Abstract: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.