Patent ID: 8688381
Filing Date: 2014-04-01
Classification: G01V,G16Z

Abstract:
1. A computer-implemented method for simultaneous encoded-source inversion of measured geophysical data, acquired under conditions where the fixed-receiver assumption of simultaneous encoded-source inversion is not valid, to determine a physical properties model for a subsurface region, comprising the following steps wherein all summing, simulating, computing, and updating are performed on a computer that is programmed to perform them: (a) obtaining a group of two or more encoded gathers of the measured geophysical data acquired under conditions where the fixed-receiver assumption is not valid, wherein each gather is associated with a single generalized source, or alternatively with a single receiver, and wherein each gather is encoded with a different encoding function selected from a set of non-equivalent encoding functions; (b) summing the encoded gathers in the group by summing all, or selected, data records in each gather that correspond to a single receiver or alternatively to a single source, and repeating for each different receiver or alternatively for each different source, resulting in a simultaneous encoded gather; (c) assuming a physical properties model of the subsurface region, said model providing values of at least one physical property at locations throughout the subsurface region; (d) simulating a synthetic simultaneous encoded gather of data, using the assumed physical properties model, wherein the simulation uses encoded source signatures, and wherein an entire simultaneous encoded gather is simulated in a single simulation operation; (e) computing an objective function measuring cross-correlation between the simultaneous encoded gather of measured data and the simulated simultaneous encoded gather; (f) updating the physical properties model by optimizing the objective function; (g) iterating steps (a)-(f) at least one more time using the updated physical properties model from the previous iteration as the assumed physical properties model in step (c), resulting in a further updated physical properties model; and (h) downloading, displaying, or saving the further updated physical properties model to computer storage.