地震岩性模拟中的多解性问题

The nonuniqueness of solutions in seismic lithologic modeling

同济大学, 上海200092

Tongji University, Shanghai 200092

地震岩性模拟(简称SLIM) 是根据波形相似原则用试探法选代反演求取地层速度等参数的方法。众所周知, 各种地震反演方法都不可避免地存在多解性。只有对所采用反演方法的实质与产生多解性的原因有透彻的理解才能正确使用, 得到逼近真值的全局极小解。本文从地层参数、地震子波和初始模型等方面讨论了地震岩性模拟中产生多解性的因素, 提出了一些能有效地减少多解性的途径, 使对实际地震资料经地震岩性模拟处理后得到的地层参数与声波测井曲线基本符合。

Seismic lithologic modeling (SLIM) is a method to obtain patameters such as intervalvelocitics, which utilizes trial iterative invcrsion on the basis of waveform similarity' It is wellknown that there are no seismic inversions which Can overcome the nonuniqueness of solutions,only when the nature of the adopted inversion method and the factors leading to the nonuniquenessare thoroughly understood, can the inversion method be correctly used and the global minimumsolution approximating the truth be dorived.In this paper, the factors leading to nonuniqucness of solutions in SLIM are discussed in thercspects of inteval parameters, seismic wavelets and initial models. Some skills, principles, andways are proposed to effectively deerease the nonuniqueness of the solutions, and to make theinteval parametcrs derived from real data through SLIM basically consistent with the acousticlogging curvcs.