螺杆式井下增压钻井装置的原理及设计

PRINCIPLE AND DESIGN OF SCREW DOWNHOLE SUPERCHARGER

井下螺杆动力增压系统是从一种全新的原理出发,利用现有成熟技术,研制出一套将螺杆钻具作为动力的井下增压装置,产生超高压水射流,实现水力机械联合破岩,提高钻井效率。增压装置主要由动力单元、动力转换单元、固液分离单元、增压单元以及高压流道单元组成,动力单元将钻柱内的钻井液压能转化为转子的旋转扭矩,由现场用螺杆钻具改进而成;动力转换单元将转子的旋转运动转换为柱塞的轴向往复运动,设计关键是两个斜置圆柱凸轮槽的轨迹;固液分离单元用以过滤进入增压缸的钻井液,防止增压缸阀门阻塞;增压单元通过柱塞的往复运动来压缩增压缸内的钻井液实现增压;高压流道单元将增压后的钻井液输送给钻头上的超高压喷嘴,改进高压合金管的连接方式,提高密封效果。该装置流道简单,制造容易,并且性能稳定、强度高、使用寿命长,能满足现场使用的需要,为新型井下增压器的设计奠定了基础。

Downhole supercharger can be used in deep well and ultra-deep well to boost pressure and improve the ROP in hard formations. Started from new principle and existing mature technology, screw downhole supercharger was developed used helicoid hydraulic motor as driving force. The supercharger generates high pressure water jet to better achieve the hydraulic machinery for rock breaking and improve drilling efficiency. In this paper, working principle of the screw downhole booster, basic structure and the design point of the funetionai unit were introduced. The screw downhole booster mainly consists of power units, power conversion modules, solid-liquid separation unit, pressure unit,and high-pressure flow channel modules. Power unit converted hydraulic pressure of fluid into rotational torque of the rotor, it was made by improving the helicoid hydraulic motor. Power conversion unit converted rotation of the rotor into axial reciprocating motion of the plunger. Solid-liquid separation unit was used to filter drilling fluid into the pressure cylinder to prevent pressure cylinder valve obstruction. Booster unit was used to increase the pressure of drilling fluid through reciprocating motion of the plunger. High-pressure flow unit deliverd the pressurized fluid to the high-pressure nozzle, and improved high-pressure alloy pipe connections to improve seal. The structure of this installation is simple and performance is stable, which can meet the needs of field use. It will be basis for the design of new downhole booster.