Some 38.6 billion cubic feet of gas are expected to be recoverable from Unocalís Happy Valley field, the Alaska Oil and Gas Conservation Commission said in approving pool rules for the accumulation.
Happy Valley is in the northern portion of the Deep Creek unit some six miles east of the town of Ninilchik on the Kenai Peninsula.
The Happy Valley No. 1 discovery well was drilled to a total measured depth of 10,871 feet in June 2003 and tested gas from two different Lower Tyonek reservoirs. The field discovery was confirmed when the Happy Valley No. 2 well was drilled in July 2003. The No. 2 flowed gas from two other Lower Tyonek reservoirs not seen in Happy Valley No. 1.
The commission said Unocal has since drilled nine additional delineation wells and acquired some 65 line miles of 2D seismic data in an attempt to delineate the structure and reservoir distribution within the field.
The Beluga and Tyonek formations were found to be commercial in a number of the wells, and Unocal built a 15-mile natural gas transmission line to, and gas production facilities at, the Happy Valley A Pad. Gas sales began in November.
The Happy Valley field produces dry gas from the Beluga and Tyonek reservoirs, with a gas composition of more than 98 percent methane. Both reservoirs have relatively low permeability.
Recoverable gas at Happy Valley is estimated at 38.6 billion cubic feet, with an estimated 56.3 bcf of gas in place in the Beluga formation, 23 bcf of which is expected to be recoverable, and 37.4 bcf of gas in place in the Tyonek reservoir was an estimated 15.6 bcf recoverable.
Commercial production, the commission said, requires commingled production from the Lower and Upper Tyonek and Beluga formation reservoirs.
Editorís note: See full story in March 13 issue of Petroleum News.