The use of tidal strain induced well pressure fluctuations for the estimation of reservoir elastic and hydraulic characteristics of single-phase fluid confined aquifers has received considerable attention over the past decade. Well-aquifer models used in these investigations fall basically into two categories, the "static; solution proposed by Bredehoeft' and the "dynamic" solution proposed by Bodvarsson. In the limit of very large transmissivity, the dynamic solution becomes identical to the static solution. The estimation of site-specific values for the storaqe coefficient and formation porosity has been carried out in several instances. In most of these cases, however, little or-no information on the values of these parameters as determined by conventional methods was available to compare with the tfdal results in order to test the model. We are currently analyzing the tidal pressure response at two wells, Elmore 3 and Sinclair 3, at the Salton Sea Geothermal Field (SSGF) in California. Considerable geophysical and geological information in addition to conventional well testing results is available for this area. We hope to use these data to more rigorously test existing tidal response models. This paper presents some preliminary results of the estimation of the effective compressibllity of the reservoir rock at Elmore 3.

In addition to the work outlined above, we are also investigating the possiblity of using tidal pressure response to better understand the nature of the geothermal resource at Raft River, Idaho. This system is structurally complex, and existing models for tidal response of homogeneous and isotropic aquifers are not applicable. Work is currently in progress on defining an appropriate model for this system., We have analyzed records from six wells at Raft River: RRGE-1, RRGE-2, RRGE-3, RRGE-4, RRGI-6, and RRGI-7. The tidal admittance has been calculated for these wells and the results are presented here.

Press the Back button in your browser, or search again.

Copyright 1979, Stanford Geothermal Program: Readers who download papers from this site should honor the copyright of the original authors and may not copy or distribute the work further without the permission of the original publisher.