层状介质中重力,地震联合反演的迭代算法

本文提出一种用于层状介质中重力、地震资料联合反演层速度、层密度及弯曲界面深度的迭代算法。该方法通过引入加权最小平方目标泛函,将层状介质中的重力、地震资料联合反演问题转化成具体的优化问题。为了得到反问题的最优解,文中系统地研究了层状介质中双摄动处理技术,以及层状介质中波场摄动的一阶 Born 近似解与理论重力异常摄动解。并应用 Tarantola 的反演理论,导出了梯度算子的计算公式。然后应用最速下降法给出了求取最优解的具体算法,得到了一种类似于地震偏移与空间更投影的迭代反演方法。对理论模型进行重力、地震联合反演的结果表明,该方法不仅可碱少未知参数的个数,提高反演的收敛速度,而且可减少反演的不适定性,不失为一种可行的多参数反演方法。

Iterative algorithm for joint inversion of gravimetric and seismic data in layered medium.

We present an iterative algorithm for inversely deriving the interval velocity,in- terval density and curved interface depth from gravimetric and seismic data in lay ered medium.The joint inversion problem of gravimetric and seismic data in layered medium can be converted into an optimization problem by introducing a weighted least square objective functional.In order to get the optimal solution of an inverse problem,we analyse systematically the double perturbation processing technique, the first order Born's approximate solution of wave field perturbation and the per- turbation solution of theoretical gravity anomaly in layered medium.Gradient opera- tor formula is obtained using Tarantola's inversion theory.By adopting the steepest descent means ,we develop an optimal algorithm,namely an iterative inversion algo- rithm which is similar to that in seismic migration and spatial back projection.Theo- retical joint inversion of gravimetric and seismic data indicates that this method can decrease unknown parameters,speed up convergence and reduce indeterminacy in in- version.It is really a feasible multiparameter inversion method.