The micro-nano pore structure of conglomerate in the Lower Karamay Formation of the Xinjiang Oilfield,Junggar Basin,northern China is characterized to predict its impact on fluid reserves and seepage.Authigenic clay m...The micro-nano pore structure of conglomerate in the Lower Karamay Formation of the Xinjiang Oilfield,Junggar Basin,northern China is characterized to predict its impact on fluid reserves and seepage.Authigenic clay minerals are mainly kaolinite(67%),followed by an illite/smectite mixed layer(18%),illite(10%),and chlorite(5%).For kaolinite,pore throats between 0–200 nm are dominant,accounting for 90%of the total pore throats.For illite/smectite mixed layer,pore throats also between 0–200 nm account for nearly 80%,while pore throats between 200-500 nm only account for 15%.For illite,pore throats below 100 nm account for about 80%,while pore throats in the range of 100–500 nm only account for 20%.For chlorite,most throats are below 200 nm.The pore roundness of illite is the highest,while the pore roundness of chlorite is relatively lower.The lower limits of the dynamic and static pore throat radii are 42.128 nm and 72.42 nm,respectively.The theoretical contribution rates of the illite/smectite mixed layer,kaolinite,illite and chlorite to storage/seepage are 60%/45.86%,52.72%/38.18%,37.07%/28.78%and 32.97%/26.3%,respectively.Therefore,the contribution rates of clay minerals in the study area are as follows:illite/smectite mixed layer,kaolinite,illite and chlorite.展开更多
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,int...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.展开更多
基金granted by Petro China Innovation Foundation(Grant No.2019D-5007-0214)the National Mega Project of Oil and Gas(Grant No.2017ZX05013005-009)。
文摘The micro-nano pore structure of conglomerate in the Lower Karamay Formation of the Xinjiang Oilfield,Junggar Basin,northern China is characterized to predict its impact on fluid reserves and seepage.Authigenic clay minerals are mainly kaolinite(67%),followed by an illite/smectite mixed layer(18%),illite(10%),and chlorite(5%).For kaolinite,pore throats between 0–200 nm are dominant,accounting for 90%of the total pore throats.For illite/smectite mixed layer,pore throats also between 0–200 nm account for nearly 80%,while pore throats between 200-500 nm only account for 15%.For illite,pore throats below 100 nm account for about 80%,while pore throats in the range of 100–500 nm only account for 20%.For chlorite,most throats are below 200 nm.The pore roundness of illite is the highest,while the pore roundness of chlorite is relatively lower.The lower limits of the dynamic and static pore throat radii are 42.128 nm and 72.42 nm,respectively.The theoretical contribution rates of the illite/smectite mixed layer,kaolinite,illite and chlorite to storage/seepage are 60%/45.86%,52.72%/38.18%,37.07%/28.78%and 32.97%/26.3%,respectively.Therefore,the contribution rates of clay minerals in the study area are as follows:illite/smectite mixed layer,kaolinite,illite and chlorite.
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.
文摘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.
