Phase 2 drilling operations at the Long Valley Exploratory Well (LVF 51--20)

This report describes the second drilling phase, completed to a depth of 7588 feet in November 1991, of the Long Valley Exploratory Well near Mammoth Lakes, California. The well in Long Valley Caldera is planned to reach an ultimate depth of 20,000 feet or a bottomhole temperature of 500{degrees}C (whichever comes first). There will be four drilling phases, at least a year apart with scientific experiments in the wellbore between active drilling periods. Phase 1 drilling in 1989 was completed with 20 in. casing from surface to a depth of 2558 ft., and a 3.8 in. core hole was drilled below the shoe to a depth of 2754 in. Phase 2 included a 17-{1/2} in. hole out of the 20 in. shoe, with 13-3/8 in. casing to 6825 ft., and continuous wireline coring below that to 7588 ft. This document comprises a narrative log of the daily activities, the daily drilling reports, mud logger`s reports, summary of drilling fluids used, and other miscellaneous records.