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97-530: The adjacent and geologically related South Salt Lake Oil Field , not discovered until 1970, is still productive from an urban drillsite it shares with the nearby Beverly Hills Oil Field , also run by Plains Exploration and Production. The field is one of many in the Los Angeles Basin . Immediately to the west is the San Vicente Oil Field, and to the southwest the large Beverly Hills Oil Field . To

194-600: A cap of approximately 200-foot (61 m) thickness on the underlying formations, several of which are oil-bearing. First is the Upper Pliocene Pico Formation , which is not petroleum-bearing in the Salt Lake field. Underneath the Pico are the late Miocene and Pliocene Repetto and Puente Formations. The Repetto Formation is a sandstone and conglomerate unit probably deposited in a submarine fan environment, and

291-445: A cap rock) is a fundamental part of the trap that prevents hydrocarbons from further upward migration. A capillary seal is formed when the capillary pressure across the pore throats is greater than or equal to the buoyancy pressure of the migrating hydrocarbons. They do not allow fluids to migrate across them until their integrity is disrupted, causing them to leak. There are two types of capillary seal whose classifications are based on

388-406: A consequence, oil and natural gas are often found together. In common usage, deposits rich in oil are known as oil fields, and deposits rich in natural gas are called natural gas fields. In general, organic sediments buried in depths of 1,000 m to 6,000 m (at temperatures of 60 ° C to 150 °C) generate oil, while sediments buried deeper and at higher temperatures generate natural gas. The deeper

485-407: A few, very large offshore drilling rigs, due to the cost and logistical difficulties in working over water. Rising gas prices in the early 21st century encouraged drillers to revisit fields that previously were not considered economically viable. For example, in 2008 McMoran Exploration passed a drilling depth of over 32,000 feet (9754 m) (the deepest test well in the history of gas production) at

582-621: A fifth drilling island, located at the northern corner of Avenue of the Stars and Constellation Boulevard in Century City , finished abandoning it in 1990. Originally constructed in the 1950s on what was then an unused back lot of Twentieth Century Fox Studios, its production steadily declined in the 1970s, and by 1989 the last well was shut down. Land use changes and soaring real estate values contributed to its elimination. The city of Los Angeles handles all building permits and air permitting issues for

679-513: A portion of the Beverly Hills Field, intending to apply modern mapping and secondary recovery technology to the mature oil field, as previous operators were moving out, in favor of easier prospects in less highly regulated environments. Field operators began using waterflooding in 1968 in several pools in the East Area (now operated by BreitBurn and Plains). In this method, produced water

776-471: A result of changes in the structure of the subsurface from processes such as folding and faulting , leading to the formation of domes , anticlines , and folds. Examples of this kind of trap are an anticline trap, a fault trap, and a salt dome trap. They are more easily delineated and more prospective than their stratigraphic counterparts, with the majority of the world's petroleum reserves being found in structural traps. Stratigraphic traps are formed as

873-435: A result of lateral and vertical variations in the thickness, texture, porosity, or lithology of the reservoir rock. Examples of this type of trap are an unconformity trap, a lens trap and a reef trap. Hydrodynamic traps are a far less common type of trap. They are caused by the differences in water pressure, that are associated with water flow, creating a tilt of the hydrocarbon-water contact. The seal (also referred to as

970-498: A series of lawsuits in 2003, in which parents of students at the school, observing what they believed to be excess rates of certain cancers among those exposed to toxins emitted from the facility, attempted to have it shut down. Plaintiffs claimed that a "cluster" of 280 cancers—primarily Hodgkin's disease , non-Hodgkin's lymphoma , and thyroid cancer , recorded over a period of about 30 years—were caused by emissions of volatile organic compounds (including benzene and toluene ) from

1067-502: A significantly higher displacement pressure such that the pressure required for tension fracturing is actually lower than the pressure required for fluid displacement—for example, in evaporites or very tight shales. The rock will fracture when the pore pressure is greater than both its minimum stress and its tensile strength then reseal when the pressure reduces and the fractures close. Unconventional (oil & gas) reservoirs are accumulations where oil and gas phases are tightly bound to

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1164-467: A situation similar to that at the Beverly Hills field. Originally, Los Angeles planned to put a Metro subway line along Fairfax Avenue, but chose to reroute it because of the high levels of methane gas in the subsurface environment, since this flammable gas posed a safety risk. It was only later that the oil field was recognized as the source of the methane gas. This hazard was realized spectacularly on

1261-446: A wide area, creating an eerie scene with pillars of flame lighting the night. Four blocks were cordoned off by emergency crews as officials scrambled to determine what had happened. Since naturally occurring methane is odorless – utility companies add mercaptans to alert people to the presence of this flammable gas – no one had noticed the buildup of methane, so it may have accumulated to an explosive concentration slowly. The source of

1358-408: A year or two. In 1973, highly saline wastewater, formerly dumped into the city's storm drains, was reinjected into the reservoir both as a convenient, non-polluting disposal method, and to increase reservoir pressure to enhance oil recovery. Similarly, gas produced from the oil field was reinjected into the reservoir between 1961 and 1971; facilities did not exist to capture, store, and transport it, as

1455-543: Is a prolific petroleum reservoir throughout the Los Angeles Basin. Underneath the Repetto is the late Miocene Puente Formation . All of these rock units are faulted and folded, forming structural traps, with oil trapped in anticlinal folds and along fault blocks. A total of six producing horizons, lettered A through F from top to bottom, have been identified in the Salt Lake field. Only Pool "A", first to be discovered,

1552-610: Is a subsurface accumulation of hydrocarbons contained in porous or fractured rock formations. Such reservoirs form when kerogen (ancient plant matter) is created in surrounding rock by the presence of high heat and pressure in the Earth's crust . Reservoirs are broadly classified as conventional and unconventional reservoirs. In conventional reservoirs, the naturally occurring hydrocarbons, such as crude oil ( petroleum ) or natural gas , are trapped by overlying rock formations with lower permeability , while in unconventional reservoirs

1649-428: Is an economic benefit worthy of commercial attention. Oil fields may extend up to several hundred kilometers across the surface, meaning that extraction efforts can be large and spread out across the area. In addition to extraction equipment, there may be exploratory wells probing the edges to find more reservoir area, pipelines to transport the oil elsewhere, and support facilities. Oil fields can occur anywhere that

1746-402: Is analogous to saying that the oil which can be extracted forms within the source rock itself, as opposed to accumulating under a cap rock. Oil sands are an example of an unconventional oil reservoir. Unconventional reservoirs and their associated unconventional oil encompass a broad spectrum of petroleum extraction and refinement techniques, as well as many different sources. Since the oil

1843-403: Is being pursued at a higher rate because of the scarcity of conventional reservoirs around the world. After the discovery of a reservoir, a petroleum engineer will seek to build a better picture of the accumulation. In a simple textbook example of a uniform reservoir, the first stage is to conduct a seismic survey to determine the possible size of the trap. Appraisal wells can be used to determine

1940-452: Is best to manage the gas cap effectively, that is, placing the oil wells such that the gas cap will not reach them until the maximum amount of oil is produced. Also a high production rate may cause the gas to migrate downward into the production interval. In this case, over time the reservoir pressure depletion is not as steep as in the case of solution-based gas drive. In this case, the oil rate will not decline as steeply but will depend also on

2037-426: Is called the stock tank oil initially in place . As a result of studying factors such as the permeability of the rock (how easily fluids can flow through the rock) and possible drive mechanisms, it is possible to estimate the recovery factor, or what proportion of oil in place can be reasonably expected to be produced. The recovery factor is commonly 30–35%, giving a value for the recoverable resources. The difficulty

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2134-490: Is contained within the source rock, unconventional reservoirs require that the extracting entity function as a mining operation rather than drilling and pumping like a conventional reservoir. This has tradeoffs, with higher post-production costs associated with complete and clean extraction of oil being a factor of consideration for a company interested in pursuing a reservoir. Tailings are also left behind, increasing cleanup costs. Despite these tradeoffs, unconventional oil

2231-590: Is high at 2.73% in each pool. In the South Salt Lake field, two pools have been identified, both in 1970: the Clifton Sands and the Dunsmuir Sands, at 1,000 feet (300 m) and 2,500 feet (760 m) depth respectively. Oil is found in several steeply dipping sand units bounded by impermeable rocks; the sands pinch out towards the ground surface, and oil accumulates in the upper portions. The oil in this field

2328-509: Is in the Repetto, having an average depth of only about 1,000 feet (300 m) below ground surface (bgs). Pools "B" and "C" were found by 1904, and the deeper pools "D", "E", and "F", ranging from 2,850 to 3,300 feet (1,000 m) bgs, were found in 1960 with the resumption of drilling from the Gilmore Drilling Island. Oil from the field is heavy and sulfurous, with API gravity ranging from 9 to 22, but usually 14-18; sulfur content

2425-431: Is more accurate to divide the oil industry into three sectors: upstream ( crude oil production from wells and separation of water from oil ), midstream (pipeline and tanker transport of crude oil) and downstream ( refining of crude oil to products, marketing of refined products, and transportation to oil stations). More than 65,000 oil fields are scattered around the globe, on land and offshore. The largest are

2522-483: Is north of Pico between Doheny Drive and Cardiff Ave. Yet another drilling island, the largest of the four, containing over fifty active wells and operated by Plains Exploration & Production , is north of Pico between Genesee Avenue and Spaulding Avenue. This drilling island also contains wells that angle northeast into the Salt Lake Oil Field . Within the boundary of the adjacent Cheviot Hills Oil Field, and on

2619-490: Is recoverable using current technologies. Oil was discovered in the northern Los Angeles basin in 1893, not far from the city center, and development of the Los Angeles City Oil Field was fast. By 1895, that field was producing over half of the oil in the state, and drillers began looking for even more new oil prospects around the basin, attempting to match the enormous finds taking place simultaneously just over

2716-412: Is reinjected into the reservoir to increase pressure (as oil is pumped out, internal reservoir pressure naturally decreases, resulting in a reduced pumping rate; a common way to restore pumping rates is to reinject wastewater into the reservoir to restore the original reservoir pressure). Water reinjection is also a convenient means of wastewater disposal, which in an urban setting is a practical problem, as

2813-630: Is shared between Iran and Qatar . The second largest natural gas field is the Urengoy gas field , and the third largest is the Yamburg gas field , both in Russia . Like oil, natural gas is often found underwater in offshore gas fields such as the North Sea , Corrib Gas Field off Ireland , and near Sable Island . The technology to extract and transport offshore natural gas is different from land-based fields. It uses

2910-535: Is slightly less heavy than in the main Salt Lake field, with API gravity ranging from 22 to 26. Sulfur content was not reported. In the 1890s, dairy farmer Arthur F. Gilmore found oil on his land, probably in the vicinity of the La Brea Tar Pits. The field was named after the Salt Lake Oil Company, the first firm to arrive to drill in the area. The discovery well was spudded (started) in 1902. Details of

3007-413: Is that reservoirs are not uniform. They have variable porosities and permeabilities and may be compartmentalized, with fractures and faults breaking them up and complicating fluid flow. For this reason, computer modeling of economically viable reservoirs is often carried out. Geologists, geophysicists, and reservoir engineers work together to build a model that allows simulation of the flow of fluids in

Salt Lake Oil Field - Misplaced Pages Continue

3104-739: Is the larger Modelo Formation , consisting of several sand units: the D/M Sands (the topmost), the Hauser Sand, around 4,500 feet (1,400 m) below sea level, and the Ogden Sand, around 7,200 feet (2,200 m) below sea level. Beneath the Ogden Sand is a nodular shale unit, also grouped with the Modelo; it contains no oil. Both the Ogden and the Hauser are richly productive, while a few oil-bearing pinch-outs are found in

3201-432: Is the usual practice in current oil fields with nearby gas infrastructure. Operations at this drilling site, known as the "MacFarland Drilling Island" or the "Gilmore Drilling Island", continued until the 1990s. This drilling island contained about 40 wells, and was dismantled beginning in 2001. The former 1-acre (4,000 m) site is on The Grove Drive, across the street and west of Pan-Pacific Park . According to Texaco,

3298-403: Is unusual for being a large, continuously productive field in an entirely urban setting. All drilling, pumping, and processing operations for the 97 currently active wells are done from within four large "drilling islands", visible on Pico and Olympic boulevards as large windowless buildings, from which wells slant diagonally into different parts of the producing formations, directly underneath

3395-917: Is usually necessary to drill into the Earth's crust, although surface oil seeps exist in some parts of the world, such as the La Brea Tar Pits in California and numerous seeps in Trinidad . Factors that affect the quantity of recoverable hydrocarbons in a reservoir include the fluid distribution in the reservoir, initial volumes of fluids in place, reservoir pressure, fluid and rock properties, reservoir geometry, well type, well count, well placement, development concept, and operating philosophy. Modern production includes thermal , gas injection , and chemical methods of extraction to enhance oil recovery. A virgin reservoir may be under sufficient pressure to push hydrocarbons to

3492-577: The Beverly Center , east of San Vicente Boulevard between Beverly Blvd. and 3rd Street. Since normal vertical drilling is impractical in a dense urban environment – active oil wells are loud, malodorous, and generally make poor neighbors – drilling from the tightly clustered wells in the island is directional, with wells slanting into different parts of the formation, similar to the technique used for drilling offshore fields from oil platforms. Only eleven wells, all in this drilling enclosure, remain active of

3589-612: The Ghawar Field in Saudi Arabia and the Burgan Field in Kuwait , with more than 66 to 104 billion barrels (9.5×10 m ) estimated in each. In the modern age, the location of oil fields with proven oil reserves is a key underlying factor in many geopolitical conflicts. Natural gas originates by the same geological thermal cracking process that converts kerogen to petroleum. As

3686-546: The aquatic ecosystem , which is usually a sea but might also be a river, lake, coral reef, or algal mat , the formation of an oil or gas reservoir also requires a sedimentary basin that passes through four steps: Timing is also an important consideration; it is suggested that the Ohio River Valley could have had as much oil as the Middle East at one time, but that it escaped due to a lack of traps. The North Sea , on

3783-407: The buoyancy forces driving the upward migration of hydrocarbons through a permeable rock cannot overcome the capillary forces of a sealing medium. The timing of trap formation relative to that of petroleum generation and migration is crucial to ensuring a reservoir can form. Petroleum geologists broadly classify traps into three categories that are based on their geological characteristics:

3880-610: The Blackbeard site in the Gulf of Mexico. ExxonMobil 's drill rig there had reached 30,000 feet by 2006, without finding gas, before it abandoned the site. Crude oil is found in all oil reservoirs formed in the Earth's crust from the remains of once-living things. Evidence indicates that millions of years of heat and pressure changed the remains of microscopic plants and animals into oil and natural gas. Roy Nurmi, an interpretation adviser for Schlumberger oil field services company, described

3977-643: The D/M sand, which otherwise forms an impermeable cap to the Hauser. The deepest unit in the field which is being pumped is a portion of the Ogden Sands in the East Area of the field, discovered in 1967, which is at an average depth of 10,800 feet (3,300 m). According to BreitBurn Energy, one of the two principal producers on the eastern part of the field, there were 600 million barrels of oil originally in place; since 111 million have been recovered, about 489 million remain. They do not state what percentage of that reserve

Salt Lake Oil Field - Misplaced Pages Continue

4074-556: The Los Angeles basin were growing almost as fast as operators could drill new wells. The eastern portion of the field—known simply as the East Area—is the most productive, and is also the most recently discovered of all the major oil fields in the Los Angeles Basin, as it was not found until 1966. It reached its peak production quickly, within two years of discovery, reporting 11.8 million barrels for 1968. In 1988, BreitBurn Energy bought

4171-645: The Tehachapis in Kern County . In July 1900, W.W. Orcutt drilled into the Wolfskill zone of the Repetto Sands, about 2,500 feet (760 m) below ground surface, discovering the Beverly Hills Field. While the oil was of reasonably good quality—it was light, with a high API gravity between 33 and 60, although with a high sulfur content—development was slow, since the Wolfskill find was relatively small, and other fields in

4268-410: The actual capacity. Laboratory testing can determine the characteristics of the reservoir fluids, particularly the expansion factor of the oil, or how much the oil expands when brought from the high pressure and high temperature of the reservoir to a "stock tank" at the surface. With such information, it is possible to estimate how many "stock tank" barrels of oil are located in the reservoir. Such oil

4365-619: The approximate elevation of this portion of the Los Angeles Basin is about 200 feet). The uppermost producing unit was the first to be discovered, and consists of oil-bearing structures called the Wolfskill Zone, within the Repetto Sands , a Pliocene -age feature principally in the western part of the field. Oil in these sands is mainly found in pinch-out structures, in which oil is trapped in more permeable sub-units within impermeable sands. Underneath this unit, separated by an unconformity ,

4462-530: The area is within the city of Los Angeles, and is heavily urbanized, making the Salt Lake Field one of a very few active oil fields in the United States in an entirely urban setting. While the entire former field area is dotted with abandoned wells , now entirely overbuilt with dense residential and commercial development, all active drilling takes place from a shielded, soundproofed drilling island adjacent to

4559-465: The boreholes going straight down into the target formations. Since this method of field development is not possible in a large city with no open land, all the wells tapping into the Beverly Hills field are clustered into four drilling islands—oil production and processing facilities tightly packed into windowless, soundproofed buildings—so as to have a minimal impact on adjacent land uses. The westernmost of these buildings, containing wells and which accesses

4656-459: The boundary between the basin and the mountains. Several other faults cut through the field, including the 3rd Street Fault and the 6th Street Fault; the latter of these is presumed to be the conduit through which crude oil has emerged on the surface as the La Brea Tar Pits , which are at Hancock Park at the southern boundary of the oil field, near Wilshire Boulevard . A layer of sediments of Quaternary age, both alluvial and shallow marine, forms

4753-605: The bounds of the Beverly Hills Oil Field . The only active operator is also Plains Exploration and Production; as of 2009, there were 16 active wells in the South Salt Lake field. The field is near the northern edge of the Los Angeles Basin , about two miles (3 km) south of the Hollywood Hills , the nearest portion of the Santa Monica Mountains . The Santa Monica Fault, not known to be active, demarcates

4850-414: The designated West Area of the field, is on the grounds of Beverly Hills High School at the corner of Olympic Boulevard and Heath Avenue, just southeast of the baseball diamond. This facility also houses storage tanks, several oil-water separator units, a pump house, compressor house, and an office building. A facility similar to the one adjacent to Beverly Hills High School, operated by BreitBurn Energy,

4947-605: The discovery well – depth, exact location, production rate – are not known. Development of the field was fast, as oil wells spread across the landscape, with drillers hoping to match the production boom taking place a few miles to the east at the Los Angeles City field. Peak production was in 1908. By 1912, there were 326 wells, 47 of which had already been abandoned, and by 1917 more than 450, which had by then produced more than 50 million barrels of oil. After this peak, production declined rapidly. Land values rose, corresponding to

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5044-502: The drilling island, currently hidden behind sound walls. Samples of air taken near the site by the South Coast Air Quality Management District (AQMD) showed nothing unusual, and the cases were thrown out in 2006 and 2007. The judge who dismissed the cases, Superior Court Judge Wendell Mortimer Jr. said that he was unpersuaded that the facility caused any harm, and also "found no evidence that the school district

5141-493: The east are the Los Angeles City Oil Field and Los Angeles Downtown Oil Fields, the former one of the earliest to be drilled in the basin, and the one responsible along with the Salt Lake Field for the early twentieth-century oil boom in the area. Abutting the field to the southwest is the recently discovered and still active South Salt Lake Oil Field. The land above the two oil fields has a mean elevation of approximately 200 feet (61 m) above sea level, and slopes gently towards

5238-404: The fast growth of the adjacent city of Los Angeles, and the field was mostly idled in favor of housing and commercial development. The early wells were abandoned; many of their exact locations are not known, and are now covered with buildings and roads. By the 1960s, new developments in slant drilling technology were making possible exploitation of otherwise unrecoverable petroleum resources, and

5335-416: The fault, as well as the old wellbores – until it reached the ground surface. Isotopic analysis of the near-surface methane supported this theory, as the specific isotope distributions did not match what would have been expected had the gas been recently produced by a recent biogenic mechanism, and they correlated strongly with isotopic analysis of oil field gas. This finding had enormous implications for all of

5432-482: The field, but 8,732,941 barrels of water . Of this, 7,280,887 barrels were reinjected back into the reservoir. Since many of the residents of the area own the mineral rights to their properties, they are entitled to royalty payments from the oil produced from underneath their land. In 1975, there were 6,200 individuals getting such payments. Development of the field has not been without controversy. The drilling island adjacent to Beverly Hills High School occasioned

5529-546: The foundation. 34°04′24″N 118°21′12″W  /  34.0733°N 118.3532°W  / 34.0733; -118.3532 Beverly Hills Oil Field The Beverly Hills Oil Field is a large and currently active oil field underneath part of the US cities of Beverly Hills, California , and portions of the adjacent city of Los Angeles . Discovered in 1900, and with a cumulative production of over 150 million barrels of oil, it ranks 39th by size among California's oil fields, and

5626-457: The gas before it could attain explosive concentrations. In 1989, a similar methane gas buildup occurred underneath 3rd Street and adjacent buildings, probably because of the accidental plugging of a gas-venting well built after the Ross incident. Since the venting well had become clogged with a buildup of debris, methane slowly collected under the street and adjacent impermeable surfaces, bursting out on

5723-402: The gas bubbles drive the oil to the surface. The bubbles then reach critical saturation and flow together as a single gas phase. Beyond this point and below this pressure, the gas phase flows out more rapidly than the oil because of its lowered viscosity. More free gas is produced, and eventually the energy source is depleted. In some cases depending on the geology the gas may migrate to the top of

5820-407: The geology of the underlying rock allows, meaning that certain fields can be far away from civilization, including at sea. Creating an operation at an oil field can be a logistically complex undertaking, as it involves the equipment associated with extraction and transportation, as well as infrastructure such as roads and housing for workers. This infrastructure has to be designed with the lifespan of

5917-599: The grounds of the Hillcrest Country Club about 500 feet (150 m) south of the intersection of Pico Boulevard and Century Hill East, is a fourth, smaller drilling island, operated by Hillcrest Beverly Oil Corp. This small drilling island includes 12 active wells directionally drilled into the Beverly Hills Oil Field, as well as several others drilled into the Cheviot Hills Field. The operators of

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6014-449: The last oil company to own it, the site had become uneconomic to operate; towards the end the depleted oil field was only yielding about 30 barrels of oil a day from that location. With the shutting down of the Gilmore drilling island, royalty payments to many of the property owners of the land directly over the field ended. Some of them had been receiving monthly checks for as much as $ 2,500,

6111-434: The liquid sections applying extra pressure. This is present in the reservoir if there is more gas than can be dissolved in the reservoir. The gas will often migrate to the crest of the structure. It is compressed on top of the oil reserve, as the oil is produced the cap helps to push the oil out. Over time the gas cap moves down and infiltrates the oil, and the well will produce more and more gas until it produces only gas. It

6208-438: The location of oil-water contact and with it the height of the oil bearing sands. Often coupled with seismic data, it is possible to estimate the volume of an oil-bearing reservoir. The next step is to use information from appraisal wells to estimate the porosity of the rock. The porosity of an oil field, or the percentage of the total volume that contains fluids rather than solid rock, is 20–35% or less. It can give information on

6305-413: The methane gas was controversial; early theories involved a biogenic origin for the methane, in which it was seen as the product of decomposition of organic matter from an old swamp. In this scenario, a rising water table forced the gas from the pore spaces within the soil upwards to the surface. A later theory, and the one now accepted, was that the gas originated in the oil field itself, and had migrated to

6402-444: The more than 450 once scattered over the landscape now known as Midtown Los Angeles. Other wells within the enclosure produce from the adjacent San Vicente and Beverly Hills fields. The adjacent South Salt Lake Oil Field is much smaller than its northern neighbor. Discovered in 1970, and only about a mile long by a thousand feet across, this field is exploited entirely from an urban drillsite at Genesee Avenue and Pico Boulevard within

6499-437: The morning of Tuesday, February 7, 1989, in a fountain of mud, water, and methane gas; no explosion occurred, since there was no source of ignition, and city emergency crews quickly cordoned off the area. To prevent similar incidents, Los Angeles further upgraded their City Building Code to require new buildings to have adequate venting systems, and be underlain with an impermeable membrane to prevent methane from getting in beneath

6596-561: The multimillion-dollar residences and commercial structures of one of the wealthiest cities in the United States. Annual production from the field was 1.09 million barrels in 2006, 966,000 barrels in 2007, and 874,000 in 2008, and the field retains approximately 11 million barrels of oil in reserve, as estimated by the California Department of Conservation . The largest operators as of 2009 were independent oil companies Plains Exploration & Production and BreitBurn Energy. While

6693-465: The night of March 24, 1985, when a Ross clothing store filled with gas overnight and exploded, injuring 23 people. Seepage of methane upwards along conduits, such as faults and old well boreholes, caused an explosion at a Ross Dress for Less store in 1985 on 3rd Street in the Fairfax District which injured 23 people. The Ross Dress for Less store still stands in the 6200 block of 3rd Street, on

6790-438: The oil and form a secondary gas cap. Some energy may be supplied by water, gas in water, or compressed rock. These are usually minor contributions with respect to hydrocarbon expansion. By properly managing the production rates, greater benefits can be had from solution-gas drives. Secondary recovery involves the injection of gas or water to maintain reservoir pressure. The gas/oil ratio and the oil production rate are stable until

6887-436: The oil field in mind, as production can last many years. Several companies, such as Hill International , Bechtel , Esso , Weatherford International , Schlumberger , Baker Hughes and Halliburton , have organizations that specialize in the large-scale construction of the infrastructure to support oil field exploitation. The term "oilfield" can be used as a shorthand to refer to the entire petroleum industry . However, it

6984-454: The oil field is unusual for being entirely within the confines of a large city, it is but one of many in the Los Angeles basin which are now overbuilt by dense residential and commercial development. The field is long and narrow, about four miles (6 km) long by a half-mile to mile across. Its long axis is aligned in a generally east-west direction, extending from the vicinity of the intersection of Santa Monica Boulevard and Beverly Glen on

7081-628: The oil field. The field is a faulted anticlinal structure with oil trapped by a combination of structural and stratigraphic mechanisms. Bounding the field on the south is the Brentwood-Las Cienegas Fault, and the field ends on the west near the Santa Monica Fault Complex. The minimum depth to the larger deposits of profitably extractable oil varies from about 5600 to about 7,200 feet (2,200 m) below ground surface, or 5400 to 7,000 feet (2,100 m) below sea level (as

7178-724: The other hand, endured millions of years of sea level changes that successfully resulted in the formation of more than 150 oil fields. Although the process is generally the same, various environmental factors lead to the creation of a wide variety of reservoirs. Reservoirs exist anywhere from the land surface to 30,000 ft (9,000 m) below the surface and are a variety of shapes, sizes, and ages. In recent years, igneous reservoirs have become an important new field of oil exploration, especially in trachyte and basalt formations. These two types of reservoirs differ in oil content and physical properties like fracture connectivity, pore connectivity, and rock porosity . A trap forms when

7275-406: The placement of the well with respect to the gas cap. As with other drive mechanisms, water or gas injection can be used to maintain reservoir pressure. When a gas cap is coupled with water influx, the recovery mechanism can be highly efficient. Water (usually salty) may be present below the hydrocarbons. Water, as with all liquids, is compressible to a small degree. As the hydrocarbons are depleted,

7372-431: The preferential mechanism of leaking: the hydraulic seal and the membrane seal. A membrane seal will leak whenever the pressure differential across the seal exceeds the threshold displacement pressure, allowing fluids to migrate through the pore spaces in the seal. It will leak just enough to bring the pressure differential below that of the displacement pressure and will reseal. A hydraulic seal occurs in rocks that have

7469-429: The pressure. As the reservoir depletes, the pressure falls below the bubble point , and the gas comes out of solution to form a gas cap at the top. This gas cap pushes down on the liquid helping to maintain pressure. This occurs when the natural gas is in a cap below the oil. When the well is drilled the lowered pressure above means that the oil expands. As the pressure is reduced it reaches bubble point, and subsequently

7566-485: The process as follows: Plankton and algae, proteins and the life that's floating in the sea, as it dies, falls to the bottom, and these organisms are going to be the source of our oil and gas. When they're buried with the accumulating sediment and reach an adequate temperature, something above 50 to 70 °C they start to cook. This transformation, this change, changes them into the liquid hydrocarbons that move and migrate, will become our oil and gas reservoir. In addition to

7663-491: The reduction in pressure in the reservoir allows the water to expand slightly. Although this unit expansion is minute, if the aquifer is large enough this will translate into a large increase in volume, which will push up on the hydrocarbons, maintaining pressure. With a water-drive reservoir, the decline in reservoir pressure is very slight; in some cases, the reservoir pressure may remain unchanged. The gas/oil ratio also remains stable. The oil rate will remain fairly stable until

7760-408: The reservoir pressure drops below the bubble point when critical gas saturation is reached. When the gas is exhausted, the gas/oil ratio and the oil rate drops, the reservoir pressure has been reduced, and the reservoir energy is exhausted. In reservoirs already having a gas cap (the virgin pressure is already below bubble point), the gas cap expands with the depletion of the reservoir, pushing down on

7857-409: The reservoir, leading to an improved estimate of the recoverable resources. Reserves are only the part of those recoverable resources that will be developed through identified and approved development projects. Because the evaluation of reserves has a direct impact on the company or the asset value, it usually follows a strict set of rules or guidelines. To obtain the contents of the oil reservoir, it

7954-410: The rock fabric by strong capillary forces, requiring specialised measures for evaluation and extraction. Unconventional reservoirs form in completely different ways to conventional reservoirs, the main difference being that they do not have "traps". This type of reservoir can be driven in a unique way as well, as buoyancy might not be the driving force for oil and gas accumulation in such reservoirs. This

8051-419: The rocks have high porosity and low permeability, which keeps the hydrocarbons trapped in place, therefore not requiring a cap rock . Reservoirs are found using hydrocarbon exploration methods. An oil field is an area of accumulated liquid petroleum underground in multiple (potentially linked) reservoirs, trapped as it rises to impermeable rock formations. In industrial terms, an oil field implies that there

8148-410: The source, the "drier" the gas (that is, the smaller the proportion of condensates in the gas). Because both oil and natural gas are lighter than water, they tend to rise from their sources until they either seep to the surface or are trapped by a non-permeable stratigraphic trap. They can be extracted from the trap by drilling. The largest natural gas field is South Pars/Asalouyeh gas field, which

8245-530: The south-southwest, away from the Santa Monica Mountains, draining via Ballona Creek towards Santa Monica Bay in the Pacific Ocean. The productive region of the field is approximately three miles long by one mile across, with the long axis west to east along and parallel to Beverly Boulevard , from near its intersection with La Cienega Boulevard to past its intersection with Highland Avenue . All of

8342-438: The southeast corner of Ogden Ave. and 3rd. Overnight on March 24, 1985, methane gas filled an auxiliary room at the store and ignited, causing a spectacular explosion which blew out the windows and tore the roof off of the building, injuring 23 people, and reducing the inside to rubble. In addition to blowing up the building, the methane explosion burst out portions of the adjacent parking lot and sidewalks, venting burning gas over

8439-454: The structural trap, the stratigraphic trap, and the far less common hydrodynamic trap . The trapping mechanisms for many petroleum reservoirs have characteristics from several categories and can be known as a combination trap. Traps are described as structural traps (in deformed strata such as folds and faults) or stratigraphic traps (in areas where rock types change, such as unconformities, pinch-outs and reefs). Structural traps are formed as

8536-404: The surface along a combination of the 3rd Street Fault and any number of improperly abandoned boreholes from the hundreds of now-lost wells drilled in the early years of the twentieth century. The reinjection of wastewater into the field to increase oil recovery increased the reservoir pressure to the point that gas was forced upwards along the paths of least resistance – newly formed fractures along

8633-452: The surface. As the fluids are produced, the pressure will often decline, and production will falter. The reservoir may respond to the withdrawal of fluid in a way that tends to maintain the pressure. Artificial drive methods may be necessary. This mechanism (also known as depletion drive) depends on the associated gas of the oil. The virgin reservoir may be entirely semi-liquid but will be expected to have gaseous hydrocarbons in solution due to

8730-433: The urban development over old oil fields, and resulted in the construction of gas monitoring and venting wells in several locations in Los Angeles. The city of Los Angeles designated approximately 400 blocks overlying the old oil field as a "High Potential Methane Zone" as a result of the 1985 explosion and subsequent investigation, and later required all structures to have a methane detector, to give warning of accumulation of

8827-626: The urban fields in Los Angeles, such as the Salt Lake field, began to attract the attention of enterprising oil companies. In 1961, working from a drilling site near the Farmer's Market at the corner of 3rd Street and Fairfax Avenue , the Standard Oil Company of California again began to draw oil from the field, having recently discovered three new productive sand units (pools "D", "E", and "F"). Wells drilled into these producing horizons flowed without assistance only briefly, requiring pumping within

8924-487: The volume of water pumped from the reservoir often exceeds that of crude oil; while oil fields in isolated areas often use large evaporation ponds for water disposal, that luxury is not available for crowded urban sites with higher environmental standards. For example, in 2008, the California Department of Conservation, Division of Oil, Gas, and Geothermal Resources (DOGGR) reported 882,953 barrels of oil produced from

9021-407: The water begins to be produced along with the oil, the recovery rate may become uneconomical owing to the higher lifting and water disposal costs. If the natural drives are insufficient, as they very often are, then the pressure can be artificially maintained by injecting water into the aquifer or gas into the gas cap. The force of gravity will cause the oil to move downward of the gas and upward of

9118-431: The water reaches the well. In time, the water cut will increase, and the well will be watered out. The water may be present in an aquifer (but rarely one replenished with surface water ). This water gradually replaces the volume of oil and gas that is produced out of the well, given that the production rate is equivalent to the aquifer activity. That is, the aquifer is being replenished from some natural water influx. If

9215-442: The water. If vertical permeability exists then recovery rates may be even better. These occur if the reservoir conditions allow the hydrocarbons to exist as a gas. Retrieval is a matter of gas expansion. Recovery from a closed reservoir (i.e., no water drive) is very good, especially if bottom hole pressure is reduced to a minimum (usually done with compressors at the wellhead). Any produced liquids are light-colored to colorless, with

9312-520: The west, east along Pico Boulevard , past La Cienega and Fairfax Avenue , to around the intersection of Pico and Hauser. From north to south the field is much narrower, extending near the middle of the field from near Monte Mar Drive in Los Angeles to about two blocks north of Olympic Boulevard in Beverly Hills. The total productive area of the field, projected to ground surface, covers about 1,200 acres (4.9 km ). In most oil fields, wells are drilled at optimum spacing for petroleum extraction with

9409-473: Was aware of any danger." Additionally, the University of Southern California Medical School stated that the particular cancers noted in the lawsuits are not known to be caused by exposure to petroleum and its byproducts. 34°03′23″N 118°23′22″W  /  34.0563°N 118.3894°W  / 34.0563; -118.3894 Petroleum reservoir A petroleum reservoir or oil and gas reservoir

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