The pump jack is a workhorse oil pump used to pull oil out of the ground.
When oil stops gushing out of the ground, you pump it out of the ground, thats what a pump jack is for. Oil hasnt gushed out of oil wells in the U.S. in probably 40-50 years.
There is an electric motor that drives the pump 24 hours a day 365 days a year.
I found this website that has specs for their biggest 15 horsepower pump jack.
A 15 horsepower 90% efficient motor will use 12.4 kW, which is 298 kWhr per day and 108,916 kWhr per year.
Deeper wells produce less per unit of pumping and shallower wells produce more.
This particular model with a 5000 foot deep well can produce 100 barrels per day.
Ahh, but 100 barrels of what?
This report shows that california onshore wells produced 195 million barrels of oil and 2.3 billion barrels of water.
I think that means that out of those 100 barrels pumped, you get 7.8 of oil and 92.2 of water.
Thus over the year you would get 2847 barrels of oil from your well, and it takes 38kWhr of electricity to pump each barrel up.
Since each barrel yields about 19.5 gallons of gasoline when refined, thats 2 kWhr of electricity to pump the oil out of the ground.
Turns out that 15 horsepower is a little pump. This website describes pump jacks up to 100 horse:
How deep are wells really? Not sure but the EIA shows that the average depth of new development wells has risen from 3861 feet in 1950 to 4938 feet in 2008.
California has 42000 oil wells, it is unclear how many of them use pump jacks.
This site claims that California used 3.7 billion kWhr of electricity in 2000 to extract its 253 million barrels of oil. Thats 14kWhr per barrel, and the average producing well was 2500 feet deep.
By 2009 onshore production was down to 208 million barrels. How much is energy per barrel up? The average depth has probably gone up, not sure how much. But the report shows 2000 new wells drilled per year, if 2000 new wells are drilled each year and 2000 are retired, that turns over more than 40% of the wells over 9 years. The average new well depth in that span has been near 5000 feet. ( If you replace a 2500 foot well with a 5000 foot well and get the same volume you need more horsepower which means more kW ) The total amount of liquid pumped is probably the same while the percentage that is oil has gone down. If the amount of electricity used is the same, then we’re up to 18kWhr per barrel.
Of course this energy is used to pump the oil up to the surface. How much energy is used to pump it to the refinery and separate the water from the oil is still unclear.