斜井中地质导向电磁波测量数值模拟分析

定向井开采借助于定向随钻电磁波测量仪器准确划分已钻地层、预测待钻进地层、实时控制钻头沿期望轨迹钻进，大大提高了油气采收率。为此，研究了斜井中地质导向随钻测量仪器的响应特性。结果表明：①由定向响应信号的正、负可判断围岩与目的层的相对位置。②为减小或消除地层倾角和地层各向异性对定向响应的影响，应该采用对称布置线圈对进行测量；把两对单发、单收线圈对的定向测量结果叠加在一起，在接近地层边界时只对相对倾角敏感，在距地层界面较远时，定向响应信号受各向异性和相对倾角影响较小，定向响应曲线简单。③数值仿真了地层相对倾角小于20°时的定向测量响应，认为当目的层厚度不超过6m时，地质导向信号对低井斜角探测具有很好的灵敏性，这种方法弥补了井眼成像的不足，具有较高的测量精度，并且极具实时性。

Numerical simulation of the geo-steering electromagnetic wave measurement while drilling in inclined wells

The electromagnetic wave measurement while drilling tool in the directional well mining identifies the drilled formation and the formation to be drilled, and ensures the bit in a right tracjectory, so the oil and gas recovery will be greatly improved.We conduct a study on the electromagnetic wave measurement while drilling tool in inclined wells.The following understandings are obtained:①The distance from the surrounding rock layer to the target can be judged by the positive or negative of the directional response signal; ②The influence of formation inclination and formation anisotropy on the directional response can be reduced or eliminated with symmetric coil arrangement for measurement.The directional measurements of two pairs of single emissing and single receiving coil system should be superimposed together.When the tool is located near the formation boundary, the directional response signal is only sensitive to the inclination, and when the tool is far from the formation boundary, the directional response signal is less affected by anisotropy and inclination, and the directional response curve is simple; ③A numerical simulation for the directional measurement response of formation dip angle less than 20° is carried out.If the target thickness is less 6m, the geo-steering signals are very sensitive to well dip angle.The proposed method has a high real-time measurement accuracy and compensates the shortage of the current borehole imaging.