With the development of the Tazhong No. 1 carbonate gas condensate reservoir in China, it has become more and more important to study the characteristics of gas condensate well deliverability. A single-well radial sim...With the development of the Tazhong No. 1 carbonate gas condensate reservoir in China, it has become more and more important to study the characteristics of gas condensate well deliverability. A single-well radial simulator for dual-permeability reservoirs was established to study the influences of fluid properties, permeability, and pressure drawdown on well deliverability with and without the capillary number effect. The simulation shows that well deliverability basically maintains its initial value and is not affected by the capillary number when the formation pressure is higher than dew-point pressure. However, well deliverability drops rapidly when the formation pressure is lower than dew-point pressure. Even if the condensate dropout is very low, well deliverability without the capillary number effect reduces to 50 percent of its initial value when reservoir pressure declines to 95 percent of dew-point pressure, but well deliverability is significantly improved if the capillary number effect exists. The capillary number effect is most significant when reservoir pressure is just lower than dew point pressure, then the effect decreases; the reduction of well deliverability is mainly caused by the reduction of gas relative permeability of the matrix system near the wellbore.展开更多
The flowing mechanism of a low permeability gas reservoir is different from a conventional gas reservoir,especially for that with higher irreducible water saturation the threshold pressure gradient exists. At present,...The flowing mechanism of a low permeability gas reservoir is different from a conventional gas reservoir,especially for that with higher irreducible water saturation the threshold pressure gradient exists. At present,in all the deliverability equation,the additional pressure drop caused by the threshold pressure gradient is viewed as constant,but this method has big error in the practical application. Based on the non-Darcy steady flow equation,the limited integral of the additional pressure drop is solved in this paper and it is realized that the additional pressure drop is not a constant but has something to do with production data,and a new deliverability equation is derived,with the relevant processing method for modified isochronal test data. The new deliverability equation turns out to be practical through onsite application.展开更多
Gas well deliverability evaluation and analysis are challenging due to the frequent abnormalities of deliverability test data of gas condensate wells caused by seepage of oil and gas phases in the reservoirs.To this e...Gas well deliverability evaluation and analysis are challenging due to the frequent abnormalities of deliverability test data of gas condensate wells caused by seepage of oil and gas phases in the reservoirs.To this end,based upon the pseudo-single-phase seepage equation and the oilegas two-phase seepage equation,a new deliverability evaluation method was established which is applicable to the following two cases when the flow of a gas well reaches the quasi-steady stage,i.e.,the pseudo-single-phase stable point deliverability evaluation for the case when the formation pressure is above the dew pressure;the gaseliquid two-phase stable point deliverability evaluation for the case when the formation pressure is below the dew pressure.Using this established deliverability evaluation method,based on the basic parameters of the Yaha gas field,Tarim Basin,the IPR curves were first obtained of gas wells do not get this at the same production gaseoil ratio and at the formation pressure above and below the dew point pressure;then,according to the four condensate gas fields,such as Yaha,Tazhong I,Qianmiqiao and Dina 2,the absolute open flow(AOF)potentials of condensate gas wells under different gaseoil production ratios were calculated.Finally,through statistical analysis of the calculation results from typical wells,the following findings were obtained.This new deliverability evaluation method under the two states of condensate gas wells with quasi-single-phase and gaseliquid two-phase stable points can be used to avoid cases due to the oilegas flow in a condensate gas well which has remained unresolved by the classical deliverability evaluation methods.Also,with the increase of gaseoil ratios in gas condensate wells,a variable discrepancy is gradually reduced in AOF potentials calculated respectively by the quasi-single-phase and gaseliquid two-phase stable point deliverability evaluation equations.For the condensate gas wells with high condensate content and low condensate gas production rates,the AOF potentials calculated by the gaseliquid two-phase stable point deliverability equation is more appropriate and reliable compared with that obtained by classical methods.展开更多
In order to quickly and accurately evaluate gas well deliverability,it is necessary to clarify the applicable conditions of the simplified laminarinertial-turbulent gas well deliverability evaluation method(i.e.,press...In order to quickly and accurately evaluate gas well deliverability,it is necessary to clarify the applicable conditions of the simplified laminarinertial-turbulent gas well deliverability evaluation method(i.e.,pressure-squared method and pressure method).In this regard,this paper analyzes the PVT data,simulation wells and field case wells of typical gas reservoirs in China by reviewing the formal evolution of the flow control equation for the real gases in porous media.Then,the applicable conditions of binomial pressure-squared method and pressure method are discussed.And the following research results were obtained.First,when the pressure is lower than 14 MPa,p/(μZ) is basically a constant;and when the pressure is higher than 42 MPa,μZ is basically a constant.Second,the applicable range of the pressure-squared method can be increased from 14 to 20 MPa.In this case,the relative error of absolute open flow potential calculated using the pressure-squared method is less than 5%compared with the pseudo-pressure method.If the pressure is between 20 and 30 MPa,the relative error of the absolute open flow potential calculated using the pressure-squared method is less than 10%.Third,when the pressure exceeds 80 MPa,the relative error of the absolute open flow potential calculated using the pressure method is less than 10%compared with the pseudo-pressure method.If the pressure-squared method is used in the case of high pressure,the calculated absolute open flow potential is lower and the relative error is close to 25%.Fourth,in the case of low pressure,if the pressure is constant,the higher the temperature is,the smaller the relative error between the pressure-squared method and the pseudo-pressure method is.In the case of high pressure,if the pressure is constant,the higher the temperature is,the greater the relative error between the pressure method and the pseudo-pressure method.In conclusion,it is recommended to adopt the pseudo-pressure method in laminareinertial-turbulent gas well deliverability analysis.In the case of low pressure(below 30 MPa),the pressure-squared method can be used.In the case of high pressure(above 80 MPa),the pressure method can be applied.展开更多
Predicting the deliverability change laws of a gas well in the early stage is one of the technical difficulties in natural gas development.The commonly used steady seepage analysis methods have relatively large errors...Predicting the deliverability change laws of a gas well in the early stage is one of the technical difficulties in natural gas development.The commonly used steady seepage analysis methods have relatively large errors.And this problem cannot be solved effectively by the classical methods of production decline analysis and pressure transient well test analysis.To solve this problem,this paper did calculation based on the well test model of constant-pressure production,changed the previous approximate method of simplifying the calculation of the exponential integral function,and accurately calculated the analytical solution of absolute openflow potential of a gas well.In addition,the deliverability instability characteristics of different types of gas wells were quantitatively described by taking vertical wells in homogeneous reservoirs as the reference benchmark.Then,combined with the deliverability evaluation needs of a new well,a new practical method focusing on solving the problems of gas formation testing analysis was researched and developed,and also applied on site at some key wells in the hot spots of natural gas development in the Sichuan Basin.And the following research results were obtained.First,the accurate formula for the analytical solution of well test model significantly enhances the adaptability to short-term test conditions.Second,the newly established chart briefly reveals the quantitative relationship between the unstable deliverability characteristics of a gas well and the main influencing factors.Third,if the char-acteristic parameter of turbulence effect is unknown,it is necessary to perform iterative calculation of the variable skin factor when the well test model of constant-pressure production is used to analyze the change trend of the absolute openflow potential of a gas well.Fourth,by con-ducting comparative analysis on the calculation results of typical cases,the decline laws of the absolute openflow potential of different types of gas wells can be understood further.It is concluded that this new method is capable of improving the prediction accuracy of the unstable deliverability of gas wells.Therefore,it can be widely applied to the deliverability evaluation of gas wells in the exploration stage,the evaluation stage of early development and the commissioning stage of new development and production wells,which is conducive to the formulation of natural gas exploration and development decision.展开更多
Calculating the absolute open flow potential timely and investigating production capacity so as to adjust working system of production wells is one of main means to effectively recovery gas reservoirs during intermedi...Calculating the absolute open flow potential timely and investigating production capacity so as to adjust working system of production wells is one of main means to effectively recovery gas reservoirs during intermediate and late development stage.In order to obtain the open flow potential of gas wells accurately,a new method which utilized a single steady point was proposed in this research,which was based on deliverability formula of a gas well in pseudo-steady state flow with pseudo-pressure form.The influence on factor B in binomial productivity equation caused by the changed permeability was taken into consideration.According to the stable production data,reservoir permeability K can be determined by iterative method firstly,and the coefficient A,B in binomial productivity equation can be calculated with the open flow potential subsequently.It illustrated clearly by a practical example that the new method was suitable for gas wells especially when the producing pressure drop is large.Additionally,the error between the open flow potential value and interpretation result from the multi-point test was small,which proved it to be more simple,economic and effective than the common one.展开更多
Hydrogen has emerged as a promising alternative to meet the growing demand for sustainable and renewable energy sources.Underground hydrogen storage(UHS)in depleted gas reservoirs holds significant potential for large...Hydrogen has emerged as a promising alternative to meet the growing demand for sustainable and renewable energy sources.Underground hydrogen storage(UHS)in depleted gas reservoirs holds significant potential for large-scale energy storage and the seamless integration of intermittent renewable energy sources,due to its capacity to address challenges associated with the intermittent nature of renewable energy sources,ensuring a steady and reliable energy supply.Leveraging the existing infrastructure and well-characterized geological formations,depleted gas reservoirs offer an attractive option for large-scale hydrogen storage implementation.However,significant knowledge gaps regarding storage performance hinder the commercialization of UHS operation.Hydrogen deliverability,hydrogen trapping,and the equation of state are key areas with limited understanding.This literature review critically analyzes and synthesizes existing research on hydrogen storage performance during underground storage in depleted gas reservoirs;it then provides a high-level risk assessment and an overview of the techno-economics of UHS.The significance of this review lies in its consolidation of current knowledge,highlighting unresolved issues and proposing areas for future research.Addressing these gaps will advance hydrogen-based energy systems and support the transition to a sustainable energy landscape.Facilitating efficient and safe deployment of UHS in depleted gas reservoirs will assist in unlocking hydrogen’s full potential as a clean and renewable energy carrier.In addition,this review aids policymakers and the scientific community in making informed decisions regarding hydrogen storage technologies.展开更多
On July 4,2024,Chinese President Xi Jinping attends the“Shanghai Cooperation Organization Plus”meeting in Astana,Kazakhstan,and delivers a speech titled“Joining Hands to Build a More Beautiful Home of the Shanghai ...On July 4,2024,Chinese President Xi Jinping attends the“Shanghai Cooperation Organization Plus”meeting in Astana,Kazakhstan,and delivers a speech titled“Joining Hands to Build a More Beautiful Home of the Shanghai Cooperation Organization”.展开更多
KeLa-2 gas reservoir is the largest uncompartimentalized gas field so far discovered in China, with a reserve of hundreds of billions of cubic meters of dry gas. It has such features as extremely long interval (550m)...KeLa-2 gas reservoir is the largest uncompartimentalized gas field so far discovered in China, with a reserve of hundreds of billions of cubic meters of dry gas. It has such features as extremely long interval (550m), high pressure (74.5MPa) and pressure coefficient (2.022). Gas reservoirs with a pressure coefficient of over 2.0 are not commonly found. The abnormal high-pressure reservoirs are quite different in characteristic and performance during the process of depletion exploitation. Therefore, it is necessary to know the property of pressure sensitivity for this abnormal high-pressure reservoir. The aim of this paper is to test the reservoir pressure sensitivity and to analyze its effect on the deliverability of gas. Through some experiments, the permeability change with the confining pressure of rock samples from KeLa-2 abnormal high-pressure gas reservoir is measured. A power function is used to match the measured data, and to derive an empirical equation to describe the change of permeability through the change of the reservoir pressure or effective overburden pressure. Considering the permeability change during the development of reservoirs, a conventional deliverability equation is modified, and the deliverability curve for KeLa-2 gas reservoir is predicted. The research indicates that the extent of the pressure sensitivity of rock samples from KeLa-2 is higher than that from the Daqing oilfield. KeLa-2 reservoir rock has the feature of an undercompaction state. The pressure sensitivity of a reservoir may decrease the well deliverability. It is concluded that for KeLa-2 reservoir the predicted absolute open flow (AOF), when the pressure sensitivity is taken into account, is approximately 70% of the AOF when permeability is constant and does not change with pressure.展开更多
FOCAC sends the powerful message that China and Africa are pursuing joint development,modernisation and growth.The recently held 2024 Summit of the Forum on China-Africa Cooperation(FOCAC)in Beijing under the theme Jo...FOCAC sends the powerful message that China and Africa are pursuing joint development,modernisation and growth.The recently held 2024 Summit of the Forum on China-Africa Cooperation(FOCAC)in Beijing under the theme Joining Hands to Advance Modernisation and Build a High-Level China-Africa Community with a Shared Future unequivocally demonstrated that FOCAC remains the most important flagship collaborative platform between China and Africa and continues to deliver wide-ranging.展开更多
Objective:The objective of this work is to design and fabricate a novel multifunctional nanocarrier combining thrombus-targeted imaging and ultrasound-mediated drug delivery for the theranostics of thrombotic diseases...Objective:The objective of this work is to design and fabricate a novel multifunctional nanocarrier combining thrombus-targeted imaging and ultrasound-mediated drug delivery for the theranostics of thrombotic diseases.Impact Statement:This study develops a new technology that can accurately visualize the thrombus and deliver drugs with controllable properties to diagnose and treat thrombotic diseases.Introduction:Thrombotic diseases are a serious threat to human life and health.The diagnosis and treatment of thrombotic diseases have always been a challenge.In recent years,nanomedicine has brought new ideas and new methods for the theranostics of thrombotic diseases.However,there are also many problems need to be solved,such as biosafety and stability of nanocarriers,early diagnosis,and timely treatment of thrombotic diseases,difficulty in clinical translation.Methods:The S1P@CD-PLGA-rtPA nanobubbles(NBs)were prepared by integrating sulfur hexafluoride(SF6)-loaded poly(D,L-lactide-co-glycolide)(PLGA)NBs,cyclodextrin(CD),sphingosine-1-phosphate(S1P),and recombinant tissue plasminogen activator(rtPA).Results:S1P@CD-PLGA-rtPA NBs had rapid and excellent thrombosis targeting imaging performance based on the specific interaction of S1P-S1PR1(sphingosine-1-phosphate receptor 1).Furthermore,S1P@CD-PLGA-rtPA NBs that specifically targeting to the thrombosis regions could also respond to external ultrasound to achieve accurate and efficient delivery of rtPA to enhance the thrombolysis effectiveness and efficiency.Conclusion:This study proposes a new idea and strategy of targeting thrombus in rats via the specific interaction of S1P-S1PR1.On this basis,the acoustic response properties of bubble carriers could be fully utilized by combining thrombus-specific targeted imaging and ultrasound-mediated drug delivery for effective thrombolysis,which is expected to be applied in targeted diagnosis and treatment of thrombotic diseases in the future.展开更多
It is of great significance to forecast high yield of CBM wells and analyze dynamic production by having an overall study on the characteristics of the produced CBM and determining the main factors influencing the pro...It is of great significance to forecast high yield of CBM wells and analyze dynamic production by having an overall study on the characteristics of the produced CBM and determining the main factors influencing the productivity of CBM. With the test report and the related geological parameters of a single well, methods of combining the productivity data and typical production curves were used to analyze different geological factors and how to influence the capacity of a single layer. Then, the paper proposed a new understanding about capacity characteristics of the study area and geological control factors： First, the Shanxi formation production capacity characteristics was divided into two-stages, showing signs of gas and gas break- through for 100 days. Second, two parameters, which include potential of gas production and gas production capacity, were bet- ter than the single parameter, such as gas content, coal thickness, and penetration to analyze affecting factors of single well pro- duction. Finally, comprehensive analysis concluded that the ratio of critical desorption pressure to reservoir pressure has greater influence on the production of vertical CBM wells. Besides, the potential of gas production capacity has greater impact at stage of showing gas signs; the coal reservoir pressure and gas production capacity have greater impact at stage of gas breakthrough for 100 days. Thus, to seek the coal bed methane with high ratio of critical desorption pressure to reservoir pressure and high yield of gas will be important guarantee to the success of the coal bed methane exploration and development.展开更多
As for ultra-low permeability reservoir,the adaptability of common nine-spot well pattern is studied through large-scale flat models made by micro-fractured natural sandstone outcrops.Combined with non-linear porous f...As for ultra-low permeability reservoir,the adaptability of common nine-spot well pattern is studied through large-scale flat models made by micro-fractured natural sandstone outcrops.Combined with non-linear porous flow characteristics,the concept of dimensionless pressure sweep efficiency and deliverability index are put forward to evaluate the physical models' well pattern adaptability.Through experiments,the models' pressure distribution is measured and on which basis,the pressure gradient fields are drawn and the porous flow regions of these models are divided into dead oil region,non-linear porous flow region,and quasi-linear porous flow region with the help of twin-core non-linear porous flow curve.The results indicate that rectangular well pattern in fracture reservoirs has the best adaptability,while the worst is inverted nine-spot equilateral well pattern.With the increase of drawdown pressure,dead oil region decreases,pressure sweep efficiency and deliverability index increase; meantime,the deliverability index of rectangular well pattern has much more rational increase.Under the same drawdown pressure,the rectangular well pattern has the largest pressure sweep efficiency.展开更多
This paper examines five cases of mistranslation to shed light on the deliverability and truthfulness of mistranslations.In some cases,a“mistranslation”turns out to be a brilliant translation.Case 1:At a meeting for...This paper examines five cases of mistranslation to shed light on the deliverability and truthfulness of mistranslations.In some cases,a“mistranslation”turns out to be a brilliant translation.Case 1:At a meeting for the UN Security Council Resolution 242,an intentional mistranslation may have been conducted between English and French texts,so Arab nations and Israel would agree.Case 2:At the time of the Sino-Japan diplomatic normalization,Japanese Prime Minister Tanaka made an apology to China that was mistranslated into something banal sounding.Case 3:During his US visit to see President Reagan,Japanese Prime Minister Nakasone’s remarks for an aircraft carrier were mistranslated.Case 4:In TPP negotiations,an ultimatum was pronounced by a Japanese interpreter,although the Japanese negotiator had not said it.Case 5:At a Japanese event,a supposedly deaf composer was dubbed a“digital-age Beethoven”in English;but he replaced it with a“modern-day Beethoven”in Japanese to make himself sound more significant.In hindsight,some cases of mistranslations are hard to judge as mistakes.However,identifying mistranslations helps reveal cultural differences and complicated political differences,and can help improve the quality of translation and interpretation.展开更多
There is lack of performance monitoring technologies and related standards and specifications in the Puguang gas field,which is ultra-deep with high sulfur content.In this paper,five key technologies of dynamic monito...There is lack of performance monitoring technologies and related standards and specifications in the Puguang gas field,which is ultra-deep with high sulfur content.In this paper,five key technologies of dynamic monitoring were developed and the related standards and specifications were formulated by investigating high-sulfur gas fields at home and abroad,combined with equipment development,laboratory experiments,theoretical research and field tests.The five key technologies include gas production profile logging,downhole sampling and fluid phase analysis,dynamic water invasion prediction and water producing horizon identification,gas well productivity testing and evaluation,and development monitoring and safety control of high-sulfur ultra-deep wells.Then,these key technologies were applied for verification in the Puguang gas field.And the following research results were obtained.First,the sulfur-resistant gas production profile logging tool has a tem-perature resistance of 175℃and pressure resistance of 105 MPa.Forty-three well times gas production profile logging is carried out with a success ratio of 100%.Second,the high-sulfur downhole pressure sampler has a temperature resistance of 150℃and pressure resistance of 70 MPa.Seven well times downhole pressure sampling is carried out with a success ratio of 100%.Third,elemental sulfur is precipitated in the formation when the formation pressure drops to 29.5 MPa.And no sulfur is deposited in the wellbore when the production rate of gas well is higher than 20×10^(4)m^(3)/d.Fourth,water producing horizons can be identified accurately and water breakthrough time of gas wells can be predicted by using water producing horizon identification technology and dynamic water invasion prediction model.Water influx rates can be controlled and water-free gas production period of gas wells can be extended by optimizing and adjusting the working systems of gas wells.And fifth,full coverage of gas well productivity testing is realized by using the testing technology of"downhole implanted gauge&cable delivery&wellhead flow-variable rate",pressure calculation model and well testing interpretation model,and the productivity evaluation results of gas wells are accurate.Sixth,the dynamic gas tight pressure of the cable multi-stage leakage control system of super-high pressure and gas tightness is 50 MPa,and the processing technology for waste gas of blowout hookup is applied to 143 well times testing operation with zero leakage and zero pollution.In conclusion,these performance monitoring technologies have been playing an important role in scientifically formulating the production and reserves increase measures and ensuring long-term stable production of the Puguang gas field.展开更多
Recombinant bacteria secreting the transmembrane-truncated region of white spot syndrome virus （WSSV） envelope protein VP28 named DhpVB were constructed, using live Escherichia coli as a deliverer and a con- stituti...Recombinant bacteria secreting the transmembrane-truncated region of white spot syndrome virus （WSSV） envelope protein VP28 named DhpVB were constructed, using live Escherichia coli as a deliverer and a con- stitutive secretory expression plasmid as the expression vector. With the ability to deliver recombinant pro- tein products outside, DhpVB could make VP28 directly interact with the shrimp when injected into shrim- p. In order to test the protection potential, live DhpVB were injected into the marine shrimp Exopalamon carincauda Holthuis for three times and WSSV challenge was performed twice simultaneously at the last two injections of the bacteria. The results showed that DhpVB displayed statistically significant advantage over bacteria without VP28 after the second challenge with an average RI （Resistance index） of 0.67±0.08, compared with 0.41±0.09 of bacteria without VP28 （P 〈0.05）. The data suggested that a quasi-immune response may exist in E. carincauda and live bacteria carrying VP28 could enhance the shrimp resistance against WSSV.展开更多
Mr.Chairman,Ladies and Gentlemen,It is a great honour and pleasure for me tohave the opportunity to deliver this lecture on“How Acupuncture-Moxibustion Should Go For-ward into the 21st Century”.In 1978,the Internati...Mr.Chairman,Ladies and Gentlemen,It is a great honour and pleasure for me tohave the opportunity to deliver this lecture on“How Acupuncture-Moxibustion Should Go For-ward into the 21st Century”.In 1978,the International Conference onPrimary Health Care held in Alma-Ata recog-nized the potential of traditional medicine in ex-tending primary health care to underserved pop-ulations.In many developing countries,in fact,people have always used both traditional展开更多
Opportunistic networks are random networks and do not communicate with each other among respective communication areas.This situation leads to great difficulty in message transfer.This paper proposes a reducing energy...Opportunistic networks are random networks and do not communicate with each other among respective communication areas.This situation leads to great difficulty in message transfer.This paper proposes a reducing energy consumption optimal selection of path transmission(OSPT) routing algorithm in opportunistic networks.This algorithm designs a dynamic random network topology,creates a dynamic link,and realizes an optimized selected path.This algorithm solves a problem that nodes are unable to deliver messages for a long time in opportunistic networks.According to the simulation experiment,OSPT improves deliver ratio,and reduces energy consumption,cache time and transmission delay compared with the Epidemic Algorithm and Spray and Wait Algorithm in opportunistic networks.展开更多
The Film Copy Deliverer Problem (FDP),much more difficult than TSP,is a new problem in the combination optimization. In this paper,a new algorithm is introduced. First,the FDP is converted to TSP. Then an evolutionary...The Film Copy Deliverer Problem (FDP),much more difficult than TSP,is a new problem in the combination optimization. In this paper,a new algorithm is introduced. First,the FDP is converted to TSP. Then an evolutionary algorithm based on inversion operator is adopted. Compared with other Genetic Algorithms,it is not only more simple and easier to realize but also faster and more accurate.展开更多
基金Project "973",a national fundamental research development program,for its financial support
文摘With the development of the Tazhong No. 1 carbonate gas condensate reservoir in China, it has become more and more important to study the characteristics of gas condensate well deliverability. A single-well radial simulator for dual-permeability reservoirs was established to study the influences of fluid properties, permeability, and pressure drawdown on well deliverability with and without the capillary number effect. The simulation shows that well deliverability basically maintains its initial value and is not affected by the capillary number when the formation pressure is higher than dew-point pressure. However, well deliverability drops rapidly when the formation pressure is lower than dew-point pressure. Even if the condensate dropout is very low, well deliverability without the capillary number effect reduces to 50 percent of its initial value when reservoir pressure declines to 95 percent of dew-point pressure, but well deliverability is significantly improved if the capillary number effect exists. The capillary number effect is most significant when reservoir pressure is just lower than dew point pressure, then the effect decreases; the reduction of well deliverability is mainly caused by the reduction of gas relative permeability of the matrix system near the wellbore.
基金National Basic Research Program of China(2007CB209506)
文摘The flowing mechanism of a low permeability gas reservoir is different from a conventional gas reservoir,especially for that with higher irreducible water saturation the threshold pressure gradient exists. At present,in all the deliverability equation,the additional pressure drop caused by the threshold pressure gradient is viewed as constant,but this method has big error in the practical application. Based on the non-Darcy steady flow equation,the limited integral of the additional pressure drop is solved in this paper and it is realized that the additional pressure drop is not a constant but has something to do with production data,and a new deliverability equation is derived,with the relevant processing method for modified isochronal test data. The new deliverability equation turns out to be practical through onsite application.
基金supported by the PetroChina Major Science and Technology Project(No.2014E-3203)。
文摘Gas well deliverability evaluation and analysis are challenging due to the frequent abnormalities of deliverability test data of gas condensate wells caused by seepage of oil and gas phases in the reservoirs.To this end,based upon the pseudo-single-phase seepage equation and the oilegas two-phase seepage equation,a new deliverability evaluation method was established which is applicable to the following two cases when the flow of a gas well reaches the quasi-steady stage,i.e.,the pseudo-single-phase stable point deliverability evaluation for the case when the formation pressure is above the dew pressure;the gaseliquid two-phase stable point deliverability evaluation for the case when the formation pressure is below the dew pressure.Using this established deliverability evaluation method,based on the basic parameters of the Yaha gas field,Tarim Basin,the IPR curves were first obtained of gas wells do not get this at the same production gaseoil ratio and at the formation pressure above and below the dew point pressure;then,according to the four condensate gas fields,such as Yaha,Tazhong I,Qianmiqiao and Dina 2,the absolute open flow(AOF)potentials of condensate gas wells under different gaseoil production ratios were calculated.Finally,through statistical analysis of the calculation results from typical wells,the following findings were obtained.This new deliverability evaluation method under the two states of condensate gas wells with quasi-single-phase and gaseliquid two-phase stable points can be used to avoid cases due to the oilegas flow in a condensate gas well which has remained unresolved by the classical deliverability evaluation methods.Also,with the increase of gaseoil ratios in gas condensate wells,a variable discrepancy is gradually reduced in AOF potentials calculated respectively by the quasi-single-phase and gaseliquid two-phase stable point deliverability evaluation equations.For the condensate gas wells with high condensate content and low condensate gas production rates,the AOF potentials calculated by the gaseliquid two-phase stable point deliverability equation is more appropriate and reliable compared with that obtained by classical methods.
基金Project supported by Major Science&Technology Project of PetroChina Company Limited“Research and application of key technologies for development of deepeultra-deep gas reservoirs in Kuqa Depression”(No.:2018E-1803).
文摘In order to quickly and accurately evaluate gas well deliverability,it is necessary to clarify the applicable conditions of the simplified laminarinertial-turbulent gas well deliverability evaluation method(i.e.,pressure-squared method and pressure method).In this regard,this paper analyzes the PVT data,simulation wells and field case wells of typical gas reservoirs in China by reviewing the formal evolution of the flow control equation for the real gases in porous media.Then,the applicable conditions of binomial pressure-squared method and pressure method are discussed.And the following research results were obtained.First,when the pressure is lower than 14 MPa,p/(μZ) is basically a constant;and when the pressure is higher than 42 MPa,μZ is basically a constant.Second,the applicable range of the pressure-squared method can be increased from 14 to 20 MPa.In this case,the relative error of absolute open flow potential calculated using the pressure-squared method is less than 5%compared with the pseudo-pressure method.If the pressure is between 20 and 30 MPa,the relative error of the absolute open flow potential calculated using the pressure-squared method is less than 10%.Third,when the pressure exceeds 80 MPa,the relative error of the absolute open flow potential calculated using the pressure method is less than 10%compared with the pseudo-pressure method.If the pressure-squared method is used in the case of high pressure,the calculated absolute open flow potential is lower and the relative error is close to 25%.Fourth,in the case of low pressure,if the pressure is constant,the higher the temperature is,the smaller the relative error between the pressure-squared method and the pseudo-pressure method is.In the case of high pressure,if the pressure is constant,the higher the temperature is,the greater the relative error between the pressure method and the pseudo-pressure method.In conclusion,it is recommended to adopt the pseudo-pressure method in laminareinertial-turbulent gas well deliverability analysis.In the case of low pressure(below 30 MPa),the pressure-squared method can be used.In the case of high pressure(above 80 MPa),the pressure method can be applied.
基金Project supported by the National Major Science and Technology Project“Demonstrative Project of Large Carbonate Gas Field Development in Sichuan Basin”(No.2016ZX05052).
文摘Predicting the deliverability change laws of a gas well in the early stage is one of the technical difficulties in natural gas development.The commonly used steady seepage analysis methods have relatively large errors.And this problem cannot be solved effectively by the classical methods of production decline analysis and pressure transient well test analysis.To solve this problem,this paper did calculation based on the well test model of constant-pressure production,changed the previous approximate method of simplifying the calculation of the exponential integral function,and accurately calculated the analytical solution of absolute openflow potential of a gas well.In addition,the deliverability instability characteristics of different types of gas wells were quantitatively described by taking vertical wells in homogeneous reservoirs as the reference benchmark.Then,combined with the deliverability evaluation needs of a new well,a new practical method focusing on solving the problems of gas formation testing analysis was researched and developed,and also applied on site at some key wells in the hot spots of natural gas development in the Sichuan Basin.And the following research results were obtained.First,the accurate formula for the analytical solution of well test model significantly enhances the adaptability to short-term test conditions.Second,the newly established chart briefly reveals the quantitative relationship between the unstable deliverability characteristics of a gas well and the main influencing factors.Third,if the char-acteristic parameter of turbulence effect is unknown,it is necessary to perform iterative calculation of the variable skin factor when the well test model of constant-pressure production is used to analyze the change trend of the absolute openflow potential of a gas well.Fourth,by con-ducting comparative analysis on the calculation results of typical cases,the decline laws of the absolute openflow potential of different types of gas wells can be understood further.It is concluded that this new method is capable of improving the prediction accuracy of the unstable deliverability of gas wells.Therefore,it can be widely applied to the deliverability evaluation of gas wells in the exploration stage,the evaluation stage of early development and the commissioning stage of new development and production wells,which is conducive to the formulation of natural gas exploration and development decision.
基金Fund project:National Basic Research Program of China(973 Program-2014CB239205).
文摘Calculating the absolute open flow potential timely and investigating production capacity so as to adjust working system of production wells is one of main means to effectively recovery gas reservoirs during intermediate and late development stage.In order to obtain the open flow potential of gas wells accurately,a new method which utilized a single steady point was proposed in this research,which was based on deliverability formula of a gas well in pseudo-steady state flow with pseudo-pressure form.The influence on factor B in binomial productivity equation caused by the changed permeability was taken into consideration.According to the stable production data,reservoir permeability K can be determined by iterative method firstly,and the coefficient A,B in binomial productivity equation can be calculated with the open flow potential subsequently.It illustrated clearly by a practical example that the new method was suitable for gas wells especially when the producing pressure drop is large.Additionally,the error between the open flow potential value and interpretation result from the multi-point test was small,which proved it to be more simple,economic and effective than the common one.
基金supporting this work and funding research through the project Enabling Large-Scale Hydrogen Underground Storage in Porous Media(21.RP2.0091)。
文摘Hydrogen has emerged as a promising alternative to meet the growing demand for sustainable and renewable energy sources.Underground hydrogen storage(UHS)in depleted gas reservoirs holds significant potential for large-scale energy storage and the seamless integration of intermittent renewable energy sources,due to its capacity to address challenges associated with the intermittent nature of renewable energy sources,ensuring a steady and reliable energy supply.Leveraging the existing infrastructure and well-characterized geological formations,depleted gas reservoirs offer an attractive option for large-scale hydrogen storage implementation.However,significant knowledge gaps regarding storage performance hinder the commercialization of UHS operation.Hydrogen deliverability,hydrogen trapping,and the equation of state are key areas with limited understanding.This literature review critically analyzes and synthesizes existing research on hydrogen storage performance during underground storage in depleted gas reservoirs;it then provides a high-level risk assessment and an overview of the techno-economics of UHS.The significance of this review lies in its consolidation of current knowledge,highlighting unresolved issues and proposing areas for future research.Addressing these gaps will advance hydrogen-based energy systems and support the transition to a sustainable energy landscape.Facilitating efficient and safe deployment of UHS in depleted gas reservoirs will assist in unlocking hydrogen’s full potential as a clean and renewable energy carrier.In addition,this review aids policymakers and the scientific community in making informed decisions regarding hydrogen storage technologies.
文摘On July 4,2024,Chinese President Xi Jinping attends the“Shanghai Cooperation Organization Plus”meeting in Astana,Kazakhstan,and delivers a speech titled“Joining Hands to Build a More Beautiful Home of the Shanghai Cooperation Organization”.
文摘KeLa-2 gas reservoir is the largest uncompartimentalized gas field so far discovered in China, with a reserve of hundreds of billions of cubic meters of dry gas. It has such features as extremely long interval (550m), high pressure (74.5MPa) and pressure coefficient (2.022). Gas reservoirs with a pressure coefficient of over 2.0 are not commonly found. The abnormal high-pressure reservoirs are quite different in characteristic and performance during the process of depletion exploitation. Therefore, it is necessary to know the property of pressure sensitivity for this abnormal high-pressure reservoir. The aim of this paper is to test the reservoir pressure sensitivity and to analyze its effect on the deliverability of gas. Through some experiments, the permeability change with the confining pressure of rock samples from KeLa-2 abnormal high-pressure gas reservoir is measured. A power function is used to match the measured data, and to derive an empirical equation to describe the change of permeability through the change of the reservoir pressure or effective overburden pressure. Considering the permeability change during the development of reservoirs, a conventional deliverability equation is modified, and the deliverability curve for KeLa-2 gas reservoir is predicted. The research indicates that the extent of the pressure sensitivity of rock samples from KeLa-2 is higher than that from the Daqing oilfield. KeLa-2 reservoir rock has the feature of an undercompaction state. The pressure sensitivity of a reservoir may decrease the well deliverability. It is concluded that for KeLa-2 reservoir the predicted absolute open flow (AOF), when the pressure sensitivity is taken into account, is approximately 70% of the AOF when permeability is constant and does not change with pressure.
文摘FOCAC sends the powerful message that China and Africa are pursuing joint development,modernisation and growth.The recently held 2024 Summit of the Forum on China-Africa Cooperation(FOCAC)in Beijing under the theme Joining Hands to Advance Modernisation and Build a High-Level China-Africa Community with a Shared Future unequivocally demonstrated that FOCAC remains the most important flagship collaborative platform between China and Africa and continues to deliver wide-ranging.
基金supported by the project of National Natural Science Foundation of China(81971750)Natural Science Foundation of Jiangsu Province(Grant No.BK20222002)+1 种基金National Key Research and Development Program of China(2018YFA0704103)Project 333 of Jiangsu Province.
文摘Objective:The objective of this work is to design and fabricate a novel multifunctional nanocarrier combining thrombus-targeted imaging and ultrasound-mediated drug delivery for the theranostics of thrombotic diseases.Impact Statement:This study develops a new technology that can accurately visualize the thrombus and deliver drugs with controllable properties to diagnose and treat thrombotic diseases.Introduction:Thrombotic diseases are a serious threat to human life and health.The diagnosis and treatment of thrombotic diseases have always been a challenge.In recent years,nanomedicine has brought new ideas and new methods for the theranostics of thrombotic diseases.However,there are also many problems need to be solved,such as biosafety and stability of nanocarriers,early diagnosis,and timely treatment of thrombotic diseases,difficulty in clinical translation.Methods:The S1P@CD-PLGA-rtPA nanobubbles(NBs)were prepared by integrating sulfur hexafluoride(SF6)-loaded poly(D,L-lactide-co-glycolide)(PLGA)NBs,cyclodextrin(CD),sphingosine-1-phosphate(S1P),and recombinant tissue plasminogen activator(rtPA).Results:S1P@CD-PLGA-rtPA NBs had rapid and excellent thrombosis targeting imaging performance based on the specific interaction of S1P-S1PR1(sphingosine-1-phosphate receptor 1).Furthermore,S1P@CD-PLGA-rtPA NBs that specifically targeting to the thrombosis regions could also respond to external ultrasound to achieve accurate and efficient delivery of rtPA to enhance the thrombolysis effectiveness and efficiency.Conclusion:This study proposes a new idea and strategy of targeting thrombus in rats via the specific interaction of S1P-S1PR1.On this basis,the acoustic response properties of bubble carriers could be fully utilized by combining thrombus-specific targeted imaging and ultrasound-mediated drug delivery for effective thrombolysis,which is expected to be applied in targeted diagnosis and treatment of thrombotic diseases in the future.
文摘It is of great significance to forecast high yield of CBM wells and analyze dynamic production by having an overall study on the characteristics of the produced CBM and determining the main factors influencing the productivity of CBM. With the test report and the related geological parameters of a single well, methods of combining the productivity data and typical production curves were used to analyze different geological factors and how to influence the capacity of a single layer. Then, the paper proposed a new understanding about capacity characteristics of the study area and geological control factors： First, the Shanxi formation production capacity characteristics was divided into two-stages, showing signs of gas and gas break- through for 100 days. Second, two parameters, which include potential of gas production and gas production capacity, were bet- ter than the single parameter, such as gas content, coal thickness, and penetration to analyze affecting factors of single well pro- duction. Finally, comprehensive analysis concluded that the ratio of critical desorption pressure to reservoir pressure has greater influence on the production of vertical CBM wells. Besides, the potential of gas production capacity has greater impact at stage of showing gas signs; the coal reservoir pressure and gas production capacity have greater impact at stage of gas breakthrough for 100 days. Thus, to seek the coal bed methane with high ratio of critical desorption pressure to reservoir pressure and high yield of gas will be important guarantee to the success of the coal bed methane exploration and development.
基金Project(2011ZX05013-006)supported by the National Science and Technology Project of China
文摘As for ultra-low permeability reservoir,the adaptability of common nine-spot well pattern is studied through large-scale flat models made by micro-fractured natural sandstone outcrops.Combined with non-linear porous flow characteristics,the concept of dimensionless pressure sweep efficiency and deliverability index are put forward to evaluate the physical models' well pattern adaptability.Through experiments,the models' pressure distribution is measured and on which basis,the pressure gradient fields are drawn and the porous flow regions of these models are divided into dead oil region,non-linear porous flow region,and quasi-linear porous flow region with the help of twin-core non-linear porous flow curve.The results indicate that rectangular well pattern in fracture reservoirs has the best adaptability,while the worst is inverted nine-spot equilateral well pattern.With the increase of drawdown pressure,dead oil region decreases,pressure sweep efficiency and deliverability index increase; meantime,the deliverability index of rectangular well pattern has much more rational increase.Under the same drawdown pressure,the rectangular well pattern has the largest pressure sweep efficiency.
文摘This paper examines five cases of mistranslation to shed light on the deliverability and truthfulness of mistranslations.In some cases,a“mistranslation”turns out to be a brilliant translation.Case 1:At a meeting for the UN Security Council Resolution 242,an intentional mistranslation may have been conducted between English and French texts,so Arab nations and Israel would agree.Case 2:At the time of the Sino-Japan diplomatic normalization,Japanese Prime Minister Tanaka made an apology to China that was mistranslated into something banal sounding.Case 3:During his US visit to see President Reagan,Japanese Prime Minister Nakasone’s remarks for an aircraft carrier were mistranslated.Case 4:In TPP negotiations,an ultimatum was pronounced by a Japanese interpreter,although the Japanese negotiator had not said it.Case 5:At a Japanese event,a supposedly deaf composer was dubbed a“digital-age Beethoven”in English;but he replaced it with a“modern-day Beethoven”in Japanese to make himself sound more significant.In hindsight,some cases of mistranslations are hard to judge as mistakes.However,identifying mistranslations helps reveal cultural differences and complicated political differences,and can help improve the quality of translation and interpretation.
基金Project supported by the National Major Science and Technology Project“Safe&Effective Development of High-Sulfur Gas Reservoir(PhaseⅢ)”(No.:2016ZX05017)the Sinopec’s“Ten-Project”Scientific Research Project“Enhanced Gas Recovery Technology for Ultra-Deep&High-Sulfur Gas Field”(No.:P18062).
文摘There is lack of performance monitoring technologies and related standards and specifications in the Puguang gas field,which is ultra-deep with high sulfur content.In this paper,five key technologies of dynamic monitoring were developed and the related standards and specifications were formulated by investigating high-sulfur gas fields at home and abroad,combined with equipment development,laboratory experiments,theoretical research and field tests.The five key technologies include gas production profile logging,downhole sampling and fluid phase analysis,dynamic water invasion prediction and water producing horizon identification,gas well productivity testing and evaluation,and development monitoring and safety control of high-sulfur ultra-deep wells.Then,these key technologies were applied for verification in the Puguang gas field.And the following research results were obtained.First,the sulfur-resistant gas production profile logging tool has a tem-perature resistance of 175℃and pressure resistance of 105 MPa.Forty-three well times gas production profile logging is carried out with a success ratio of 100%.Second,the high-sulfur downhole pressure sampler has a temperature resistance of 150℃and pressure resistance of 70 MPa.Seven well times downhole pressure sampling is carried out with a success ratio of 100%.Third,elemental sulfur is precipitated in the formation when the formation pressure drops to 29.5 MPa.And no sulfur is deposited in the wellbore when the production rate of gas well is higher than 20×10^(4)m^(3)/d.Fourth,water producing horizons can be identified accurately and water breakthrough time of gas wells can be predicted by using water producing horizon identification technology and dynamic water invasion prediction model.Water influx rates can be controlled and water-free gas production period of gas wells can be extended by optimizing and adjusting the working systems of gas wells.And fifth,full coverage of gas well productivity testing is realized by using the testing technology of"downhole implanted gauge&cable delivery&wellhead flow-variable rate",pressure calculation model and well testing interpretation model,and the productivity evaluation results of gas wells are accurate.Sixth,the dynamic gas tight pressure of the cable multi-stage leakage control system of super-high pressure and gas tightness is 50 MPa,and the processing technology for waste gas of blowout hookup is applied to 143 well times testing operation with zero leakage and zero pollution.In conclusion,these performance monitoring technologies have been playing an important role in scientifically formulating the production and reserves increase measures and ensuring long-term stable production of the Puguang gas field.
基金The National Basic Research Program of China (973 Program) under contract No. 2012CB114403General Program of National Natural Science Foundation of China to Dr. Fuhua Li under contract No. 31072203+1 种基金National Hightech Research and Development Program under contract Nos 2012AA10A404 and 2012AA092205China Agriculture Research System under contract No. CARS-47
文摘Recombinant bacteria secreting the transmembrane-truncated region of white spot syndrome virus （WSSV） envelope protein VP28 named DhpVB were constructed, using live Escherichia coli as a deliverer and a con- stitutive secretory expression plasmid as the expression vector. With the ability to deliver recombinant pro- tein products outside, DhpVB could make VP28 directly interact with the shrimp when injected into shrim- p. In order to test the protection potential, live DhpVB were injected into the marine shrimp Exopalamon carincauda Holthuis for three times and WSSV challenge was performed twice simultaneously at the last two injections of the bacteria. The results showed that DhpVB displayed statistically significant advantage over bacteria without VP28 after the second challenge with an average RI （Resistance index） of 0.67±0.08, compared with 0.41±0.09 of bacteria without VP28 （P 〈0.05）. The data suggested that a quasi-immune response may exist in E. carincauda and live bacteria carrying VP28 could enhance the shrimp resistance against WSSV.
文摘Mr.Chairman,Ladies and Gentlemen,It is a great honour and pleasure for me tohave the opportunity to deliver this lecture on“How Acupuncture-Moxibustion Should Go For-ward into the 21st Century”.In 1978,the International Conference onPrimary Health Care held in Alma-Ata recog-nized the potential of traditional medicine in ex-tending primary health care to underserved pop-ulations.In many developing countries,in fact,people have always used both traditional
基金Supported by the National Natural Science Foundation of China(No.61379057,61073186,61309001,61379110,61103202)Doctoral Fund of Ministry of Education of China(No.20120162130008)the National Basic Research Program of China(973 Program)(No.2014CB046305)
文摘Opportunistic networks are random networks and do not communicate with each other among respective communication areas.This situation leads to great difficulty in message transfer.This paper proposes a reducing energy consumption optimal selection of path transmission(OSPT) routing algorithm in opportunistic networks.This algorithm designs a dynamic random network topology,creates a dynamic link,and realizes an optimized selected path.This algorithm solves a problem that nodes are unable to deliver messages for a long time in opportunistic networks.According to the simulation experiment,OSPT improves deliver ratio,and reduces energy consumption,cache time and transmission delay compared with the Epidemic Algorithm and Spray and Wait Algorithm in opportunistic networks.
文摘The Film Copy Deliverer Problem (FDP),much more difficult than TSP,is a new problem in the combination optimization. In this paper,a new algorithm is introduced. First,the FDP is converted to TSP. Then an evolutionary algorithm based on inversion operator is adopted. Compared with other Genetic Algorithms,it is not only more simple and easier to realize but also faster and more accurate.
