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From oil well to gas tank

August 03, 2005

California's oil refineries produce 90% of the gasoline sold in the state, and the price at the pump can spike sharply if one of the sites experiences a major production problem. Each year, about 17 billion gallons of gasoline are manufactured here, a total that exceeds the output of every country except the United States.



Refining the oil

A refinery is a sophisticated factory that uses heat and chemicals to break down oil's thousands of kinds of hydrocarbons. It takes three or four days for a 42-gallon barrel of crude oil to travel through the refinery's many processing units, resulting in about 20 gallons of gasoline and 24 gallons of other petroleum products.


Process of making oil into gasoline

1. Transportation: Crude oil transported by tanker and pipeline to refinery.

Most of California's nearly 100 terminals are marine terminals. At these facilities, petroleum is transferred from or to tankers or barges.

2. Boiler: Petroleum heated to high temperatures.

Safety flares eliminate excess fuel gas, turning hydrocarbon vapors into water vapor and carbon dioxide.

3. Distillation tower: Hydrocarbons, each with its own boiling point, rise like steam from a tea kettle into a distillation tower that is cooler at the top. Vapors turn to liquid as they cool. Liquids are collected in trays and piped to other units.

Oil products:

Liquid gas (heating, cooking, plastics)

Naphtha (reprocessed to make gasoline)


Kerosene (jet and tractor fuel)*

Lubricating oil (motor oil, lubricants)

Diesel (diesel fuel and heating oil)*

Heavy gas oil (industrial fuel)*

Residual (coke, asphalt, tar, waxes)*

4. Reprocessing unit: Leftover substances are reprocessed by heat or chemical process to make gasoline components. Impurities such as sulfur and nitrogen are removed.

5. Blender unit: Components to make specific types of gasoline are mixed in a machine that functions as a giant blender.

6. Delivery: The gasoline is piped to terminals, where tanker trucks pick it up for delivery to service stations.

*Starting material for making other products


History of the state's refineries

1861: First oil well in California is drilled manually in Humboldt County.

1866: First steam-powered rig in California drills an oil well in Ojai.

1900: Standard Oil buys Pacific Coast Oil Co. and funds the largest refinery in California in Richmond.

1911: El Segundo is selected as the site for the second refinery in the state.

1929: Blowout prevention equipment becomes mandatory on oil and gas wells drilled in California.

1980s: Cogeneration, a process in which a refinery uses its waste energy to produce heat or electricity, hastens the spread of projects using steam to recover more oil from wells, which dramatically increases oil production.

1990s: 3D-seismic data and 3D-computer modeling of reservoirs bring new life to old fields.


California's major refineries

Capacity, in barrels of crude oil per day

Chevron: 502,901

BP/Arco: 260,000

Shell: 253,400

Valero: 220,000

ConocoPhillips/76: 206,300

Tesoro: 166,000

Exxon Mobil: 149,000

Big West: 66,000

Paramount: 50,000

Kern: 25,000

Other: 118,800

Total: 1,898,601


Where the state's crude oil comes from

Alaska 22%

Foreign sources 36%

California 42%


One barrel of crude oil can produce all of this:

12 cylinders (14.1 oz.) of liquefied gases such as propane

Enough gasoline to drive a medium-sized car (17 mpg) over 280 miles

Asphalt to make about one gallon of tar for patching roofs or streets

Lubricants to make about a quart of motor oil

Distillate fuel to drive a large truck (5 mpg) almost 40 miles

Nearly 70 kilowatt hours of electricity

About 4 pounds of charcoal briquettes

Wax for 170 birthday candles or 27 wax crayons

There are enough petrochemicals left in that same barrel to provide the base for one of the following:

39 polyester shirts

750 pocket combs

540 toothbrushes

65 plastic dustpans

23 toy hoops

195 one-cup measuring cups

11 plastic telephone housings

135 4-inch rubber balls


Sources: Energy Information Administration, California Energy Commission, Chevron Corp., Exxon Mobil Corp., City of El Segundo website. Graphics reporting by Nancy Rivera Brooks, R. Toro

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