Kern Front Oil Field
Encyclopedia
Kern County, California
Spreading across the southern end of the California Central Valley, Kern County is the fifth-largest county by population in California. Its economy is heavily linked to agriculture and to petroleum extraction, and there is a strong aviation and space presence. Politically, it has generally...
. Discovered in 1912, and with a cumulative production of around 210 Moilbbl of oil, it ranks 29th in size in the state, and is believed to retain approximately ten percent of its original oil (approximately 22 million barrels), according to the official estimates of the California Department of Oil, Gas, and Geothermal Resources (DOGGR). It is adjacent to the much larger Kern River Oil Field
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...
, which is to the southeast, and the Mount Poso Oil Field
Mount Poso Oil Field
The Mount Poso Oil Field is a large oil and gas field in the lower foothills of the Sierra Nevada Mountains in Kern County, California. Discovered in 1926, and relatively close to exhaustion with less than three percent of its original oil remaining, it is the 21st largest field in California by...
to the north.
Setting
Oildale, California
Oildale is a census-designated place in Kern County, California, United States. Oildale is located north-northwest of downtown Bakersfield, at an elevation of 469 feet . The population was 32,684 at the 2010 census, up from 27,885 at the 2000 census...
, and ten miles (16 km) north of Bakersfield
Bakersfield, California
Bakersfield is a city near the southern end of the San Joaquin Valley in Kern County, California. It is roughly equidistant between Fresno and Los Angeles, to the north and south respectively....
, in the first gentle rise of the hills above the floor of the San Joaquin Valley
San Joaquin Valley
The San Joaquin Valley is the area of the Central Valley of California that lies south of the Sacramento – San Joaquin River Delta in Stockton...
. It is about six miles (10 km) long by two and a half across, with the long axis being in the north-south direction, comprising a productive surface area of 5495 acres (22.2 km²). Elevations vary from approximately 500 to 1000 feet (304.8 m) above sea level. The field is spread out, especially compared to the exceedingly dense development in the adjacent Kern River Oil Field, which has one of the densest oil developments in the United States, with over 9,000 oil wells clustered in just several square miles. The Kern Front Field is bounded on the west by California State Route 65
California State Route 65
State Route 65 , commonly known as Highway 65, is a north–south state highway in the U.S. state of California composed of two segments connecting Bakersfield to Exeter and Roseville to Olivehurst...
, on the southwest by James Road, and on the southeast by Bakersfield-Glennville Road. Oilfields Road runs south to north through the field.
Being within the ecological subsection of the California Central Valley
California Central Valley
California's Central Valley is a large, flat valley that dominates the central portion of California. It is home to California's most productive agricultural efforts. The valley stretches approximately from northwest to southeast inland and parallel to the Pacific Ocean coast. Its northern half is...
known as the Hardpan Terraces, at an elevation of less than 1000 feet (304.8 m), the predominant native vegetation is needlegrass
Needlegrass
The term needlegrass may refer to any of several genera of grasses, including:*Achnatherum*Aristida *Nassella*Stipa...
. The climate is hot and arid, with summertime temperatures routinely exceeding 100 °F (37.8 °C); the mean freeze-free period runs from about 250 to 300 days. Mean annual precipitation is around 10 inches (254 mm), almost all as rain and almost all in the winter; summers are charactistically rainless.
Geology
The Kern Front Field contains two major producing units, the Etchegoin Formation and the Chanac, both sedimentary, but unconformably overlain. The Etchegoin is a PliocenePliocene
The Pliocene Epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch...
marine sand, and the Chanac is a Pliocene
Pliocene
The Pliocene Epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch...
non-marine sand. Each is interbedded with silts and clays, and the sands have a high porosity, ranging from 25-33 percent, making them singularly suitable as petroleum reservoirs. Overlying the Etchegoin and Chanac formations is the Pleistocene Kern River Formation, which is highly productive in the adjacent Kern River Oil Field. These units all have a northwest strike and a small southwest dip. A large north-trending fault on the east side of the field provides a structural seal on that side; on the northeast, the up-dip side of the field, the sands grade into relatively impermeable silts and clays, providing a seal in that direction. Many small southwest-trending faults run across the field. The California DOGGR recognizes only one producing pool – the Etchegoin-Chanac – and commingles the production data.
Many sedimentary units underlie these petroleum-bearing sands, but they either have not produced much oil or have not been completely explored. Basement rocks – the granitic complex representing the huge Sierra Nevada batholith, and probably of late Jurassic
Jurassic
The Jurassic is a geologic period and system that extends from about Mya to Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...
age – occur at a depth of approximately 7000 feet (2,133.6 m). The deepest well on the Kern Front Field, the Atlantic Richfield Company "Kramer No. 1", reached a depth of 7738 feet (2,358.5 m) before bumping into the basement complex.
Oil from the field is heavy crude, with an API gravity
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...
averaging 14, and a sulfur content of 0.9 percent by weight. Since this oil is heavy, it is viscous and flows easily only when assisted by steam injection or other enhanced recovery techniques.
The average depth of the oil bearing units is about 2300 feet (701 m), and the thickness of the oil-bearing strata ranges from 100 to 700 feet (213.4 m). Since the depth of the oil is relatively shallow, the temperature is relatively low, at only 100 degrees Fahrenheit (many of the deeper zones in Central Valley oil fields produce oil over 200 °F (93.3 °C), a greater safety hazard to workers). In 1983, the date of DOGGR's data compilation, the water table in the field was at 2500 feet (762 m) below ground surface.
History, production, and operations
Standard Oil Company of California discovered the field in 1912 with the drilling of their Well No. 1, into the Etchegoin pool, to a depth of 2836 feet (864.4 m). The well still exists, as Chevron Corp. Well No. 1. Peak production for the field was in 1929, during which 4535029 barrels (721,012 m³) of oil were pumped from the ground.Production steadily declined from that peak until the invention of the steam injection
Steam injection (oil industry)
Steam injection is an increasingly common method of extracting heavy oil. It is considered an enhanced oil recovery method and is the main type of thermal stimulation of oil reservoirs. There are several different forms of the technology, with the two main ones being Cyclic Steam Stimulation and...
method in the 1960s. Cyclic steam injection (the "huff and puff method" began in 1964, and production again rose, as the heavy oil flowed more freely to pumping wells. In 1978, former operator Chevron Corp. began steam flooding in the southern portion of the field, and Century Oil Management did the same in the northern portion. Petro-Lewis Corporation tested steam foam solution and a steam foam encapsulated in a polymer gel to see if steamflood performance could be improved.
Gas production on the field peaked in 1980.
One of the current operators, Tearlach Resources, has claimed that the field may actually contain a potential reserve of 500 Moilbbl. This estimate is based on work done by the operators of the field in 1990, Mobil, ARCO and Occidental, and involves both recovering previously uneconomic deposits, as well as exploring deeper, previously unexplored zones, which some of the geologists believed may be petroleum-bearing.
As of the beginning of 2009, there were 838 producing oil wells on the field. p. 63 If some of the current proposals for further exploration and development are enacted, such as those by Tearlach, this number could increase considerably.
Current operators include Bellaire, Vintage, E&B Natural Resource Management, West American Energy Corp., and a few others. The field operators deliver some wastewater from oil production to Valley Waste Disposal, with some wastewater being filtered and softened to make feedwater for steam boilers. Valley Waste skims residual oil and grease from the water, and the water is conveyed to Cawelo Water District, where it is re-used for irrigation.