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.
