基于分段摩阻因数的水平井延伸极限分析及应用

Analysis and application of horizontal well extension limit based on sectional friction factor

利用系统聚类分析,将整个井眼划分为多个不同摩阻因数的井段,结合钻柱摩阻扭矩模型,采用模拟退火算法反演计算各个井段摩阻因数的最优值;基于分段摩阻因数,考虑钻机承载能力、岩石破碎条件、摩阻力条件、钻柱强度条件、钻柱刚度条件,建立水平井延伸极限判断准则和预测模型。现场应用结果表明:采用分段摩阻因数反演方法计算的大钩载荷和井口扭矩的预测值与实测数据具有良好的相关关系,平均误差绝对值分别为3.72%、3.45%,较传统反演方法预测精度分别提高54.8%、51.8%。随摩阻因数的增大,水平井延伸极限明显降低。该结果可为水平井延伸极限预测提供参考。

The whole borehole is divided into several well sections with different friction factors by using system cluster analysis.Combined with the drill string friction torque model,the simulated annealing algorithm is used to inverse and calculate the optimal value of friction factor of each well section.Based on the sectional friction factor,considering the bearing capacity of the drilling rig,rock crushing conditions,friction conditions,drill string strength conditions and drill string stiffness conditions,the judgment criterion and prediction model of horizontal well extension limit are established.The field application results show that the predicted values of hook load and wellhead torque obtained by the segmented friction factor inversion method have a good correlation with the measured data.The average absolute error values are 3.72% and 3.45% respectively,which are 54.8% and 51.8% higher than the prediction accuracy of the traditional inversion method.With the increase of friction factor,the extension limit of horizontal well decreases obviously.The results can provide a reference for the prediction of extension limit of horizontal wells.