The Summerland Offshore Oil Field – distinct from the offshore portion of the main Summerland field , as it was more than a mile from shore – was not discovered until 1957 . Its oil was from the same source rock as the deeper pool of the onshore field , the Vaqueros Sandstone , but the API gravity of the oil was lower ( 35 ) allowing it to flow freely . This field was drilled from two oil platforms , Hilda and Hazel , erected in 1958 and 1960 respectively . Platform Hazel was the first platform in California to be constructed onshore and towed to the site by barges . Both were anchored to the sea floor , which was approximately underneath each platform . They produced a cumulative total of 27.6 million barrels of oil and 97.8 million cubic feet of natural gas before being demolished in 1996 . Peak production from the Summerland Offshore field was in 1964 , at almost 3.8 million barrels , but the cost to maintain the operation , combined with the diminishing returns from the field , and public sentiment opposing drilling in the Santa Barbara Channel – as these platforms were close to the site of the notorious 1969 oil spill – led their operator , Chevron Corp. , to shut them down
1969 oil spill
1969 Santa Barbara oil spill
Summerland Oil Field