Patent ID: 8316934
Filing Date: 2012-11-27
Classification: E21B

Abstract:
1. A method of allocating hydrocarbon production among three or more formations produced by a hydrocarbon well, comprising: obtaining one or more measured values of isotopic concentration from each of three or more formations; obtaining a measured value of isotopic concentration from a commingled flow of from the hydrocarbon well, the commingled flow including flow from each of the three or more formations; randomly selecting a contribution, a, for a first one of the formations, wherein a comprises a fraction of the commingled flow in the range of 0 to 1; randomly selecting a contribution, b, for a second one of the formations, from within a range between 0 and (1−a); operating a computer to evaluate a mixing equation, the mixing equation corresponding to a relationship of contributions from each of the three or more formations to the isotopic concentration value from the commingled flow, the operating step comprising evaluating the mixing equation at the contributions for the first and second ones of the formations and at the measured value of isotopic concentration for the commingled flow, to provide a contribution for a third one of the formations; storing a set of contributions for the first, second, and third ones of the formations resulting from the operating step; repeating the randomly selecting, operating, and storing steps a plurality of times; operating the computer to derive one or more relationships between each of the one or more selected pairs of the formations, from the stored sets of contributions, so that the mixing equation corresponds to a relationship of a contribution to commingled flow from one of the plurality of formations to the isotopic concentration value from the commingled flow; operating the computer to evaluate the mixing equation to identify an allocation of production from one of the formations; and operating the computer to evaluate the one or more relationships between one or more selected pairs of the formations to determine an allocation of production for each formation.