CHANGING WELLBORE STORAGE IN GAS WELL TESTING

Authors

  • Edward ML. Tobing Research and Development Centre for Oil and Gas Technology "LEMIGAS"

DOI:

https://doi.org/10.29017/SCOG.31.2.1008

Keywords:

Changing Wellbore Storage, Gas Well Testing

Abstract

Extended wellbore storage can be mistakenly interpreted as a reservoir response in gas well testing with surface shut in. This interpretation usually results in false value for permeability, skin and reservoir size and shape. This paper investigates changing wellbore storage in pressure transient testing with surface shut-in in gas well. This study was prompted by the observation, that in gas wells, many of the buildup tests obtained with surface shut-in exhibited complex reservoir model behavior with relatively low skin. The results presented in this paper are based on well test simulation and field data from North Sumatera. This work demonstrates the effect changing wellbore storage on the pressure derivative curve. Knowledge of the expected pressure derivative shape, and duration, will improve the design of buildup tests that will allow enough time for the actual reservoir response to be observed. This will result in a reliable reservoir model and correct estimation of permeability and skin factor.

References

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Hasan, A.R., and Kabir, C.S : “Modeling Changing Storage During a Shut-in Test,†SPE Annual Conference in Washington, DC, October 4-7, 1992. 47 CHANGING WELLBORE STORAGE IN GAS WELL LEMIGAS SCIENTIFIC CONTRIBUTIONS EDWARD ML. TOBING VOL. 31. NO. 2, AUGUST 2008 : 40 - 48

Yitang, Z, and Fuming, Z.: “Well Test Analysis in The Case of Changing Wellbore Storage,†SPE 22424.

Fair, W.B. Jr.: “Generalized of Wellbore Effects in Pressure Transient Analysisâ€, SPE 24715 presented at the 67th SPE Annual Conference in Washington, DC, October 4-7, 1992.

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Issue

Vol. 31 No. 2 (2008)

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Articles

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Copyright (c) 1970 SCIENTIFIC CONTRIBUTIONS OIL AND GAS (SCOG)

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