Frequency-domain 2D marine CSEM inversion using the improved Gauss-Newton optimization algorithm
A stable and fast inversion is essential for marine controlled-source electromagnetic(CSEM)data interpretation.In this paper,a 2D marine CSEM inversion algorithm based on the improved Gauss-Newton optimization algorithm is developed.For the 2.5D CSEM forward solver used in inversion,the staggered finite-difference(SFD)discretization is applied and the linear system of equations is solved by a direct matrix factorizing solver,which could solve multi-transmitter electromagnetic(EM)responses efficiently with only one time of the matrix factorization per frequency.Furthermore,the improved interpolating algorithm is applied for accurately calculating the EM fields for arbitrarily located seafloor receivers in a more efficient way.The adjoint-equation method is used for calculating the sensitivities implicitly and the Gauss-Newton optimization algorithm with quasi-quadratic convergence is applied which makes the 2D inversion developed converges in a more efficient way.A way using the sensitivity matrix is also applied for selecting the regularization parameter automatically to make the inversion converge in a more stable way.Numerical tests demonstrate the efficiency and stability of the inversion algorithm developed.
万方数据
维普
