"positive displacement mud motor"

ダウンホールモーター PDM 正転位泥モーター 水平方向掘削用

A downhole motor (also known as a positive displacement motor, PDM, or mud motor) is a downhole drilling tool that converts the hydraulic power of drilling fluid into mechanical power to rotate the drill bit . Unlike conventional rotary drilling where the entire drillstring rotates from the surface, ...