井中激电三维数值模拟及井眼影响因素分析  

3D numerical simulation of in-hole IP and analysis of borehole influencing factors

作　　者：高文龙 严良俊[1,2] 周磊[1,2] GAO WenLong;YAN Liangjun;ZHOU Lei(Key Laboratory of Exploration Technology for Oil and Gas Resources,Ministry of Education,Yangtze University,Wuhan 430100,China;School of Geophysics and Petroleum Resources,Yangtze University,Wuhan 430100,China)

机构地区：[1]长江大学油气资源与勘探技术教育部重点实验室,武汉430100 [2]长江大学地球物理与石油资源学院,武汉430100

出　　处：《地球物理学进展》2021年第3期1257-1266,共10页Progress in Geophysics

基　　金：国家重点研发计划“井中/井间大功率激发极化探测技术与仪器研制”(2018YFC0603302);国家自然科学基金面上项目(41274121);国家自然科学青年基金(41904077)联合资助。

摘　　要：本文基于异常电位法,使用变步长有限差分的数值模拟方法,通过matlab编程实现了井中激电的三维数值模拟,由具有解析解的球形异常体模型验证了其正确性.同时,分析了侵入带、井径、不同电极系装置和不同井液电阻率对井中激电的影响,通过分析表明井径越小,井液电阻率与背景电阻率差别越大,其对视电阻率的影响就会越大,反之影响会变小;随着测点与点源距离的增加,电流密度随之减小,无论井径还是井液电阻率的影响等也会相应减小;井液及其侵入带相对于围岩低阻时,含有侵入带的视电阻率曲线较无侵入时突变范围变宽,而视极化率响应曲线突变范围变窄.最后根据不同条件下的视电阻率或视极化率响应,采用"自适应噪声滤波"算法对井液电阻率和侵入带等的影响进行了校正,结果表明,此校正方法具有一定的校正效果.This thesis is based on the abnormal potential method,using the variable step size finite difference numerical simulation method,through Matlab to realize the three-dimensional numerical simulation of the in-hole IP method,and its correctness is verified by the spherical anomaly model with the analytical solution.At the same time,the influence of invasion zone,well diameter,different electrode system devices,and different fluids on the induced polarization in the well is analyzed.The analysis shows that the smaller the well’s diameter and the greater the difference between the resistivity of the well fluid and the background resistivity,its influence on the actual apparent resistance will be greater,otherwise,the influence will be smaller;as the distance between the measuring point and the point source is farther,the current density will be smaller,and the influence of well’s diameter and well fluid will be correspondingly smaller and smaller.When the fluid and its intrusive zone have low resistance relative to the surrounding rock,the apparent resistivity curve with the intrusive zone has a wider mutation range than when there is no invasion,and the apparent polarizability response curve has a narrower mutation range.Finally,according to the apparent resistivity or apparent polarizability response under different conditions,the"adaptive noise canceling"algorithm is used to correct the influence of well fluids.The results show that this correction method has a certain correction effect.

关 键 词：异常电位法 有限差分法 井中激电 视极化率或视电阻率 

分 类 号：P631[天文地球—地质矿产勘探]