纵波和转换波AVO联合反演技术

Simultaneous P- and S-wave AVO inversion

1. 西南石油学院 四川南充 637100;2. 中国石化石油勘探开发研究院南京石油物探研究所,江苏南京 210014

Southwest Petroleum Institute, Nan-chong 637100, China

纵波和转换波AVO联合反演,增加了反演问题的约束条件,因而使反演方程的稳定性得到了提高,而密度参数作为未知数与波阻抗一起参与反演,则增加了一个重要的岩性参数。应用射线追踪法来确定共角度道集旅行时,所采用的混合射线追踪法是在矩形网格三点扰动法基础上的一种改进,取矩形网格的3个点,在Fermat最小旅行时原则下求取中间点的位置,而不是任意扰动,因此计算速度比扰动法快。数值模拟结果证明了P波和PS波AVO联合反演的可行性。

Simultaneous P- and S-wave AVO inversion imposes additional constraints in inversion, which improves the stability of inversion. Simultaneous density and wave impedance inversion yields an extra important lithological parameter. Hybrid ray tracing is a-dopted to obtain travel-times for common angle gather. The ray tracing method is an improved 3-point perturbation on rectangular grid, which uses 3 points on the grids to determine the midpoint of the grid under Fermat’s principle. It is faster comparing with the perturbation method. The feasibility of simultaneous P-and PS-wave AVO inversion is tested on synthetic data.