Abstract
This paper presents modeling of a novel tertiary enhanced oil recovery (EOR) method. In this process, slugs of gas and surfactant solution are injected (coinjection or alternate injection) to mobilize and then displace the residual oil saturation. The objective of this paper is to model the mechanisms behind the process through history matching the experimental data and simulation of a field-scale reservoir pilot. A four-phase chemical flooding reservoir simulator (UTCHEM) was used to history match a recently published coreflooding experiment and simulate the field-scale reservoir. The results from the history matching and reservoir simulation revealed that interfacial tension (IFT) reduction between oil and water by the surfactant, displacement of oil by gas, and mobility control of gas are believed to be the main contributors to increase oil production. Based on these key findings, modeling of low-tension surfactant-gas flooding achieves a recovery of 91% of initial oil (Sio=0.56) in laboratory coreflood and a wide range of recovery factors between 65–88% of residual oil trapped by water in the numerical models in reservoir scale.