Method for characterizing the coherence of an environment characteristic measurements

Abstract

A method for evaluating the coherence of environmental measurements of a given geological medium or field using well logging data is disclosed. A series of N geological parameters are each measured at a series of reference points found in reference wells within this medium. Each reference point is at a different depth and has known lithological characteristics, and the N measurements form a reference observation (Xi) corresponding to that point. The same N parameters are measured at application points found in one or more application wells, at depths identical to those of the reference points, forming an application observation (x) for each application point. A neighboring domain (Di) and acceptance class are defined for each reference observation (Xi). Each application observation (x) is then compared with all of reference observations (Xi) using a nearest-neighbor algorithm to determine the degree of membership of the application observation in each reference observation's acceptance class. This degree of membership is then used to predict or estimate the lithological characteristics for each application point.