Have you ever dug a hole in the ground hoping to find something? If so, in general terms, you may have dug a well. In this Drilling Minute, we’ll introduce oil & gas wells and how they are made.
One definition of the word well is, “a plentiful source,” but in physical terms, it usually means a hole dug into the ground to obtain:
But how did people know to drill for oil?
Much like water, oil and gas can work its way up to the surface on its own. As it turns out, mankind has been using petroleum products seeped to the surface for over 40,000 years, when bitumen tar, a type of heavy oil, was used as an adhesive. It is estimated that up to 5 million barrels of oil still naturally seeps from the floor into the Gulf of Mexico every year! Throughout history, when people needed more than they could easily collect from the surface, they drilled down to get more, which we are still doing today.
Today’s wells are almost always several thousands of feet deep. Usually, the well is drilled in multiple sections of decreasing sizes. Each section is drilled to a safe depth, and then steel casing is cemented in place. The casing is set to protect drinking water and minerals near the surface from the oil below, and to keep the well from caving in.
Today’s wells also have increasingly complex trajectories, including vertical, curve, tangent, and horizontal sections to increase the amount of oil recovered.
In order to drill these deep and complex wells, complex and powerful drilling machinery is needed. Many people confuse production equipment with a drilling rig, but a drilling rig is only on location while the well is being drilled. Wells are usually drilled in only weeks or months, while they can be produced for several years.
Mankind has been drilling for oil for thousands of years, and it doesn’t look like there are any signs of stopping. Ever since the Chinese were drilling wells nearly 1,000 feet deep as far back as 3-400 A.D., there has been a bit at the end of the action, which is the topic of the next Drilling Minute.
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