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Thermal loads on casing and tubing strings: Difference between revisions

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Changes in temperature will increase or decrease tension in the casing string because of thermal contraction and expansion, respectively. The increased axial load, because of pumping cool fluid into the wellbore during a stimulation job, can be the critical axial design criterion. In contrast, the reduction in tension during production, because of thermal expansion, can increase buckling and possibly result in compression at the wellhead.  
Changes in temperature will increase or decrease tension in the casing string because of thermal contraction and expansion, respectively. The increased axial load, because of pumping cool fluid into the wellbore during a stimulation job, can be the critical axial design criterion. In contrast, the reduction in tension during production, because of thermal expansion, can increase buckling and possibly result in compression at the wellhead.  


===Temperature dependant yield===
===Temperature dependent yield===
Changes in temperature not only affect loads but also influence the load resistance. Because the material’s yield strength is a function of temperature, higher wellbore temperatures will reduce the burst, collapse, axial, and triaxial ratings of the casing.
Changes in temperature not only affect loads but also influence the load resistance. Because the material’s [[Glossary:Yield strength|yield strength]] is a function of temperature, higher wellbore temperatures will reduce the burst, collapse, axial, and triaxial ratings of the casing.


===Sour gas well design===
===Sour gas well design===

Revision as of 13:02, 29 October 2014

To evaluate a given casing design, a set of loads is necessary. Casing loads result from running the casing, cementing the casing, subsequent drilling operations, production and well workover operations. Temperature changes and resulting thermal expansion loads are induced in casing by drilling, production, and workovers, and these loads might cause buckling (bending stress) loads in uncemented intervals. In shallow normal-pressured wells, temperature will typically have a secondary effect on tubular design. In other situations, loads induced by temperature can be the governing criteria in the design.

Temperature effects on tubular design

Annular fluid expansion pressure

Increases in temperature after the casing is landed can cause thermal expansion of fluids in sealed annuli and result in significant pressure loads. Most of the time, these loads need not be included in the design because the pressures can be bled off. However, in subsea wells, the outer annuli cannot be accessed after the hanger is landed. The pressure increases will also influence the axial load profiles of the casing strings exposed to the pressures because of ballooning effects.

Tubing thermal expansion

Changes in temperature will increase or decrease tension in the casing string because of thermal contraction and expansion, respectively. The increased axial load, because of pumping cool fluid into the wellbore during a stimulation job, can be the critical axial design criterion. In contrast, the reduction in tension during production, because of thermal expansion, can increase buckling and possibly result in compression at the wellhead.

Temperature dependent yield

Changes in temperature not only affect loads but also influence the load resistance. Because the material’s yield strength is a function of temperature, higher wellbore temperatures will reduce the burst, collapse, axial, and triaxial ratings of the casing.

Sour gas well design

In sour environments, operating temperatures can determine what materials can be used at different depths in the wellbore.

Tubing internal pressure

Produced temperatures in gas wells will influence the gas gradient inside the tubing because gas density is a function of temperature and pressure.

References

See also

Tubing changes from pressure and temperature

Internal pressure loads on casing and tubing strings

External pressure loads on casing and tubing strings

Mechanical loads on casing and tubing strings

Strength of casing and tubing

Casing design

Casing and tubing buckling

PEH:Casing Design

Noteworthy papers in OnePetro

External links

General references

Aadnoy, B.S. 1996 Modern Well Design. Rotterdam, The Netherlands: Balkema Publications.

Adams, A.J. and MacEachran, A. 1994. Impact on Casing Design of Thermal Expansion of Fluids in Confined Annuli. SPE Drill & Compl 9 (3): 210-216. SPE-21911-PA. http://dx.doi.org/10.2118/21911-PA.

Banon, H., Johnson, D.V., and Hilbert, L.B. 1991. Reliability Considerations in Design of Steel and CRA Production Tubing Strings. Presented at the SPE Health, Safety and Environment in Oil and Gas Exploration and Production Conference, The Hague, Netherlands, 11-14 November. SPE-23483-MS. http://dx.doi.org/10.2118/23483-MS.

Brand, P.R., Whitney, W.S., and Lewis, D.B. 1995. Load and Resistance Factor Design Case Histories. Presented at the Offshore Technology Conference, Houston, 1-4 May. OTC-7937-MS. http://dx.doi.org/10.4043/7937-MS.

Economides, M.J., Waters, L.T., and Dunn-Norman S. 1998. Petroleum Well Construction. New York City: John Wiley & Sons.

Galambos, T.V., Ellingwood, B., MacGregor, J.G. et al. 1982. Probability-based Load Criteria: Assessment of Current Design Practice. J. of the Structural Division, ASCE, 108 (5): 959-977.

Halal, A.S. and Mitchell, R.F. 1994. Casing Design for Trapped Annular Pressure Buildup. SPE Drill & Compl 9 (2): 107-114. SPE-25694-PA. http://dx.doi.org/10.2118/25694-PA.

Lewis, D.B., Brand, P.R., Whitney, W.S. et al. 1995. Load and Resistance Factor Design for Oil Country Tubular Good. Presented at the Offshore Technology Conference, Houston, 1-4 May. OTC-7936-MS. http://dx.doi.org/10.4043/7936-MS.

Manual for Steel Construction, Load and Resistance Factor Design. 1986. Chicago: American Institute of Steel Construction.

Mitchell, R.F. 1996. Forces on Curved Tubulars Caused By Fluid Flow. SPE Prod & Oper 11 (1): 30-34. SPE-25500-PA. http://dx.doi.org/10.2118/25500-PA.

Mitchell, R.F.: “Casing Design,” in Drilling Engineering, ed. R. F. Mitchell, vol. 2 of Petroleum Engineering Handbook, ed. L. W. Lake. (USA: Society of Petroleum Engineers, 2006). 287-342.

Prentice, C.M. 1970. "Maximum Load" Casing Design. J. Pet Tech 22 (7): 805-811. SPE-2560-PA. http://dx.doi.org/10.2118/2560-PA.

Rackvitz, R. and Fiessler, B. 1978. Structural Reliability Under Combined Random Load Processes. Computers and Structures 9: 489.