煤层气水平井连通工具测量误差分析

针对使用MWD随钻测量完成煤层气水平井钻井中的连通作业成功率低的问题,研制了旋磁定位工具MTS。介绍了连通作业的工艺过程及MTS的测量原理,从测量滞后、工作方式及误差传播和误差椭球等方面对MWD和MTS工具的测量误差进行了分析对比。MWD可在钻井过程全程使用,但受钻具组合和工作方式的影响,测量数据滞后,且会产生较大的测量误差;MTS为近钻头测量,能有效消除测量滞后效应,且距离目标点越近,测量误差越小;MTS测量距离较短,在连通作业接近靶点区域可对MWD的测量提供有力补充和校准。

Measuring errors analysis in communicating operation for CBM horizontal wells

For the problem of low success rate in the communicating operation of CBM horizontal well drilling operations using MWD, the rotating magnetic locating tool, MTS, was developed, which can supply powerful supplement and calibration for MWD measurement within a certain distance. The paper described the technical process and role of the communication. Beginning with the measuring principle of MTS, the measurement errors of the two tools were compared in three aspects: measurement lagging, working style, and error propagation and error ellipsoid. Field examples of the successful application of MTS in the CBM connectivity operations were described. The result can be obtained that different measurement principle and different working way cause different error propagation, thereby lead to the difference on measurement accuracy and communicating job success rate.