Patent Document ID: 20150073755
Application ID: 14330767
Patent Flag: 0

Claim One:
1. An iterative method for inverting measured geophysical data to infer a subsurface model of one or more physical properties, comprising: (a) using a subsurface property model, computing an objective function measuring misfit between model-simulated data and the measured geophysical data, wherein the model-simulated data are generated using a computer; (b) computing a gradient of the objective function with respect to parameters of the model; (c) preconditioning the gradient by multiplying at least one vector by a Hessian matrix, said Hessian matrix resulting from an operator of second derivatives with respect to parameters of the model operating on the objective function, wherein the Hessian matrix is approximated by a banded matrix obtained by neglecting matrix elements in the Hessian matrix that are not close to its diagonals or sub-diagonals according to a selected diagonal-proximity criterion; (d) using the preconditioned gradient to update the model; and (e) repeating (a)-(d) at least once using the updated model.