McKittrick Oil Field

The oil field is in the McKittrick Valley and the adjacent foothills of the Temblor Range at the western edge of the San Joaquin Valley. California State Route 33 and 58 intersect at the town of McKittrick, and both routes cross over portions of the field. The climate is hot and arid to semi-arid, with an average annual rainfall of , and summertime highs commonly exceeding . Some subfreezing temperatures occur in the winter, with the mean freeze-free period being from 250 to 275 days. Drainage is to the northeast, away from the Temblors towards the Central Valley, and streams are dry for most of the year. The predominant vegetation in the vicinity of the field is low scrub, in particular the saltbush Atriplex lentiformis. Elevations on the field range from approximately . Many other productive oil fields are nearby. Adjacent to the north is the enormous, and densely developed Cymric Oil Field, and beyond that the South Belridge Oil Field; to the east is the Elk Hills Oil Field, famous in the Teapot Dome Scandal of the Warren G. Harding administration; adjacent to the southwest is the Belgian Anticline Oil Field, along Route 58; and to the southeast is the huge Midway-Sunset Oil Field, the third largest oil field in the United States. The total productive area of the field is . The field is about long on the southeast to northwest axis, and about across. ==Geology and paleontology==

The predominant geologic feature, and the one that makes the McKittrick field distinctive, is the presence of a huge block of Monterey shale – more than long, approximately wide, and up to thick – which slipped off of the slopes of the adjacent Temblor Range during the Pleistocene and moved eastward onto the plain, almost entirely covering the field, and forming an impermeable cap over the oil-bearing rock. This mass of stone, consisting of over of rock, moved from its source region, and down about in elevation. While it probably did not move into its present position all at once, the incident must have been dramatic. Another unusual feature of the McKittrick field is its large tar seeps, points on the surface where petroleum has migrated upwards, forming pools. In California, the McKittrick Tar Pits are second only to the La Brea Tar Pits in fame, and have yielded dozens of skeletons of extinct megafauna with ages from about 10,000 to 40,000 years. The tar seeps outcrop in an area about long, adjacent to the McKittrick Thrust Fault, which defines the southwestern boundary of the oil field. They are found in areas where the overlying Monterey formation, which tumbled down the Temblors during the Pleistocene, eroded away, exposing the oil-bearing strata. When oil reaches the surface, it is exposed to biodegradation, evaporation, and oxidation, forming asphaltum. This series of tar seeps is the most extensive in the state, although none of the individual seeps are as large as the La Brea Tar Pits. Oil in the McKittrick field is in 13 separate pools: eight in the Northeast Area, and five in the Main Area. The most productive pools have been the Tulare-San Joaquin, Olig, and Basal Reef Ridge in the Main Area, and the Tulare-San Joaquin, Phacoides, and Oceanic in the Northeast Area. Oil API gravity varies between the different pools, with some bearing heavy crude of API gravity 12, and others with lighter oil, such as the Phacoides which reported an average value of 33. Enhanced recovery techniques such as fire flooding and steam flooding have been used since the 1960s to improve recovery of the heavier oils, while water flooding was used in the 1970s and early 1980s in the Phacoides to improve recovery (with limited success, as that pool peaked in 1966). Major paleontological study of the remains in the tar pits began in 1921 with the first large road cut through the area. Skeletons of many now-extinct mammals have been recovered, including camels, mammoths, dire wolves, saber toothed cats, deer, and bison. Bird species found include ducks, storks, herons, and various shorebirds – mainly species adapted to forage in shallow water. ==History, production, and operations==

with streaks of oil, McKittrick oilfield. There are numerous oil seeps in this area. 2000 photo. The McKittrick Tar Pits have been known to the local Native American population, the Yokuts, from prehistoric times. They used the asphaltum as a sealant, for waterproofing, for decoration, for adhesive, and for trade. Many of the deeper pools were found in the 1960s, and some of them proved not only to have higher quality oil, but were more productive. In the Northeast Area, the Phacoides, Oceanic, and Point of Rocks pools vary from below ground surface; the temperature of the oil varies from at that depth, and the initial reservoir pressures were also high, up to , pressures that would have caused major blowouts and gushers during the early part of the century, but can be better managed with modern technology. As of 2008, there were 1,135 producing oil wells on the field. Producers besides Chevron Corp., the largest, included Aera Energy LLC, Berry Petroleum, Vintage, E & B Natural Resources Management Corp., Plains Exploration & Production, Longbow LLC, and others. ==California Historical Landmark==

California Historical Landmark reads: :NO. 376 CALIFORNIA STANDARD OIL WELL 1 - This well was one of the early wells that in 1899 started a new oil field called the McKittrick Field. The well pumped about 150 barrels of oil per day for the first six months - its last production was in April 1929. ==See also==