Phase behavior of CO_(2)-shale oil in nanopores  

作　　者：WANG Yuhan LEI Zhengdong LIU Yishan PAN Xiuxiu CHEN Zhewei ZHANG Yuanqing ZHENG Xiaoyu LIU Pengcheng HAN Yi 

机构地区：[1]China University of Geosciences,Beijing 100083,China [2]Research Institute of Petroleum Exploration and Development,PetroChina,Beijing 100083,China [3]State Key Laboratory of Enhanced Oil Recovery,Beijing 100083,China [4]State Key Laboratory of Continental Shale Oil,Daqing 163000,China [5]University of Chinese Academy of Sciences,Beijing 100049,China [6]Exploration and Development Research Institute of PetroChina Daqing Oilfield Co.,Ltd.,Daqing 163712,China [7]China University of Petroleum(Beijing),Beijing 102249,China

出　　处：《Petroleum Exploration and Development》2025年第1期182-195,共14页石油勘探与开发(英文版)

基　　金：Supported by the National Natural Science Foundation of China Joint Fund(U22B2075).

摘　　要：Considering the interactions between fluid molecules and pore walls,variations in critical properties,capillary forces,and the influence of the adsorbed phase,this study investigates the phase behavior of the CO_(2)-shale oil within nanopores by utilizing a modified Peng-Robinson(PR)equation of state alongside a three-phase(gas-liquid-adsorbed)equilibrium calculation method.The results reveal that nano-confinement effects of the pores lead to a decrease in both critical temperature and critical pressure of fluids as pore size diminishes.Specifically,CO_(2) acts to inhibit the reduction of the critical temperature of the system while promoting the decrease in critical pressure.Furthermore,an increase in the mole fraction of CO_(2) causes the critical point of the system to shift leftward and reduces the area of the phase envelope.In the shale reservoirs of Block A in Gulong of the Daqing Oilfield,China,pronounced confinement effects are observed.At a pore diameter of 10 nm,reservoir fluids progressively exhibit characteristics typical of condensate gas reservoirs.Notably,the CO_(2) content in liquid in 10 nm pores increases by 20.0%compared to that in 100 nm pores,while the CO_(2) content in gas decreases by 10.8%.These findings indicate that confinement effects enhance CO_(2) mass transfer within nanopores,thereby facilitating CO_(2) sequestration and improving microscopic oil recovery.

关 键 词：shale oil NANOPORES nano-confinement effect phase behavior PR equation of state 

分 类 号：P61[天文地球—矿床学]