CO2多元气与原油相行为及传质规律OA

The large-scale deployment of carbon capture,utilization and storage(CCUS)technologies and the growing demand for low-cost gas sources provide new opportunities for the development of CO2 multicomponent gas flooding.However,the interphase mass transfer mechanisms between CO2 multicomponent gas and crude oil system remains unclear.In this work,non-equilibrium and equilibrium phase experiments,equation-of-state calculations,molecular dynamics simulations,and reservoir-scale numerical simulations were combined to investigate the phase behavior and interphase mass transfer mechanisms of CO2 multicomponent gas and crude oil system.The results show that non-equilibrium systems exhibit spatially heterogeneous local mass transfer.CO2 demonstrates the strongest dynamic mass transfer capacity,while under the same conditions,the dynamic mass transfer effect of N2 is extremely weak.The extraction effect of CO2 multicomponent gas on hydrocarbon components in crude oil exhibits a nonlinear"critical response".When the CO2 mole fraction reaches a critical extraction threshold of approximately 70％,the overall extraction capacity of the system increases significantly,and heavy hydrocarbon components are more sensitive to changes in CO2 concentration.As the crude oil becomes lighter,oil displacement efficiency exhibits weak dependence on the extraction of heavy components by the multicomponent gas.This study provides a theoretical basis for optimizing multicomponent gas composition and selecting low-cost gas sources,and offers a valuable guidance for the field application of CO2 multicomponent gas flooding.