Permeability, electrical impedance, and acoustic velocities on reservoir rocks from the Geysers field

Conference · Tue Dec 31 04:00:00 EST 1996

OSTI ID:472093

Boitnott, G N; Boyd, P J ^[1]

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1. New England Research, Inc., White River Junction, VT (United States)

Previous measurements of acoustic velocities on NEGU-17 cores indicate that saturation effects are significant enough to cause V{sub p}/V{sub s}, anomalies observed in the field. In this study we report on the results of new measurements on core recently recovered from SB-15-D along with some additional measurements on the NEGU-17 cores. The measurements indicate correlations between mechanical, transport, and water storage properties of the matrix which may prove useful for reservoir assessment and management. The SB-15-D material is found to be similar to the NEGU-17 material in terms of acoustic velocities, being characterized by a notably weak pressure dependence on the velocities and a modest V{sub p}/V{sub s} signature of saturation. The effect of saturation on V{sub p}/V{sub s} appears to result in part from a chemo-mechanical weakening of the shear modulus due to the presence of water. Electrical properties of SB-15-D material are qualitatively similar to those of the NEGU-17 cores, although resistivities of SB-15-D cores are notably lower and dielectric permittivities higher than in their NEGU-17 counterparts. While some limited correlations of measured properties with depth are noted, no clear change in character is observed within SB-15-D cores which can be associated with the proposed caprock/reservoir boundary.

• OSTI ID: 472093
• Report Number(s): CONF-960124--
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
ACOUSTIC MEASUREMENTS
CALIFORNIA
GEOLOGY
GEOTHERMAL RESOURCES
GEYSERS GEOTHERMAL FIELD
PETROGRAPHY
RESERVOIR ROCK