An industry-DOE cost-shared project is underway to evaluate the technical feasibility of developing an EGS power generation project on the eastern side of the Desert Peak geothermal field. Analysis of existing geological and geophysical data is complemented by new geologic mapping and gravity work in the Hot Springs Mountains undertaken by researchers with funding from the Great Basin Center for Geothermal Energy at the University of Nevada Reno (UNR). An existing well (DP 23-1) is the focus of much of the Phase I investigation, including re-interpretation of lithology, acquisition and analysis of a well bore imaging log, and conducting and analyzing a step-rate injection test. As of June 2003, the project is about half complete; results are summarized below. Phase I work remaining to modeling, numerical modeling and the development of a be completed includes conceptual detailed plan to guide upcoming field activities.

This paper describes a low-risk, low-cost and modular alternative to the conventional Hot Dry Rock or Enhanced Geothermal Systems (EGS). In this approach, which we have named the Earth Energy Extraction System (“Triple- E” System), the injected fluid is allowed to get preheated in the injection wellbore before reaching the reservoir; this preheating is achieved through injection in ultra-slim diameter wells (2.5 to 7.5cm) and by keeping the rate of injection very low (on the order of 10 liters per second). The injected fluid then heats up further as it travels to the production well through pores and fractures in the rock. The injection wells are terminated close to and at a shallower level than the top of the productive interval in the production well. This approach avoids the two main technical limitations associated with conventional EGS: (a) creating a significant reservoir volume by artificial fracturing; and (b) fluid loss control. This approach reduces dependence on the occurrence of natural permeability that limits the scope of conventional geothermal technology. The risk of cooling of the production well by shortcircuiting of injected water, a common concern in both EGS and conventional geothermal projects, is significantly reduced by preheating of the injected water.

Thermal waters produced from large oil fields are currently the most important geothermal resources in Los Angeles County. Assuming that various technological and economic considerations are favorable, many of these fields are promising sources of heat for diverse applications outside the field operations. Otherwise, the County does not appear to have any large, near-surface geothermal resources.

The purpose of this project was to determine and evaluate possible geothermal resources for potential development at U.S. naval reservations in the greater San Diego, California area. The work was done through the auspices of a cooperative agreement between the U.S. Department of Energy, San Francisco Operations Office and the U.S. Department of Navy, China Lake Naval Weapons Center for joint research on geothermal energy at U.S. military installations.

The purpose of this project was to determine and evaluate sources of geothermal energy at two military bases in southern California, the Long Beach Naval Shipyard and Naval Station and the Seal Beach Naval Weapons Station. One part of the project focused on the natural geothermal characteristics beneath the naval bases. Another part focused on the geothermal energy produced by oilfield operations on and adjacent to each base. Results of the study are presented here for the U.S. Department of the Navy to use in its program to reduce its reliance on petroleum by the development of different sources of energy. The study was accomplished under a cooperative agreement between the U.S. Department of Energy's San Francisco Operations Office and the Department of the Navy's Naval Weapons Center, China Lake, California, for joint research and development of geothermal energy at military installations.

SUMMARY: This report presents the results of a cooperative study of geothermal systems in the region from Aurora, Nevada, and Bridgeport, California, south to Long Valley, California, by the Division of Mines and Geology and the Division of Earth Sciences of the University of Nevada, Las Vegas. The study is the initialreconnaissance phase of a project that was proposed to span several years. Magmatic and hydrothermal systems have been common in this region for the last 15 million years. The objectives of this study were to begin determination of the properties ~nd interactions of these systems and to develop hypotheses on the locations of undiscovered, active systems _in the region. SpeCial emphasis was given to the re~ional relationships and controls of the systems. New data presented include a Bouguer gravity map of the region, several gravity and magnetic profiles, a resistivity profile near Aurora, and a potassium-argon date on Mud Spring volcano, also near Aurora. New interpretations are presented regarding relative 8Qes and distributions of thermal fluids, gravity anomalies, d~pths to pre-Cenozoic: basement, structural controls of the geothermal systems, and the late Cenozoic tectonic-magmatic evolution of the region. The U.S. Department of Energy provided most of the funds for this project.