The Potential of Carbon Dioxide Gas Injection Application in Improving Oil Recovery

Abstract

AbstractCarbon dioxide (CO2) gas could increase oil recovery by means of swelling, evaporating and lowering oil viscosity. In the displacement front, injected gas may become enriched by the oil components and gas may dissolve into the reservoir oil. By assuming that local thermodynamic equilibrium is occurring at the oil-gas interface, the phase behavior can be calculated by the equation of state.The displacement process can be modeled by a set of differential equations, called the mass balance equations, which can be written for each component in the reservoir oil and the CO2 gas injected. The linear velocity component in the mass balance equation is expressed by Darcy’s law for oil and gas phase flow, which comprise oil and gas permeability, oil and gas viscosity and pressure gradient terms. A set of the flow equation then solved numerically by the use of a one dimensional compositional simulator. The simulator has been validated by analytical methods, which is based on the method of characteristics.In this study, we want to see the potential of CO2 injection application in improving oil recovery by simulating a slim tube experiments. CO2 gas is available in large quantity in the Natuna Sea and some place in Kalimantan, Indonesia. The benefit of the study is that we could predict the recovery efficiency of CO2 gas injection in the field by combining the results here with the macroscopic areal sweep and invasion efficiencies obtained from other models or simulations. And, the potential application of the study is that we could have a good estimate of the recovery improvement under CO2 gas injection, which will be the basic input parameters for the economic feasibility study and also a decision can then be made whether to implement or abandon the prospective project.