Inversion of contrasts of elastic parameter based on immunogenetic algorithm
Zhang Hai-yan1, Li Qing-zhong1,2
1. College of Marine Geo-Science,Ocean University of China,Qingdao City,Shandong Province,266100,China;
2. BGP,CNPC,Zhuozhou City,Hebei Province,072751,China
Abstract:The quantitative prestack AVO inversion can effectively use the information of the change of amplitude versus incident angle to provide lithologic parameters inversion in a more all-round way.The adaptive immunogenetic algorithm presented by the paper is to use density mechanism to carry out immunoregulation,increasing the multiplicity of antibody;introducing memory cell can ensure the convergence of optimum algorithm;adaptively selecting such probability parameters as crossover and mutation can guide iterative search.The algorithm overcame the "premature" phenomenon in conventional genetic algorithm and has good convergence,which can be widely used for inversion of geophysics with multi-parameter and multi-extreme.The approximate formula of Ursenbach PP-wave reflectivity adopted in the paper is suitable to the situation that the incident angle is larger and the contrasts of elastic parameters around the reflection interface are relatively larger.It is shown by testing results of multiple bed models that the inversion algorithm is stable,high-efficient and inverted contrasts of P-wave velocity and of density having higher accuracy,especially the contrast of density has important meaning to look for residual oil/gas.
张海燕, 李庆忠. 基于免疫遗传算法的弹性参数变化率反演[J]. 石油地球物理勘探, 2008, 43(6): 704-710.
Zhang Hai-yan, Li Qing-zhong. Inversion of contrasts of elastic parameter based on immunogenetic algorithm. OGP, 2008, 43(6): 704-710.