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Title: Application of joint inversion for mapping fluid parameters

Conference ·
OSTI ID:807422

A two-dimensional joint inversion technique, based on a least-squares criterion of the data misfit and model smoothness, has been developed using electromagnetic (EM) and seismic traveltime data to assess the feasibility of directly inverting for hydrological parameters, such as fluid electrical conductivity, porosity, and saturation. This is accomplished by relating hydrological parameters to geophysical properties with the help of the empirical Archie's law and the Wyllie time average equation. While the latter links the underground seismic wave velocity and subsurface media porosity, the former relates the bulk formation conductivity to hydrological parameters such as fluid conductivity and porosity. Direct joint inversion using various geophysical data also reduces the non-uniqueness of the problem since common parameters are involved, as is the porosity related to both seismic traveltime and magnetic field. This newly developed joint inversion algorithm has been applied to a set of crosshole seismic and EM field data provided by Chevron as part of the Lost Hills CO{sub 2} pilot project in Southern California. Both EM and seismic pre- and post-injection data were evaluated in terms of hydrological parameters using general empirical relationships derived from logging data. The results show that the injection has decreased the water saturation and bulk conductivity in the whole inter-well section. Layered structure in the region is clearly displayed and major changes in water saturation and bulk conductivity are also observed.

Research Organization:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Organization:
USDOE Director, Office of Science. Office of Basic Energy Studies. Chemical Sciences, Geosciences, and Biosciences Division (US)
DOE Contract Number:
AC03-76SF00098
OSTI ID:
807422
Report Number(s):
LBNL-51494; R&D Project: 468103; B& R KC0303010; TRN: US200305%%683
Resource Relation:
Conference: The 6th SEGJ International Symposium Imaging Technology, Tokyo (JP), 01/22/2003--01/24/2003; Other Information: PBD: 13 Sep 2002
Country of Publication:
United States
Language:
English