The flow characteristics of deionized water in hydrophilic and hydrophobic microtubes with diameters of 14.9,5.03 and 2.05 μm are investigated experimentally.The results indicate that the flow characteristics of deio...The flow characteristics of deionized water in hydrophilic and hydrophobic microtubes with diameters of 14.9,5.03 and 2.05 μm are investigated experimentally.The results indicate that the flow characteristics of deionized water in microtubes with diameter of 14.9 μm are in agreement with the classical Hagen-Poiseuille(H-P) equation,but for hydrophilic and hydrophobic microtubes with smaller diameters,the results show significant departure from the prediction of conventional theory,and the discrepancies are influenced by wettability of the microtubes and increase as the Reynolds numbers decrease.Besides,flows of fluid in cores are the macroscopic reflection of flows in countless micron-sized pore throats,the influence of wettability on microscale flow in pore throats will cause the change of seepage characteristic in cores.Therefore,flow experiments of brine through cores with different wettabilities are conducted.The results demonstrate that wettability exerts similar influence on water flows in cores and microtubes.展开更多
Carbon dioxide reacts with porous media while flowing through them enhancing their permeability.Its flow behavior as well as the permeability enhancement effects were studied in synthetic cores,natural cores and micro...Carbon dioxide reacts with porous media while flowing through them enhancing their permeability.Its flow behavior as well as the permeability enhancement effects were studied in synthetic cores,natural cores and microtubes with an inner diameter of 5 μm.The results show that the permeability of H2O-saturated cores(containing carbonate ingredients) was enhanced by increasing the injection volume of a CO2-H2O solution.This enhancement is attributable to carbon dioxide's corrosion,which is justified by SEM scanning.The same phenomenon occurs with a CO2-H2O solution in microtubes,but for a different reason.The gas flow velocity of carbon dioxide in microtubes was approximately 100% faster than that of nitrogen because of the scale and the squeezing effects.Carbon dioxide molecules dissolved in water accelerate the diffusion rate of water molecules within the boundary layer,which in turn diminishes the thickness of the water film and enlarges the effective pore size.This flow behavior facilitates the injection of carbon dioxide into low-permeability reservoirs for oil-displacement and formation energy buildup purposes.This behavior also increases the potential for carbon dioxide channeling or release from the formation.展开更多
基金Supported by the National Natural Science Foundation of China (Grant No.50574060)National Basic Research Program of China (973Program) (Grant No.2005CB221303)
文摘The flow characteristics of deionized water in hydrophilic and hydrophobic microtubes with diameters of 14.9,5.03 and 2.05 μm are investigated experimentally.The results indicate that the flow characteristics of deionized water in microtubes with diameter of 14.9 μm are in agreement with the classical Hagen-Poiseuille(H-P) equation,but for hydrophilic and hydrophobic microtubes with smaller diameters,the results show significant departure from the prediction of conventional theory,and the discrepancies are influenced by wettability of the microtubes and increase as the Reynolds numbers decrease.Besides,flows of fluid in cores are the macroscopic reflection of flows in countless micron-sized pore throats,the influence of wettability on microscale flow in pore throats will cause the change of seepage characteristic in cores.Therefore,flow experiments of brine through cores with different wettabilities are conducted.The results demonstrate that wettability exerts similar influence on water flows in cores and microtubes.
基金the "973" Project from the Ministry of Science and Technology of China (Grant No.2006CB705805)the National Key Technology R&D Program (Grant Nos.2006BAB03B06 & 2007BAB17B0B)
文摘Carbon dioxide reacts with porous media while flowing through them enhancing their permeability.Its flow behavior as well as the permeability enhancement effects were studied in synthetic cores,natural cores and microtubes with an inner diameter of 5 μm.The results show that the permeability of H2O-saturated cores(containing carbonate ingredients) was enhanced by increasing the injection volume of a CO2-H2O solution.This enhancement is attributable to carbon dioxide's corrosion,which is justified by SEM scanning.The same phenomenon occurs with a CO2-H2O solution in microtubes,but for a different reason.The gas flow velocity of carbon dioxide in microtubes was approximately 100% faster than that of nitrogen because of the scale and the squeezing effects.Carbon dioxide molecules dissolved in water accelerate the diffusion rate of water molecules within the boundary layer,which in turn diminishes the thickness of the water film and enlarges the effective pore size.This flow behavior facilitates the injection of carbon dioxide into low-permeability reservoirs for oil-displacement and formation energy buildup purposes.This behavior also increases the potential for carbon dioxide channeling or release from the formation.
