Spectral data processing method for detection of hydrocarbons
AssigneePhillips Petroleum Company
InventorKenneth R. Sundberg
Life of this patent
Estimating the term…
Abstract
A method of processing spectral data for the earth's surface is provided which effectively identifies areas having a high probability of containing hydrocarbons. The method involves processing of intensity values for various wavebands of radiation reflected from areas of the earth's surface which correspond to image elements called pixels. The intensity values are employed in conjunction with predetermined hydrocarbon productivity data (i.e. drilled productive, dry holes) to derive discriminant probability functions whose values for various pixels are indicative of the presence of hydrocarbons in those pixels.
Claims16
A method of processing spectral data for a preselected set of pixels which correspond to adjacent areas of the earth's surface comprising:
- (a) selecting n waveband(s) as represented by the positive integers 1, . . . n;
- (b) obtaining intensity values for each waveband with respect to electromagnetic radiation reflected from areas of the earth's surface corresponding to each pixel so as to yield an intensity data set {x.sub.1, . . . , x.sub.n } for each pixel where x.sub.1, . . . , x.sub.n correspond to the intensity values for respective wavebands 1, . . . , n;
- (c) dividing said intensity data sets into a predetermined number of disjoint data set clusters, wherein any one intensity data set is contained in only one cluster;
- (d) determining the value of each of monotonic functions f.sub.1 (x), . . . , f.sub.n (x), where x represents intensity, for each respective waveband for each pixel in each cluster so as to yield a function data set {f.sub.1 (x.sub.1), . . . , f.sub.n (x.sub.n)} for each pixel in each cluster, wherein f.sub.1 (x.sub.1), . . . , f.sub.n (x.sub.n) are hereinafter denoted as y.sub.1, . . . , y.sub.n respectively;
- (e) selecting certain productive pixels and dry pixels, associated with each of the clusters, previously determined to correspond to hydrocarbon-bearing and nonbearing areas of the earth's surface respectively;
- (f) determining a discriminant probability function, being a function of y.sub.1, . . . , y.sub.n, for each cluster by utilizing the function data sets corresponding to the productive pixels and dry pixels associated with each respective cluster;
- (g) determining for at least one cluster the value P of its corresponding discriminant probability function with respect to at least one function data set and its corresponding pixel, said value of the discriminant probability function being indicative of the probability of the presence of hydrocarbons;
- (h) determining said at least one pixel to be either potentially productive or dry with respect to hydrocarbons based on its corresponding discriminant probability function value.
A method of processing spectral data for a preselected set of pixels which correspond to adjacent areas of the earth's surface comprising:
- (a) selecting n waveband(s) as represented by the positive integers 1, . . . n;
- (b) obtaining intensity values for each waveband with respect to electromagnetic radiation reflected from areas of the earth's surface corresponding to each pixel so as to yield an intensity data set {x.sub.1, . . . , x.sub.n } for each pixel where x.sub.1, . . . , x.sub.n correspond to the intensity values for respective wavebands 1, . . . , n;
- (c) dividing said intensity data sets into a predetermined number of disjoint data set clusters, wherein any one intensity data set is contained in only one cluster;
- (d) determining the value of each of monotonic functions f.sub.1 (x), . . . , f.sub.n (x) where x represents intensity, for each respective waveband for each pixel in each cluster so as to yield a function data set {f.sub.1 (x.sub.1), . . . , f.sub.n (x.sub.n)} for each pixel in each cluster, wherein f.sub.1 (x.sub.1), . . . , f.sub.n (x.sub.n) are hereinafter denoted as y.sub.1, . . . , y.sub.n respectively;
- (e) selecting certain productive pixels and dry pixels, associated with each of the clusters, previously determined to correspond to hydrocarbon-bearing and nonbearing areas of the earth's surface respectively;
- (f) determining a discriminant probability function, being a function of y.sub.1, . . . , y.sub.n, for each cluster by utilizing the function data sets corresponding to the productive pixels and dry pixels associated with each respective cluster;
- (g) determining for each cluster the value P of its corresponding discriminant probability function with respect to each function data set and its corresponding pixel, said value of the discriminant probability function being indicative of the probability of the presence of hydrocarbons;
- (h) plotting a map of the areas corresponding to said pixels based on the P values associated with said pixels.
Dependencies are inferred from the claim text.