Beam inversion by monte carlo back projection
AssigneeChevron U.S.A. Inc.
InventorN. Ross Hill
Life of this patent
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Abstract
The present invention is directed to a method and system for minimizing artifacts in a seismic image of a subsurface region of interest, wherein the image is determined a data beam set derived from recorded seismic data and a modeled beam set derived at least in part from a velocity model related to a subsurface region. The artifacts, which may result from cycle skipping and coherent noise, result in misalignment of the modeled and data beam sets. The present invention utilizes a Monte Carlo inversion technique to update the velocity model and thus minimize the artifact in the seismic image.
Claims7
A computer-implemented method for minimizing artifacts in a seismic image of a subsurface region of interest, the image based on a data beam set derived from recorded seismic data and a modeled beam set derived at least in part from a velocity model related to a subsurface region and the seismic image, the method comprising:
- determining a cross-correlation function between the modeled beam set and data beam set over a predetermined range of time shifts;
- and
- performing a Monte Carlo inversion including a back-projection and a global minimization to update the velocity model.
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 non-transitory 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, and 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 non-transitory computer storage media beam pairs of crosscorrelated modeled beams and data beams that for a measured time shift have a cross-correlation value that exceeds a determined threshold, and repeating the crosscorrelating and storing operations until a determined number of corresponding data beams have been modeled;
- and
- performing a Monte Carlo inversion of 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.
Dependencies are inferred from the claim text.