The Summerland Oil Field (and Summerland Offshore Oil Field) is an inactive oil field in Santa Barbara County, California, about four miles (6 km) east of the city of Santa Barbara, within and next to the unincorporated community of Summerland. First developed in the 1890s, and richly productive in the early 20th century, the Summerland Oil Field was the location of the world's first offshore oil wells, drilled from piers in 1896. This field, which was the first significant field to be developed in Santa Barbara County, produced 3.18 million of barrels of oil during its 50-year lifespan, finally being abandoned in 1939-40. Another nearby oil field entirely offshore, discovered in 1957 and named the Summerland Offshore Oil Field, produced from two drilling platforms in the Santa Barbara Channel before being abandoned in 1996.
Setting
The formerly productive region of the Summerland Oil Field is on the coast of southern Santa Barbara County, about four miles (6 km) east of the city of Santa Barbara, and includes most of the town of Summerland, as well as adjacent parts of Montecito. It covers an area of a bit more than a square mile – – of which 380, a little more than half, is onshore.
The climate is Mediterranean, with an equable temperature regime year-round, and most of the precipitation falling between October and April in the form of rain. Freezes are rare. Runoff is towards the ocean. Bluffs rise sharply behind the beach, but rather than having an extended plateau behind the bluffs, as is the case along much of the south coast of Santa Barbara County, the land rises with a moderate slope towards the Santa Ynez Mountains. The town of Summerland is built on the coast-facing part of this hillside, taking advantage of the ocean view, with modern residential and commercial development covering long-abandoned oil wells. The offshore part of the main Summerland field was in shallow water adjacent to the beach, and was drilled from piers. A popular beach extends the length of the former oil field, immediately below the town, and a park – Lookout Park – sits atop the bluffs.
Summerland Offshore Oil Field is a separate field in the Santa Barbara Channel about one and a half miles offshore, but within the 3-mile limit inside of which oil leasing is subject to state rather than federal regulation. Two oil platforms, named Hilda and Hazel, formerly stood on this field; Chevron Corp. dismantled them in 1996 and production from this field ended. The Carpinteria Offshore Oil Field, about four miles (6 km) to the southeast, also once contained a pair of platforms dismantled that same year, and its three remaining platforms outside the limit are visible from the shore at Summerland.
Geology
The Summerland field is contained in a series of sedimentary rock units in a trough known as the Carpinteria Basin. Oil is trapped in the Pleistocene-age Casitas Formation underneath impermeable sediments, although petroleum regularly makes its way to the surface in the form of asphalt seeps, here as elsewhere on the south coast of Santa Barbara County. Another unit underneath the Casitas Formation, the Oligocene-age Vaqueros Sandstone, also has considerable quantities of petroleum, with the capping unit being the impermeable Miocene-age Rincon Formation.
Oil in the Casitas Formation is shallow, at an average depth of only , accounting for its early discovery and easy exploitation. In the Vaqueros formation the average depth to oil is in the main Summerland field, and in the Summerland Offshore field.
History, operations, and production
Oil and asphalt seeps in the vicinity of the Summerland field were known since prehistoric times, as the native Chumash peoples used tar from this spot and other similar seeps as sealant for their tomols, the watercraft with which they skilfully navigated the Santa Barbara Channel. Sometime before 1894, enterprising petroleum prospectors recognized the likelihood that economically viable deposits of oil and gas were the source for these seeps, and began digging. The first finds of petroleum were extremely heavy oil – API gravity of 7, so essentially asphalt – but undeterred, they continued searching for more marketable oil. The earliest known oil well in the vicinity of Summerland dates from 1886, and was drilled on the side of Ortega Hill, the topographic prominence just west of Summerland. While the well failed to produce marketable quantities of oil, it showed that there were indeed petroleum-bearing strata only several hundred feet below ground surface – well within the reach of late 19th-century drilling technology.