钻井双壁钻具研制与应用

The Development and Application of Double-Wall Drill Tools

为解决在充气钻井液欠平衡压力钻井时,使用常规井下动力钻具和随钻测量仪器进行井眼轨迹控制中遇到的技术难题,研制了双壁钻具。详细介绍了合理解决双壁钻具高压钻井液流道直径、气道直径和钻具强度等问题的方法,根据具体情况制定了特定的扣型,确定了双壁钻具的具体参数。现场试验表明,使用充气钻井液进行欠平衡钻井时,应用双壁钻具可使井下动力钻具和随钻仪器的性能不受影响,能进行正常的井眼轨迹控制。

A double-wall drill tool has been developed to solve problems arising in the process of con- trolling the wellbore trajectory using conventional downhole mud motor and MWD in under-balanced drilling with aerated drilling fluid. This paper introduces in detail how to solve the problems of drilling fluid flow diameter, gas flow diameter and drill tool strength. A special thread type according to different conditions and parameters of double-wall tool were determined. Field experiments indicate that using doublewall drill tools can prevent impacting the performance of the downhole mud motor and MWD and the well trajectory can be controlled in under-balanced drilling with aerated drilling fluid.