螺杆钻具使用手册.doc

上海奥森油田服务
Shanghai Ocean Oilfield Service Co. Downhole Motor
--------------------------------------------------------- Downhole Motor
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2
By-pass Valve Assembly
It has two positions of by-pass and close (). It is in by-pass position during trip operation, circulates mud fluid in the drill string into the annular space by-passing the idle motor, so that no mud may spray out onto the platform during the trip operation. When mud flow rate and pressure reach the setting value, the valve stem moves down and closes the valve. Meanwhile, mud stream flows through the motor, and converts the pressure energy into mechanical energy. As mud flow rate is too low, or mud pump stops, and as the created pressure is not enough to overcome spring force and static friction force, the spring presses the stem upward ,and by-pass is in open position.
Motor Assembly
It consists of stator and rotor. Stator is made by squeezing rubber sleeve on the wall of steel tube. There forms spiral structure with a certain geometric parameter. Rotor is a crome-plated screw rod.
Stator and rotor matches with each other, to form spiral line and seal cavity through their guide rail difference. With rotor running in the stator, the seal cavity is moving along its axial direction, continuously forms and disappears ,to complete its energy conversion. This is the basic principle of screw drill.〔motor〕
Spiral seal line on rotor is divided into single end and multi-end ( stator with one more end than rotor). The less ends the motor has, the higher speed and the lower torque is. The more ends it has, the lower speed and the higher torque is. shows the sectional profile of several typical motors.
3．1旁通阀总成
它有旁通和关闭两个位置〔如图2〕，在起下钻作业过程中处于旁通位置，使钻柱中泥浆循环绕过不工作马达进入环空，这样起下钻时泥浆不溢于井台上。当泥浆流量和压力到达标准设定值时，阀芯下移，关闭旁通阀孔，此时泥浆流经马达，把压力能转变成机械能。当泥浆流量值过小或停泵时，所产生的压力不足以克服弹簧力和静摩擦力时，弹簧把阀芯顶起，旁通阀孔又处于开启位置。
3．2马