The transientflow testing of ultra-deepwater gas wells is greatly impacted by the low temperatures of seawater encountered over extended distances.This leads to a redistribution of temperature within the wellbore,which...The transientflow testing of ultra-deepwater gas wells is greatly impacted by the low temperatures of seawater encountered over extended distances.This leads to a redistribution of temperature within the wellbore,which in turn influences theflow behavior.To accurately predict such a temperature distribution,in this study a comprehensive model of theflowing temperature and pressurefields is developed.This model is based on principles offluid mechanics,heat transfer,mass conservation,and energy conservation and relies on the Runge-Kutta method for accurate integration in time of the resulting equations.The analysis includes the examination of the influence of various factors,such as gasflow production rate,thermal diffusivity of the formation,and thermal diffusivity of seawater,on the temperature and pressure profiles of the wellbore.The keyfindings can be summarized as follows:1.Higher production rates during testing lead to increasedflowing temperatures and decreased pressures within the wellbore.However,in the presence of a seawater thermocline,a crossover inflowing temperature is observed.2.An increase in wellbore pressure is associated with larger pipe diameters.3.Greater thermal diffusivity of the formation results in more rapid heat transfer from the wellbore to the formation,which causes lowerflowing temperatures within the wellbore.4.In an isothermal layer,higher thermal diffusivity of seawater leads to increased wellboreflowing temperatures.Conversely,in thermocline and mixed layer segments,lower temperatures are noted.5.Production test data from a representative deep-water gas well in the South China Sea,used to calculate the bottom-seafloor-wellhead temperature and pressurefields across three operating modes,indicate that the average error in temperature prediction is 2.18%,while the average error in pressure prediction is 5.26%,thereby confirming the reliability of the theoretical model.展开更多
Internal solitary waves(ISWs) contain great energy and have the characteristics of emergency and concealment. To avoid their damage to offshore engineering, a new generation of monitoring and early warning system for ...Internal solitary waves(ISWs) contain great energy and have the characteristics of emergency and concealment. To avoid their damage to offshore engineering, a new generation of monitoring and early warning system for ISWs was developed using technologies of double buoys monitoring, intelligent realtime data transmission, and automatic software identification. The system was applied to the second natural gas hydrates(NGHs) production test in the Shenhu Area, South China Sea(SCS) and successfully provided the early warning of ISWs for 173 days(from October 2019 to April 2020). The abrupt changes in the thrust force of the drilling platform under the attack of ISWs were consistent with the early warning information, proving the reliability of this system. A total of 93 ISWs were detected around the drilling platform. Most of them occurred during the spring tides in October–December 2019 and April 2020, while few of them occurred in winter. As suggested by the theoretical model, the full-depth structure of ISWs was a typical current profile of mode-1, and the velocities of wave-induced currents can reach 80 cm/s and30 cm/s, respectively, in the upper ocean and near the seabed. The ISWs may be primarily generated from the interactions between the topography and semidiurnal tides in the Luzon Strait, and then propagate westward to the drilling platform. This study could serve as an important reference for the early warning of ISWs for offshore engineering construction in the future.展开更多
This paper analyses the principle of microwave humidity testing. According to the problems in the production procedure of ceramic products, a microwave humidity testing system is designed and analyzed for its advantag...This paper analyses the principle of microwave humidity testing. According to the problems in the production procedure of ceramic products, a microwave humidity testing system is designed and analyzed for its advantages. Furthermore, the system has been applied to the production line that produces ceramic products and the testing results are also satisfying.展开更多
High concentrated and heterogeneous distribution of gas hydrates have been identified in the gas hydrate production test region in the Shenhu area,South China Sea.The gas hydrate-bearing sediments with high saturation...High concentrated and heterogeneous distribution of gas hydrates have been identified in the gas hydrate production test region in the Shenhu area,South China Sea.The gas hydrate-bearing sediments with high saturation locate at two ridges of submarine canyon with different thickness and saturations just above the bottom simulating reflection.The crossplots of gamma ray,acoustic impedance(P-impedance)and porosity at four sites show that the sediments can be divided into the upper and lower layers at different depths,indicating different geotechnical reservoir properties.Therefore,the depositional environments and physical properties at two ridges are analyzed and compared to show the different characteristics of hydrate reservoir.High porosity,high P-wave velocity,and coarse grain size indicate better reservoir quality and higher energy depositional environment for gas hydrate at Sites W18 and W19 than those at Sites W11 and W17.Our interpretation is that the base of canyon deposits at Sites W18 and W19 characterized by upward-coarsening units may be turbidity sand layers,thus significantly improving the reservoir quality with increasing gas hydrate saturation.The shelf and slope sliding deposits compose of the fine-grained sediments at Sites W11 and W17.The gas hydrate production test sites were conducted at the ridge of W11 and W17,mainly because of the thicker and larger area of gas hydrate-bearing reservoirs than those at Sites W18 and W19.All the results provide useful insights for assessing reservoir quality in the Shenhu area.展开更多
Forest tree species reproduction is a key factor in maintaining the genetic diversity of future generations and the stability of forest ecosystems.The ongoing ash dieback disease could affect the reproductive ecology ...Forest tree species reproduction is a key factor in maintaining the genetic diversity of future generations and the stability of forest ecosystems.The ongoing ash dieback disease could affect the reproductive ecology of Fraxinus excelsior L.and have a major impact on the quantity and quality of pollen and seeds.In this study,we investigated pollen production and viability of pollen and seeds of ash trees with different health status from 2018 to 2022.Inflorescences were collected from 105 trees(pollen production),pollen from 125 trees(pollen viability),and seeds from 53 trees(seed quality)in two seed orchards and in one floodplain forest in southern Germany.Not all parameters were examined at every site every year.The average pollen production per tree was estimated at 471.2±647.9 billion pollen grains.In addition,we found that a high number of inflorescences did not equate to high pollen production per inflorescence.Pollen production of healthy and diseased trees did not differ significantly,although only 47%of severely diseased male trees(vs.72%for healthy trees)produced flowers.With regards to pollen viability,the TTC test showed an average viability of 73%±17%.Overall,there was a slight tendency for diseased trees to have less viable pollen.However,a significant difference could only be calculated for trees in the floodplain forest.The percentage of germinable seeds in 2018 was 38%in the floodplain forest and 57%in one of the seed orchards.The percentage of viable seeds(TTC test)ranged from 17 to 22%in the orchards in 2020.Non-viable seeds were usually heavily infested by insects.In general,seed quality was not significantly different between healthy and diseased trees.Our results indicate that ash dieback affects flower formation and pollen viability but not pollen production or seed quality.Nevertheless,the fact that hardly any flowering was observed,especially for trees that were seriously affected,suggests a negative effect of ash dieback on reproductive performance.Thus,severely diseased trees will transfer their genes to a smaller extent to the next generation.展开更多
Mechatronic products usually endure the variable stress spectrum when they operate in certain operational condition and environmental condition, which obey the Weibull distribution. In accordance with the features of ...Mechatronic products usually endure the variable stress spectrum when they operate in certain operational condition and environmental condition, which obey the Weibull distribution. In accordance with the features of mechatronic product, this paper analyzes the failure mode, its corresponding sensitive stress and the design principles of life testing profiles. Based on the above analyses, this paper presents a synthetic stress life testing method based on the hybrid Weibull distribution and its statistical method under variable stress spectrum to evaluate the reliability and life indices of mechatronic products. Because the mechatronic products have many characteristics such as high price, long life and small testing samples, the synthetic stress life testing method under variable load spectrum can simulate the real various spectra, decrease the life testing time and reduce the testing samples. So it is effective to carry out the life testing to mechatronic products. The application results of hydraulic pumps indicate that this method can easily handle the experimental data under variable amplitude spectrum, obtain the high precision parameters point estimation and confidence interval estimation and reduce the testing cost greatly.展开更多
Despite the widespread use of malaria rapid diagnostic test(RDT)in clinical practice,there are a lot of challenges.We conducted a secondary analysis of 129 malaria RDT data from rounds 5–8 of the World Health Organiz...Despite the widespread use of malaria rapid diagnostic test(RDT)in clinical practice,there are a lot of challenges.We conducted a secondary analysis of 129 malaria RDT data from rounds 5–8 of the World Health Organization(WHO)product testing summary and discuss the causes of false-negative(FN)results with a focus on low parasite density,improper RDT storage,operation and interpretation,and Plasmodium falciparum with a pfhrp2/3 gene deletion.The results demonstrated that the malaria RDTs currently commercially available might cause FN results in practice.展开更多
This paper focuses on the production testing of Memristor Ratioed Logic (MRL) gates. MRL is a family that uses memristors along with CMOS inverters to design logic gates. Two-input NAND and NOR gates are inv...This paper focuses on the production testing of Memristor Ratioed Logic (MRL) gates. MRL is a family that uses memristors along with CMOS inverters to design logic gates. Two-input NAND and NOR gates are investigated using the stuck at fault model for the memristors and the five-fault model for the transistors. Test escapes may take place while testing faults in the memristors. Therefore, two solutions are proposed to obtain full coverage for the MRL NAND and NOR gates. The first is to apply scaled input voltages and the second is to change the switching threshold of the CMOS inverter. In addition, it is shown that test speed and order should be taken into consideration. It is proven that three ordered test vectors are needed for full coverage in MRL NAND and NOR gates, which is different from the order required to obtain 100% coverage in the conventional NAND and NOR CMOS designs.展开更多
Reservoir safety, testing-string safety, and flow control are key factors that should be considered in deep-water unconsolidated sandstone gas well testing work system. Combined with the feature of testing reservoir, ...Reservoir safety, testing-string safety, and flow control are key factors that should be considered in deep-water unconsolidated sandstone gas well testing work system. Combined with the feature of testing reservoir, pipe string type and sea area, the required minimum testing flow rate during cleaning up process, as well as minimum test flow rate without hydrate generation, pipe string erosion critical production, the maximum testing flow rate without destroying sand formation and the minimum output of meeting the demand of development was analyzed;based on the above critical test flow rates, testing working system is designed. Field application showed that the designed work system effectively provided good guidance for field test operations;no sand production or hydrate generation happened during the test process;the test parameter evaluated the reservoir accurately;the safe and efficient test operation was achieved.展开更多
As production automation systems have been and are becoming more and more complex, the task of quality assurance is increasingly challenging. Model-based testing is a research field addressing this challenge and many ...As production automation systems have been and are becoming more and more complex, the task of quality assurance is increasingly challenging. Model-based testing is a research field addressing this challenge and many approaches have been suggested for different applications. The goal of this paper is to review these approaches regarding their suitability for the domain of production automation in order to identify current trends and research gaps. The different approaches are classified and clustered according to their main focus which is either testing and test case generation from some form of model automatons, test case generation from models used within the development process of production automation systems, test case generation from fault models or test case selection and regression testing.展开更多
China is the biggest country of rice production and consumption in the world;more than 50% of the population feeds chiefly on rice. The quality of rice and its role as a staplefood carry much weight. The rice qualitie...China is the biggest country of rice production and consumption in the world;more than 50% of the population feeds chiefly on rice. The quality of rice and its role as a staplefood carry much weight. The rice qualities are those aspects concerning processing, appearance,cooking, nutrition and safety of the product. The study, formulation and implementation of standardson rice qualities and testing bear heavily on the improving of rice qualities, human health,substitution of rice varieties, promoting quality rice production and regulating rice market.展开更多
At Baiyin dairy farm, the Chinese herbal additive was added into feed which was then fed to dairy cows from August to October, 2014, and the changes in milk production and quality were observed. The test showed that t...At Baiyin dairy farm, the Chinese herbal additive was added into feed which was then fed to dairy cows from August to October, 2014, and the changes in milk production and quality were observed. The test showed that the additive added into the feed had obvious milk-increasing effect, the milk production was im- proved by 12.67%-17.26%, and the milk quality was improved. The additive has the effects of preventing miscarriage, expelling parasite and preventing diseases. The nutritional components in the feed additive were determined, and the results showed that the contents of protein, crude fat, Ca and P in the additive were 12.29%, 2.66%, 1.8% and 0.22%, respectively.展开更多
Based on the plane of weakness theory, a model for predicting borehole stability in fractured reservoirs under different stress states was estiblisted and the equations for solving borehole stability were developed. T...Based on the plane of weakness theory, a model for predicting borehole stability in fractured reservoirs under different stress states was estiblisted and the equations for solving borehole stability were developed. The minimum downhole pressures required to maintain borehole stability under different natural fracture occurrences were calculated by using the data from a well in the Tazhong (central Tarim) area, Tarim Basin, west China. Several conclusions were drawn for naturally fractured reservoirs with a dip angle from less than 10° to greater than 30°. Application in three wells in the Tazhong area indicates that this model is practically useful.展开更多
Natural gas hydrates (NGH)is one of key future clean energy resources.Its industrialized development will help remit the huge demand of global natural gas,relieve the increasing pressure of the environment, and play a...Natural gas hydrates (NGH)is one of key future clean energy resources.Its industrialized development will help remit the huge demand of global natural gas,relieve the increasing pressure of the environment, and play a vital role in the green sustainable growth of human societies.Based on nearly two decades' studying on the reservoir characteristics in the South China Sea (SCS)and the knowledge of reservoir system,the China Geological Survey (CGS)conducted the first production test on an optimal target selected in Shenhu area SCS in 2017.Guided by the "three-phase control"exploitation theory which focused on formation stabilization,technologies such as formation fluid extraction,well drilling and completing, reservoir stimulating,sand controlling,environmental monitoring,monitoring and preventing of secondary formation of hydrates were applied.The test lasted for 60 days from May 10^th when starting to pump, drop pressure and ignite to well killing on July 9^th,with gas production of 3.09×10^5 m^3 in total,which is a world record with the longest continuous duration of gas production and maximal gas yield.This successful test brings a significant breakthrough on safety control of NGH production.展开更多
In May and July of 2017,China Geological Survey (CGS),and Guangzhou Marine Geological Survey (GMGS)carried out a production test of gas hydrate in the Shenhu area of the South China Sea and acquired a breakthrough of ...In May and July of 2017,China Geological Survey (CGS),and Guangzhou Marine Geological Survey (GMGS)carried out a production test of gas hydrate in the Shenhu area of the South China Sea and acquired a breakthrough of two months continuous gas production and nearly 3.1×10^5 m^3 of production. The gas hydrate reservoir in the Shenhu area of China,is mainly composed of fine-grained clay silt with low permeability,and very difficult for exploitation,which is very different from those discovered in the USA,and Canada (both are conglomerate),Japan (generally, coarse sand)and India (fracture-filled gas hydrate).Based on 3D seismic data preserved-amplitude processing and fine imaging,combined with logging-while-drilling (LWD)and core analysis data,this paper discusses the identification and reservoir characterization of gas hydrate orebodies in the Shenhu production test area.We also describe the distribution characteristics of the gas hydrate deposits and provided reliable data support for the optimization of the production well location.Through BSR feature recognition,seismic attribute analysis, model based seismic inversion and gas hydrate reservoir characterization,this paper describes two relatively independent gas hydrate orebodies in the Shenhu area,which are distributed in the north-south strip and tend to be thicker in the middle and thinner at the edge.The effective thickness of one orebody is bigger but the distribution area is relatively small.The model calculation results show that the distribution area of the gas hydrate orebody controlled by W 18/W 19 is about 11.24 km^2,with an average thickness of 19 m and a maximum thickness of 39 m,and the distribution area of the gas hydrate orebody controlled by W11/W17 is about 6.42 km^2,with an average thickness of 26 m and a maximum thickness of 90 m.展开更多
文摘The transientflow testing of ultra-deepwater gas wells is greatly impacted by the low temperatures of seawater encountered over extended distances.This leads to a redistribution of temperature within the wellbore,which in turn influences theflow behavior.To accurately predict such a temperature distribution,in this study a comprehensive model of theflowing temperature and pressurefields is developed.This model is based on principles offluid mechanics,heat transfer,mass conservation,and energy conservation and relies on the Runge-Kutta method for accurate integration in time of the resulting equations.The analysis includes the examination of the influence of various factors,such as gasflow production rate,thermal diffusivity of the formation,and thermal diffusivity of seawater,on the temperature and pressure profiles of the wellbore.The keyfindings can be summarized as follows:1.Higher production rates during testing lead to increasedflowing temperatures and decreased pressures within the wellbore.However,in the presence of a seawater thermocline,a crossover inflowing temperature is observed.2.An increase in wellbore pressure is associated with larger pipe diameters.3.Greater thermal diffusivity of the formation results in more rapid heat transfer from the wellbore to the formation,which causes lowerflowing temperatures within the wellbore.4.In an isothermal layer,higher thermal diffusivity of seawater leads to increased wellboreflowing temperatures.Conversely,in thermocline and mixed layer segments,lower temperatures are noted.5.Production test data from a representative deep-water gas well in the South China Sea,used to calculate the bottom-seafloor-wellhead temperature and pressurefields across three operating modes,indicate that the average error in temperature prediction is 2.18%,while the average error in pressure prediction is 5.26%,thereby confirming the reliability of the theoretical model.
基金funded by the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) (GML2019ZD0307)the Marine Geological Survey Program of China Geological Survey (DD20190218, DD20221706)+1 种基金the Key Program of Marine Economy Development Special Foundation of Department of Natural Resources of Guangdong Province (GDNRC [2020] 043)the National Natural Science Foundation of China (41806074, 41730528)。
文摘Internal solitary waves(ISWs) contain great energy and have the characteristics of emergency and concealment. To avoid their damage to offshore engineering, a new generation of monitoring and early warning system for ISWs was developed using technologies of double buoys monitoring, intelligent realtime data transmission, and automatic software identification. The system was applied to the second natural gas hydrates(NGHs) production test in the Shenhu Area, South China Sea(SCS) and successfully provided the early warning of ISWs for 173 days(from October 2019 to April 2020). The abrupt changes in the thrust force of the drilling platform under the attack of ISWs were consistent with the early warning information, proving the reliability of this system. A total of 93 ISWs were detected around the drilling platform. Most of them occurred during the spring tides in October–December 2019 and April 2020, while few of them occurred in winter. As suggested by the theoretical model, the full-depth structure of ISWs was a typical current profile of mode-1, and the velocities of wave-induced currents can reach 80 cm/s and30 cm/s, respectively, in the upper ocean and near the seabed. The ISWs may be primarily generated from the interactions between the topography and semidiurnal tides in the Luzon Strait, and then propagate westward to the drilling platform. This study could serve as an important reference for the early warning of ISWs for offshore engineering construction in the future.
文摘This paper analyses the principle of microwave humidity testing. According to the problems in the production procedure of ceramic products, a microwave humidity testing system is designed and analyzed for its advantages. Furthermore, the system has been applied to the production line that produces ceramic products and the testing results are also satisfying.
基金Supported by the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(No.GML2019ZD0104)the National Natural Science Foundation of China(Nos.U19B2005,42076072)+1 种基金the Pilot National Laboratory for Marine Science and Technology(Qingdao)Initial Foundation(No.JCZX202019)the Research Start-up Funds of Zhufeng Scholars Program。
文摘High concentrated and heterogeneous distribution of gas hydrates have been identified in the gas hydrate production test region in the Shenhu area,South China Sea.The gas hydrate-bearing sediments with high saturation locate at two ridges of submarine canyon with different thickness and saturations just above the bottom simulating reflection.The crossplots of gamma ray,acoustic impedance(P-impedance)and porosity at four sites show that the sediments can be divided into the upper and lower layers at different depths,indicating different geotechnical reservoir properties.Therefore,the depositional environments and physical properties at two ridges are analyzed and compared to show the different characteristics of hydrate reservoir.High porosity,high P-wave velocity,and coarse grain size indicate better reservoir quality and higher energy depositional environment for gas hydrate at Sites W18 and W19 than those at Sites W11 and W17.Our interpretation is that the base of canyon deposits at Sites W18 and W19 characterized by upward-coarsening units may be turbidity sand layers,thus significantly improving the reservoir quality with increasing gas hydrate saturation.The shelf and slope sliding deposits compose of the fine-grained sediments at Sites W11 and W17.The gas hydrate production test sites were conducted at the ridge of W11 and W17,mainly because of the thicker and larger area of gas hydrate-bearing reservoirs than those at Sites W18 and W19.All the results provide useful insights for assessing reservoir quality in the Shenhu area.
文摘Forest tree species reproduction is a key factor in maintaining the genetic diversity of future generations and the stability of forest ecosystems.The ongoing ash dieback disease could affect the reproductive ecology of Fraxinus excelsior L.and have a major impact on the quantity and quality of pollen and seeds.In this study,we investigated pollen production and viability of pollen and seeds of ash trees with different health status from 2018 to 2022.Inflorescences were collected from 105 trees(pollen production),pollen from 125 trees(pollen viability),and seeds from 53 trees(seed quality)in two seed orchards and in one floodplain forest in southern Germany.Not all parameters were examined at every site every year.The average pollen production per tree was estimated at 471.2±647.9 billion pollen grains.In addition,we found that a high number of inflorescences did not equate to high pollen production per inflorescence.Pollen production of healthy and diseased trees did not differ significantly,although only 47%of severely diseased male trees(vs.72%for healthy trees)produced flowers.With regards to pollen viability,the TTC test showed an average viability of 73%±17%.Overall,there was a slight tendency for diseased trees to have less viable pollen.However,a significant difference could only be calculated for trees in the floodplain forest.The percentage of germinable seeds in 2018 was 38%in the floodplain forest and 57%in one of the seed orchards.The percentage of viable seeds(TTC test)ranged from 17 to 22%in the orchards in 2020.Non-viable seeds were usually heavily infested by insects.In general,seed quality was not significantly different between healthy and diseased trees.Our results indicate that ash dieback affects flower formation and pollen viability but not pollen production or seed quality.Nevertheless,the fact that hardly any flowering was observed,especially for trees that were seriously affected,suggests a negative effect of ash dieback on reproductive performance.Thus,severely diseased trees will transfer their genes to a smaller extent to the next generation.
文摘Mechatronic products usually endure the variable stress spectrum when they operate in certain operational condition and environmental condition, which obey the Weibull distribution. In accordance with the features of mechatronic product, this paper analyzes the failure mode, its corresponding sensitive stress and the design principles of life testing profiles. Based on the above analyses, this paper presents a synthetic stress life testing method based on the hybrid Weibull distribution and its statistical method under variable stress spectrum to evaluate the reliability and life indices of mechatronic products. Because the mechatronic products have many characteristics such as high price, long life and small testing samples, the synthetic stress life testing method under variable load spectrum can simulate the real various spectra, decrease the life testing time and reduce the testing samples. So it is effective to carry out the life testing to mechatronic products. The application results of hydraulic pumps indicate that this method can easily handle the experimental data under variable amplitude spectrum, obtain the high precision parameters point estimation and confidence interval estimation and reduce the testing cost greatly.
基金supported by the National Grand Program on Key Infectious Disease(2018ZX10103002-001-007)the Biosafety Special Program(19SWAQ 13)。
文摘Despite the widespread use of malaria rapid diagnostic test(RDT)in clinical practice,there are a lot of challenges.We conducted a secondary analysis of 129 malaria RDT data from rounds 5–8 of the World Health Organization(WHO)product testing summary and discuss the causes of false-negative(FN)results with a focus on low parasite density,improper RDT storage,operation and interpretation,and Plasmodium falciparum with a pfhrp2/3 gene deletion.The results demonstrated that the malaria RDTs currently commercially available might cause FN results in practice.
文摘This paper focuses on the production testing of Memristor Ratioed Logic (MRL) gates. MRL is a family that uses memristors along with CMOS inverters to design logic gates. Two-input NAND and NOR gates are investigated using the stuck at fault model for the memristors and the five-fault model for the transistors. Test escapes may take place while testing faults in the memristors. Therefore, two solutions are proposed to obtain full coverage for the MRL NAND and NOR gates. The first is to apply scaled input voltages and the second is to change the switching threshold of the CMOS inverter. In addition, it is shown that test speed and order should be taken into consideration. It is proven that three ordered test vectors are needed for full coverage in MRL NAND and NOR gates, which is different from the order required to obtain 100% coverage in the conventional NAND and NOR CMOS designs.
文摘Reservoir safety, testing-string safety, and flow control are key factors that should be considered in deep-water unconsolidated sandstone gas well testing work system. Combined with the feature of testing reservoir, pipe string type and sea area, the required minimum testing flow rate during cleaning up process, as well as minimum test flow rate without hydrate generation, pipe string erosion critical production, the maximum testing flow rate without destroying sand formation and the minimum output of meeting the demand of development was analyzed;based on the above critical test flow rates, testing working system is designed. Field application showed that the designed work system effectively provided good guidance for field test operations;no sand production or hydrate generation happened during the test process;the test parameter evaluated the reservoir accurately;the safe and efficient test operation was achieved.
文摘As production automation systems have been and are becoming more and more complex, the task of quality assurance is increasingly challenging. Model-based testing is a research field addressing this challenge and many approaches have been suggested for different applications. The goal of this paper is to review these approaches regarding their suitability for the domain of production automation in order to identify current trends and research gaps. The different approaches are classified and clustered according to their main focus which is either testing and test case generation from some form of model automatons, test case generation from models used within the development process of production automation systems, test case generation from fault models or test case selection and regression testing.
文摘China is the biggest country of rice production and consumption in the world;more than 50% of the population feeds chiefly on rice. The quality of rice and its role as a staplefood carry much weight. The rice qualities are those aspects concerning processing, appearance,cooking, nutrition and safety of the product. The study, formulation and implementation of standardson rice qualities and testing bear heavily on the improving of rice qualities, human health,substitution of rice varieties, promoting quality rice production and regulating rice market.
文摘At Baiyin dairy farm, the Chinese herbal additive was added into feed which was then fed to dairy cows from August to October, 2014, and the changes in milk production and quality were observed. The test showed that the additive added into the feed had obvious milk-increasing effect, the milk production was im- proved by 12.67%-17.26%, and the milk quality was improved. The additive has the effects of preventing miscarriage, expelling parasite and preventing diseases. The nutritional components in the feed additive were determined, and the results showed that the contents of protein, crude fat, Ca and P in the additive were 12.29%, 2.66%, 1.8% and 0.22%, respectively.
文摘Based on the plane of weakness theory, a model for predicting borehole stability in fractured reservoirs under different stress states was estiblisted and the equations for solving borehole stability were developed. The minimum downhole pressures required to maintain borehole stability under different natural fracture occurrences were calculated by using the data from a well in the Tazhong (central Tarim) area, Tarim Basin, west China. Several conclusions were drawn for naturally fractured reservoirs with a dip angle from less than 10° to greater than 30°. Application in three wells in the Tazhong area indicates that this model is practically useful.
文摘Natural gas hydrates (NGH)is one of key future clean energy resources.Its industrialized development will help remit the huge demand of global natural gas,relieve the increasing pressure of the environment, and play a vital role in the green sustainable growth of human societies.Based on nearly two decades' studying on the reservoir characteristics in the South China Sea (SCS)and the knowledge of reservoir system,the China Geological Survey (CGS)conducted the first production test on an optimal target selected in Shenhu area SCS in 2017.Guided by the "three-phase control"exploitation theory which focused on formation stabilization,technologies such as formation fluid extraction,well drilling and completing, reservoir stimulating,sand controlling,environmental monitoring,monitoring and preventing of secondary formation of hydrates were applied.The test lasted for 60 days from May 10^th when starting to pump, drop pressure and ignite to well killing on July 9^th,with gas production of 3.09×10^5 m^3 in total,which is a world record with the longest continuous duration of gas production and maximal gas yield.This successful test brings a significant breakthrough on safety control of NGH production.
文摘In May and July of 2017,China Geological Survey (CGS),and Guangzhou Marine Geological Survey (GMGS)carried out a production test of gas hydrate in the Shenhu area of the South China Sea and acquired a breakthrough of two months continuous gas production and nearly 3.1×10^5 m^3 of production. The gas hydrate reservoir in the Shenhu area of China,is mainly composed of fine-grained clay silt with low permeability,and very difficult for exploitation,which is very different from those discovered in the USA,and Canada (both are conglomerate),Japan (generally, coarse sand)and India (fracture-filled gas hydrate).Based on 3D seismic data preserved-amplitude processing and fine imaging,combined with logging-while-drilling (LWD)and core analysis data,this paper discusses the identification and reservoir characterization of gas hydrate orebodies in the Shenhu production test area.We also describe the distribution characteristics of the gas hydrate deposits and provided reliable data support for the optimization of the production well location.Through BSR feature recognition,seismic attribute analysis, model based seismic inversion and gas hydrate reservoir characterization,this paper describes two relatively independent gas hydrate orebodies in the Shenhu area,which are distributed in the north-south strip and tend to be thicker in the middle and thinner at the edge.The effective thickness of one orebody is bigger but the distribution area is relatively small.The model calculation results show that the distribution area of the gas hydrate orebody controlled by W 18/W 19 is about 11.24 km^2,with an average thickness of 19 m and a maximum thickness of 39 m,and the distribution area of the gas hydrate orebody controlled by W11/W17 is about 6.42 km^2,with an average thickness of 26 m and a maximum thickness of 90 m.