Pore-Scale Investigation of Crude Oil/CO2 Compositional Effects on Oil Recovery by Carbonated Water Injection

Abstract

Through coreflood and micromodel studies, it has been shown that carbonated water injection (CWI) can improve oil recovery compared to conventional waterflood. However, in most early studies, either a refined oil or dead crude oil had been used, which is not representative of a real oil reservoir where the oil has significant dissolved gases. In such studies, oil swelling and oil viscosity reduction had been introduced as the main mechanisms of additional oil recovery by CWI. However, in our direct flow visualization (micromodel) studies reported here, we have used live crude oil, and we have observed the formation and growth of a new gaseous phase inside the oil when it comes in contact with carbonated water (CW). The aim of this work is to visually study the effect of this phenomenon on oil recovery by CWI at pore scale. In this paper, we present the results of two high-pressure high-temperature direct flow visualization (micromodel) experiments which have been performed using a live crude oil sample. T...