MRI study on CO2 flooding characteristics in n-decane saturated glass bead packs

CO2 enhanced oil recovery (EOR) offers the potential for both increasing domestic oil production and storing significant volumes of carbon dioxide emissions. Laboratory scale experiments are effective methods for the visualization and quantification of flooding characters. In this paper a series of experiments on n-decane displacement by both gaseous and supercritical CO2 flooding in glass bead pack were carried out using a 400 MHz magnetic resonance imaging (MRI) system. Images were obtained for direct visualization of the displacement procedures as CO2 was injected and processed to quantify the displacement parameters using image intensity analysis. Channeling and viscous fingering phenomena appeared obviously in the case of gaseous CO2 flooding. But there was no such two phase flow behavior in supercritical CO2 flooding because of the miscibility of supercritical CO2 with n-decane. Residual saturation of n-decane in glass bead packs was evaluated to be 32.2% for gaseous CO2 flooding and 14.5% for supercritical CO2 flooding. It was proved that miscible phase displacement can improve the efficiency of CO2 flooding notably.