The gammaray index is usually computed from a well log such as a gammaraylog.
自然伽马指数通常由自然伽马或其它测井曲线计算得到。
2
For some sandstone reservoirs with high natural gammaray existed in Ordos Basin, it is difficult to be correctly identified and to calculate its shale content with gammaraylog only.
对鄂尔多斯盆地存在的高自然伽马砂岩储层，仅用自然伽马测井资料难以正确识别并计算其泥质含量。
3
Based on the features of mudstone with higher gammaray than sandstone in sandstone -mudstone section, we can distinguish sandstone reservoir from the drilling profiles with gammaraylog.