The high-efficient development of shale oil is one of the urgent problems in the petroleum industry. The technology of CO_(2) enhanced oil recovery(EOR) has shown significant effects in developing shale oil. The effec...The high-efficient development of shale oil is one of the urgent problems in the petroleum industry. The technology of CO_(2) enhanced oil recovery(EOR) has shown significant effects in developing shale oil. The effects of several glycol ether additives with low molecular weight on the interactions between CO_(2) and oil were investigated here. The solubility of glycol ether additive in CO_(2) was firstly characterized. Then,the effects of glycol ether additives on the interfacial tension(IFT) between CO_(2) and hexadecane and the volume expansion and extraction performance between CO_(2) and hexadecane under different pressures was investigated. The experimental results show that diethylene glycol dimethyl ether(DEG), triethylene glycol dimethyl ether(TEG), and tetraethylene glycol dimethyl ether(TTEG) all have low cloud point pressure and high affinity with CO_(2). Under the same mass fraction, DGE has the best effect to reduce the IFT between hexadecane and CO_(2) by more than 30.0%, while an overall reduction of 20.0%-30.0% for TEG and 10.0%-20.0% for TTEG. A new method to measure the extraction and expansion rates has been established and can calculate the swelling factor accurately. After adding 1.0% DEG, the expansion and extraction amounts of CO_(2) for hexadecane are respectively increased to 1.75 times and 2.25 times. The results show that glycol ether additives assisted CO_(2) have potential application for EOR. This study can provide theoretical guidance for the optimization of CO_(2) composite systems for oil displacement.展开更多
Three poly(vinyl acetate)(PVAc)oligomers with controlled molecular weight and narrow molecular distribution are synthesized by reversible addition-fragmentation chain transfer(RAFT)polymerization.The effects of the re...Three poly(vinyl acetate)(PVAc)oligomers with controlled molecular weight and narrow molecular distribution are synthesized by reversible addition-fragmentation chain transfer(RAFT)polymerization.The effects of the reaction temperature and the added amount of initiator of the PVAc polymerization are discussed.In addition,the phase behavior of the prepared PVAc in pressured CO2 is determined via the cloud point method.The results indicate that the cloud point of PVAc increases with the increase in the molecular weight,the PVAc concentration,and the temperature.The cloud point pressures for the PVAc mass concentration of 0.12%with the molecular weight of 1 550,2 120,and 2 960 g/mol are 13.48,13.83 and 15.43 MPa,respectively,at the temperature of 35℃.It reveals that the solubility of PVAc in ScCO2 at relatively low pressure is remarkably limited.展开更多
This research investigates the role of dispersion of nanoparticles in gas during gas recycling process to improve the gas condensate recovery via altering the carbonate reservoirs wettability.The nanoparticles were sy...This research investigates the role of dispersion of nanoparticles in gas during gas recycling process to improve the gas condensate recovery via altering the carbonate reservoirs wettability.The nanoparticles were synthesized and analyzed using dynamic light scattering(DLS),energy-dispersive X-ray(EDX),and transmission electron microscopy(TEM).After that,the dispersion of nanoparticles in methane was investigated by cloud point pressures measurement.Also,the effectiveness of methane/nanoparticles solutions was assessed through the contact angle experiments and gas recycling process.Based on the cloud point pressures results,the nanoparticles can be dispersed in methane at pressures commensurate with hydrocarbon reservoirs.Gas/nanoparticles single-phase solutions increased the contact angles of gas condensate and n-decane from 12°to 121°and 135.5°,respectively,for fluorinated silica,and to 100.5°and 108°for fluorinated titania.The shift from oil-wet to gas-wet conditions enhanced the recovery factor from 55%to 76%,marking a 21%improvement in gas condensate recovery during gas recycling.Furthermore,the pressure drop ratio decreased by 60%,due to better surface wettability and reduced condensate blockage.Comparative results indicated that the dispersion of fluorinated silica nanoparticles in gas outperformed fluorinated titania in altering wettability.These results emphasize the potential of current new approach,through dispersion of fluorinated nanoparticles in gas;to improve gas condensate recovery during gas recycling,especially in low-permeability carbonate reservoirs.展开更多
基金financial supports from the National Natural Science Foundation of China (Grant Nos. 42090024, 52174049)the Natural Science Foundation of Shandong Province of China (No. ZR2019MEE058)。
文摘The high-efficient development of shale oil is one of the urgent problems in the petroleum industry. The technology of CO_(2) enhanced oil recovery(EOR) has shown significant effects in developing shale oil. The effects of several glycol ether additives with low molecular weight on the interactions between CO_(2) and oil were investigated here. The solubility of glycol ether additive in CO_(2) was firstly characterized. Then,the effects of glycol ether additives on the interfacial tension(IFT) between CO_(2) and hexadecane and the volume expansion and extraction performance between CO_(2) and hexadecane under different pressures was investigated. The experimental results show that diethylene glycol dimethyl ether(DEG), triethylene glycol dimethyl ether(TEG), and tetraethylene glycol dimethyl ether(TTEG) all have low cloud point pressure and high affinity with CO_(2). Under the same mass fraction, DGE has the best effect to reduce the IFT between hexadecane and CO_(2) by more than 30.0%, while an overall reduction of 20.0%-30.0% for TEG and 10.0%-20.0% for TTEG. A new method to measure the extraction and expansion rates has been established and can calculate the swelling factor accurately. After adding 1.0% DEG, the expansion and extraction amounts of CO_(2) for hexadecane are respectively increased to 1.75 times and 2.25 times. The results show that glycol ether additives assisted CO_(2) have potential application for EOR. This study can provide theoretical guidance for the optimization of CO_(2) composite systems for oil displacement.
基金The Natural Science Foundation of Jiangsu Province(No.BK20130602)the Applied Basic Research Program of Suzhou(No.SYG201836)the Project of the Collaborative Innovation Center of Suzhou Nano Science and Technology
文摘Three poly(vinyl acetate)(PVAc)oligomers with controlled molecular weight and narrow molecular distribution are synthesized by reversible addition-fragmentation chain transfer(RAFT)polymerization.The effects of the reaction temperature and the added amount of initiator of the PVAc polymerization are discussed.In addition,the phase behavior of the prepared PVAc in pressured CO2 is determined via the cloud point method.The results indicate that the cloud point of PVAc increases with the increase in the molecular weight,the PVAc concentration,and the temperature.The cloud point pressures for the PVAc mass concentration of 0.12%with the molecular weight of 1 550,2 120,and 2 960 g/mol are 13.48,13.83 and 15.43 MPa,respectively,at the temperature of 35℃.It reveals that the solubility of PVAc in ScCO2 at relatively low pressure is remarkably limited.
文摘This research investigates the role of dispersion of nanoparticles in gas during gas recycling process to improve the gas condensate recovery via altering the carbonate reservoirs wettability.The nanoparticles were synthesized and analyzed using dynamic light scattering(DLS),energy-dispersive X-ray(EDX),and transmission electron microscopy(TEM).After that,the dispersion of nanoparticles in methane was investigated by cloud point pressures measurement.Also,the effectiveness of methane/nanoparticles solutions was assessed through the contact angle experiments and gas recycling process.Based on the cloud point pressures results,the nanoparticles can be dispersed in methane at pressures commensurate with hydrocarbon reservoirs.Gas/nanoparticles single-phase solutions increased the contact angles of gas condensate and n-decane from 12°to 121°and 135.5°,respectively,for fluorinated silica,and to 100.5°and 108°for fluorinated titania.The shift from oil-wet to gas-wet conditions enhanced the recovery factor from 55%to 76%,marking a 21%improvement in gas condensate recovery during gas recycling.Furthermore,the pressure drop ratio decreased by 60%,due to better surface wettability and reduced condensate blockage.Comparative results indicated that the dispersion of fluorinated silica nanoparticles in gas outperformed fluorinated titania in altering wettability.These results emphasize the potential of current new approach,through dispersion of fluorinated nanoparticles in gas;to improve gas condensate recovery during gas recycling,especially in low-permeability carbonate reservoirs.
