Seismic anomaly detection using double-windowed statistical analysis

摘要

Method for identifying geologic features from seismic data (11) using seismic anomaly detection by a double-windowed statistical analysis. Subtle features that may be obscured using a single window on the data are made identifiable using two moving windows of user-selected size and shape: a pattern window located within a sampling window larger than the pattern window (12). If Gaussian statistics are assumed, the statistical analysis may be performed by computing mean and covariance matrices for the data within the pattern window in its various positions within the sampling window (13). Then a specific measure of degree of anomaly for each voxel such as a residue value may be computed for each sampling window using its own mean and covariance matrix (14), and finally the resulting residue volume may be analyzed, with or without thresholding, for physical features indicative of hydrocarbon potential (15).

主权项

1. A method for inferring presence of hydrocarbons from a seismic data volume representing a subsurface region, using local statistical distributions of seismic data values, comprising:
(a) using two moving windows of user-selected size and shape, one being a pattern window and the other a sampling window larger than the pattern window, wherein the sampling window moves to different locations in the seismic data volume to sample the seismic data volume, and at each location of the sampling window the pattern window moves about within the sampling window; (b) for each sampling window location, computing a statistical distribution of seismic data values for all pattern windows contained within the sampling window; (c) from the statistical distribution within a sampling window, computing an outlier probability or residue for each sampling window; and (d) generating, with a computer, a subsurface image that identifies geologic features, including hydrocarbon accumulations, within the seismic data volume using the outlier probabilities or residues for the sampling windows.