侧向测井电极系结构影响分析及阵列化测量新方法

针对目前广泛使用的侧向测井电极系结构和聚焦方式，利用有限元数值模拟方法研究了三种常见的侧向测井电极系结构对电极系数、井眼影响系数、径向探测深度的影响；对比硬件聚焦中监督电极残余电位差对测井响应的影响，引入聚焦系数，提出了一种利用软件聚焦实现阵列化测量的新方法；利用Oklamoha标准地层模型验证了方法的正确性。结果表明，不同电极系结构和电极系的不同部分对测井响应的作用不同，其中电极系绝缘部分长度对探测特性的影响很大，在电极系设计过程中应重视绝缘尺寸对探测特性的影响。采用软件聚焦方式，不仅消除了硬件聚焦方式中残余电位差的影响，而且在不改变双侧向电极系结构的基础上，选择聚焦系数为0~1.1，得到了不同径向探测深度的测井曲线，实现了类似于阵列侧向测井中的阵列化测量。测量结果表明，电极系数随着聚焦系数的增大而减小，井眼影响系数保持在0.80~1.16，并提高了径向探测能力，最大探测深度达到2.0 m以上，获得更丰富的地层电阻率分布信息。

Effect of Electrode Array Structures in Laterolog and a New Array Measurement Method

Based on the widely used electrode array structures and focusing ways in laterolog,effects of three conventional electrode array structures on electrode coefficient, borehole effect and radial investigation have been studied systematically using the finite element method.In addition,we have analyzed the effects of hardware focusing way and software focusing way on logging responses using the contrast of vision.An array measurement method using software focusing has been presented simultaneously,which had been tested using the Oklamoha standard formation.The results show that different electrode array structures and different parts have various effects on the detection characteristics.The status of insulator section should be attached great importance to,because their influence on detection characteristics is extraordinary obvious.The software way not only eliminates the negative influence of remainder potential difference in hardware focusing way,but also realizes array measurement similar to the array laterolog based on the importing of focusing coefficient with the range of 0 1.1,nevertheless,the electrode structure is consistent with the dual laterolog.The electrode coefficient decreases with the increase of focusing coefficient,borehole effect correction ranges from 0.8 to 1.16 and this method improves the radial investigation depth with the largest one exceeding 2.0 m, obtaining more abundant radial formation resistivity information.