摘要
In the pursuit of sustainable oil and gas resource extraction,the innovative integration of carbon capture,utilization,and storage(CCUS)technology has emerged as the most promising approach.During the CCUS process,intricate physicochemical interactions between the injected CO_(2),facilitated through various injection strategies(Water Alternative Gas:WAG/Continue Gas Injection:CGI)and the formation fluids and heterogeneous mineral assemblages within the reservoir trigger alterations in mineral structures,consequently impacting permeability and recovery factors,constituting a pivotal aspect.Precisely delineating and quantifying these interactions is paramount for optimizing process design and evaluating reservoir dynamics in the successful implementation of CCUS operations.This study has carried out qualitative and quantitative characterization of mineral heterogeneity,different pore types,and mineral combination characteristics from a low-permeability sandstone reservoir.Additionally,the effect on the physical properties of minerals from different development methods(WAG/CGI)was investigated using numerical simulation for CCUS applications.The results indicate that the saturated CO_(2)fluid selectively dissolves the potassium feldspar(orthoclase)in intergranular pores,while the intergranular pores are filled with illite and secondary precipitated clay minerals.It initially dissolves the sensitive mineral(ankerite)in the intergranular pores.The decrease of ankerite and increase of illite result from the prolonged contact period between saturated CO_(2)and minerals,which changes the mineral cementation to argillaceous type,thus affecting permeability in the context of CCUS.The spatial impact on reservoir physical properties depends on the spatial heterogeneity of the original sensitive minerals(ankerite,anorthite,illite,etc.)distributed in the study area.In the WAG scheme,the physicochemical interaction between saturated CO_(2)and reservoir minerals is more intense than in the CGI scheme for CCUS operations,significantly impacting cumulative production.
基金
support of The National Foreign Experts Program(Grant no.QN2022060001L)
Ministry of Science and Technology of China and Intelligent Reservoir Numerical Simulation Technology(Grant no.2023DJ8403),China National Petroleum Corporation.
