How do Pumpjacks work?
Pumpjacks dot the landscape in California, Texas, and many other parts of the country. They sit just off the road in the middle of nowhere, just bobbing along. We know they pump oil, but how do they actually work? Let’s take a look at pumpjacks: how they are built, how they function, and how much oil they actually produce.
Image Credit: CBC.ca
Where did pumpjacks come from?
After Edwin Drake built the first oil well around 1859 (check out our history of oil article for more information), effort went into designing systems to artificially lift petroleum from the ground. Manual pumping moved to power by other methods, including steam engines, but more than 60 years after Drake’s first well, a new technology arrived. The pumpjack, also known as the Grasshopper, Donkey, Thirsty bird, or horse-head, would change the way oil was drawn for the next 100 years. In 1925, Walter Trout was working for Lufkin Foundry & Machine in Lufkin, Texas. He sketched an idea for a counterbalanced pump jack, and by the end of the year it was in operation in Humble, Texas.
The design was well balanced and operation was smooth, but the resulting appearance was a hard sell at first. According to AOGHS, Trout said, “The well was perfectly balanced, but even with this result, it was such a funny looking, odd thing that it was subject to ridicule and criticism, and it took a long time, nearly a year, before we could convince many the idea was a good one.” Modern-day stripper wells look very similar, but technology has advanced. Wells even use “smart” technology to monitor operations remotely with very minimal human intervention. These technologies can also help keep wells alive that if stopped, would likely never restart due to low pressure.
Image Credit: San Joaquin Valley Geology
How do pumpjacks work?
The base attaches to the ground and supports the rest of the mechanism. There are two cranks with counterweights that act to save energy as the sucker rod is pulled up. The walking beam pivots up and down and is attached to the horse head, which pushes and pulls the sucker rod to draw oil. As the oil rod moves down underground, a valve opens and allows oil to move from the well into the plunger holding chamber. When the rod moves back up, the upper valve is opened and another valve in the lower system is opened. The low pressure causes the oil to flow to the surface, pressurized by the plunger.
All of this requires power, so a special engine that runs on electricity or gas rotates the counterweight to move the pivoting beam. Electric motors are common, but in more isolated locations without electricity, internal combustion engines can be used as well. Many pumpjacks also use natural gas, which is casing gas that comes from the well, providing fuel at the point of use. Pumpjacks can move approximately 1-10 gallons of liquid with each stroke, at up to 20 strokes per minute. This liquid has to be separated into water and oil and picked up at regular intervals. Generally, the larger the pumpjack, the deeper the oil reserves, as it takes more power to pump the oil to the surface, requiring a larger mechanism.
Image Credit: Energy Education
Are pumpjacks still in use?
They are still in use, usually in areas where there is not a lot of oil. In the 20th century, hundreds of pumpjacks might have been installed over one oilfield. This can still be done, and multiple pumpjacks can be connected to one power source for efficiency.
Check out this video for a great visual on how pumpjacks operate:
Video Credit: Concerning Reality
Happy Fun Fact Friday!