Patent ID: 9568627
Date: 2017-02-14
CPC Classifications: G01V

Claim:
1. A method for imaging a volume in the Earth's subsurface, comprising a) accepting as input to a computer recordings of signals acquired by a plurality of seismic sensors disposed in a selected pattern above the volume in response to repeated actuations of at least one seismic energy source, the recorded signals from each sensor summed for the plurality of actuations of the at least one seismic energy source; b) in the computer, calculating a travel time of seismic energy from a position of the at least one seismic energy source to at least one selected image point in the volume and from the at least one image point to each seismic sensor; c) in the computer, generating a time-delayed scanline gather from the travel times using a predetermined model of spatial distribution of acoustic properties of formations in the volume; d) in the computer, generating a template image of backscattered acoustic energy from the at least one image point based on the predetermined model; e) in the computer, performing singular value decomposition on the time-delayed scanline gather; f) in the computer, projecting the template image onto the decomposed time delayed scanline gather to determine a signal component and an interference component therein; g) in the computer, inverse time-delay transforming the determined signal components prior to further performing (c) through (f) until a selected number of components of interference have been determined and subsequently removed from the signal component; h) in the computer, calculating a weight for each sensor to implement a spatial filter to be applied to the time delayed signal component from which the selected number of interference components have been removed; i) in the computer, applying the product of each weight to each sensor signal and summing the weighted sensor signals from all the seismic sensors such that the at least one image point corresponds to a focal point of beamforming; and j) at least one of storing and displaying an output of the beamforming at the at least one selected image point.