自然伽马能谱测井对砂砾岩地层的精细划分

Using gamma spectrometry log for fine sandstone/gravel formation division.

本文以中国K油田一口井的自然伽马能谱测井响应为实例，充分利用各种测井曲线判别沉积和间断的测井曲线特征。从自然伽马能谱测井图上可以看到两个明显的突变界面，深度分别为2760m和3180m。在2760m附近，铀含量从1～4ppm突变为5～10ppm，钾含量从1．5％～2％突变为0．5％左右；在3180m附近，铀含量从5ppm左右突变为2ppm，钾含量从0．5％突变为1．5％～2．5％。结合其他常规测井曲线特征，完成了复杂的洪积-冲积-扇三角洲相的混合堆积砂砾岩地层的精细划分，为该油田的油藏开发调整方案的建立打下了良好基础。

Taking the gamma spectrometry log response in one well,situated in K oilfield in China,as a case,the paper fully used various loggings to identify the feature the sedimentation and depositional break reflected.It is seen from the gamma spectrometry log diagram there are two obviously sudden-changing interfaces where the depths are 2760m and 3180m respectively.Around 2760m,Uranium-bearing content suddenly changes from 1~4ppm to 5~10ppm,potassium-bearing content suddenly changes from 1.5% to about 0.5%; around 3180m,Uranium-bearing content suddenly changes from 5ppm to 2ppm,potassium-bearing content suddenly changes from 0.5% to 1.5%~2.5%.In combination with other ordinary loggings feature,the fine division of strata in mixed accumulational sandstone/gravel stone with complex diluvial-alluvial-fan delta facies was finished,which laid good foundation for geologic research on adjustment of reservoir development scheme.