气体钻水平井中的摩扭系数反算与分析

RESEARCH ON TORQUE-DRAG IN HORIZONTAL SECTION BY AIR DRILLING METHOD

气体钻水平段时摩阻扭矩问题比较突出,大大增加了水平段轨迹控制难度和风险。结合川东北气体钻水平段现场试验,开展了气体钻水平段摩阻扭矩预测分析研究。模拟计算分析表明,气体钻井条件下摩擦系数比常规钻井大许多,是导致气体钻水平段严重摩阻扭矩的直接原因。气体钻水平段要严格设计和使用倒装钻具组合,加重钻杆以下的普通钻杆(斜坡钻杆)长度要合理,应尽可能使加重钻杆位于直井段及小斜度井眼内,以便尽可能降低摩阻扭矩及其不利影响。

The matter of torque and drag in horizontal section by air drilling method is more severe,which increases more difficulty and hazard on horizontal drilling.Based on site experiments in the North-east of Sichuan Province,prediction and analysis on torque and drag have been completed.Simulating analysis have demonstrated that the frictional coefficient under the gas drilling condition was bigger than that of common drilling methods,which was the immediate cause of the severe matter of torque and drag.Furthermore,drilling the horizontal section by air drilling method should design and use the reversal bottom-hole assembly strictly to reduce torque and drag and its disadvantages.The key to design the reversal assembly was that the length of the common drill pipe should be appropriate to ensure that the extra-heavy drill rod lies in horizontal section and the high angle section.