一种改进的侧向测井电极系探测深度表征方法  

An Improved Method for Characterizing Investigation Depth of Laterolog Sondes

作　　者：冯琳伟 尹志军[2] 贺飞 阮亦军 王炜 黄继贞 

机构地区：[1]中国石油集团测井有限公司技术中心,陕西西安710077 [2]中国石油大学地球科学学院,北京102249

出　　处：《测井技术》2011年第B12期638-641,共4页Well Logging Technology

摘　　要：侧向测井电极系探测深度的传统定义方法是采用伪几何因子理论，这种基于纵向无限厚地层模型定义的侧向测井电极系的探测深度具有一定局限性，不能合理表现电极系的径向探测能力。通过对侧向测井电极系探测深度表征方法的分析，给出了一种改进的有限厚地层探测深度伪几何因子公式表征方法，利用有限元方法对双侧向测井和阵列侧向测井的探测深度进行计算分析，对电极系的径向探测特性进行综合描述。利用有限元数值模拟方法对5700双侧向测井仪器（1239）电极系、EILog高分辨率双侧向测井仪器（HRDL）电极系和EILog阵列侧向测井仪器（HAL）电极系的3种侧向测井仪器的响应曲线幅度进行对比，结果在6～8m以下厚度的地层中3种电极系探测深度接近。随地层厚度的不断加大，1239和HRDL探测深度趋向无限厚数值，HAL探测深度基本保持不变。3种电极系结构的实测曲线也说明了在6～8m厚度以下的地层，3种电极系的测量曲线幅度接近，与有限厚探测深度指标吻合，说明无限厚探测深度指标不能反映该厚度的实际特性。改进后的表征方法更合理。The conventional definition method for determining the depth of investigation of laterolog sonde based on the longitudinal infinite thick stratum model is to use pseudo geometric factor theory. This kind of infinite thick characterization method can not thoroughly assess the radial in vestigation capability of electrodes. Based on analyzing the characterization of the depth of inves tigation of the laterolog electrodes, given are limitations of the conventional method and an im- proved pseudo geometric factor algorithm for characterizing the limited thick detecting depth. Furthermore, the depths of investigation of dual laterolog and array laterolog are computed and analyzed using the finite element method. The finite element method is used to compare the curve amplitudes obtained from three laterolog electrodes such as 1239, HRDI. and HAL, the result of which shows the investigation depths of the three electrodes are very approximate within 6 to 8 m interval of interest. As the interval thickness increases, the investigation depth of 1239 and HRDL electrode approache to unlimited depth, but the investigate depth of HAl. electrode re- mains the same. The actual curve amplitudes measured with the 3 electrodes also show the curve amplitudes are closer in the intervals below 6 to 8 m thickness, which is consistent with finite thick investigation depth index, so, the infinite intestigation depth index cannot reflect the actual characteristics of this interval thickness. The practical measurements show that the improved method is more reasonable.

关 键 词：测井仪器 探测深度 表征方法 伪几何因子 双侧向测井 阵列侧向测井 数值模拟 围岩影响 

分 类 号：P631.81[天文地球—地质矿产勘探]