Coal Oil Point seep field

Platform Holly & oil slick in water, February 2016. Doc Searls, the photographer, a frequent flyer from SB, said this was more oil than he is used to seeing. Oil slicks increase after earthquakes.
Ellwood Oil Fields, sources of the seeps
Tar balls at the beach, Coal Oil Point, looking WNW. This was an unusually heavy accumulation, in June 2003. Inset shows oily sheen from fresh tar balls.

The Coal Oil Point seep field (COP) in the Santa Barbara Channel offshore from Goleta, California, is a marine petroleum seep area of about three square kilometres, within the Offshore South Ellwood Oil Field and stretching from the coastline southward more than three kilometers (1.9 mi). Major seeps are located in water depths from 20 to 80 meters (66 to 262 ft). The seep field is among the largest and best studied areas of active marine seepage in the world. These perennial and continuous oil and gas seeps have been active on the northern edge of the Santa Barbara Channel for at least 500,000 years.[1] The combined seeps in the field release about 40 tons of methane per day and about 19 tons of reactive organic gas (ethane, propane, butane and higher hydrocarbons); about twice the hydrocarbon air pollution released by all the cars and trucks in Santa Barbara County in 1990.[2] The liquid petroleum produces a slick that is many kilometres long and when degraded by evaporation and weathering, produces tar balls which wash up on the beaches for miles around.[3][4]

This seep also releases on the order of 100 to 150 barrels (16 to 24 m3) of liquid petroleum per day.[5] The field produces about 9 cubic meters of natural gas per barrel of petroleum.[4]

Leakage from the natural seeps near Platform Holly, the production platform for the South Ellwood Offshore oilfield, has decreased substantially, probably from the decrease in reservoir pressure due to the oil and gas produced at the platform.[6][4]

  1. ^ Boles, J. R.; Eichhubl, P.; Garven, G.; Chen, J. (2004). "Evolution of a hydrocarbon migration pathway along basin bounding faults: evidence from fault cement". American Association of Petroleum Geologists Bulletin. 88 (7): 947–970. doi:10.1306/02090403040.
  2. ^ J. Scott Hornafius, D. Quigley and B, P, Luyendyk, "The world's most spectacular marine hydrocarbon seeps (Coal Oil Point, California): quantification of emissions," Journal of Geophysical Research, v.104, n.C9, 15 September 1999, p.20,709
  3. ^ Leifer, I.; Luyendyk, B. P.; Broderick, K. (2006). "Tracking an oil slick from multiple natural sources, Coal Oil Point, California". Journal of Marine and Petroleum Geology. 23 (5): 621–630. doi:10.1016/j.marpetgeo.2006.05.001.
  4. ^ a b c UCSB Hydrocarbon Seeps project
  5. ^ Panzar, Javier; Serna, Joseph; Hamilton, Matt (July 29, 2015). "Big oil slick off Santa Barbara County coast sparks new concerns". Los Angeles Times.
  6. ^ Quigley, D. C.; Hornafius, J. S.; Luyendyk, B. P.; Francis, R. D.; Clark, J.; Washburn, L. (1999). "Decrease in Natural Marine Hydrocarbon Seepage near Coal Oil Point, California Associated with Offshore Oil Production". Geology. 27 (11): 1047–1050. Bibcode:1999Geo....27.1047Q. doi:10.1130/0091-7613(1999)027<1047:DINMHS>2.3.CO;2.