The Elk Hills Oil Field
(formerly the Naval Petroleum Reserve No. 1
, or NPR-1) is a large oil field
in northwestern Kern County
, in the Elk Hills of the San Joaquin Valley
in the United States
, about twenty miles (32 km) west of Bakersfield
. Discovered in 1911, and having a cumulative production of close to of oil at the end of 2006, it is the fifth-largest oil field in California, and the seventh-most productive field in the United States. Its estimated remaining reserves, as of the end of 2006, were around , and it had 2,387 active oil-producing wells. It is by an order of magnitude the largest natural gas-producing oil field in California, having produced over of gas since its discovery, and retaining over in reserve.
The principal operator on the field is Occidental of Elk Hills, a subsidiary of Occidental Petroleum. Largely as a consequence of their operations at Elk Hills, Occidental is the third-largest petroleum producer in California.
The oil field underlies the Elk Hills, a range of low hills trending west to east with a high elevation of . To the north, east, and southeast are the agricultural fields of the San Joaquin Valley, and to the southwest is the Buena Vista Valley. Across that valley is the town of Taft
, and the enormous Midway-Sunset Oil Field
, the largest in California. West of the Elk Hills is the large McKittrick Oil Field
, and northwest is the even larger Cymric Oil Field
. Although the Elk Hills is only one field of many in a region of oil fields, it is geographically distinct because its boundaries correspond with the shape of the hills that give it its name.
Skyline Road, which is closed to public entry, follows the long axis of the field. It begins near McKittrick and goes east, following the crest of the hills. Perpendicular to this road, and about halfway down its length, is Elk Hills Road, which connects the town of Taft to the south with Buttonwillow to the north. Two guarded gates to the Occidental Petroleum operations, 3 and 4, make up the intersection with Skyline Road on the summit of the range.
Overall the oil field is approximately long roughly following the crestline of the hills, and approximately across at the widest point. It encompasses considered productive, or about .
The Elk Hills Oil Field has a complex stratigraphy
compared to other nearby fields, many of which are a single large pool in a simple structural trap
. Thirteen separate oil pools have been identified so far in the Elk Hills Field, in rock units ranging in age from Oligocene
. The shallowest formation, the Tulare, was the first in which oil was found, at below ground surface, and the deepest, the Oligocene portion of the Temblor containing the Agua Pool at a depth of , was not found until 1977.
Production and political history
Associated Oil Company discovered the field in June 1911, with the drilling of their "Well No. 1," to a depth of . The official "discovery" well, however, was drilled by the Standard Oil Company ("Hay No. 1") in January, 1919. By 1912 the field's capacity was considered to be significant enough that President William Howard Taft
, concerned about the long-term availability of petroleum for the U.S. Navy, designated the region as the nation's first Naval Petroleum Reserve.
The dusty Elk Hills have a prominent role in U.S. political history, for it was the lease of this land by Secretary of the Interior Albert B. Fall, to Pan American Petroleum in 1922 in return for personal loans at no interest, that brought on the Teapot Dome scandal which ruined the reputation of the administration of Warren G. Harding, now commonly considered to be the most corrupt in U.S. history. In 1927 the U.S. Supreme Court invalidated the lease, and returned the Elk Hills to the U.S. government.
The oil field went largely untapped, held as a reserve, until the mid-1970s, when Congress passed the Naval Petroleum Reserves Production Act in response to the 1973-1974 Arab Oil Embargo. In 1976 the Carter Administration opened the lands for drilling and production again. Bechtel Petroleum Operations reached peak production in 1981, pumping 42 million barrels (6.7 million cubic meters) of oil out of the Stevens Pool in that year alone.
A drive to privatize some government lands during the mid-1990s succeeded in 1997 with the sale of the reserve to Occidental Petroleum, the highest bidder. Occidental took over operations in early 1998 and has been the principal operator since then; in 2008 they had a 78% interest in the oil field. Current reserves are claimed to be either 106,554,000 barrels of oil (according to the California Department of Conservation) or 484,000,000 barrels of oil equivalent (according to Occidental Petroleum).
- California Oil and Gas Fields, Volumes I, II and III. Vol. I (1998), Vol. II (1992), Vol. III (1982). California Department of Conservation, Division of Oil, Gas, and Geothermal Resources (DOGGR). 1,472 pp. Elk Hills field information is on pp. 168-173. PDF file available on CD from www.consrv.ca.gov.
- California Department of Conservation, Oil and Gas Statistics, Annual Report, December 31, 2006.
- Center for Public Integrity: timeline of events at Elk Hills