用磁流源并矢Green函数的递推矩阵方法计算层状各向异性地层中多分量感应测井响应

Computing the response of multi-component induction logging in layered anisotropic formation by the recursive matrix method for magnetic-current-source dyadic Green's function

采用递推矩阵方法计算各向异性介质的磁流源并矢Green函数,并利用上述并矢Green函数对层状各向异性倾斜地层中多分量感应测井的响应进行数值模拟,分析了线圈距、层厚、倾角和围岩对多分量感应测井响应的影响.计算发现,共面视电导率比共轴视电导率变化规律复杂,不能反映地层电导率的真实情况.各向异性地层共轴视电导率随井眼相对倾角的增加而减小,而共面视电导率随井眼相对倾角的增加而增加.仪器的垂向分辨率、围岩各向异性对目的层响应的影响程度取决于线圈距,围岩各向异性对高电导率目的层中测井响应的影响大于对高电阻率目的层中测井响应的影响.

A recursive matrix method is adopted for computing the magnetic-current-source dyadic Green＇s function in anisotropic media. The response of multi-component induction logging in layered and deviated anisotropic formation is simulated by using the obtained dyadic Greenrs function. The influence of coil spacing, bed thickness, deviation angle and shoulder bed on the response is analyzed. It has shown from computation that the changing pattern of coplanar apparent conductivity is more complex than coaxial apparent conductivity and can not reflect the formation＇s real conductivity. The coaxial apparent conductivity decreases with the increase of deviation angle in anisotropic formation, while the coplanar apparent conductivity increases with the increase of deviation angle. The tool＇s vertical resolution and the influence of shoulder bed＇s anisotropy on the toolt s response in target formation bed are determined by coil spacing, the influence of the shoulder bed＇s anisotropy on the response in high-conductivity target formation is bigger than that in high-resistivity target formation.