In this study, a numerical model is developed to investigate the hydrate dissociation and gas production in porous media by depressurization. A series of simulation runs are conducted to study the impacts of permeabil...In this study, a numerical model is developed to investigate the hydrate dissociation and gas production in porous media by depressurization. A series of simulation runs are conducted to study the impacts of permeability characteristics, including permeability reduction exponent, absolute permeability, hydrate accumulation habits and hydrate saturation, sand average grain size and irreducible water saturation. The effects of the distribution of hydrate in porous media are examined by adapting conceptual models of hydrate accumulation habits into simulations to govern the evolution of permeability with hydrate decomposition, which is also compared with the conventional reservoir permeability model, i.e. Corey model. The simulations show that the hydrate dissociation rate increases with the decrease of permeability reduction exponent, hydrate saturation and the sand average grain size. Compared with the conceptual models of hydrate accumulation habits, our simulations indicate that Corey model overpredicts the gas production and the performance of hydrate coating models is superior to that of hydrate filling models in gas production, which behavior does follow by the order of capillary coating〉pore coating〉pore filling〉capillary filling. From the analysis of tl/2, some interesting results are suggested as follows： （1） there is a ＂switch＂ value （the ＂switch＂ absolute permeability） for laboratory-scale hydrate dissociation in porous media, the absolute permeability has almost no influence on the gas production behavior when the permeability exceeds the ＂switch＂ value. In this study, the ＂switch＂ value of absolute permeability can be estimated to be between 10 and 50 md. （2） An optimum value of initial effective water saturation Sw,e exists where hydrate dissociation rate reaches the maximum and the optimum value largely coincides with the value of irreducible water saturation Swr,e. For the case of Sw,e〈,Swr,e, or Sw,e〉Swr,e, there are different control mechanisms dominating the process of hydrate dissociation and gas production.展开更多
This paper summarizes the important progress in the field of oil and gas production engineering during the"Thirteenth Five-Year Plan"period of China,analyzes the challenges faced by the current oil and gas p...This paper summarizes the important progress in the field of oil and gas production engineering during the"Thirteenth Five-Year Plan"period of China,analyzes the challenges faced by the current oil and gas production engineering in terms of technological adaptability,digital construction,energy-saving and emission reduction,and points out the future development direction.During the"Thirteenth Five-Year Plan"period,series of important progresses have been made in five major technologies,including separated-layer injection,artificial lift,reservoir stimulation,gas well de-watering,and workover,which provide key technical support for continuous potential tapping of mature oilfields and profitable production of new oilfields.Under the current complex international political and economic situation,oil and gas production engineering is facing severe challenges in three aspects:technical difficulty increases in oil and gas production,insignificant improvements in digital transformation,and lack of core technical support for energy-saving and emission reduction.This paper establishes three major strategic directions and implementation paths,including oil stabilization and gas enhancement,digital transformation,and green and low-carbon development.Five key research areas are listed including fine separated-layer injection technology,high efficiency artificial lift technology,fine reservoir stimulation technology,long term gas well de-watering technology and intelligent workover technology,so as to provide engineering technical support for the transformation,upgrading and high-quality development of China’s oil and gas industry.展开更多
With the vigorous promotion of energy conservation and implementation of clean energy strategies,China＇s natural gas industry has entered a rapid development phase,and natural gas is playing an increasingly important...With the vigorous promotion of energy conservation and implementation of clean energy strategies,China＇s natural gas industry has entered a rapid development phase,and natural gas is playing an increasingly important role in China＇s energy structure.This paper uses a Generalized Weng model to forecast Chinese regional natural gas production,where accuracy and reasonableness compared with other predictions are enhanced by taking remaining estimated recoverable resources as a criterion.The forecast shows that China＇s natural gas production will maintain a rapid growth with peak gas of 323 billion cubic meters a year coming in 2036;in 2020,natural gas production will surpass that of oil to become a more important source of energy.Natural gas will play an important role in optimizing China＇s energy consumption structure and will be a strategic replacement of oil.This will require that exploration and development of conventional natural gas is highly valued and its industrial development to be reasonably planned.As well,full use should be made of domestic and international markets.Initiative should also be taken in the exploration and development of unconventional and deepwater gas,which shall form a complement to the development of China＇s conventional natural gas industry.展开更多
This study deals with the optimization of best working conditions in molten melt for the production of hydrogen(H2) gas.Limited research has been carried out on how electrochemical process occurs through steam splitti...This study deals with the optimization of best working conditions in molten melt for the production of hydrogen(H2) gas.Limited research has been carried out on how electrochemical process occurs through steam splitting via molten hydroxide.54 combinations of cathode,anode,temperature and voltage have been investigated for the optimization of best working conditions with molten hydroxide for hydrogen gas production.All these electrochemical investigations were carried out at 225 to 300℃ temperature and 1.5 to 2.5 V applied voltage values.The current efficiency of 90.5,80.0 and 68.6% has been achieved using stainless steel anodic cell with nickel,stainless steel and platinum working cathode respectively.For nickel cathode,an increase in the current directly affected the hydrogen gas flow rate at cathode.It can be hypothesized from the noted results that increase in current is directly proportional to operating temperature and applied voltage.Higher values were noted when the applied voltages increased from 1.5 to 2.5 V at 300℃,the flow rate of hydrogen gas increased from 1.5 to 11.3 cm^(3) min^(-1),1.0 to 13 cm^(3) min^(-1) in case of electrolysis@stainless steel and@graphite anode respectively.It is observed that the current efficiency of stainless steel anodic cell was higher than the graphite anodic cell.Therefore,steam splitting with the help of molten salts has shown an encouraging alternate to current methodology for H2 fuel production.展开更多
Monocyclic nitrogen-rich 3-(aminomethyl)-4,5-diamine-1,2,4-triazole(1)and fused cyclic 3,7-diamine-6-(aminomethyl)-[1,2,4]triazolo[4,3-b][1,2,4]triazole(9)were synthesized through the convenient cyclization reaction f...Monocyclic nitrogen-rich 3-(aminomethyl)-4,5-diamine-1,2,4-triazole(1)and fused cyclic 3,7-diamine-6-(aminomethyl)-[1,2,4]triazolo[4,3-b][1,2,4]triazole(9)were synthesized through the convenient cyclization reaction from the readily available reactant.Their energetic salts with high nitrogen content were proved to be rare examples of divalent monocyclic/fused cyclic cationic salts according to the single crystal analyses.The structure of intermediate B was also identified and verified by its trivalent cation crystal 17.5H_2O indirectly.Energetic compounds 2-8 and 10-17 were fully characterized by NMR spectroscopy,infrared spectroscopy,differential scanning calorimetry,elemental analysis.These energetic salts exhibit good thermal stability with decomposition temperatures ranged from 182℃to 245℃.The sensitivity of compounds 2,6,10 and 14 is similar or superior to that of RDX while the others were much more insensitive to mechanical stimulate.Furthermore,detonation velocity of 10(8843 m/s)surpass that of RDX(D=8795 m/s).Considering the high gas production volume(≥808 L/kg)of 2,4,10and 12,constant-volume combustion experiments were conduct to evaluate their gas production capacities specifically.These compounds possess much higher maximum gas-production pressures(P_(max):7.88-10.08 MPa)than the commonly used reagent guanidine nitrate(GN:P_(max)=4.20 MPa),which indicate their strong gas production capacity.展开更多
The process of ionizing normal saline induced by femtosecond laser is studied from the perspective of gas production rate and composition.When the repetition rate is less than 1000 Hz,each laser pulse independently ge...The process of ionizing normal saline induced by femtosecond laser is studied from the perspective of gas production rate and composition.When the repetition rate is less than 1000 Hz,each laser pulse independently generates ionization gas.At the same time,we discovered the inhibitory effect of meglumini diatrizoici on the ionization process and explained the reasons for this inhibition.Finally,the gas composition proved that the primary gas production mechanism of the femtosecond laser is the decomposition of water molecular,and the composition of the solution after the reaction proved the decomposition effect of the laser on meglumine.展开更多
基金supported by the National Science and Technology Major Project,China (Grant No. 2011ZX05026-004-07)the National High Technology Research and Development Program of China (863 Program,Grant No. 2006AA09209-5)Major State Basic Research Development Program of China (973 Program,Grant No. 2009CB219507)
文摘In this study, a numerical model is developed to investigate the hydrate dissociation and gas production in porous media by depressurization. A series of simulation runs are conducted to study the impacts of permeability characteristics, including permeability reduction exponent, absolute permeability, hydrate accumulation habits and hydrate saturation, sand average grain size and irreducible water saturation. The effects of the distribution of hydrate in porous media are examined by adapting conceptual models of hydrate accumulation habits into simulations to govern the evolution of permeability with hydrate decomposition, which is also compared with the conventional reservoir permeability model, i.e. Corey model. The simulations show that the hydrate dissociation rate increases with the decrease of permeability reduction exponent, hydrate saturation and the sand average grain size. Compared with the conceptual models of hydrate accumulation habits, our simulations indicate that Corey model overpredicts the gas production and the performance of hydrate coating models is superior to that of hydrate filling models in gas production, which behavior does follow by the order of capillary coating〉pore coating〉pore filling〉capillary filling. From the analysis of tl/2, some interesting results are suggested as follows： （1） there is a ＂switch＂ value （the ＂switch＂ absolute permeability） for laboratory-scale hydrate dissociation in porous media, the absolute permeability has almost no influence on the gas production behavior when the permeability exceeds the ＂switch＂ value. In this study, the ＂switch＂ value of absolute permeability can be estimated to be between 10 and 50 md. （2） An optimum value of initial effective water saturation Sw,e exists where hydrate dissociation rate reaches the maximum and the optimum value largely coincides with the value of irreducible water saturation Swr,e. For the case of Sw,e〈,Swr,e, or Sw,e〉Swr,e, there are different control mechanisms dominating the process of hydrate dissociation and gas production.
基金Supported by the Basic Science Center Project of National Natural Science Foundation of China(72088101)National Natural Science Funded Project(52074345)CNPC Scientific Research and Technology Development Project(2020D-5001-21)。
文摘This paper summarizes the important progress in the field of oil and gas production engineering during the"Thirteenth Five-Year Plan"period of China,analyzes the challenges faced by the current oil and gas production engineering in terms of technological adaptability,digital construction,energy-saving and emission reduction,and points out the future development direction.During the"Thirteenth Five-Year Plan"period,series of important progresses have been made in five major technologies,including separated-layer injection,artificial lift,reservoir stimulation,gas well de-watering,and workover,which provide key technical support for continuous potential tapping of mature oilfields and profitable production of new oilfields.Under the current complex international political and economic situation,oil and gas production engineering is facing severe challenges in three aspects:technical difficulty increases in oil and gas production,insignificant improvements in digital transformation,and lack of core technical support for energy-saving and emission reduction.This paper establishes three major strategic directions and implementation paths,including oil stabilization and gas enhancement,digital transformation,and green and low-carbon development.Five key research areas are listed including fine separated-layer injection technology,high efficiency artificial lift technology,fine reservoir stimulation technology,long term gas well de-watering technology and intelligent workover technology,so as to provide engineering technical support for the transformation,upgrading and high-quality development of China’s oil and gas industry.
基金the National Social Science Funds of China (13&ZD159)the National Natural Science Foundation of China (71303258, 71373285)+1 种基金MOE (Ministry of Education in China) Project of Humanities and Social Sciences (13YJC630148)Science Foundation of China University of Petroleum, Beijing (ZX20150130) for sponsoring this joint research
文摘With the vigorous promotion of energy conservation and implementation of clean energy strategies,China＇s natural gas industry has entered a rapid development phase,and natural gas is playing an increasingly important role in China＇s energy structure.This paper uses a Generalized Weng model to forecast Chinese regional natural gas production,where accuracy and reasonableness compared with other predictions are enhanced by taking remaining estimated recoverable resources as a criterion.The forecast shows that China＇s natural gas production will maintain a rapid growth with peak gas of 323 billion cubic meters a year coming in 2036;in 2020,natural gas production will surpass that of oil to become a more important source of energy.Natural gas will play an important role in optimizing China＇s energy consumption structure and will be a strategic replacement of oil.This will require that exploration and development of conventional natural gas is highly valued and its industrial development to be reasonably planned.As well,full use should be made of domestic and international markets.Initiative should also be taken in the exploration and development of unconventional and deepwater gas,which shall form a complement to the development of China＇s conventional natural gas industry.
基金the financial supports from the EPSRC (EP/J000582/1 and EP/F026412/1)Ningbo Municipal People’s Government (3315 Plan and 2014A35001-1)。
文摘This study deals with the optimization of best working conditions in molten melt for the production of hydrogen(H2) gas.Limited research has been carried out on how electrochemical process occurs through steam splitting via molten hydroxide.54 combinations of cathode,anode,temperature and voltage have been investigated for the optimization of best working conditions with molten hydroxide for hydrogen gas production.All these electrochemical investigations were carried out at 225 to 300℃ temperature and 1.5 to 2.5 V applied voltage values.The current efficiency of 90.5,80.0 and 68.6% has been achieved using stainless steel anodic cell with nickel,stainless steel and platinum working cathode respectively.For nickel cathode,an increase in the current directly affected the hydrogen gas flow rate at cathode.It can be hypothesized from the noted results that increase in current is directly proportional to operating temperature and applied voltage.Higher values were noted when the applied voltages increased from 1.5 to 2.5 V at 300℃,the flow rate of hydrogen gas increased from 1.5 to 11.3 cm^(3) min^(-1),1.0 to 13 cm^(3) min^(-1) in case of electrolysis@stainless steel and@graphite anode respectively.It is observed that the current efficiency of stainless steel anodic cell was higher than the graphite anodic cell.Therefore,steam splitting with the help of molten salts has shown an encouraging alternate to current methodology for H2 fuel production.
基金supported by the National Natural Science Foundation of China(No.21875110,22075143)the Science Challenge Project(No.TZ2018004)the Qing Lan Project for the grant。
文摘Monocyclic nitrogen-rich 3-(aminomethyl)-4,5-diamine-1,2,4-triazole(1)and fused cyclic 3,7-diamine-6-(aminomethyl)-[1,2,4]triazolo[4,3-b][1,2,4]triazole(9)were synthesized through the convenient cyclization reaction from the readily available reactant.Their energetic salts with high nitrogen content were proved to be rare examples of divalent monocyclic/fused cyclic cationic salts according to the single crystal analyses.The structure of intermediate B was also identified and verified by its trivalent cation crystal 17.5H_2O indirectly.Energetic compounds 2-8 and 10-17 were fully characterized by NMR spectroscopy,infrared spectroscopy,differential scanning calorimetry,elemental analysis.These energetic salts exhibit good thermal stability with decomposition temperatures ranged from 182℃to 245℃.The sensitivity of compounds 2,6,10 and 14 is similar or superior to that of RDX while the others were much more insensitive to mechanical stimulate.Furthermore,detonation velocity of 10(8843 m/s)surpass that of RDX(D=8795 m/s).Considering the high gas production volume(≥808 L/kg)of 2,4,10and 12,constant-volume combustion experiments were conduct to evaluate their gas production capacities specifically.These compounds possess much higher maximum gas-production pressures(P_(max):7.88-10.08 MPa)than the commonly used reagent guanidine nitrate(GN:P_(max)=4.20 MPa),which indicate their strong gas production capacity.
基金the National Natural Science Foundation of China(Grant No.81927805)the Fundamental Research Funds for the Central Universities of HUST(Grant No.2019kfyXKJC062)+2 种基金the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2019B030302003)the Science and Technology Planning Project of Guangdong Province,China(Grant No.2018B090944001)China Postdoctoral Science Foundation(Grant No.2018M632837)。
文摘The process of ionizing normal saline induced by femtosecond laser is studied from the perspective of gas production rate and composition.When the repetition rate is less than 1000 Hz,each laser pulse independently generates ionization gas.At the same time,we discovered the inhibitory effect of meglumini diatrizoici on the ionization process and explained the reasons for this inhibition.Finally,the gas composition proved that the primary gas production mechanism of the femtosecond laser is the decomposition of water molecular,and the composition of the solution after the reaction proved the decomposition effect of the laser on meglumine.
