Seismic velocity and attenuation structure of the Geysers geothermal field, California

Journal Article · Fri Apr 01 04:00:00 EST 1994 · Geothermics (International Journal of Geothermal Research and its Applications); (United Kingdom)

DOI:https://doi.org/10.1016/0375-6505(94)90033-7· OSTI ID:6841976

Zucca, J J; Hutchings, L J; Kasameyer, P W ^[1]

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1. Lawrence Livermore National Lab., CA (United States)

The Geysers geothermal field is located in northern California and is one of the world's largest producers of electricity from geothermal energy. A key resource management issue at this field is the distribution of fluid in the matrix of the reservoir rock. In this paper, the authors interpret seismic compressional-wave velocity and quality quotient (Q) data at The Geysers in terms of the geologic structure and fluid saturation in the reservoir. Their data consist of waveforms from approximately 300 earthquakes. Using compressional-wave arrival times, they invert for earthquake location, origin time, and velocity within a three-dimensional grid. Using the pulse width of the compressional wave, they invert for the pulse width contribution associated with the source and the one-dimensional Q structure. They find that the velocity structure correlates with known mapped geologic units. The dry steam reservoir, which is known from steam well drilling, is mostly correlated with low velocity. The correlation is best for those areas where the steam pressure has been reduced by production. The Q increases with depth to the top of the dry steam reservoir and decreases with depth within the reservoir. This decrease of Q with depth suggests that the liquid saturation of the reservoir rock matrix increases with depth.

• OSTI ID: 6841976
• Journal Information: Geothermics (International Journal of Geothermal Research and its Applications); (United Kingdom), Journal Name: Geothermics (International Journal of Geothermal Research and its Applications); (United Kingdom) Vol. 23:2; ISSN GTMCAT; ISSN 0375-6505
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
150200* -- Geology & Hydrology of Geothermal Systems
150301 -- Geothermal Exploration & Exploration Technology-- Geophysical Techniques & Surveys
ATTENUATION
CALIFORNIA
DATA ANALYSIS
DEVELOPED COUNTRIES
EARTHQUAKES
FUNCTIONS
GEOTHERMAL FIELDS
GEYSERS GEOTHERMAL FIELD
MICROEARTHQUAKES
NORTH AMERICA
RESPONSE FUNCTIONS
SEISMIC EVENTS
SEISMIC WAVES
USA