This work numerically investigates surfactant effects on spontaneous water imbibition in oil-wet carbonates.An open boundary core-scale imbibition model with 9×9×10 gridblocks was used in UTCHEM to simulate ...This work numerically investigates surfactant effects on spontaneous water imbibition in oil-wet carbonates.An open boundary core-scale imbibition model with 9×9×10 gridblocks was used in UTCHEM to simulate carbonate core plug exposure to a vast water body.The simulation models were developed based on surfactant-assisted imbibition tests that were conducted in secondary and tertiary oil production modes using Amott cells at 75℃.Capillary and gravity forces were captured by history matching the experiments.Through history matching,the inputs for surfactant adsorption and diffusion,capillary pressure and relative permeability were calibrated.In tertiary mode,the surfactants-assisted imbibition process presents the performance in mixed-wet state rather than oil-wet state,which is governed by wettability alteration.A simulation model for surfactant-assisted imbibition in secondary mode was used to investigate the effects of various factors including interfacial tension(IFT)reduction,wettability alteration,adsorption,volume of surrounding water and capillary force.The simulation results suggest that surfactant-assisted water imbibition in secondary mode is gravity dominant,which is facilitated by both IFT reduction and wettability alteration caused by addition of proper surfactants.Different from water imbibition in water-wet core,it presents vertically dominant oil flow with a hemispherical oil-rich area and uneven remaining oil saturation.It is obvious that sufficient surfactant supply in vast water is required to make effective imbibition,in consideration of surfactant consumption and changes in concentration gradients.This core-scale modeling provides insights of surfactant-assisted imbibition in initially oil-wet carbonates and helps scale up the application in a cost-effective way.展开更多
基于软件实现的多核系统模拟器执行计算密集/数据密集任务的时效性极差,且存在模拟精度和性能评估准确性差的不足,限制其在多核系统结构优化探索中的应用。文章提出一种周期精确的软硬件协同多核系统模拟器(cycle accurate hardware-sof...基于软件实现的多核系统模拟器执行计算密集/数据密集任务的时效性极差,且存在模拟精度和性能评估准确性差的不足,限制其在多核系统结构优化探索中的应用。文章提出一种周期精确的软硬件协同多核系统模拟器(cycle accurate hardware-software co-simulator,CAHSCS),通过在传统模拟器架构中引入硬件计算和存储模块,CAHSCS能有效改善全系统的模拟速度、精度,提高性能评估的准确性。复杂真实任务加载实验结果表明,CAHSCS将大规模复杂数据的运算效率提高了10倍,显著加快了系统设计收敛速度。展开更多
文摘This work numerically investigates surfactant effects on spontaneous water imbibition in oil-wet carbonates.An open boundary core-scale imbibition model with 9×9×10 gridblocks was used in UTCHEM to simulate carbonate core plug exposure to a vast water body.The simulation models were developed based on surfactant-assisted imbibition tests that were conducted in secondary and tertiary oil production modes using Amott cells at 75℃.Capillary and gravity forces were captured by history matching the experiments.Through history matching,the inputs for surfactant adsorption and diffusion,capillary pressure and relative permeability were calibrated.In tertiary mode,the surfactants-assisted imbibition process presents the performance in mixed-wet state rather than oil-wet state,which is governed by wettability alteration.A simulation model for surfactant-assisted imbibition in secondary mode was used to investigate the effects of various factors including interfacial tension(IFT)reduction,wettability alteration,adsorption,volume of surrounding water and capillary force.The simulation results suggest that surfactant-assisted water imbibition in secondary mode is gravity dominant,which is facilitated by both IFT reduction and wettability alteration caused by addition of proper surfactants.Different from water imbibition in water-wet core,it presents vertically dominant oil flow with a hemispherical oil-rich area and uneven remaining oil saturation.It is obvious that sufficient surfactant supply in vast water is required to make effective imbibition,in consideration of surfactant consumption and changes in concentration gradients.This core-scale modeling provides insights of surfactant-assisted imbibition in initially oil-wet carbonates and helps scale up the application in a cost-effective way.
文摘基于软件实现的多核系统模拟器执行计算密集/数据密集任务的时效性极差,且存在模拟精度和性能评估准确性差的不足,限制其在多核系统结构优化探索中的应用。文章提出一种周期精确的软硬件协同多核系统模拟器(cycle accurate hardware-software co-simulator,CAHSCS),通过在传统模拟器架构中引入硬件计算和存储模块,CAHSCS能有效改善全系统的模拟速度、精度,提高性能评估的准确性。复杂真实任务加载实验结果表明,CAHSCS将大规模复杂数据的运算效率提高了10倍,显著加快了系统设计收敛速度。
