双源距碳氧比测井技术研究  

On Dual Detector Carbon/Oxygen Logging

作　　者：郑华[1] 刘宪伟[1] 董建华[1] 

机构地区：[1]大庆油田有限责任公司测试技术服务分公司,黑龙江大庆163453

出　　处：《测井技术》2005年第2期159-163,共5页Well Logging Technology

基　　金：中国石油专题(合同号010102 2 J 1);大庆油田 3项课题资助

摘　　要：井眼效应限制了单源距C/O测井的应用,为此开发了双源距C/O测井仪器DDCO及相应解释模块。利用蒙特卡罗模拟结果,合理设计了仪器外径、屏蔽体材料与尺寸、源距以及晶体体积比例。通过改变中子管安装与供电方式,实现了理想屏蔽长度与短源距的设计。为减小伽马射线计数的涨落,采用了高性能大尺寸BGO晶体。通过缩短脉冲幅度分析器的模数转换时间,在一定程度上解决了近探测器电路中信号堆积问题。在数据处理方面,通过能谱漂移校正和减氢峰法生成更准确的非弹净谱,采用虚拟探测器技术提高了曲线统计性,通过反褶积提高了测井曲线的纵向分辨率。根据模拟和刻度结果建立了解释模型,通过自补偿消除了井眼效应。结果表明,在35%孔隙度砂岩条件下测量地层含油饱和度精度达到8%。该技术已经应用于多个油田,测井资料为制定稳油控水方案提供了准确的依据,由于测井前不需洗井、刮蜡等作业,受到用户普遍欢迎。An innovative dualspaced C/O tool, DDCO, and r elated interpretation module are developed to correct borehole effect, which has been a pullback of using singlespaced C/O log. The tool structure, including outside diameter, shield material and thickness, spacing, as well as size ratio of detector crystals, is optimized through considering Monte Carlo simulation re sults. The designs of shield thickness and shorts spacing are implemented by alt ering buildin and power supply of the neutron tube. High performance largesi ze BGO crystal is adopted to reduce fluctuation of gammaray counts. Shortening analoguedigitalconverting time of pulse height analyzer solves the problem of signal pileup in the circuit for near detector. In data processing, more ac curate net inelastic spectra are obtained through the energy correction for spec tral drift and subtracting capture spectrum from total inelastic spectrum accord ing to the areas of hydrogen peak in these spectra, and statistic availability i s increased by utilizing virtual detector technique. Vertical resolution of logg ing curve is enhanced by deconvolution. Based on the results of simulation and p ittest, a novel interpretation model is set up, and the borehole effect is eli minated therein by selfcompensation. The outcome of these innovations is that the precision of oil saturation reaches 8% under the condition of 35% of porous sandstone. Oil companies generally accept this technique, as no well cleanout or paraffin cutting is needed before logging. It is applied to several oil fields, and the logs provide good bases for stabilizing oil production and controlling water production.

关 键 词：测井仪器 含油饱和度 碳氧比 双源距 解释 

分 类 号：P631.829[天文地球—地质矿产勘探] P631.84[天文地球—地质学]