邻井随钻电磁测距防碰工具模拟试验研究

利用水平井、加密井和丛式井开发低渗透、页岩油气等低品位油气资源时，为了防止钻井过程中相邻井发生碰撞，研制了能够精确测量邻井距离的随钻电磁测距防碰工具。在对邻井随钻电磁防碰测距导向算法研究的基础上，设计加工了邻井随钻电磁测距防碰工具原理样机，并进行了地面模拟试验，分析了探管与套管不同位置关系对邻井距离和方位测量精度的影响。模拟试验结果表明:由于磁源磁场强度较弱，探管与套管平行放置且相距0.50~3.00 m时，该工具可以较准确地计算出邻井距离和方位信息；距离大于3.00 m时，计算结果误差变大；套管接箍位置会造成计算结果偏差较大，因此实际测量时应充分考虑套管接箍对测量结果的影响；探管与套管的夹角不大于50°时系统计算结果较准确，夹角大于50°时需换用其他类型的防碰工具进行测量。研究结果验证了邻井随钻电磁防碰工具原理的准确性，为进一步完善邻井随钻电磁防碰系统理论及工具改进提供了理论依据。 

Experiment Research on an Electromagnetic Anti-Collision Detection Tool while Drilling Adjacent Wells

To use horizontal wells,infill wells and cluster wells to exploit low-permeability oilfields,shale gas reservoirs and other low-quality hydrocarbon resources,it is necessary to eliminate the possibility of collisions with adjacent wells.Accordingly,while-drilling electromagnetic anti-collision tools have been developed to measure distances from adjacent wells accurately.In addition to perform researches related to algorithms for distance measuring and direction guiding,prototypes of the while-drilling electromagnetic anti-collision tools were designed and manufactured.Furthermore,simulation tests were conducted on the ground to analyze impacts of relative positions of the sensor and casing on accuracies in measuring of distances and azimuth of adjacent wells.Simulation test results showed the tool could accurately identify distances and azimuths of adjacent wells in cases with sensor and casing placed in parallel at distances of 0.50-3.00 m due to low strengths of magnetic fields.In cases with distances over 3.00 m,calculation results displayed significant deviations.Care should be taken during field applications to consider the impacts of casing joints on measurement results.In cases with included angles between the sensor and the casing are less than 50°,the calculation results of the tool were very accurate.In cases with included angles over 50°,anti-collision tools of other types should be deployed instead.Relevant research results validated the accuracy of the principle of the while-drilling electromagnetic anti-collision tool and provided reliable theoretical supports for the development of this electromagnetic detection tool.