The Round Mountain Oil Field is a large oil and gas field in the foothills of the
Sierra Nevada, about northeast of
Bakersfield, California, United States. It is east of the giant
Kern River Oil Field
The Kern River Oil Field is a large oil field in Kern County in the San Joaquin Valley of California, north-northeast of Bakersfield in the lower Sierra foothills. Yielding a cumulative production of close to of oil by the end of 2006, it is ...
, one of the largest in the United States, and also close to the
Mount Poso Oil Field
The Mount Poso Oil Field is a large oil and gas field in the lower foothills of the Sierra Nevada in Kern County, California, United States. Discovered in 1926, it is the 21st largest field in California by total ultimate oil recovery, having a cu ...
and
Kern Front Oil Field. With a cumulative total recovery of more than of oil, it is the 48th largest oil field in California, but remains relatively productive with still about ten percent of its reserves remaining in the ground, according to the California Department of Oil, Gas, and Geothermal Resources (DOGGR).
Setting
The oil field is northeast of the city of Bakersfield, between the
Kern River
The Kern River, previously Rio de San Felipe, later La Porciuncula, is an Endangered, Wild and Scenic river in the U.S. state of California, approximately long. It drains an area of the southern Sierra Nevada mountains northeast of Bakersfield ...
and
Poso Creek, in the lower foothills of the Sierra Nevada. The main access to the field is from the south, by way of Round Mountain Road, which also passes through the huge and much more densely developed
Kern River Oil Field
The Kern River Oil Field is a large oil field in Kern County in the San Joaquin Valley of California, north-northeast of Bakersfield in the lower Sierra foothills. Yielding a cumulative production of close to of oil by the end of 2006, it is ...
. Elevations on the Round Mountain Field range from around at Poso Creek to at Round Mountain itself. Topographic relief is high in some parts of the field, especially the northern part of the Main Area, which is intersected by numerous deep canyons.
Being mostly within the ecological subsection of the
California Central Valley known as the Hardpan Terraces, the predominant native vegetation is
needlegrass, with some scrub occurring, especially on north-facing slopes. The climate is hot and arid, with summertime temperatures routinely exceeding ; the mean freeze-free period runs from about 250 to 300 days. Mean annual precipitation is around , almost all as rain and almost all in the winter; summers are generally rainless. Runoff is quick, and streams are dry in the summer and early autumn; water from the area flows out by Poso Creek and the Kern River to closed basins in the southern San Joaquin Valley, including
Buena Vista Lake
Buena Vista Lake was a fresh-water lake in Kern County, California, in the Tulare Lake Basin in the southern San Joaquin Valley, California.
Buena Vista Lake was the second largest of several similar lakes in the Tulare Lake basin, and was fed ...
.
The field itself is spread out into five named areas, several of which consist of multiple discontiguous productive regions. The Main Area is the largest, consisting of one pool about long by across, extending north to south from Poso Creek to Kern River, and including Round Mountain. North of the main area is the Coffee Canyon Area, and northeast is the Pyramid Area. To the west of the Main Area are the two separate pools in the Sharktooth Area, and the two pools in the Alma Area. The total productive area of the entire field is , or approximately four square miles.
Geology
![RoundMountainOilFieldGeologicCrossSection](https://upload.wikimedia.org/wikipedia/commons/1/11/RoundMountainOilFieldGeologicCrossSection.png)
Oil in the Round Mountain Field comes from four primary pools, the Freeman-Jewett, Pyramid Hill, Vedder, and Walker. Each resides in a
sedimentary
Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...
formation equivalently named, and are listed from top to bottom in stratigraphic sequence. The Freeman-Jewett and Pyramid Hill are of
Miocene
The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...
Age; the Vedder of
Oligocene; and the lowest-lying productive unit, the
Walker Formation, was deposited during the
Eocene
The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', " ...
and Oligocene. Of these units, the Vedder has been by far the most productive, with over of oil being extracted.
The field is bounded on the northeast by a fault which serves as a
structural trap
In petroleum geology, a trap is a geological structure affecting the reservoir rock and caprock of a petroleum system allowing the accumulation of hydrocarbons in a reservoir. Traps can be of two types: stratigraphic or structural. Structural trap ...
since it is upgradient from the oil pools. Basement rocks underneath the productive units are of
Jurassic
The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of ...
age, and at around are not particularly deep for a Kern County oil field. The deepest well on the field is the Killingsworth "Alma" No. 6, at , which reached the granitic basement.
Oil from the field is generally heavy, with
API gravity
The American Petroleum Institute gravity, or API gravity, is a measure of how heavy or light a petroleum liquid is compared to water: if its API gravity is greater than 10, it is lighter and floats on water; if less than 10, it is heavier and sinks ...
ranging from 13 at the Sharktooth and Alma areas to 22 in the Jewett pool in the Main Area. Waterflooding and cyclic steam processes have been used to retrieve some of the heavier petroleum since the early 1960s.
History, production, and operations
The discovery well was drilled by
Getty Oil
Getty Oil was an American oil marketing company with its origins as part of the large integrated oil company founded by J. Paul Getty.
History
J. Paul Getty incorporated Getty Oil in 1942. He had previously worked in the oil fields of Oklaho ...
, now part of
Chevron Corp.
Chevron Corporation is an American multinational energy corporation. The second-largest direct descendant of Standard Oil, and originally known as the Standard Oil Company of California (shortened to Socal or CalSo), it is headquartered in Sa ...
, in May 1927, in the Pyramid Hill pool of the Main Area. Dates of discovery of other parts of the field were 1928 for the Coffee Canyon Area, 1937 for the Pyramid Area, 1943 for the Sharktooth Area, and most recently 1974 for the Alma Area. The peak production for the field as a whole was 1938, during which barrels of oil were pumped out.
As of 2008, Chevron retained no operating units in the field, and the current operators included Macpherson Oil Co., Coffee Petroleum, Pace Diversified Corp., and Arthur McAdams. None of the major oil companies had operations at Round Mountain.
DOGGR query interface, sorted by well status on Round Mountain Field
/ref>
References
* ''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. South Cuyama Oil Field information pp. 120–124. PDF file available on CD from www.consrv.ca.gov.
* ''California Department of Conservation, Oil and Gas Statistics, Annual Report, December 31, 2006.''
Notes
{{coord, 35.4904, -118.8940, type:landmark_source:enwiki-googlemaplink, display=title
Oil fields in Kern County, California
Oil fields in California