基于微扰法的裂缝发育层段的感应测井电磁场解析解  

Analytical solution of induction logging electromagnetic field in fracture development formation based on perturbation method

作　　者：刘智颖 徐松 罗兵[1] 张绪平 许巍[2] LIU Zhiying;XU Song;LUO Bing;ZHANG Xuping;XU Wei(Research Institute of Petroleum Exploration and Development,Jianghan Oilfield Branch Co.,SINOPEC,Wuhan,Hubei 430223,China;College of Geophysics and Petroleum Resources,Yangtze University,Wuhan,Hubei 430100,China)

机构地区：[1]中国石化江汉油田分公司勘探开发研究院,湖北武汉430223 [2]长江大学地球物理与石油资源学院,湖北武汉430100

出　　处：《石油地球物理勘探》2024年第6期1378-1394,共17页Oil Geophysical Prospecting

摘　　要：根据微扰法的思想,将裂缝的影响看作原状地层电磁场的微扰,在径向分层介质的亥姆霍兹方程解的基础上,研究了柱外无穷小天线振子电磁场的解析解,从而提出了一种适用于任意裂缝产状,以及任意井径、任意泥浆电阻率的感应测井电磁场的解析解法。据此,以中国常用的HDIL 1515 EA/MA阵列感应测井仪为例,计算了4种裂缝性地层模型中接收线圈的感应电动势,并绘制了视电导率曲线(理论图版)。研究表明,在裂缝发育层段,阵列感应视电导率曲线并不会出现“大幅度尖峰”的现象。同时,在油基泥浆条件下,微裂缝密集发育的地层段中,7个子阵列的视电导率曲线呈现出幅度差异,且其特征明显不同于泥浆侵入层段,可以作为微裂缝发育段的识别标志。Inspired by the electromagnetic perturbation method,we regard the influence of fractures as the perturbation of electromagnetic fields of undisturbed formations.Based on the solution of the Helmholtz equation in radial layered media,we propose an analytical solution of induction logging electromagnetic fields applicable to any fracture occurrence,any well diameter,and any mud resistivity after studying the analytical solution of the electromagnetic field of infinitesimal antenna vibrator outside the column.Relying on this,we take the HDIL 1515 EA/MA array induction logging tool commonly used in China as an example to calculate the induced electromotive forces of receiver coils in four kinds of fractured formation models and draw the(theoretical charts of)apparent conductivity curves.The research shows that there is not necessarily a spike in the array induced apparent conductivity curve in the fracture development formation.At the same time,under the condition of oil-based mud,the apparent conductivity curves of the seven sub-arrays in the formations where microfractures are densely developed show amplitude differences,and they can be used to identify the microfracture development section for the different characteristics compared with mud invasion formations.

关 键 词：感应测井 裂缝性地层 电磁场微扰法 并矢格林函数 

分 类 号：P631[天文地球—地质矿产勘探]