uncertainty reflects a reasonable range of estimated potentially recoverable volumes for an individual accumulation or a project. In the case of reserves, and where appropriate, this range of uncertainty can be reflected in estimates for proved reserves (IP), proved, plus probable reserves (2P), and proved, plus probable, plus possible reserves (3P) scenarios. For other resource categories, the equivalent terms low estimate, best estimate, and high estimate are recommended Glossary of Reserves/Resources Terminology - 2005.

Resources

Term used to encompass all quantities of petroleum (recoverable and unrecoverable) naturally occurring in an accumulation on or within the Earth’s crust, discovered and undiscovered, plus those quantities already produced. Further, it includes all types of petroleum whether currently considered conventional or unconventional. (See Total Petroleum Initially-in-Place.) Glossary of Petroleum Resources Management System - June 2018 (revised version)

Resources Categories

Subdivisions of estimates of resources to be recovered by a project(s) to indicate the associated degrees of uncertainty. Categories reflect uncertainties in the total petroleum remaining within the accumulation (in-place resources), that portion of the in-place petroleum that can be recovered by applying a defined development project or projects, and variations in the conditions that may impact commercial development (e.g., market availability and contractual changes). The resource quantity uncertainty range within a single resources class is reflected by either the 1P, 2P, 3P, Proved, Probable, Possible, or 1C, 2C, 3C or 1U, 2U, 3U resources categories. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Resources Classes

Subdivisions of resources that indicate the relative maturity of the development projects being applied to yield the recoverable quantity estimates. Project maturity may be indicated qualitatively by allocation to classes and sub-classes and/or quantitatively by associating a project’s estimated likelihood of commerciality. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Resources Type

Describes the accumulation and is determined by the combination of the type of hydrocarbon and the rock in which it occurs. Glossary of Petroleum Resources Management System - June 2018 (revised version)

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Revenue-Sharing Contract

Contracts that are very similar to the PSCs with the exception of contractor payment in these contracts, the contractor usually receives a defined share of revenue rather than a share of the production. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Reversionary interest 

The right of future possession of an interest in a property when a specified condition has been met Glossary of Reserves/Resources Terminology - 2005.

Risk

The probability of loss or failure. Risk is not synonymous with uncertainty. Risk is generally associated with the negative outcome, the term “chance” is preferred for general usage to describe the probability of a discrete event occurring. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Risk and Reward

Risk and reward associated with oil and gas production activities are attributed primarily from the variation in revenues cause by technical and economic risks. The exposure to risk in conjunction with entitlement rights is required to support an entity’s resources recognition. Technical risk affects an entity’s ability to physically extract and recover hydrocarbons and is usually dependent on a number of technical parameters. Economic risk is a function of the success of a project and is critically dependent on cost, price, and political or other economic factors. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Risk Service Contract

Agreements that are very similar to the production-sharing agreements in that the risk is borne by the contractor but the mechanism of contractor payment is different. With a RSC, the contractor usually receives a defined share of revenue rather than a share of the production. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Royalty

A type of entitlement interest in a resource that is free and clear of the costs and expenses of development and production to the royalty interest owner. A royalty is commonly retained by a resources owner (lessor/host) when granting rights to a producer (lessee/contractor) to develop and produce that resource. Depending on the specific terms defining the royalty, the payment obligation may be expressed in monetary terms as a portion of the proceeds of production or as a right to take a portion of production in-kind. The royalty terms may also provide the option to switch between forms of payment at discretion of the royalty owner. Glossary of Petroleum Resources Management System - June 2018 (revised version)

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S

Sales

The quantity of petroleum and any non-hydrocarbon product delivered at the custody transfer point (reference point) with specifications and measurement conditions as defined in the sales contract and/or by regulatory authorities. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Shale Gas

Although the terms shale gas and tight gas are often used interchangeably in public discourse, shale formations are only a subset of all low-permeability tight formations, which include sandstones and carbonates, as well as shales, as sources of tight gas production. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Shale Oil

Although the terms shale oil and tight oil are often used interchangeably in public discourse, shale formations are only a subset of all low-permeability tight formations, which include sandstones and carbonates, as well as shales, as sources of tight oil production Glossary of Petroleum Resources Management System - June 2018 (revised version)

Shut-in reserves 

Shut-in reserves are expected to be recovered from

1. Completion intervals which are open at the time of the estimate, but which have not started producing,

2. Wells which were shut-in for market conditions or pipeline connections, or

3. Wells not capable of production for mechanical reasons

Glossary of Reserves/Resources Terminology - 2005.

Shut-In Resources

Resources planned to be recovered from (1) completion intervals that are open at the time of the estimate, but which have not started producing; (2) wells that were shut-in for market conditions or pipeline connections; or (3) wells not capable of production for mechanical reasons that can be remediated at a limited cost compared to the cost of the well. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Solution gas 

Solution Gas is a natural gas which is dissolved in crude oil in the reservoir at the prevailing reservoir conditions of pressure and temperature. It is a subset of Associated Gas Glossary of Reserves/Resources Terminology - 2005.

Sour natural gas 

Sour Natural Gas is a natural gas that contains sulphur, sulphur compounds and/or carbon dioxide in quantities that may require removal for effective use Glossary of Reserves/Resources Terminology - 2005.

Split Classification

A single project should be uniquely assigned to a sub-class along with its uncertainty range, For example, a project cannot have quantities categorized as 1C, 2P, and 3P. This is referred to as “split classification.” If there are differing commercial conditions, separate sub-classes should be defined. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Split Conditions

The uncertainty in recoverable quantities is assessed for each project using resources categories. The assumed commercial conditions are associated with resource classes or sub-classes and not with the resources categories. For example, the product price assumptions are those assumed when classifying projects as Reserves, and a different price would not be used for assessing Proved versus Probable reserves. That would be referred to as “split conditions.” Glossary of Petroleum Resources Management System - June 2018 (revised version)

Stochastic 

Adjective defining a process involving or containing a random variable or variables or involving chance or probability such as a stochastic stimulation Glossary of Reserves/Resources Terminology - 2005.

Stochastic

Adjective defining a process involving or containing a random variable or variables or involving likelihood or probability, such as a stochastic simulation. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Sub-Commercial

A project subdivision that is applied to discovered resources that occurs if either the technical or commercial maturity conditions of project have not yet been achieved. A project is sub-commercial if the degree of commitment is such that the accumulation is not expected to be developed and placed on production within a reasonable time-frame. Sub-commercial projects are classified as Contingent Resources. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Sunk Cost

Money spent before the effective date and that cannot be recovered by any future action. Sunk costs are not relevant to future business decisions because the cost will be the same regardless of the outcome of the decision. Sunk costs differ from committed (obligated) costs, where there is a firm and binding agreement to spend specified amounts of money at specific times in the future (i.e., after the effective date). Glossary of Petroleum Resources Management System - June 2018 (revised version)

Sweet natural gas 

Sweet Natural Gas is a natural gas that contains no sulphur or sulphur compounds at all, or in such small quantities that no processing is necessary for their removal in order that the gas may be used directly as a non-corrosive domestic heating fuel Glossary of Reserves/Resources Terminology - 2005.

Synthetic Crude Oil

A mixture of hydrocarbons derived by upgrading (i.e., chemically altering) natural bitumen from oil sands, kerogen from oil shales, or processing of other substances such as natural gas or coal. Synthetic crude oil may contain sulfur or other non- hydrocarbon compounds and has many similarities to crude oil. Glossary of Petroleum Resources Management System - June 2018 (revised version)

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T

Taxes

Obligatory contributions to the public funds, levied on persons, property, or income by governmental authority. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Technical Forecast

The forecast of produced resources quantities that is defined by applying only technical limitations (i.e., well-flow-loading conditions, well life, production facility life, flow-limit constraints, facility uptime, and the facility’s operating design parameters). Technical limitations do not take into account the application of either an economic or license cutoff. (See also Technically Recoverable Resources) Glossary of Petroleum Resources Management System - June 2018 (revised version)

Technical Uncertainty

Indication of the varying degrees of uncertainty in estimates of recoverable quantities influenced by the range of potential in-place hydrocarbon resources within the reservoir and the range of the recovery efficiency of the recovery project being applied. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Technically Recoverable Resources

Those quantities of petroleum producible using currently available technology and industry practices, regardless of commercial or accessibility considerations. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Technology Under Development

Technology that is currently under active development and that has not been demonstrated to be commercially viable. There should be sufficient direct evidence (e.g., a test project/pilot) to indicate that the technology may reasonably be expected to be available for commercial application. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Tight Gas

Gas that is trapped in pore space and fractures in very low-permeability rocks and/ or by adsorption on kerogen, and possibly on clay particles, and is released when a pressure differential develops. It usually requires extensive hydraulic fracturing to facilitate commercial production. Shale gas is a sub-type of tight gas. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Tight Oil

Crude oil that is trapped in pore space in very low-permeability rocks and may be liquid under reservoir conditions or become liquid at surface conditions. Extensive hydraulic fracturing is invariably required to facilitate commercial maturity and economic production. Shale oil is a sub-type of tight oil. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Total Petroleum Initially In Place

All estimated quantities of petroleum that are estimated to exist originally in naturally occurring accumulations, discovered and undiscovered, before production. Glossary of Petroleum Resources Management System - June 2018 (revised version)

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U

Uncertainty

The range of possible outcomes in a series of estimates. For recoverable resources assessments, the range of uncertainty reflects a reasonable range of estimated potentially recoverable quantities for an individual accumulation or a project. (See also Probability.) Glossary of Petroleum Resources Management System - June 2018 (revised version)

Unconventional Resources

Unconventional resources exist in petroleum accumulations that are pervasive throughout a large area and lack well-defined OWC or GWC (also called “continuous-type deposits”). Such resources cannot be recovered using traditional recovery projects owing to fluid viscosity (e.g., oil sands) and/or reservoir permeability (e.g., tight gas/oil/CBM) that impede natural mobility. Moreover, the extracted petroleum may require significant processing before sale (e.g., bitumen upgraders). Glossary of Petroleum Resources Management System - June 2018 (revised version)

Under development 

All necessary approvals have been obtained, and development of the project is underway Glossary of Reserves/Resources Terminology - 2005.

Undeveloped Reserves

Those quantities expected to be recovered through future investments: (1) from new wells on undrilled acreage in known accumulations, (2) from deepening existing wells to a different (but known) reservoir, (3) from infill wells that will increase recovery, or (4) where a relatively large expenditure (e.g., when compared to the cost of drilling and completing a new well) is required to recomplete an existing well. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Undiscovered Petroleum Initially In Place

That quantity of petroleum estimated, as of a given date, to be contained within accumulations yet to be discovered. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Unitization 

Process whereby owners of adjoining properties allocate reserves, production, costs, etc Glossary of Reserves/Resources Terminology - 2005.

Unproved reserves 

Unproved reserves are based on geologic and/or engineering data similar to that used in estimates of proved reserves; but technical, contractual, economic, or regulatory uncertainties preclude such reserves being classified as proved. Unproved reserves may be further classified as probable reserves and possible reserves. Unproved reserves may be estimated assuming future economic conditions different from those prevailing at the time of the estimate. The effect of possible future improvements in economic conditions and technological developments can be expressed by allocating appropriate quantities of reserves to the probable and possible classifications Glossary of Reserves/Resources Terminology - 2005.

Unrecoverable Resources

Those quantities of discovered or undiscovered PIIP that are assessed, as of a given date, to be unrecoverable by the currently defined project(s). A portion of these quantities may become recoverable in the future as commercial circumstances change, technology is developed, or additional data are acquired. The remaining portion may never be recovered owing to physical/chemical constraints represented by subsurface interaction of fluids and reservoir rocks. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Upgrader

A general term applied to processing plants that convert extra-heavy crude oil and natural bitumen into lighter crude and less viscous synthetic crude oil. While the detailed process varies, the underlying concept is to remove carbon through coking or to increase hydrogen by hydrogenation processes using catalysts. Glossary of Petroleum Resources Management System - June 2018 (revised version)

V

W

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Well abandonment 

The permanent plugging of a dry hole or of a well that no longer produces petroleum or is no longer capable of producing petroleum profitably. Several steps are involved in the abandonment of a well: permission for abandonment and procedural requirements are secured from official agencies; the casing is removed and salvaged if possible; and one or more cement plugs and/or mud are placed in the borehole to prevent migration of fluids between the different formations penetrated by the borehole Glossary of Reserves/Resources Terminology - 2005.

Wet Gas

Natural gas from which no liquids have been removed before the reference point. The wet gas is accounted for in resources assessments, and there is no separate accounting for contained liquids. It should be recognized that this is a resources assessment definition and not a phase behavior definition. Glossary of Petroleum Resources Management System - June 2018 (revised version)

Working Interest

An entity’s equity interest in a project before reduction for royalties or production share owed to others under the applicable fiscal terms. Glossary of Petroleum Resources Management System - June 2018 (revised version)

X

Y

Z

Publication Notes

PRMS 2011

Reference Terms

Note: The reference provides the chapter where the term is used (first number) and the number of times the term appears in that chapter (number after the period). For example, 4.12 means the term appears in Chapter 4 and is used 12 times.

PRMS 2007

Appendix A: Glossary of Terms Used in Resources Evaluations
Table 1: Recoverable Resources Classes and Sub-Classes
Table 2: Reserves Status Definitions and Guidelines
Table 3: Reserves Category Definitions and Guidelines

Originally published in January 2005, the SPE/WPC/AAPG Glossary has herein been revised to align with the 2007 SPE/WPC/AAPG/SPEE Petroleum Resources Management System document. The glossary provides high-level definitions of terms use in resource evaluations. Where appropriate, sections and/or chapters within the 2007 and/or 2001 documents are referenced to best show the use of selected terms in context. Read more...

PRMS 2005

Glossary of Terms Used in Petroleum Reserves/Resources Definitions

For several decades, the terminology used in the classification of petroleum reserves and resources has been the subject of study and ongoing revision. Since the mid-1930s, numerous technical organizations, regulatory bodies, and financial institutions have introduced ever more complex terminologies for the classification of petroleum reserves. In addition, the evolution of technology has yielded more precise engineering methods for reserve evaluation and has intensified the need for an improved nomenclature to achieve consistency among professionals working with petroleum reserves terminology. Read more...

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See also

Petroleum Reserves & Resources Definitions


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