Patent ID: 7372264
Filing Date: 2008-05-13
Classification: E21B,G01N

Abstract:
1. A method for estimating levels of contamination in borehole fluids, comprising the steps of: (a) providing a first mathematical contamination function model which expresses a time behavior of one or more fluid properties of a mixture of formation fluids and contamination fluids drawn from a borehole, where said one or more fluid properties are sensitive to the fraction of contamination fluids in the mixture; (b) providing a second mathematical mixing law function model expressing at least one of said one or more fluid properties of a fluid mixture in terms of corresponding properties of formation fluids and contamination fluids in the mixture; (c) drawing fluids from the borehole into a fluid analyzer; (d) measuring at least one of said one or more properties of the drawn fluids by the analyzer; and (e) estimating the level of contamination in the fluids drawn from the borehole at one or more points in time based on the at least one measured fluid property and the provided mathematical models in step (a) and step (b).