Rincon Oil Field facts for kids

The Rincon Oil Field is a large area on the coast of Southern California where oil is found deep underground. It's located about 10 miles (16 km) northwest of Ventura and 20 miles (32 km) east of Santa Barbara. This oil field is the westernmost one on land that follows a long, curved underground rock structure called the Ventura Anticline.

Oil was first found here in 1927. While most of its oil has been used, it's still producing oil today, with 77 active wells in 2008. The oil from Rincon travels through pipelines to refineries near Los Angeles. As of 2009, Occidental Petroleum managed the land-based part of the field, and Greka Energy managed the part under the ocean. The offshore operations are mostly run from Rincon Island, an artificial island.

Where is the Rincon Oil Field Located?

The Rincon Oil Field is in an area with steep hills, which are part of the Santa Ynez Mountains. Some of these hills, like Rincon Mountain and Red Mountain, are over 2,100 feet (640 meters) high. Highway 101 runs along the narrow strip of land where the hills meet the Pacific Ocean. Small streams flow from the hills directly into the ocean, but they only flow when it rains.

This area is very prone to landslides. For example, in 2005, a landslide in the nearby town of La Conchita sadly killed 10 people. During very rainy winters, landslides can even block Highway 101.

The plants that grow here naturally are coastal sage scrub and chaparral. The weather is Mediterranean, meaning it has cool, rainy winters and mild summers. Morning fog and clouds help keep the summers from getting too hot. About 15 inches (38 cm) of rain fall each year, with a bit more in the higher areas.

How Oil is Processed Near Rincon

The Rincon Oil and Gas Processing Facility is next to the oil field, on a flattened hilltop about a mile east of Pitas Point. This facility doesn't process oil from the Rincon field itself. Instead, it handles oil from offshore fields like Dos Cuadras and Carpinteria. This oil then goes into the M-143 pipeline, which passes through the Rincon field on its way to Ventura.

However, a very large tank at this plant, which can hold 268,000 barrels, stores oil from the Rincon field before it's sent through the pipeline.

What is Rincon Island?

The part of the Rincon oil field that is under the ocean is mostly in shallow water. Workers access this part from Rincon Island. This is an artificial island located about two-thirds of a mile (1.1 km) south of Punta Gorda. A 3,000-foot (914 m) long causeway, which is like a narrow bridge, connects the island to the mainland.

This causeway is too narrow for regular cars, but it holds pipelines. These pipelines carry oil, water from the oil field, and natural gas back to the shore. Once on land, these liquids and gases are processed at the La Conchita Oil and Gas Processing Facility.

What is the Geology of the Rincon Oil Field?

The Rincon field is at the western end of the Ventura Anticline. Imagine a long house with a gabled roof; the anticline is a similar long, narrow, upward-curving rock structure underground. Oil has gathered in large amounts beneath this structure. Two other oil fields on land, the San Miguelito field and the huge Ventura Oil Field, also follow this anticline to the southeast.

West of the Rincon field, the anticline continues under the ocean. It holds the Carpinteria offshore field and the Dos Cuadras field. The Dos Cuadras field was the source of the well-known 1969 Santa Barbara oil spill in 1969.

The ground surface around the Rincon field is unique. It includes some of California's most landslide-prone areas. Much of the surface is made of recent landslide deposits, which are very likely to slide again.

Where is the Oil Found?

All the oil-rich layers in the Rincon field are found in the Pico Formation. This is a thick layer of rock that formed from sediments in a shallow ocean between 5.3 and 1.6 million years ago. This formation contains sandstones, siltstones, and conglomerates. These rocks are porous enough under the anticline to hold a lot of oil.

The field is divided into three main parts: the Main Area (west), Oak Grove, and Padre Canyon (east). Each part has several layers where oil is found, all within the Pico Formation. These oil layers range in depth from 3,400 feet (1,036 m) in the shallowest part of the Main Area to about 13,000 feet (3,962 m) deep in the Oak Grove Area. The oil found here is considered "medium-grade."

History and Operations of the Rincon Oil Field

The Rincon field was discovered in December 1927. This was during the end of California's big oil boom, when many of the state's largest oil fields were found and the systems to transport and refine oil were built. The Pan American Petroleum Company drilled the first successful well, called Hobson Fee No. 3. It went down 2,557 feet (780 m) and found oil under high pressure.

More oil discoveries followed in the next few years. While these wells weren't huge gushers, they made enough profit to encourage more drilling. The "Miley" oil-producing layer was found in 1928. Deeper oil zones in the main area were found in 1929, with the deepest at 7,800 feet (2,377 m). Chanslor-Canfield Midway Oil Co. discovered the Oak Grove Area in 1931, and Continental Oil Co. found the Padre Canyon area in 1936. The even deeper oil zones in these areas were not found until about 30 years later.

How Oil Production Changed Over Time

To get more oil out of the ground, a method called waterflooding began in 1961. By the end of the 1960s, most parts of the field were using this method. Waterflooding involves injecting water into the oil-bearing rock to push the oil towards the wells.

The Rincon field produced the most oil in 1972, when over 4.6 million barrels were reported for the year. This was a bit unusual for California oil fields. Often, peak production happens within the first few years after discovery. However, Rincon had a second peak after new technologies like waterflooding were developed in the 1960s.

In 1993, Vintage Petroleum bought the Rincon and nearby San Miguelito oil fields from other companies. To make operations more efficient, Vintage combined these two fields into one managed unit. In 2006, Occidental Petroleum bought Vintage, keeping their name and making them a part of Occidental. Occidental still operates the onshore part of the field under the Vintage name.

In 2002, Greka Energy acquired Rincon Island Limited Partnership. This included Rincon Island and a small land-based area near Highway 101. This onshore area has several wells that are drilled at an angle into the offshore oil formations. Greka continues to operate these facilities as of 2010.

Images for kids

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  Location of the Rincon Oil Field in Southern California. Other oil fields are shown in dark gray.

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  Detail of the Rincon Oil Field, on the Ventura County coast, on an aerial photograph basemap.

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  Map showing the Rincon anticlinal trend.

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  Rincon Oil Field Structure Map

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  Central area of operations on Rincon Island. The island is connected to the mainland by a narrow 3,000-foot (914 m) long causeway.