Seismic characterization of a naturally fractured gas reservoir
- and others
Two lines of 9-component (9C) seismic reflection data, parallel and perpendicular to the dominant fracture azimuth, and two 9C VSPs, were acquired in upper Green River gas reservoirs of the Bluebell-Altamont field, in northeastern Utah. The work is one of four projects sponsored by the U.S. Department of Energy, to demonstrate how exploration for and reservoir characterization in naturally fractured gas reservoirs can more effectively and efficiently use P-wave seismic. This multidisciplinary project aims to integrate the seismic response (both P-Wave and S-Wave) with the geologic setting, including stratigraphic changes, structural setting, in-situ stress field, and changes in fracture density and orientation, with evidence of fractures from geologic sources, and production data, including information on preferred flow direction in the reservoirs (maximum horizontal permeability). The normal incidence, isotropic P-Wave response was modeled from sonic logs and the resultant P-Wave synthetic data used as a reference for further work. The P-Wave seismic data showed azimuthal variations in AVO response at the tiepoint, interpreted to indicate vertical, aligned, gas-filled fractures. The 9C VSP documented the S1 and S2 polarizations, S1 and S2 reflection characters, and travel time anisotropy in the fractured upper Green River. The S-Wave reflection seismic lines displayed travel time and amplitude anomalies consistent with the geologic evidence of the dominant fracture azimuth (N30W) and in-situ stress field; the S-wave data were interpreted for fracture orientation and relative fracture density along the lines. Consistency between the P-Wave AVO and the S-Wave interpretations provided a measure of confidence in the use of P-Wave pre-stack data to correctly characterize the fractures in this naturally fractured reservoir.
- OSTI ID:
- 542850
- Report Number(s):
- CONF-951013-; TRN: 97:004463-0038
- Resource Relation:
- Conference: SEG `95: 65. annual meeting and international exposition of the Society of Exploration Geophysicists (SEG), Houston, TX (United States), 8-13 Oct 1995; Other Information: PBD: 1995; Related Information: Is Part Of SEG/Houston `95 - technical program; PB: 1623 p.
- Country of Publication:
- United States
- Language:
- English
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