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Estimation of reservoir properties using transient pressure data: An asymptotic approach
Author(s) -
Vasco D. W.,
Keers Henk,
Karasaki Kenzi
Publication year - 2000
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2000wr900179
Subject(s) - borehole , amplitude , geology , inversion (geology) , computation , reservoir modeling , inverse problem , transient (computer programming) , electrical conductor , mathematical analysis , mechanics , algorithm , mathematics , seismology , geotechnical engineering , computer science , engineering , physics , operating system , quantum mechanics , electrical engineering , tectonics
An asymptotic formulation of the inverse problem for flow reveals that the inversion may be partitioned into two complementary subproblems. In the first problem the arrival time associated with the peak slope of the transient curve is directly related to reservoir properties. The second inverse problem is similar to current methods for interpreting flow data; the transient head amplitudes are related to reservoir storage and conductivity. The first subproblem, the arrival time inversion, involves much less computation than does amplitude matching. Furthermore, it appears to be more robust with respect to the starting model. Therefore the solution to the arrival time inversion provides a starting model for amplitude matching. The methodology is particularly suited to the analysis of observations from well tests. We apply the approach to observations from two interference tests conducted at the Borehole Test Facility in Oklahoma. Using the transient pressure measurements, we image a shallow conductive fracture. The existence and location of the fracture has been verified by both geophysical and borehole data. In particular, core from a slant well contains an open, vertical fracture which coincides with our conductive feature.