采用轴对称二维模型对实际地层井间电磁响应进行成像的精确性研究  

Precision of imaging cross-hole electromagnetic responses in real formation by using axial symmetric 2-D model

作　　者：魏宝君 任臣 吴康康 党峰 WEI Baojun;REN Chen;WU Kangkang;DANG Feng(College of Science in China University of Petroleum(East China),Qingdao 266580,China;China Petroleum Logging Company Limited,Xi an 710077,China)

机构地区：[1]中国石油大学(华东)理学院,山东青岛266580 [2]中国石油集团测井有限公司,陕西西安710077

出　　处：《中国石油大学学报（自然科学版）》2020年第2期42-51,共10页Journal of China University of Petroleum(Edition of Natural Science)

基　　金：国家科技重大专项(2017ZX05019-006)。

摘　　要：采用二维积分方程和体积分方程分别模拟轴对称二维井间地层和三维井间地层模型中异常体的响应,并分析三维异常体沿垂直于发射—接收剖面方向的厚度和偏心程度以及在发射—接收剖面的横向位置对其响应的影响。采用Born迭代方法,通过反演不同模型的模拟数据获得发射—接收剖面的二维电导率成像。结果表明,在将三维地层中得到的井间测量数据在发射—接收剖面采用轴对称二维模型进行成像时,其成像质量与异常体沿垂直于发射—接收剖面方向的厚度和偏心程度直接相关。只要异常体沿垂直于发射—接收剖面方向的厚度足够大且其中心点距离发射—接收剖面较近,就可以采用轴对称二维井间地层模型实现高质量成像。异常体厚度越小、偏心程度越高,成像效果越差。The abnormal body s responses in axial symmetric 2-D and 3-D cross-hole formation model were simulated by 2-D integral equation and volume integral equation respectively.The influence of the 3-D abnormal body s thickness and eccentricity along the direction perpendicular to the transmitter-receiver section on its responses was analyzed,and the influence of the body s horizontal position on its responses was also analyzed.The Born iteration method(BIM)was used to image the 2-D conductivity on the transmitter-receiver section by inverting the simulated data for different formation models.Both forward modeling and imaging results show that the imaging quality is directly related to the 3-D abnormal body s thickness and eccentricity along the direction perpendicular to the transmitter-receiver section when the axial symmetric 2-D model is adopted to get the conductivity distribution on the transmitter-receiver section by inverting the data measured in 3-D cross-hole formation.As long as the 3-D abnormal body is thick enough along the direction perpendicular to the transmitter-receiver section and its center is close enough to the transmitter-receiver section,it is feasible to get high quality imaging by adopting axial symmetric 2-D cross-hole formation model.The imaging quality will become worse if the abnormal body s thickness becomes much smaller and its eccentricity becomes much bigger.

关 键 词：井间电磁响应 积分方程 轴对称二维模型 三维模型 井间电磁成像 

分 类 号：P631.9[天文地球—地质矿产勘探]