Using second derivative of transient pressure in welltest analysis of low permeability gas reservoirs

Hassan Bahrami*, M. Reza Rezaee, Akim Kabir, Jamal Siavoshi, Husky Energy, Rochdi Jammazi

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

5 Citations (Scopus)

Abstract

Welltest interpretation requires diagnosis of reservoir flow regimes in order to determine the basic reservoir characteristics such as average reservoir permeability and skin factor. Due to wellbore storage effect, wellbore phenomena and complexity of reservoir response from heterogeneous reservoir layers, detection of the reservoir flow regimes using standard welltest diagnostic plots might be challenging and have some uncertainties. In pressure transient testing, there are instances where the flow regimes might not clearly be revealed on diagnostic plots of pressure build-up and its derivative, such as incomplete pressure build-up tests, low permeability reservoirs and multi-phase producing wells. In such cases, the Semi-Log plot of first and second derivative of transient pressure versus time can be used to reduce the uncertainties associated with welltest analysis. This paper describes a new method for well test interpretation using second derivative of transient pressure. Two field examples are shown in which a reliable radial flow regime on pressure build-up data could not be detected using standard plots. The second derivative approach was used to predict radial flow regime trend and estimate the reservoir permeability and skin factor, which the results were in good agreement with production data in these wells.

Original languageEnglish
Title of host publicationSPE Production and Operations Conference and Exhibition 2010, POCE 10
Pages1-9
Number of pages9
Publication statusPublished - 2010
Externally publishedYes
EventSPE Production and Operations Conference and Exhibition 2010, POCE 10 - Tunis, Tunisia
Duration: 8 Jun 201010 Jun 2010

Publication series

NameSPE Production and Operations Symposium, Proceedings

Conference

ConferenceSPE Production and Operations Conference and Exhibition 2010, POCE 10
Country/TerritoryTunisia
CityTunis
Period8/06/1010/06/10

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