Extended Brigham Model for Residual oil Saturation Measurement by Partitioning Tracer Tests

Abstract

Abstract Brigham’s model has been used extensively in the petroleum industry for the design and interpretation of interwell tracer tests. The model is based on correlation and has included physical dispersion as an input parameter. In spite of its limitations, the model is useful in estimating layer heterogeneity, layer distribution, permeability contrast and dispersion in the reservoir. However, the model can only handle non-partitioning tracers that have no solubility in oil. With the advancement in partitioning tracer technology and interpretation technique, interwell partitioning tracer test has gained its popularity, especially in China, for determining residual oil saturation Sorw between wells. Partitioning tracer test also finds its application in environmental protection, where the test is routinely run to determine the amount of non-aqueous liquid phase NAPL trapped underground due to spill or seepage. While sophisticated streamline or finite difference simulators have been increasingly used to determine Sorw distribution from the tracer production data, simple semi-quantitative model still has its merits in providing a direct, unambiguous estimate of average Sorw along the tracer flow path. This paper broadens the scope of the original Brigham’s model by incorporating partitioning tracers into the model using a chromatographic transformation technique. By matching the partitioning and non-partitioning tracer curves, Sorw can be determined by layers. The extended Brigham model was applied to the Ranger oil field multiple tracer test and the residual oil saturation determined compared favorably with those obtained by chromatographic transformation method and numerical simulation.