波阻抗反演中的一种建模方法

Building of initial model for wave impedance inversion

1. 中国石化江汉油田物探处,湖北潜江433100;2. 中国石化江汉油田研究院物探分院,湖北潜江433100

Geophysical Prospecting Division of Jianghan Oilfield Company, Qianjiang 433100, China

初始模型是波阻抗反演寻优算法的初始解, 其准确与否直接影响反演寻优过程的搜索方向与收敛速度。初始模型的构建要作好测井曲线与地震记录的层位标定, 要求以地质理论为指导, 正确解释层位及确定井控制范围。提出了以正常层位、断层、尖灭点及其组合来描述各种复杂的地下构造。在测井资料少或分布不均的地方, 借助虚拟井技术作为插值控制, 然后用层位文件和断层文件来生成层位场, 为插值建模创造良好的数学基础及实现条件。插值过程由层位场和井控制文件控制, 通过层位间的距离采用拉伸压缩方便地实现包括逆断层在内的初始模型的建立。

The initial acoustic impedance model is the initial solution for acoustic impedance inversion. Construction of initial model should first calibrate the horizons between well logs and seismic records, and interpret horizons correctly and determine the controlling range of each well guided under the geology theory. We propose a method to characterize subsurface structures in terms of horizons, faults, pinchouts, and associations. In case of sparse or uneven well controls, we use pseudo-wells to guide interpolation. The interpolation is constrained by horizon information and well data. The proposed method can tackle reverse faults in the construction of initial model.