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Water for hydraulic fracturing
Water is the most commonly used fluid in hydraulic fracturing, and it is used in large quantities. Chemicals are added to the water to aid in fracturing and prevent damage to the reservoir, and normally less than 1 percent of the fluid contents are chemical compounds. Because fracturing involves a large amount of water, innovations to reuse/recycle and safely dispose of the water are an important part of environmental stewardship.
Hydraulic fracturing is the process of pumping fluid into a wellbore at an injection rate too high for the formation to accept without breaking. During injection, the formation’s resistance to flow increases, and the pressure in the wellbore increases to a value called the break-down pressure, which is the sum of the in-situ compressive stress and the strength of the formation. When the formation “breaks down,” a fracture is formed, and the injected fluid flows through it.
Fluid not containing any solid (called the “pad”) is injected first, until the fracture is wide enough to accept a propping agent. The purpose of the propping agent is to keep apart the fracture surfaces once the pumping operation ceases, the pressure in the fracture decreases bellow the compressive in-situ stress trying to close the fracture. In deep reservoirs, man-made ceramic beads are used to hold open or “prop” the fracture. In shallow reservoirs, sand is normally used as the propping agent.
Water comprises 95 percent of typical fracking fluid, followed by 4.5 percent sand and 0.5 percent other chemical additives. The chemicals serve multiple functions, including limiting the growth of bacteria and preventing corrosion of the well casing.  The conditions of the well being fractured determine the number of chemical additives used. Typically, very low concentrations of between three and 12 additive chemicals will be used, depending on the characteristics of the water and the formation being fractured. Each component serves a specific purpose. For example, the predominant fluids used for fracture treatments in the gas shale plays are water‐based fracturing fluids mixed with friction‐reducing additives (called slickwater). The addition of friction reducers allows fracturing fluids and proppants, like sand or small ceramic beads, to be pumped to the target zone at a higher rate and reduced pressure than with water alone. Other additives include: biocides to prevent microorganism growth and reduce biofouling of the fractures; oxygen scavengers and other stabilizers to prevent corrosion of metal pipes; and acids to remove drilling mud damage within the near‐wellbore area.
Large quantities of relatively fresh water are essential in hydraulic fracturing. Water quality is a key factor in fracturing because impurities can reduce the efficiency of the additives used in the process. Most water used in hydraulic fracturing comes from surface water sources like lakes, rivers, aquifers, and municipal supplies, which may have to be hauled over long distances. But groundwater can be used to supplement surface water supplies where it is plentiful. In some areas, the water used for fracturing is controlled by a river basin commission or water resources board. In other places, water is owned by private individuals who can distribute it as they choose. 
Quantity of water used
An average of four to six million gallons of water are used to complete and stimulate contemporary unconventional wells. The amount of water used in hydraulic fracturing, particularly in shale gas formations, appears substantial, but it is small when compared to other water uses such as agriculture, manufacturing, and municipal water supplies. For example, electric generation uses nearly 150 million gallons a day in the Susquehanna River Basin, while the projected total demand for peak Marcellus Shale activity in the same area is 8.4 million gallons per day. Horizontal well high-volume fracturing use has accelerated significantly since 2005. Per a Department of Energy report conducted by ALL Consulting, "Estimates of peak drilling activity in New York, Pennsylvania, and West Virginia indicate that maximum water use in the Marcellus, at the peak of production for each state, assuming 5 million gallons of water per well, would be about 650 million barrels per year. This represents less than 0.8 percent of the 85 billion barrels per year used in the area overlying the Marcellus Shale in New York, Pennsylvania, and West Virginia."
Disposal and recycling of wastewater
After stimulation treatment, water used to fracture the well, in amounts as large as 50%, can rise back to the surface, along with the initial production, as flowback water. Flowback and produced waters, both part of the production stream, must be separated from the formation. In most cases, flowback and produced water are disposed into an injection well, put in evaporation ponds, or treated and disposed of according to government regulations. Water management can significantly add to the cost and environmental footprint of oil production and innovations in water management can provide significant economic and environmental gains. New treatment technologies make recycling of water recovered from hydraulic fracturing possible. Methods for recycling fracking water include anaerobic and aerobic biologic treatment, clarification, filtration, electrocoagulation, blending (directly diluting wastewater with freshwater), and evaporation.  Recycling of produced water and fracture flowback water for reuse in hydraulic fracturing is on the rise in the development of unconventional resource plays. Factors driving the conservation of water include the limitations in sources of fresh water in areas with a high rate of development, attractive economics of recycling compared with tanker truck transportation costs, minimization of road traffic to reduce environmental impacts, and water disposal costs.
- Boschee, P. 2012. Handling Produced Water from Hydraulic Fracturing. Oil and Gas Facilities 1 (1): 23—26.
- FracFocus. 2014. Chemical Use In Hydraulic Fracturing. http://fracfocus.org/water-protection/drilling-usage.
- Lord, P., Weston, M., Fontenelle, L.K., et al. 2013. Recycling Water: Case Studies in Designing Fracturing Fluids Using Flowback, Produced, and Nontraditional Water Sources. Presented at the SPE Latin-American and Caribbean Heath, Safety, Environment and Social Responsibility Conference, Lima, Peru, 26-27 June. SPE-165641-MS. http://dx.doi.org/10.2118/165641-MS.
- FracFocus. 2014. Hydraulic Fracturing Water Usage. https://fracfocus.org/water-protection/hydraulic-fracturing-usage.
- Pierce, D., Bertrand, K., CretiuVasiliu, C. 2010. Water Recycling helps with Sustainability. Presented at the SPE Asia Pacific Oil and Gas Conference and Exhibition, 18-20 October, Brisbane, Queensland, Australia. SPE-134137-MS. http://dx.doi.org/10.2118/134137-MS.
Noteworthy papers in OnePetro
Abou-Sayed, A., Thompson, T.W., Keckler, K. 1994. Safe injection pressures for disposing of liquid wastes: A case study for deep well injection. Presented at Rock Mechanics in Petroleum Engineering, 29-31 August, Delft, Netherlands SPE-28126-MS. http://dx.doi.org/10.2118/28126-MS.
Blauch, M.E. 2010. Developing Effective and Environmentally Suitable Fracturing Fluids Using Hydraulic Fracturing Flowback Waters. Presented at the SPE Unconventional Gas Conference, 23-25 February, Pittsburgh, Pennsylvania, USA. SPE-131784-MS.http://dx.doi.org/10.2118/131784-MS.
Campin, D. 2013. Environmental Regulation of Hydraulic Fracturing in Queensland. SPE Annual Technical Conference and Exhibition, 30 September-2 October, New Orleans. SPE-166146-MS. http://dx.doi.org/10.2118/166146-MS.
Carter, K.E., Hammack, R.W., Hakala, J.A. 2013. Hydraulic Fracturing and Organic Compounds - Uses, Disposal and Challenges. Presented at the SPE Eastern Regional Meeting, Pittsburgh, Pennsylvania, USA, 20-22 August. SPE-165692-MS. http://dx.doi.org/10.2118/165692-MS.
Crane, B., Warren, W. 2011. Improved Process Provides More Effective Ultraviolet Light Disinfection of Fracturing Fluids. Presented at the SPE Americas E&P Health, Safety, Security, and Environmental Conference, Houston, 21-23 March. SPE-142217-MS. http://dx.doi.org/10.2118/142217-MS.
Edwards, J., Jones, D., Tudor, R. 2009. Benefits of Quality Hydrocarbon Fracturing Fluid Recycling. Presented at the Canadian International Petroleum Conference, Calgary, 16-18 June. PETSOC-2009-056-EA. http://dx.doi.org/10.2118/2009-056-EA.
Ely, J.W., Fraim, M., Horn, A.D. 2011. Game Changing Technology For Treating And Recycling Frac Water. SPE Annual Technical Conference and Exhibition, Denver, 30 October-2 November. SPE-145454-MS. http://dx.doi.org/10.2118/145454-MS.
Fedorov, A., Carrasquilla, J., Cox, A. 2014. Avoiding Damage Associated to Produced Water Use in Hydraulic Fracturing. SPE International Symposium and Exhibition on Formation Damage Control, Lafayette, Louisiana, USA, 26-28 February. SPE-168193-MS. http://dx.doi.org/10.2118/168193-MS.
Gloe, L.M., Neal, G., Kleinwolterink, K. 2010. UV Light Treatment Reduces the Amount of Biocide Required to Disinfect Water for Fracturing Fluids. SPE International Conference on Health, Safety and Environment in Oil and Gas Exploration and Production, Rio de Janeiro, 12-14 April. SPE-126851-MS. http://dx.doi.org/10.2118/126851-MS.
Haghshenas, A., Nasr-El-Din, H.A. 2014. Effect of Dissolved Solids on Reuse of Produced Water in Hydraulic Fracturing Jobs. Presented at the SPE Latin America and Caribbean Petroleum Engineering Conference, Maracaibo, Venezuela, 21-23 May. SPE-169408-MS. http://dx.doi.org/10.2118/169408-MS.
Horn, A.D. 2009. Breakthrough Mobile Water Treatment Converts 75% of Fracturing Flowback Fluid to Fresh Water and Lowers CO2 Emissions. Presented at the SPE Americas E&P Environmental and Safety Conference, San Antonio, Texas, USA, 23-25 March. SPE-121104-MS. http://dx.doi.org/10.2118/121104-MS.
Kakadjian, S., Thompson, J., Torres, R., et al. 2013. Stable Fracturing Fluids from Waste Water. Presented at the SPE Unconventional Resources Conference Canada, Calgary, 5-7 November. SPE-167175-MS. http://dx.doi.org/10.2118/167175-MS.
Lane, A., Peterson, R. 2014. Evaluation Tool for Wastewater Treatment Technologies for Shale Gas Operations in Ohio. Presented at the SPE/AAPG/SEG Unconventional Resources Technology Conference, 25-27 August, Denver SPE-2014-1922494-MS. http://dx.doi.org/10.15530/urtec-2014-1922494.
Montgomery, C. 2013. Fracturing Fluid Components. Presented at the ISRM International Conference for Effective and Sustainable Hydraulic Fracturing, 20-22 May, Brisbane, Australia. ISRM-ICHF-2013-034. https://www.onepetro.org/conference-paper/ISRM-ICHF-2013-034.
Mueller, D. 2013. Identification and Evaluation of Brackish Groundwater Resources and Alternate Water Sources for Hydraulic Fracturing Operations. Presented at the SPE Americas E&P Health, Safety, Security and Environmental Conference, Galveston, Texas, USA, 18-20 March. SPE-163769-MS. http://dx.doi.org/10.2118/163769-MS.
Shipman, S., McConnell, D., Mccutchan, M.P., et al. 2013. Maximizing Flowback Reuse and Reducing Freshwater Demand: Case Studies from the Challenging Marcellus Shale. Presented at the SPE Eastern Regional Meeting, Pittsburgh, Pennsylvania, USA, 20-22 August. SPE-165693-MS. http://dx.doi.org/10.2118/165693-MS.
Tischler, A., Woodworth, T.R., B.D., Sheril. 2010. Controlling Bacteria in Recycled Production Water for Completion and Workover Operations. SPE Production & Operations 25 (02) SPE-123450-PA. http://dx.doi.org/10.2118/123450-PA.
Uwiera-Gartner, M. 2013. Groundwater Considerations of Shale Gas Developments Using Hydraulic Fracturing: Examples, Additional Study and Social Responsibility. Presented at the SPE Unconventional Resources Conference Canada, 5-7 November, Calgary. SPE-167233-MS. http://dx.doi.org/10.2118/167233-MS.
Watts, R. 2013. A Day in the Life of a Barrel of Water: Evaluating Total Life Cycle Costs of Hydraulic Fracturing Fluids. Presented at the SPE Annual Technical Conference and Exhibition, New Orleans, 30 September-2 October. SPE-166113-MS. http://dx.doi.org/10.2118/166113-MS.
Burnett, David. 2012. New Options for Produced Water Treatment and Re-use in Gas/Oil Shale Fracturing. https://webevents.spe.org/products/new-options-for-produced-water-treatment-and-re-use-in-gasoil-shale-fracturing
Palmgren, Tor. 2013. Treatment Options for Reuse of Frac Flowback and Produced Water from Shales. https://webevents.spe.org/products/treatment-options-for-reuse-of-frac-flowback-and-produced-water-from-shales
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