倾斜线圈随钻电磁波电阻率测量仪器的响应模拟及应用

采用各向异性水平层状介质磁偶极子源并矢格林函数计算接收线圈倾斜的随钻电磁波电阻率仪器的响应,利用新的方式定义出定向相位差及幅度比信号。分析视电阻率以及定向信号的探测特性,总结出地层边界、地层对比度、相对倾角、各向异性、线圈倾斜角度对仪器响应的影响规律。结果表明,倾斜线圈仪器不但可以利用视电阻率进行地层评价,还可以利用新的定向信号探测出地层上下界面,相比传统的电磁波电阻率仪器具有更好的地层评价和地质导向功能,是一种应用前景广阔的仪器。

Response simulation and application of electromagnetic wave resistivity measurement-while-drilling tool with tilted coil

The azimuthal response of electromagnetic wave resistivity measurement while drilling with tilted coil was computed via the dyadic Green ''s function produced by magnetic dipole in a horizontally stratified anisotropic media. The directional phase difference and amplitude ratio signal were defined in a new way. The detection characteristics of apparent resistivity and directional signals were analyzed. The response rules affected by formation boundary, formation contrast ratio, relative dip, anisotropy and coil ''s tilting angle were obtained. The rule shows that the tool with tilted coil can be used not only to make formation evaluation through apparent resistivity, but also to detect upper and lower boundary of formation using directional signals. Compared with traditional electromagnetic wave resistivity tool, it has better application in formation evaluation and geosteering with more broad application prospects.