Study On The Mixture Of Supercritical CO₂ And Cosolvent To Improve Shale Oil Recovery

As unconventional oil and gas resource,shale oil can effectively alleviate the crisis of oil and gas resources.The research of shale oil in China has just started.At present,the main way of mining is to rely on natural energy for mining,the recovery is low,and a feasible method is important to improve the recovery of shale reservoir.SC-CO₂ has dual properties of gas and liquid and has good mass transfer ability and solubility.Therefore,this paper puts forward the development mode of SC-CO₂ huff-and-puff,building the experimental equipment,and the effect of the injection pressure,soaking time,huff and puff rotation on the recovery of shale oil recovery were studied.At the same time,this paper innovatively puts forward the method of mixed SC-CO₂ and co-solvent to improve the recovery of shale oil,the impact of ethanol,ethyl acetate,isopropyl alcohol and acetone were analyzed on the recovery,and the study about the effect of ethanol concentration on the recovery rate.Finally,the mechanism of co-solvent is analyzed from the influence of co-solvent on the minimum miscibility pressure of CO₂ and dodecane and the influence of CO₂ on the mass and diffusion in saturated dodecane.The results show that supercritical CO₂ and co-solvent miscibility can effectively improve the recovery of shale oil,which is a feasible experimental method.