The impact of connate water saturation and salinity on oil recovery and CO2 storage capacity during carbonated water injection in carbonate rock

作     者：Mahmood Shakiba Masoud Riazi Shahab Ayatollahi Mostafa Takband 

作者机构：Department of Petroleum EngineeringAmirkabir University of TechnologyTehranIran Enhanced Oil Recovery (EOR) Research CentreIOR/EOR Research InstituteShiraz UniversityShirazIran Petroleum Engineering DepartmentSchool of Chemical and Petroleum Eng.Shiraz UniversityShirazIran School of Chemical and Petroleum EngineeringSharif University of TechnologyTehranIran 

出 版 物：《Chinese Journal of Chemical Engineering》 (中国化学工程学报（英文版）)

年 卷 期：2019年第27卷第7期

页      面：1699-1707页

核心收录：

学科分类：0710[理学-生物学] 0830[工学-环境科学与工程（可授工学、理学、农学学位）] 08[工学] 0817[工学-化学工程与技术] 0703[理学-化学] 

基　　金：National Iranian South Oil Company 

主　　题：Carbonated water Connate water Carbonate reservoir Enhanced oil recovery Secondary recovery CO2 storage 

摘      要：Carbonated water injection(CWI)is known as an efficient technique for both CO2 storage and enhanced oil recovery(EOR).During CWI process,CO2 moves from the water phase into the oil phase and results in oil swelling.This mechanism is considered as a reason for EOR.Viscous fingering leading to early breakthrough and leaving a large proportion of reservoir un-swept is known as an unfavorable phenomenon during flooding trials.Generally,instability at the interface due to disturbances in porous medium promotes viscous fingering phenomenon.Connate water makes viscous fingers longer and more irregular consisting of large number of tributaries leading to the ultimate oil recovery reduction.Therefore,higher in-situ water content can worsen this condition.Besides,this water can play as a barrier between oil and gas phases and adversely affect the gas diffusion,which results in EOR reduction.On the other hand,from gas storage point of view,it should be noted that CO2 solubility is not the same in the water and oil phases.In this study for a specified water salinity,the effects of different connate water saturations(Swc)on the ultimate oil recovery and CO2 storage capacity during secondary CWI are being presented using carbonate rock samples from one of Iranian carbonate oil reservoir.The results showed higher oil recovery and CO2 storage in the case of lower connate water saturation,as 14%reduction of Swc resulted in 20%and 16%higher oil recovery and CO2 storage capacity,respectively.