Old Maid Flat Geothermal Exploratory Hole No. 7A Drilling and Completion Report

摘要

Drilling and testing efforts for a 6000-foot geothermal exploratory hole on the western approaches to Mount Hood, near Portland, Oregon were completed. The intent of the drilling was to encounter a hydrothermal reservoir in a postulated fracture system and confirm the existence of a moderate-temperature (200 exp 0 F) geothermal resource in the Old Main Flat (OMF) vicinity of Mount Hood. The exploratory hole, OMF No. 7A, was completed to a total depth of 6027 feet in 54 days using conventional rotary drilling techniques. The hole was found to be incapable of producing fluids with the desired temperatures. A maximum hole temperature of about 235 exp 0 F was recorded at total depth and a temperature gradient of about 3.3 exp 0 F/100 feet was exhibited over the lower 1000 feet of hole. A variety of technical data, including physical samples such as cores, cuttings, and borehole fluids, plus geophysical well logs were acquired. Data analyses are continuing, with results to be made available through future separate reports. (ERA citation 06:016742)