|
The Semitropic Oil Field is an oil and gas field in northwestern Kern County in California in the United States, within the San Joaquin Valley. Formerly known as the Semitropic Gas Field, it was discovered by the Standard Oil Company of California in 1935, and first understood to be primarily a natural gas reservoir; however, in 1956 a much deeper oil-bearing zone was discovered. The field contains the deepest oil well ever drilled in California, at .〔 p. 61. While deeper boreholes have been drilled, this is the deepest that had ever been converted into a productive oil well. It was abandoned in 1975.〕 At the end of 2008 the field still had 56 active oil wells, most of which were owned by Occidental Petroleum, and the field had an estimated 343,000 barrels of oil still recoverable with current technology.〔DOGGR 2009, p. 101.〕 ==Setting== The Semitropic field is one of the oil and gas fields in the southern San Joaquin Valley which is underneath the bottomlands of the valley, rather than in the hills which surround it. Most of the largest fields are in the lower parts of the foothills to the mountains on either side of the valley, including monstrous reservoirs such as the Kern River and Midway-Sunset fields; in the bottomlands, the fields are more deeply buried and harder to find, as they have no surface geological expression, such as a line of hills indicating an anticlinal structure hiding an oil reservoir. Like many of the fields on the west side of the valley, it is an elongate dome aligned from northwest to southeast. The field is about seven miles (11 km) long by two across, at the widest point, and has a productive area of .〔California Department of Conservation, Division of Oil, Gas, and Geothermal Resources (DOGGR). ''California Oil and Gas Fields, Volumes I, II and III''. Vol. I (1998), Vol. II (1992), Vol. III (1982). PDF file available on CD from www.consrv.ca.gov. p. 394-395〕 The field parallels Interstate 5 about five miles (8 km) to the northeast. California State Route 46, the Paso Robles Highway, cuts across the northern extremity of the field from east to west, about east of Lost Hills. The town of Wasco is about eight miles (13 km) farther east along the same route. Several small abandoned oil and gas fields adjoin the Semitropic field from the southeast to the southwest, and the small Wasco Oil Field (with only three wells remaining active) is immediately adjacent to the east. The nearest large and still active oil field is the Lost Hills field, about to the west-northwest. Terrain in the vicinity of the oil field is almost table-flat, with elevations ranging from approximately 250 to above sea level throughout the productive region, with a very slight gradient from south to north towards the Tulare Lake bed. The Semitropic Ridge, a gentle topographic prominence with a mean elevation of about twenty feet above the oil field, parallels the field to the southwest, separating it from Interstate 5. Climate is typical of the valley bottom in the south, which is arid. Temperatures in the summer routinely exceed on typically cloudless days. Rain falls mainly in the winter months, and averages 5 to . Freezes occur occasionally during the winter, and the winter months are also subject to frequent dense tule fogs, limiting visibility to near zero. Drainage from the field in generally into the irrigation canal system, but because of the flat surface gradient most rainfall soaks directly into the ground. Land use in the vicinity of the field is predominantly agricultural, with oil and gas production, storage, and transportation infrastructure interspersed with orchards and row crops. Little native vegetation remains as all the land has been converted to agricultural use. Roads cross the region at right angles, following township, range, and section lines, as do irrigation canals. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Semitropic Oil Field」の詳細全文を読む スポンサード リンク
|