"positive displacement mud motor"

موتور پایین‌چاه PDM موتور گِرداب جابجایی مثبت برای حفاری افقی جهت‌دار

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, ...