水平井钻井摩阻扭矩计算模型研究

Research of Calculation Model for Friction and Torque in Horizontal Wells

水平井已逐渐成为开发复杂油气藏的重要技术手段,但仍存在着一些问题,摩阻/扭矩问题尤为突出。基于弹性井壁对钻柱的地基反力作用,考虑井壁弹性系数对摩阻的影响,建立水平井钻井作业中钻柱的摩阻/扭矩计算模型,利用Visual Basic编制了相应的计算程序来预测水平井钻井作业中的摩阻/扭矩。根据现场作业数据,对TZ-11井钻井作业中不同工况下的摩阻/扭矩进行了计算。计算结果表明,起下钻过程中模型的计算值与实测值的平均误差不超过7%,旋转钻进时钻柱扭矩与实测值的平均误差为9.51%,具有较高的计算精度,符合工程现场应用要求,可为水平井钻井施工提供技术支撑。

Horizontal well has gradually become an important technology to develop complex reservoirs.However,it still has some problems,especially friction and torque caused by drill string and borehole wall. In consideration of the influence of wall elasticity coefficient,a calculation model for friction and torque in horizontal well is established based on the elastic borehole wall theory. And the corresponding calculation model is programmed by Visual Basic to predict the friction and torque in the drilling operation of horizontal well. According to the data of oil field TZ-11,friction and torque under different working conditions were calculated. The results show that average error between calculated values and the measured values is less than 7% in the process of tripping,and average error of torque in theoretical forecasting is 9.51% in comparison with the field test values in rotary drilling. The calculation model is reliable with high calculation precision,which can offer technical references for the application of horizontal well in oil field.