From Bureau of Economic Geology, The University of Texas at Austin (
For more information, please contact the author.

Bureau Seminar, Friday, April 15, 2005

Inversion for High-Resolution Reservoir Modeling:
a Progressive Approach

Hongliu Zeng


Acoustic impedance (AI) from poststack inversion (GLI) has been applied increasingly to reservoir modeling in mature fields. However, an inversion cannot eliminate the amplitude tuning effect without a reservoir-scale geometry constraint. Inverted AI may contain as much as a 40% error and can be used only as a "soft constraint" in high-resolution reservoir modeling and simulation. A synthetic study shows that use of a reservoir geometry (boundary position) model greatly reduces the tuning effect. In field-data application, a complex, high-resolution geometry model can be built with limited geologic knowledge of wireline logs, core, seismic reflection patterns, and outcrop analog. A progessive inversion scheme helps in implementing and improving the geometry model. Results in Cogdell field (RCRL prject) and Fullerton field (University Lands project) in the Permian Basin, west Texas, show consistent improvement in reservoir modeling when the new procedure is implemented. A reservoir simulation model that uses seismic information as a "hard constraint" is probable and feasible.