新型高分辨率自然伽马测井仪器的优化设计与资料处理技术

Optimizing Design of New High Resolution Gamma Ray Logging Device and Data Processing Technique

通过自然伽马响应函数与其探测器长度间关系的研究,选择长度为0.1m的NaI晶体作为新型高分辨率自然伽马仪器的探测器。为克服短NaI晶体会导致计数率降低和统计涨落误差增大等问题,利用4个大小完全相同的NaI晶体同时测量伽马射线强度,获得4条高分辨率自然伽马测井曲线;然后,对4条测量曲线进行累加并结合带通滤波技术充分降低统计涨落误差;在此基础上,进一步应用正则化反褶积处理提高仪器的纵向分辨率。理论模型和井场试验结果均证明,该新型高分辨率伽马仪器具有0.15m的纵向分辨率,比常规自然伽马测井仪器的分辨率提高了4倍以上。

By studying the relation between response characters and the lengths of Gamma ray detector, we choose 0.1 m length of NaI scintillation detectors to develop a new high resolution Gamma ray tool which measures the total Gamma ray flux emanating from the formation. To overcome the increase of statistical fluctuation errors arising from the reduction of Gamma ray count rates du short detector, we assemble four detectors of the same type to achieve the four logs of Gamma ra with high vertical resolution simultaneously. And we sum up the four different curves from the d and then execute low-pass filter to reduce statistical fluctuation error in the Gamma ray logs. Aft e to the y fluxes etectors er that, we apply regularized deconvolution to enhance the vertical resolution of Gamma ray logs. The theoretical modeling and field results prove that the new Gamma ray tool has the vertical resolution up to 0.15 m, whose vertical resolution is about 4 times higher than that of other conventional Gamma ray tools.