随钻方位伽马测井仪器响应数值模拟研究

Forward Algorithm of LWD Azimuthal Gamma

研究不同地质构造下的随钻方位伽马成像模式能够为快速准确识别钻头穿越地层情况提供基础。建立了随钻方位伽马测井的模拟探测模型,分析了方位伽马探测范围与地层相交于不同位置的物理模型,将笛卡尔坐标与球坐标下的模型相结合,导出了不同位置模型下的方位伽马测井响应模拟算法。将模拟结果与方位伽马测井仪实测结果对比,证明了该算法可以有效模拟方位伽马响应特征,具有较高的准确性。模拟了钻头钻遇地层时的图像并分析图像特征,为实时地质导向提供了理论依据。

The study of the LWD （Logging While Drilling） azimuthal gamma imaging mode under different geological structures can provide bases for fast and accurate identification of drilled formation. The detection model of LWD azimuthal gamma is set up, and physical models of several positions of the formation and gamma detector is established, combining the descartes coordinate with the spherical coordinate, an azimuthal gamma log response algorithm under different position models is derived. Comparing the simulated results with the measured results of the azimuthal gamma ray logging tool, it is proved that the algorithm can effectively simulate the response characteristics of the azimuthal gamma, and has a high accuracy. It simulates the gamma image and analyzes the characteristics of the image, which provides a theoretical basis for real-time geosteering.