Patent ID: 8185313

Claim:
A method for predicting hydrocarbon production potential of a subsurface region from geophysical data including at least controlled source electromagnetic survey data (“CSEM data”), comprising: (a) identifying an anomaly region within the subsurface region, characterized by resistivity higher than background or other indication of hydrocarbon potential; (b) defining at least two classification categories for the anomaly region, each category being characterized by one or more different factors related to hydrocarbon production potential, and estimating for each category a prior probability that the anomaly region is in that category, said probability being estimated without taking into account the geophysical data, wherein the at least two categories are mutually exclusive and collectively exhaustive; (c) selecting one or more rock/fluid properties that affect electrical properties of rock and other corresponding properties if another data type besides CSEM data are included in the geophysical data; (d) estimating a probability density for each rock/fluid property selected in (c), and repeating for each category if a property is treated as being category dependent; (e) using the probability densities for the rock/fluid properties, and a quantitative relationship for computing components or derivative quantities of the geophysical data from values of the rock/fluid properties, to construct, for each category, conditional joint probability distributions for the geophysical data in the anomaly region, each said conditional joint probability distribution being a probability of occurrence of one or more observed geophysical data values or one or more quantities derived therefrom, given occurrence of a given category; (f) selecting at least one specific data observation from the geophysical data, or derived there from, corresponding to the anomaly region, and using Bayes's Rule to combine the specific data with the prior probabilities for each category and the conditional joint probability distributions for the observed data to obtain updated (“posterior”) probabilities for each category; and (g) using the updated probabilities to predict hydrocarbon potential of the anomaly region.