1、Introduction Shanghai Ocean Oilfield Service Co supplied Downhole Motor to Drilling Department of Bohai Offshore pany LTD.(Tianjin), on base of mastering foreign and domestic advanced technology and linking China national situation, has developed and manufactured some types of screw drills in cooperation with oilfields and scientific research institutes. With them, we may provide satisfactory services to the oilfields. This manual mainly introduces screw drill property, application and cautions, so as for the customers to know well our screw drills, and to do better selection, application, repair and maintenance of screw drill according to drilling demand. As a result, our screw drill may bring into play in its reliable technical function, to enhance drilling economic efficiency. 2、Principle Screw drill is a kind of downhole dynamic drilling tool upon the power of drilling mud. Mud stream from the outlet of mud pump flows through a by-pass valve into the motor. This stream produces pressure loss at both inlet and outlet of the pump, to push the rotor into rotating, and to transmit the torque and speed onto the bit. The screw drill property mainly depends upon its property parameters 3、Constitution Screw drill posed of four assemblies of by-pass valve, motor, cardan shaft and drive shaft ( Fig. 1) . 前言 上海奥森油田服务有限公司为渤海石油有限公司(天津)钻井部提供螺杆钻具设备服务,与此同时联同各油田、科研院所,在消化国内外先进技术,结
