Efficiency and recovery mechanisms of carbonated water injection in heterogeneous rocks

The performance of waterflood (WF) is adversely affected by heterogeneity of the reservoir rock. Since most oil reservoirs exhibit some degree of heterogeneity, poor WF performance is a common problem and one that is difficult to remedy. In this work, we have investigated the performance of CO2-enriched (carbonated) water as a potential method for alleviating poor WF performance due to the rock heterogeneity. While there are several coreflood experiments on homogenous cores, the effectiveness of CWI for oil recovery and its recovery mechanisms in heterogeneous rocks has not been investigated before. Furthermore, in most reported coreflood experiments either dead oil or model oil have been used which is not the prevailing conditions of the most oil reservoirs with dissolved gases. Recently, we reported that when carbonated water (CW) comes in contact with "live" oil, a new gaseous phase nucleates which is a game-changer on the performance of CWI and its recovery mechanisms. In this study, through a series of integrated high-pressure high-temperature flooding and visualisation experiments, we are aiming to investigate the efficiency and recovery mechanisms of CWI on oil recovery from heterogeneous oil reservoirs when oil has dissolved gas.