page_title: Ellwood Oil Field
section_title: Geology
hierarchical_section_title: Ellwood Oil Field / Geology
caption_attribution_description: English: Elwood Oil Field Structure Map
context_page_description: Ellwood Oil Field and South Ellwood Offshore Oil Field are a pair of adjacent, partially active oil fields adjoining the city of Goleta, California, about twelve miles west of Santa Barbara, largely in the Santa Barbara Channel. A richly productive field in the 1930s, the Ellwood Oil Field was important to the economic development of the Santa Barbara area. The Japanese submarine I-17 shelled the area during World War II, the first direct naval bombardment of the U.S. continent of the war, causing an invasion scare on the West Coast.
context_section_description: The Ellwood Oil Field is roughly five miles long and up to a mile wide, with both its eastern and western extremity onshore. It is an anticlinal structure, with oil trapped stratigraphically by the anticline. The More Ranch Fault provides an impermeable barrier on the northeast. Oil occurs in several pools, with the largest being in the Vaqueros Sandstone, approximately 3,400 feet (1,000 m) below ground surface. Other significant pools occur in the Rincon Formation at a depth of 2,600 feet (790 m), and in the Upper Sespe Formation at 3,700 feet (1,100 m) below ground surface.
  The Ellwood Oil Field contained approximately 106 million barrels (16,900,000 m³) of oil, almost all of which has been removed, to the degree possible with the technology available until the early 1970s. The field now has been abandoned. The South Ellwood Offshore field has been estimated by the US Department of Energy to hold over one billion barrels of oil  and approximately 2.1 billion barrels (330,000,000 m³), most of which is in the undeveloped portion of the field.  In 1995, the Oil and Gas Journal reported 155 million barrels (24,600,000 m³) of proven reserves.
  Oil from the Ellwood field was generally light and sweet, with an API gravity averaging 38 and low sulfur content (making it "sweet" in petroleum parlance). Oil from the offshore field is medium-grade, ranging from API gravity 25 to 34, and has a higher sulfur content, requiring more processing than the oil from the decommissioned onshore field.
  Several pools have been identified in the South Ellwood Offshore field, in three major vertical zones. The upper Monterey Formation contains a large pool in a zone of fractured shale at an average depth of 3,350 feet (1,020 m) below the ocean floor. Beneath that, a separate pool exists in the Rincon Sand, 5,000 feet (1,500 m) below the ocean floor, and yet another in the Vaqueros Formation at a depth of 5,900 feet (1,800 m). The deepest well drilled to date is 6,490 feet (1,980 m) into the Rincon Formation.
caption: Elwood Oil Field Structure Map
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