Enhancement of Heavy Oil Recovery with High CO2 Injection Rates in Silica Nanochannel

Abstract

CO2 injection enhanced oil recovery has become one of the most important approaches to develop heavy oil from reservoirs. However, the microscopic displacement behavior of heavy oil in the nanochannel is still not fully understood. In this paper, we use CO2 as the displacing agent to investigate the displacement of heavy oil molecules confined between the hydroxylated silica nanochannel by nonequilibrium molecular dynamics simulations. We find that for heavy oil molecules, it requires more much higher displacing speed to fully dissipate the residual oil which is found related to the decreased CO2 adsorption on the silica nanochannel. A faster CO2 gas injection rate will lower the CO2 adsorption inside the nanochannel, and more CO2 will participate in the displacement of the heavy oil. The results from this work will enhance our understanding of the CO2 gas displacing heavy oil recovery and design guidelines for heavy oil recovery applications.

Evaluation of Potential of CO2-Enhanced Oil Recovery (EOR) and Assessment of Capacity for Geological Storage in a Mature Oil Reservoir within Upper Assam Basin, India

“…As the CO 2 injection rate is increased, more CO 2 is introduced into the reservoir, increasing the degree of mixing between CO 2 and oil. This thorough mixing enhances the displacement of oil from the reservoir pores, leading to increased recovery. , Also, at higher injection rates, more CO 2 is available to dilute the oil, resulting in greater viscosity/density reduction and oil swelling, leading to enhancement in the mobility of oil . The increase in recovery as a function of increasing CO 2 rate is also attributable to the fact that it can penetrate deeper into the reservoir, contacting more oil-bearing zones, and displacing oil effectively toward the producers.…”