A drill string is a tool that is used for boring deep holes into the ground in order to locate and extract oil or other resources. The construction of such a device allows for rapid drilling while simultaneously extracting large amounts of rock and ore from an excavation site. Mud also is injected down through the drill string to help cool the drill bit while it is in motion and to soften the surface that it is boring through, lessening the chances of an improper cut and increasing the overall lifespan of the bit. An average drill string extends 15,000 feet (4,572 m) into the ground when assembled on land and up to 30,000 feet (9,144 m) or more when constructed offshore, so the quality and precision of this instrument are paramount in order to avoid system failure and potentially becoming stuck a great distance below the Earth's surface.

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A pipe made of lengths of steel tubing that is attached to the drilling tool and rotates during drilling to form a bore.

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