South Cuyama Oil Field

The South Cuyama Oil Field is a large oil and gas field in the Cuyama Valley and the adjacent northern foothills of the Sierra Madre Mountains in northeastern Santa Barbara County, California. Discovered in 1949, and with a cumulative production of around of oil, it ranks 27th in size in the state, but is believed to retain only approximately two percent of its original oil (approximately ), according to the official estimates of the California Department of Oil, Gas, and Geothermal Resources (DOGGR). Of the top forty onshore oil fields in California, it is the most recent to be discovered, but by the end of 2008 only 87 wells remained in production. p. 63

Setting

The oil field is south of the town of New Cuyama in the portion of the Cuyama Valley that slopes gently into the northern foothills of the Sierra Madre Mountains. Parts of the field are on hilly terrain, and some is within the Los Padres National Forest. The field can be reached from California State Route 166 via Aliso Canyon Road on the northwest, and Perkins Road on the northeast; Perkins Road joins 166 at the town of New Cuyama. While these roads run roughly north-south, Foothill Road crosses through the field from east to west, eventually reaching Santa Barbara Canyon Road on the east and State Route 33. Elevations on the field range from approximately 2,200 to 3,000 feet (670 to 910 meters). The productive area of the field is approximately long by two across, with the long axis running northwest to southeast; the total productive area as reported by DOGGR is .

The climate is semi-arid, with occasional marine influence, as the Cuyama Valley is open to the sea, although through a narrow gap. Summers are hot with temperatures commonly exceeding ; winters are cool, with the mean freeze-free period being about 250 days. Average annual rainfall is about 12 inches, almost all of it falling in the winter in the form of rain, although occasional snowfall has occurred. All streams are dry in the summer, and even the Cuyama River dries up by the late summer in most years. The area is prone to brushfires in the summer and fall; indeed a fire in 1994 caused a loss of $76,000 to the operators, and in July 2006 an accident on the oil field involving a metal plate crossing power lines started the Perkins Fire, which burned on the north side of the Sierra Madre Mountains.

Native vegetation in the vicinity of the field ranges from grassland to chaparral to oak woodland. Drainage is to the north, towards the Cuyama River, along Bitter Creek, Branch Canyon Wash, and several ephemeral drainages.

Geology

Oil in the South Cuyama Basin comes from two primary pools, the Miocene-age Dibblee Sand and the Colgrove Sand, porous units in the Vaqueros Formation underneath the largely impermeable Monterey Formation. The sedimentary Cuyama Basin is cut by many small faults, and the oil exists in a series of stratigraphic traps, where it is in most cases blocked in its upward motion by impermeable blocks of Monterey, often offset by faults. The average depth of oil in the field is about below ground surface, and the thickness of the oil-bearing units rarely exceeds ; in the separate southeastern area of the field, where the Colgrove sand is below ground surface, the oil bearing rock is only thick. The source rock for the South Cuyama oil is most likely the Soda Lake Shale member of the Vaqueros Formation.

Overlying the faulted and broken Miocene rocks, which include the Monterey, Branch Canyon, and Santa Margarita Formations, and separated by an unconformity, is about 2,000 to of the Pliocene

HOME


Content is Copyleft
Website design, code, and AI is Copyrighted (c) 2014-2017 by Stephen Payne


Consider donating to Wikimedia



As an Amazon Associate I earn from qualifying purchases