Round Mountain Oil Field

Last updated February 19, 2019

The Round Mountain Oil Field is a large oil and gas field in the foothills of the Sierra Nevada, about 10 miles (16 km) northeast of Bakersfield, California, United States. It is east of the giant Kern River Oil Field, one of the largest in the United States, and also close to the Mount Poso Oil Field and Kern Front Oil Field. With a cumulative total recovery of more than 110 million barrels (17,000,000 m³) 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).^[1]

The Sierra Nevada is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primarily in Nevada. The Sierra Nevada is part of the American Cordillera, a chain of mountain ranges that consists of an almost continuous sequence of such ranges that form the western "backbone" of North America, Central America, South America and Antarctica.

Bakersfield, California City in California, United States of America

Bakersfield is a city and the county seat of Kern County, California, United States. It covers about 142 square miles (370 km²) near the southern end of the San Joaquin Valley and the Central Valley region. Bakersfield's population is approximately 380,000, making it the ninth-most populous city in California and the 52nd-most populous city in the nation. The Bakersfield–Delano Metropolitan Statistical Area, which includes all of Kern County, had a 2010 census population of 839,631, making it the 62nd largest metropolitan area in the United States. The more built-up urban area that includes Bakersfield and areas immediately around the city, such as East Bakersfield, Oildale and Rosedale, has a population of over 520,000. Bakersfield is a charter city.

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 2 billion barrels (320,000,000 m³) of oil by the end of 2006, it is the third largest oil field in California, after the Midway-Sunset Oil Field and the Wilmington Oil Field, and the fifth largest in the United States. Its estimated remaining reserves, as of the end of 2006, were around 476 million barrels (75,700,000 m³), the second largest in the state. It had 9,183 active wells, the second highest in the state. The principal operator on the field is Chevron Corporation

Setting

Round Mountain Oil Field, on a 2005 aerial photograph base. The light-shaded area is the rough extent of the productive area of the oil field. RoundMountainAerial.png — Round Mountain Oil Field, on a 2005 aerial photograph base. The light-shaded area is the rough extent of the productive area of the oil field.

The oil field is northeast of the city of Bakersfield, between the Kern River 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. Elevations on the Round Mountain Field range from around 700 feet (210 m) at Poso Creek to 1,612 feet (491 m) 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.

Poso Creek or Posey Creek is an 87.9-mile (141.5 km) intermittent stream in Kern County, California.

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 100 °F (38 °C); the mean freeze-free period runs from about 250 to 300 days. Mean annual precipitation is around 10 inches (250 mm), 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.^[2]

The term needlegrass may refer to any of several genera of grasses, including:

Buena Vista Lake was a fresh-water lake in Kern County, California, in the Tulare Lake Basin in the southern San Joaquin Valley, California.

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 5 miles (8.0 km) long by 0.5 miles (0.80 km) 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 2,630 acres (10.6 km²), or approximately four square miles.^[3]

Geology

Round Mountain Oil Field Geologic Cross Section RoundMountainOilFieldGeologicCrossSection.png — Round Mountain Oil Field Geologic Cross Section

Oil in the Round Mountain Field comes from four primary pools, the Freeman-Jewett, Pyramid Hill, Vedder, and Walker. Each resides in a sedimentary formation equivalently named, and are listed from top to bottom in stratigraphic sequence. The Freeman-Jewett and Pyramid Hill are of Miocene Age; the Vedder of Oligocene; and the lowest-lying productive unit, the Walker formation, was deposited during the Eocene and Oligocene. Of these units, the Vedder has been by far the most productive, with over 50 million barrels (7,900,000 m³) of oil being extracted.^[4]

The Miocene is the first geological epoch of the Neogene Period and extends from about 23.03 to 5.333 million years ago (Ma). The Miocene was named by Charles Lyell; its name comes from the Greek words μείων and καινός and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene is preceded by the Oligocene and is followed by the Pliocene.

The Oligocene is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present. As with other older geologic periods, the rock beds that define the epoch are well identified but the exact dates of the start and end of the epoch are slightly uncertain. The name Oligocene was coined in 1854 by the German paleontologist Heinrich Ernst Beyrich; the name comes from the Ancient Greek ὀλίγος and καινός, and refers to the sparsity of extant forms of molluscs. The Oligocene is preceded by the Eocene Epoch and is followed by the Miocene Epoch. The Oligocene is the third and final epoch of the Paleogene Period.

The Eocene Epoch, lasting from 56 to 33.9 million years ago, is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a brief period in which the concentration of the carbon isotope ¹³C in the atmosphere was exceptionally low in comparison with the more common isotope ¹²C. The end is set at a major extinction event called the Grande Coupure or the Eocene–Oligocene extinction event, which may be related to the impact of one or more large bolides in Siberia and in what is now Chesapeake Bay. As with other geologic periods, the strata that define the start and end of the epoch are well identified, though their exact dates are slightly uncertain.

The field is bounded on the northeast by a fault which serves as a structural trap since it is upgradient from the oil pools. Basement rocks underneath the productive units are of Jurassic age, and at around 4,000 feet (1,200 m) are not particularly deep for a Kern County oil field. The deepest well on the field is the Killingsworth "Alma" No. 6, at 4,418 feet (1,347 m), which reached the granitic basement.^[5]

In petroleum geology, a structural trap is a type of geological trap that forms as a result of changes in the structure of the subsurface, due to tectonic, diapiric, gravitational and compactional processes. These changes block the upward migration of hydrocarbons and can lead to the formation of a petroleum reservoir.

The Jurassic was a geologic period and system that spanned 56 million years from the end of the Triassic Period 201.3 million years ago (Mya) to the beginning of the Cretaceous Period 145 Mya. The Jurassic constitutes the middle period of the Mesozoic Era, also known as the Age of Reptiles. The start of the period was marked by the major Triassic–Jurassic extinction event. Two other extinction events occurred during the period: the Pliensbachian-Toarcian extinction in the Early Jurassic, and the Tithonian event at the end; however, neither event ranks among the "Big Five" mass extinctions.

Oil from the field is generally heavy, with API gravity 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.^[6]

History, production, and operations

The discovery well was drilled by Getty Oil, now part of Chevron Corp., 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 5,453,194 barrels (866,988.6 m³) barrels of oil were pumped out.^[7]

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.^[8]

Related Research Articles

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Buena Vista Oil Field oil field in California, United States

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The Cymric Oil Field is a large oil field in Kern County, California in the United States. While only the 14th-largest oil field in California in total size, in terms of total remaining reserves it ranks fifth, with the equivalent of over 119 million barrels (18,900,000 m³) still in the ground. Production at Cymric has been increasing faster than at any other California oil field.

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The McKittrick Oil Field is a large oil and gas field in western Kern County, California. The town of McKittrick overlies the northeastern portion of the oil field. Recognized as an oil field in the 19th century, but known by Native Americans for thousands of years due to its tar seeps, the field is ranked 19th in California by total ultimate oil recovery, and has had a cumulative production of over 303 million barrels (48,200,000 m³) of oil. The principal operators of the field as of 2008 were Chevron Corp. and Aera Energy LLC, but many independent oil exploration and production companies were also active on the field. The California Department of Oil, Gas and Geothermal Resources (DOGGR) estimates approximately 20 million recoverable barrels of oil remain in the ground.

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The Fruitvale Oil Field is a large oil and gas field in the southern San Joaquin Valley, California, within and just northwest of the city of Bakersfield, along and north of the Kern River. It is one of the few oil fields in the California Central Valley which is mostly surrounded by a heavily populated area. Discovered in 1928, and with a cumulative total recovery of more than 124 million barrels (19,700,000 m³) of oil at the end of 2006, it is 41st in size among California oil fields, and according to the California Department of Oil, Gas, and Geothermal Resources (DOGGR) its total reserve amounts to a little less than ten percent of its original oil.

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Ventura Oil Field oilfield north of the city of Ventura, California, United States

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The Brea-Olinda Oil Field is a large oil field in northern Orange County and Los Angeles County, California, along the southern edge of the Puente Hills, about four miles (6 km) northeast of Fullerton, and adjacent to the city of Brea. Discovered in 1880, the field is the sixteenth largest in California by cumulative production, and was the first of California's largest 50 oil fields to be found. It has produced over 412 million barrels of oil in the 130 years since it was first drilled, and retains approximately 19 million barrels in reserve recoverable with current technology. As of the beginning of 2009, 475 wells remained active on the field, operated by several independent oil companies, including Linn Energy, BreitBurn Energy Partners L.P., Cooper & Brain, and Thompson Energy.

The South Mountain Oil Field is a large and productive oil field in Ventura County, California, in the United States, in and adjacent to the city of Santa Paula. Discovered in 1916, and having a cumulative production of over 158 million barrels (25,100,000 m³) of oil, it is the 37th largest oil field in California and the second largest in Ventura County. As of the beginning of 2009, it retains 316 active wells, and has an estimated 1.4 million barrels (220,000 m³) of oil remaining recoverable with current technology. Vintage Production, a subsidiary of Occidental Petroleum, was the largest operator as of 2009.

The Russell Ranch Oil Field is an oil and gas field in the Cuyama Valley of northern Santa Barbara and southern San Luis Obispo Counties, California, in the United States. Discovered in 1948, and reaching peak production in 1950, it has produced over 68 million barrels (10,800,000 m³) of oil in its lifetime; with only an estimated 216,000 barrels (34,300 m³) of recoverable oil remaining, and having produced around 66,000 in 2008, it is considered to be close to exhaustion. The primary operator on the field as of 2010 is E&B Natural Resources, which also runs the nearby South Cuyama Oil Field.

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 18,876 feet (5,753 m). 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.

The Guijarral Hills Oil Field is a formerly-productive oil and gas field near Coalinga on the western side of the Central Valley in central California in the United States. Discovered in 1948, and having produced 5.4 million barrels (860,000 m³) of oil during its peak year in 1950, it now has but one active oil well producing a little over a barrel of oil a day, and is very near to exhaustion, with only 343,000 recoverable barrels of oil remaining throughout its 2,515-acre (10.18 km²) extent according to the official California State Department of Conservation estimate. As of 2010, the only active operator was Longview Production Company.

The Mountain View Oil Field is a large, mature, but still-productive oil field in Kern County, California, in the United States, in the extreme southern part of the San Joaquin Valley southeast of Bakersfield. It underlies the town of Arvin, as well as some smaller agricultural communities. The field is spread out across a large area, covering just under 8 square miles (21 km²), with wells and storage facilities widely dispersed throughout the area, scattered among working agricultural fields of broccoli and carrots as well as citrus orchards. Discovered in 1933, it has produced over 90 million barrels (14,000,000 m³) of oil in its lifetime, and although declining in production is one of the few inland California fields in which new oil is still being discovered.

The Edison Oil Field is a large oil field in Kern County, California, in the United States, in the southeastern part of the San Joaquin Valley and adjacent foothills east-southeast of Bakersfield. The field has a total productive area of over 8,000 acres (32 km²), most of which is intermingled with agricultural land uses; oil pumps and storage tanks are surrounded with row crops and orchards in much of the field's extent. Discovered in 1928, and with a cumulative production of 149 million barrels (23,700,000 m³) of oil as of 2008, and having over 6 million barrels (950,000 m³) in reserve, it is ranked 38th among California's oil fields by total ultimate recovery. It is a mature field in decline, and is run entirely by small independent operators. As of 2008, there were 40 different oil companies active on the field, one of the most in the state for a single field. 914 wells remained active on the field, averaging only two barrels of oil per well per day from the dwindling reservoirs.

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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

↑ California Department of Conservation, Oil and Gas Statistics, Annual Report, December 31, 2006, p. 67
↑ "Hardpan Terraces subregion description". U.S. Forest Service. Archived from the original on 2007-08-13. Retrieved 2014-02-22. Hardpan Terraces subregion description
↑ DOGGR, p. 374-6
↑ Chenot, David. Short Radius Lateral Drilling in the Vedder Sand: Round Mountain Oil Field, California: Final Report. U.S. Office of Scientific and Technical Information (osti.gov), 2001.
↑ DOGGR, p. 377
↑ DOGGR, pp. 376–381
↑ DOGGR, p. 376-381
↑ DOGGR query interface, sorted by well status on Round Mountain Field

Coordinates: 35°29′25″N118°53′38″W / 35.4904°N 118.8940°W / 35.4904; -118.8940

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[1] California Department of Conservation, Oil and Gas Statistics, Annual Report, December 31, 2006, p. 67

[2] "Hardpan Terraces subregion description". U.S. Forest Service. Archived from the original on 2007-08-13. Retrieved 2014-02-22. Hardpan Terraces subregion description

[3] DOGGR, p. 374-6

[4] Chenot, David. Short Radius Lateral Drilling in the Vedder Sand: Round Mountain Oil Field, California: Final Report. U.S. Office of Scientific and Technical Information (osti.gov), 2001.

[5] DOGGR, p. 377

[6] DOGGR, pp. 376–381

[7] DOGGR, p. 376-381

[8] DOGGR query interface, sorted by well status on Round Mountain Field