瞬变电磁测井视电阻率提取方法及地质导向潜力  

Method for extracting apparent resistivity from transient electromagnetic logging measurements and geosteering potential

作　　者：吴柏志 袁习勇 郭同政 杨震[1] 鲁超 邓少贵[2] WU Baizhi;YUAN Xiyong;GUO Tongzheng;YANG Zhen;LU Chao;DENG Shaogui(SINOPEC Matrix Corporation,Qingdao 266075,China;Key Laboratory of Deep Oil&Gas in China University of Petroleum(East China),Qingdao 266580,China)

机构地区：[1]中国石化经纬有限公司,山东青岛266075 [2]中国石油大学(华东)深层油气重点实验室,山东青岛266580

出　　处：《中国石油大学学报（自然科学版）》2022年第6期99-109,共11页Journal of China University of Petroleum(Edition of Natural Science)

基　　金：国家自然科学基金项目(42204121,42074134);中国博士后科学基金项目(2022M713462);中国石化集团公司科技项目(JP22503,P21080)。

摘　　要：提出晚期视电阻率公式和全区视电阻率反演两种适用于瞬变电磁测井的时间域视电阻率提取方法。模拟不同地层模型的时域视电阻率响应,并基于烟圈原理,通过分析感应涡流在全空间的扩散规律分析电阻率响应机制。结果表明:采用晚期视电阻率公式得到的视电阻率曲线在测量早期严重偏离地层电阻率真值,与之相比,全区视电阻率反演在测量早期也可以得到地层的真实电阻率。对于两层模型,当仪器位于高阻层,邻层为低阻时,整个测量周期内视电阻率都接近地层真电阻率;当仪器位于低阻层,邻层为高阻时,会出现低阻屏蔽现象,时域衰减后期的视电阻率与地层真电阻率差别较大。对于三层模型,无论仪器所在中间层为高阻或低阻,时域视电阻率都可以反映地层真实情况,不受低阻屏蔽的影响。Two time-domain methods for extracting formation resistivity from transient electromagnetic logging measurements are proposed:late-time apparent resistivity algorithm and all-time apparent resistivity inversion.Time-domain apparent resistivity responses of different formation model are simulated.We further adopt the smoke ring theory and give explanations to the above phenomenon by analyzing the smoke ring distribution in the whole space.Simulation results show that apparent resistivity curves determined by the late-time resistivity algorithm deviate from the true value at early times while the all-time inversion can get the true value at early times as well.For a two-layer model,when the tool is placed at the resistor and the adjacent layer is a conductor,apparent resistivity at all moments is very closed to the true formation value.In contrast,when the tool is placed at the conductor and the adjacent layer is a resistor,apparent resistivity at late times is quite different from the true value.However,for a three-layer model,both the early and late apparent resistivity basically reflect the true value no matter the middle layer is a resistor or conductor where the tool is placed.

关 键 词：瞬变电磁测井 时间域 晚期视电阻率 全区视电阻率 烟圈原理 

分 类 号：P631.8[天文地球—地质矿产勘探]