Ventura Oil Field facts for kids
The Ventura Oil Field is a big area where oil is found. It is located in the hills just north of Ventura in southern California. A main road, California State Route 33, goes right through it. This road connects Ventura to Ojai. The oil field is about 13 kilometers (8 miles) long and 3 kilometers (2 miles) wide. It runs from east to west.
Oil was first found here in 1919. By 2008, almost a billion barrels of oil had been taken out. This makes it the tenth-largest oil field in California. It still has about 50 million barrels of oil left. In 2009, Aera Energy LLC was in charge of all the operations at the field.
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Where is the Ventura Oil Field Located?
The Ventura Oil Field is in the hills around the city of Ventura. The Ventura River flows through the field and into the Pacific Ocean. The hills here have plants like chaparral and coastal sage scrub. These are tough plants that can live in dry areas. Along the Ventura River, you can find trees and other plants that like water.
The land in the hills is very steep. Roads for oil wells and tanks wind up and down the hills. Most of the oil field is hidden from the city by the first row of hills. The Ventura Oil Field is one of several oil fields in this area. Other nearby fields include San Miguelito Oil Field and Rincon Oil Field to the west. To the east are the South Mountain Oil Field and the Saticoy Oil Field. The total area of the field is about 3,410 acres (13.8 square kilometers).
California State Route 33 helps people get to the oil field. Other roads also lead from Ventura city to the field.
The weather here is like the Mediterranean climate. This means cool, rainy winters and mild, dry summers. The ocean helps keep the summers cool with morning clouds. The oil field is at different heights. It ranges from about 12 meters (40 feet) above sea level near the Ventura River to about 365 meters (1,200 feet) on the highest hills. Rainwater from the field flows into the Ventura River. Some eastern parts of the field drain into the Santa Clara River.
How Was the Ventura Oil Field Formed?
The main reason oil collects in the Ventura field is a large underground rock fold. This fold is called the Ventura Anticline. It is a geological structure about 26 kilometers (16 miles) long. You can see parts of it in the rocky hills. This anticline looks like a long house with a gabled roof. Oil and gas gather in large amounts under this "roof."
The main rock layer that holds oil is called the Pico Formation. This layer is made of sedimentary rock called turbidite sands. These sands have many small spaces, like a sponge, which can hold oil. Oil is also found in the Santa Margarita Formation below it.
Scientists have found eight different oil-rich areas, called zones, in the field. They are numbered 1st through 8th based on how deep they are. The 2nd zone was the first one found by Shell Oil Company in March 1919. These oil zones are found at depths from 1,120 meters (3,680 feet) to over 3,650 meters (12,000 feet).
The oil in the Ventura field likely came from the Monterey Formation. This rock layer is rich in organic material, which turns into oil over millions of years. The oil probably moved upwards and got trapped in the folded rocks above. Some oil zones are also trapped by a fault, which is a break in the rock, called the Barnard Fault.
Even with these traps, some oil naturally leaks out. These are called natural tar seeps. The native Chumash people used this natural tar to seal their boats. The oil in all the zones is similar. It has an API gravity of 29-30, which describes its density. It also has about 1 percent sulfur.
History of Oil Production
People first started working in this area in 1885. In 1903, the Ventura County Power Company drilled seven shallow gas wells. It is not known if these wells produced oil. In May 1916, the first well that produced oil for sale was drilled. It was called "Lloyd" 1 and went down 779 meters (2,555 feet). It produced 100 barrels of oil each day. Shell Oil drilled the first well into the 2nd Pool in March 1919. This well reached a depth of 1,066 meters (3,498 feet).
The discovery of oil led to a big growth in Ventura in the 1920s. More people moved there. Cars became more affordable, and new roads were built to Los Angeles and Santa Barbara.
The Ventura Oil Field was productive from the start. But it was also very challenging for early drillers. In 1928, the Lloyd No. 102 well was the deepest producing well in the world. It produced oil from 2,197 meters (7,210 feet) deep. Later, wells went even deeper. Shell Oil Company's Taylor 653 well reached 6,553 meters (21,500 feet). It went into the Monterey Formation but did not find oil at that depth. The oil found in deeper areas was very hot. For example, oil in the 4th zone was about 149°C (300°F).
Oil production at the field was highest in the 1950s. In 1954, the field produced over 31 million barrels of oil. After 1954, production started to slow down. New methods were used to get more oil out. One method is called waterflooding. This is when water that has been produced from the wells is put back into the ground. This helps push more oil out of the rocks. Waterflooding started in the late 1950s and 1960s and is still used today.
Today, Aera Energy LLC operates the entire field. Aera Energy is a partnership between ExxonMobil and Shell Oil Company. In 2009, Aera was producing about 11,600 barrels of oil each day from the field. This made them the largest oil and gas producer in Ventura County. In 2016, Aera reported producing 14,000 barrels of crude oil and 7.8 billion cubic feet of natural gas per day. This came from 414 wells in an area of 4,300 acres (1,740 hectares).
Images for kids
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The Ventura Oil Field in Ventura County, California. Other oil fields are shown in dark gray.
