Utilizing a Comprehensive 3D Model to Understand, Maintain, and Expand the Soda Lake Geothermal Resource, Nevada USA

摘要

Increasing power generation at the Soda Lake geothermal power plant requires thorough understanding of the well field and reservoir structure. A three dimensional drill-hole and geologic model was created, incorporating data from temperature surveys, wireline geophysical logs, mudlogs, narratives indicating suspected fault and fracture zones, and numerous technical papers. Once all information was compiled, it was used with other geospatial data to create a drill-hole project in Geosoft's Target software, with wells oriented in 3D space, and a variety of down-hole data displayed in both 2D and 3D. CSAMT and seismic profiles were dropped into the 3D model, where they could be viewed in conjunction with other data. For the first time, geoscientists could visualize the subsurface locations of all wells with respect to each other, geology, geophysics, and the temperature anomaly. The result was dozens of data layers that could be toggled on and off and rotated in space. This model was then imported into the Oasis Montaj project, where it was combined with geophysical data to offer a more comprehensive view of the Soda Lake geothermal field. Cross-sections, fence diagrams, and strip logs were easily produced and updated in Target via user-defined templates. Slices of 3D objects such as temperature voxels and geologic surfaces were also displayed in 2D cross sections. This model has made a valuable contribution to the overall understanding of the Soda Lake geothermal system. As a result, the team has implemented changes leading to increased production at Soda Lake. Two wells that had initially failed as producers were revisited after using the 3D model to study them in the context of their surroundings. One is now hooked into the plant as a producer, while the other is currently undergoing injection testing, with initial tests indicating improvement. An older well was also revisited, and flow tests dramatically demonstrated that a steam cap had developed beneath the well. The 3D model was used in conjunction with geophysical data to study the steam cap, and Magma now has plans for direct use of the steam. In addition, the first of several potential new wells has been targeted and is due to spud in June, 2010.