Characterization of porous media by chemical tracers using time‐of‐flight and residence time distribution concept

Abstract

AbstractChemical tracer proves itself an efficient and economic means for in‐depth and accurate reservoir characterization, where other known technology fails. In the present study, a new combination of conservative and partitioning tracer, that is, (VI) and 1‐Hexanol, was evaluated for their applicability in field. Laboratory investigation was carried out to characterize a porous medium in terms of heterogeneity, porosity, permeability, and residual oil saturation in addition to swept pore volume determination under enhanced recovery mechanism, with the help of volume balance as well as theoretical models. The tracers were first evaluated for their adsorption characteristics on sandstone at simulated temperature conditions, with more than 98% recovery. The investigation is based upon the tracer concentration measurement at the exit point as a function of time, and the response was used to infer reservoir parameters like swept pore volume, sweep efficiency, average residual oil saturation, and the Lorentz coefficient using method of moment, residence time distribution, and time‐of‐flight (TOF) concept. In the flow condition, interstitial velocity of conservative tracer was measured and used to calculate the TOF. Tortuosity and heterogeneity of the sand pack were determined from various theoretical correlations. The analytically evaluated heterogeneity values were found to match with the experimental data.