改进的模拟退火算法及其在正交偶极子各向异性反演中的应用

A modified simulated annealing method and its application to cross dipole anisotropy inversion

正交偶极子各向异性反演中一般采用快速模拟退火算法(VFSA)。为了提高VFSA算法的分辨率,提出了一种改进的VFSA算法,此算法需结合局部优化算法,即在VFSA算法的每一循环中随机产生3个点,然后运用单纯形算法进行局部寻优,所得最优解作为下一循环的初始点继续下一循环。使用改进的VFSA算法处理了大庆某井的正交偶极子声波测井数据,并将该算法与传统的VFSA算法的处理结果进行了比较。结果表明,改进的VFSA算法比传统的VFSA算法具有更好的收敛特性。若合理地选择计算参数,则改进的VFSA算法的速度下降并不明显。

Very fast simulated annealing method (VFSA) is used in cross dipole anisotropy inversion commonly. A modified VFSA was provided. The new method combined VFSA with local optimum method. In the method, three points were generated randomly within each iteration. The simplex method was used to find local minimum point. Then the local minimum point will be considered as the initial point for next iteration. The new method was compared with the traditional method. The results show that the modified VFSA demonstrates better converging characteristics than VFSA when the new method was applied to actual cross dipole logging data of Daqing Oilfield. If the parameters are properly selected, there is no obvious drop in inversion velocity.