Study of steam heat transfer enhanced by CO2 and chemical agents: In heavy oil production

Steam flooding with the assistance of carbon dioxide (CO2) and chemicals is an effective approach for enhancing super heavy oil recovery. However, the promotion and application of CO2 and chemical agent-assisted steam flooding technology have been restricted by the current lack of research on the synergistic effect of CO2 and chemical agents on enhanced steam flooding heat transfer. The novel experiments on CO2–chemicals cooperate affected steam condensation and seepage were conducted by adding CO2 and two chemicals (sodium dodecyl sulfate (SDS) and the betaine temperature-salt resistant foaming agent ZK-05200). According to the experimental findings, a “film” formed on the heat-transfer medium surface following the co-injection of CO2 and the chemical to impede the steam heat transfer, reducing the heat transfer efficiency of steam, heat flux and condensation heat transfer coefficient. The steam seepage experiment revealed that the temperature at the back end of the sandpack model was dramatically raised by 3.5–12.8 °C by adding CO2 and chemical agents, achieving the goal of driving deep-formation heavy oil. The combined effect of CO2 and SDS was the most effective for improving steam heat transfer, the steam heat loss was reduced by 6.2%, the steam condensation cycle was prolonged by 1.3 times, the condensation heat transfer coefficient was decreased by 15.5%, and the heavy oil recovery was enhanced by 9.82%. Theoretical recommendations are offered in this study for improving the CO2–chemical-assisted steam flooding technique.