CO2/CH4 Dissolved Gas Mechanism of Shengli Shale Oil Based on Molecular Dynamics
With the continue advance of CCUS-EOR projects in China,the main contents of associated gas of the shale oil shift from CH4 to CH4 and CO2 and producing gas-oil ratio increases,resulting such problems as corrosion of pipelines and flow instability.Based on shale oil in the Shengli Oilfield,the paper studies the dissolution law of CO2/CH4 in the shale oil and their competitive relationship.The results show that the saturated dissolved volume of CO2 was much larger than that of CH4 at the same temperature and pressure,the saturated dissolved volume of CO2/CH4 was negatively correlated with temperature and positively correlated with pressure,and the influence of temperature on both was the same.However,due to the larger molecular spacing of CH4,the increase of pressure on the saturated volume of CH4 was larger,which shows that the ratio of CO2/CH4 saturated dissolved volume decreased gradually with the increase of pressure.The study and its result offer some reference to form a steady gas-liquid two-phase flow when CO2/CH4 saturates in the shale oil and achieve mixed transport of shale oil and gas.
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