Simulation of Residual Oil Saturation Through Tuning of Equilibrium Constants

Abstract

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 171806, “Simulation of Residual Oil Saturation in Near-Miscible Gasflooding Through Saturation-Dependent Tuning of the Equilibrium Constants,” by Leonardo Patacchini, Sébastien Duchenne, Marcel Bourgeois, Arthur Moncorgé, and Quentin Pallotta, Total, prepared for the 2014 Abu Dhabi International Petroleum Exhibition and Conference, Abu Dhabi, 10–13 November. The paper has not been peer reviewed. Conventional miscible- or near-miscible-gasflood simulation often overestimates oil recovery, mostly because it does not capture a series of physical effects tending to limit interphase compositional exchanges. The authors present a new engineering solution to this problem in the near-miscible case. The principle is, while using a black-oil or an equation-of-state description, to dynamically decrease the K-value of heavy components and possibly increase the K-value of light components as the oil saturation reaches the desired residual limit. Introduction The novel approach covered in this paper relies on an in-house research reservoir simulator (IHRRS). The starting point of this work is the model activated through the VAPPARS keyword in Eclipse 100 (black-oil code) that is extended to compositional simulation. The benefits of the proposed method are demonstrated on a reservoir-condition tertiary gas- injection experiment, performed in laboratories, for which residual saturations are easily and successfully history matched, along with oil-phase and individual-component production rate. Thermodynamic Equilibrium in IHRRS and Saturation- Dependent Tuning of the Equilibrium Constant (SDTEC) IHRRS is a research reservoir simulator designed to treat a general number of phases where each phase can hold an arbitrary number of components. Equations important to the use of IHRRS are described in detail in the complete paper. Also, detailed discussions of the use of the SDTEC method in black-oil and compositional simulation are presented in the complete paper.