Displacement-imbibition coupling production is a pivotal technology for enhancing oil recovery(EOR)in waterflooded tight/shale oil reservoirs.However,the microscopic fluid transport mechanisms across different pore sc...Displacement-imbibition coupling production is a pivotal technology for enhancing oil recovery(EOR)in waterflooded tight/shale oil reservoirs.However,the microscopic fluid transport mechanisms across different pore scales remain inadequately understood.This study presents an innovative real-time nuclear magnetic resonance(NMR)experimental system integrated with MRI-based image processing to dynamically monitor oil-water distribution and quantify local oil saturation during injection-shut-in-production.This approach enables quantitative evaluation of pore utilization across different pore size ranges and reveals the impacts of various driving forces on oil displacement efficiency.The results show that displacement-imbibition coupling production employs multiple mechanisms to achieve balanced contributions from pores of all size scales.The displacement-imbibition oil production mainly consists of three stages:displacement-dominated injection,capillary-driven imbibition during shut-in,and displacement-imbibition coupling effects during production.Pressure oscillations significantly enhance matrix-fracture exchange by lowering pore-throat entry thresholds and redistributing pressure fields.Quantitative analysis shows that large pore dominate early displacement,while small pore contribute more during imbibition.Lithology and pore-throat connectivity critically influence displacement efficiency;vitric tuff outperforms argillaceous siltstone by up to 11.8%.Notably,greater fracture complexity increases the oil-water contact area,enhancing capillary imbibition,reducing reliance on displacement forces,and increasing the contribution of displacement-imbibition coupling effects to oil displacement efficiency by 15.35%.Artificially modifying the pressure field to induce pressure oscillations,effectively utilizing the high conductivity of fractures,and fully leveraging the displacement-imbibition coupling effects within matrix pores are crucial for achieving optimal EOR.Lastly,a new concept of nonlinear flow zoning is introduced to describe spatial variations in flow behavior under complex coupling conditions.These experimentally validated insights into matrix-fracture interactions provide theoretical support for designing improved waterflooding strategies and optimizing oil recovery in tight and shale reservoirs.展开更多
In this work, the structures of a pair of isomers were identified. And we showed the ability of the selective 1D version, performed the most common NMR experiments including the 1D-HMBC and GOESY experiments, to deter...In this work, the structures of a pair of isomers were identified. And we showed the ability of the selective 1D version, performed the most common NMR experiments including the 1D-HMBC and GOESY experiments, to determine the isom^ric composition that were found in the production process of roflumilast. The experimental results proved that this method would be even more time saving and could get more reliable results.展开更多
设计了一种基于核磁共振氟核测定4-三氟甲基吡啶和全氟丁基磺酸钾的扩散排序谱(19 F DOSY NMR)实验。在实验中分别观察到两组扩散序数,在高场的4个峰处于同一水平位置,即具有相同的扩散系数,则证明这4个峰属于同一化合物;低场的一个峰...设计了一种基于核磁共振氟核测定4-三氟甲基吡啶和全氟丁基磺酸钾的扩散排序谱(19 F DOSY NMR)实验。在实验中分别观察到两组扩散序数,在高场的4个峰处于同一水平位置,即具有相同的扩散系数,则证明这4个峰属于同一化合物;低场的一个峰则属于另一化合物,确证了样品中存在两种成分。结果表明,19 F DOSY NMR技术可用于含氟化合物高效、快速的常规分析,亦可测定含氟分子在溶液中的扩散系数,根据扩散系数变化表征分子间是否存在相互作用。展开更多
Study on the microscopic structure of clathrate hydrate has made significant progress in the past decades.This review aims to summarize the state of the art of the experimental characterization of vip molecular occu...Study on the microscopic structure of clathrate hydrate has made significant progress in the past decades.This review aims to summarize the state of the art of the experimental characterization of vip molecular occupancy in clathrate hydrate cages,which is an important area of the microscopic structures.The characterizing method and features of different vip molecular,such as hydrocarbon,carbon dioxide,hydrogen and inhibitor/promoter,in different hydrate cages have been extensively reviewed.A comprehensive use of advanced technologies such as X-ray diffraction,Raman spectroscopy and nuclear magnetic resonance may provide better understanding on the compositions and microscopic mechanisms of clathrate hydrate.展开更多
基金partially supported by the National Natural Science Foundation of China (No. 52174038)the Science Foundation of China University of Petroleum+2 种基金Beijing (No. 2462018YJRC015)the support of the Department of Chemical and Petroleum Engineering of University of Calgarythe China Scholarship Council (No. 202406440057)
文摘Displacement-imbibition coupling production is a pivotal technology for enhancing oil recovery(EOR)in waterflooded tight/shale oil reservoirs.However,the microscopic fluid transport mechanisms across different pore scales remain inadequately understood.This study presents an innovative real-time nuclear magnetic resonance(NMR)experimental system integrated with MRI-based image processing to dynamically monitor oil-water distribution and quantify local oil saturation during injection-shut-in-production.This approach enables quantitative evaluation of pore utilization across different pore size ranges and reveals the impacts of various driving forces on oil displacement efficiency.The results show that displacement-imbibition coupling production employs multiple mechanisms to achieve balanced contributions from pores of all size scales.The displacement-imbibition oil production mainly consists of three stages:displacement-dominated injection,capillary-driven imbibition during shut-in,and displacement-imbibition coupling effects during production.Pressure oscillations significantly enhance matrix-fracture exchange by lowering pore-throat entry thresholds and redistributing pressure fields.Quantitative analysis shows that large pore dominate early displacement,while small pore contribute more during imbibition.Lithology and pore-throat connectivity critically influence displacement efficiency;vitric tuff outperforms argillaceous siltstone by up to 11.8%.Notably,greater fracture complexity increases the oil-water contact area,enhancing capillary imbibition,reducing reliance on displacement forces,and increasing the contribution of displacement-imbibition coupling effects to oil displacement efficiency by 15.35%.Artificially modifying the pressure field to induce pressure oscillations,effectively utilizing the high conductivity of fractures,and fully leveraging the displacement-imbibition coupling effects within matrix pores are crucial for achieving optimal EOR.Lastly,a new concept of nonlinear flow zoning is introduced to describe spatial variations in flow behavior under complex coupling conditions.These experimentally validated insights into matrix-fracture interactions provide theoretical support for designing improved waterflooding strategies and optimizing oil recovery in tight and shale reservoirs.
文摘In this work, the structures of a pair of isomers were identified. And we showed the ability of the selective 1D version, performed the most common NMR experiments including the 1D-HMBC and GOESY experiments, to determine the isom^ric composition that were found in the production process of roflumilast. The experimental results proved that this method would be even more time saving and could get more reliable results.
文摘设计了一种基于核磁共振氟核测定4-三氟甲基吡啶和全氟丁基磺酸钾的扩散排序谱(19 F DOSY NMR)实验。在实验中分别观察到两组扩散序数,在高场的4个峰处于同一水平位置,即具有相同的扩散系数,则证明这4个峰属于同一化合物;低场的一个峰则属于另一化合物,确证了样品中存在两种成分。结果表明,19 F DOSY NMR技术可用于含氟化合物高效、快速的常规分析,亦可测定含氟分子在溶液中的扩散系数,根据扩散系数变化表征分子间是否存在相互作用。
基金Supported by the National Natural Science Foundation of China(51706248,51876222)National Key R&D Program of China(2017YFC0307304)
文摘Study on the microscopic structure of clathrate hydrate has made significant progress in the past decades.This review aims to summarize the state of the art of the experimental characterization of vip molecular occupancy in clathrate hydrate cages,which is an important area of the microscopic structures.The characterizing method and features of different vip molecular,such as hydrocarbon,carbon dioxide,hydrogen and inhibitor/promoter,in different hydrate cages have been extensively reviewed.A comprehensive use of advanced technologies such as X-ray diffraction,Raman spectroscopy and nuclear magnetic resonance may provide better understanding on the compositions and microscopic mechanisms of clathrate hydrate.
