利用逐点分层法提高自然伽马测井分辨率

井眼条件及围岩环境不统一导致测量的自然伽马值出现不同程度的失真,对失真产生的误差进行补偿可以提高曲线纵向分辨率。介绍自然伽马测井的基本原理,建立模型,求取仪器探测范围的解析表达式,并按照采样间隔对探测范围进行分层处理。通过计算各层对测井值的贡献权值实现对自然伽马测井值的校正。实际测井资料应用表明,校正前孔隙度相对误差16.2%,校正后孔隙度相对误差4.1%,校正后的孔隙度计算更为精确。

A Method to Improve Natural Gamma Logging Resolution with Point-by-point Layering

Due to the various surrounding rocks and borehole environments,the natural gamma signals are distorted to some extent.By compensating the deviation resulted from the distortion,we will get higher vertical resolution of natural gamma logs.Introduced is the basic principle of natural gamma logging.Established is an appropriate model to obtain the instrument detection range,which is layered according to different sampling intervals.The natural gamma log data calibration is realized by computing different contribution weights of each layer.Practical application shows that relative porosity error before calibration is 16.2%,and after calibration it is reduced to 4.1%.It is concluded that the calculation accuracy of natural gamma logging porosity is improved by using the above method.