Coal Oil Point seep field
The Coal Oil Point seep field offshore from Santa Barbara, California is a petroleum seep area of about three square kilometres, adjacent to the Ellwood Oil Field, and releases 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. 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.
This seep also releases on the order of 100 to 150 barrels (16 to 24 m3) of liquid petroleum per day. The field produces about 9 cubic meters of natural gas per barrel of petroleum.
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.
Written records, dating from as early as 1792, describe effects of offshore seeps in the Santa Barbara Channel. Oil and tar "slicks" have long been a trademark of the area. In 1792, Captain Cook's navigator George Vancouver recorded on passing through the Channel (Imray, 1868):
Coordinates: 34°24′0″N 119°53′0″W / 34.40000°N 119.88333°W
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