Testing, Drilling, and Logging of Geothermal Test Hole GT-2, Phase II

摘要

Geothermal Test Hole No. 2 (GT-2) is a deep exploratory hole drilled into the Precambrian-age granitic rocks underlying the Jemez Mountains of north-central New Mexico. The purpose of the hole is to confirm the suit¬ability of the Fenton Hill site for development of the world's first dry hot rock geothermal energy extraction experiment. Due to recent volcanic activity in the area, the near-surface rocks still retain a great amount of heat.nThe drilling of GT-2 to a depth of 1937 m (6356 ft) was completed in June 1974. Following the drilling, a series of hydrology experiments was performed to determine the permeability of the granitic rock at depth. Hydraulic fracturing experiments, using methods and equipment developed by the oil-well service industry, were conducted at specific zones in the granitic section of the hole. An additional 105 m C345 ft) of drilling were completed during this testing phase to allow experiments to be con-ducted in a "fresh" hole. Various diagnostic-logging operations were performed during testing and drilling. This report describes the second phase of the development of GT-2.