Method and system for seismic imaging and earth modeling using beam tomography

摘要

A beam tomography computer implemented method and system for generating improved seismic images and earth models without dependence on reflector structure is disclosed. Recorded seismic data is transformed into data beams which are compared to forward modeled beams using an earth model having a velocity model to compute raypaths and a seismic image to specify the reflectors. The tomographic updates to the earth model and velocity model are based on misalignments between the data beams and the same beams forward modeled from the velocity model and the seismic image. The updated earth model and seismic image better describe the true propagation of the beams through the earth.

主权项

1. A computer-implemented method of generating a seismic image and earth model related to a subsurface region of the earth, the method comprising:
storing in a computer storage media, a data beam set generated from recorded seismic data that samples a portion of the subsurface region; utilizing a computer system comprising one or more processors configured to communicate with the computer storage media and execute one or more computer programs configured for performing operations comprising: migrating the data beam set, comprising a plurality of data beams, using as input an initial earth model having an initial velocity model representative of the subsurface region, to generate a seismic image of the subsurface region; cross-correlating a modeled beam, derived from the seismic image and earth model, with a corresponding data beam within the data beam set; storing in the computer storage media beam pairs of cross-correlated modeled beams and data beams that for a measured time shift have a cross-correlation value that exceeds a determined threshold, and repeating the cross-correlating and storing operations until a determined number of corresponding data beams have been modeled; and inverting the measured time shifts to generate an updated earth model, having an updated velocity model, wherein the resulting updated earth model of the subsurface region is capable of generating an updated seismic image that accurately describes the propagation of the data beams through the subsurface region.