Drill String

A drill string is a long, interconnected column of pipes and tools used in drilling operations, primarily for oil, gas, or water wells. It connects the top drive or kelly at the top to the drill bit at the bottom. Broadly, the drill string consists of drill pipes, drill collars, and a bottom hole assembly (BHA). The drill string rotates to drive the bit, circulates drilling fluid to cool the bit and remove cuttings, and transmits torque and weight to penetrate the subsurface. It’s critical for maintaining well stability and achieving efficient drilling.