A Reservoir Assessment of The Geysers Geothermal Field

Stress and Fracture Orientation in the Northwest Geysers Geothermal Field

A dataset comprised of 3946 well-located and wellconstrained earthquake focal plane mechanisms recorded in the Northwest Geysers geothermal field during the period of Jan 2005 – May 2012 was used to determine stress orientations and relative magnitudes at fine scale. The stress inversions were organized into gridblocks of varying size using a three-dimensional oct-tree gridding algorithm in whi...

Determining the 3-D F’racture Structure in the Geysers Geothermal Reservoir

In t roduc t ion The bulk of the steam a t the Geysers geothermal field is produced from fractures in a. relatively impermeable graywacke massif which has lieen heated by an underlying felsite intrusion. The largest of these fractures are steeply dipping right lateral strike-slip faults which are subparallel to the N W striking Clollayomi and Mercuryville faults which form t,lie NE and SW bound...

Adsorption Characteristics of Rocks from Vapgr-dominated Geothermal Reservoir at the Geysers, Ca

Reservoir Response to Curtailments at the Geysers

Curtailment tests were conducted at the Calistoga and Bear Canyon wellfields from March to June 2001. The curtailments are found to result in lower decline rates as well as in an increased steam flow rate following the curtailed period. This increase is referred to as a “puff” and its duration is proportional to the extent of curtailments. The data from these tests have been used to develop a r...

Three-dimensional Compressional- and Shear-wave Seismic Velocity Models for the Southeast Geysers Geothermal Field, California

Three-dimensional compressionaland shear-wave velocity (“Vp” and “Vs,” respectively) structure is obtained for the SE Geysers geothermal area from microearthquake arrival-time data. The results indicate a region of high Vp and high Vs in the northwest portion of the area studied, and a low value of VpNs at depths corresponding to the upper part of the steam reservoir. The Vp and Vs anomalies ar...