China began to build its national shale gas demonstration area in 2012.The central exploration,drilling,and development technologies for medium and shallow marine shale reservoirs with less than 3,500m of buried depth...China began to build its national shale gas demonstration area in 2012.The central exploration,drilling,and development technologies for medium and shallow marine shale reservoirs with less than 3,500m of buried depth in Changning-Weiyuan,Zhaotong,and other regions had matured.In this study,we macroscopically investigated the development history of shale gas in the United States and China and compared the physical and mechanical conditions of deep and shallow reservoirs.The comparative results revealed that themain reasons for the order-ofmagnitude difference between China’s annual shale gas output and the United States could be attributed to three aspects:reservoir buried depth,reservoir physical and mechanical properties,and engineering technology level.The current engineering technology level of China could not meet the requirements of increasing production and reducing costs for deep shale gas reservoirs;they had reached the beneficial threshold development stage and lacked the capacity for large-scale commercial production.We identified several physical and mechanical reasons for this threshold development stage.Deep shale reservoirs were affected by the bedding fracture,low brittleness index,low clay mineral content,and significant areal differences,as well as by the transformation from elasticity to plasticity,difficulty in sanding,and high mechanical and strength parameters.Simultaneously,they were accompanied by six high values of formation temperature,horizontal principal stress difference,pore pressure,fracture pressure,extension pressure,and closure pressure.The key to deep shale gas horizontal well fracturing was to improve the complexity of the hydraulic fracture network,formadequate proppant support of fracture surface,and increase the practical stimulated reservoir volume(SRV),which accompanied visual hydraulic discrete network monitoring.On this basis,we proposed several ideas to improve China’s deep shale gas development involving advanced technology systems,developing tools,and supporting technologies in shale gas exploration and development in the United States.These ideas primarily involved stimulation technologies,such as vertically integrated dessert identification and optimization,horizontal well multistage/multicluster fracturing,staged tools development for horizontal wells,fractures network morphology monitoring by microseismic and distributed optical fiber,shale hydration expansion,soak well,and fracturing fluid flow back.China initially developed the critical technology of horizontal well large-scale and high-strength volume fracturing with a core of“staged fracturing with dense cutting+shorter cluster spacing+fracture reorientation by pitching+forced-sand addition+increasing diameter perforating+proppant combination by high strength and small particle size particles”.We concluded that China should continue to conduct critical research on theories and technical methods of horizontal well fracturing,suitable for domestic deep and ultra-deep marine and marine-continental sedimentary shale,to support and promote the efficient development of shale gas in China in the future.It is essential to balance the relationship between the overall utilization degree of the gas reservoir and associated economic benefits and to localize some essential tools and supporting technologies.These findings can contribute to the flourishing developments of China’s deep shale gas.展开更多
Since China put forward the Belt and Road Initiative and a community with shared future for mankind,mainstream media in the United States such as The Washington Post,The New York Times and The Wall Street Journal have...Since China put forward the Belt and Road Initiative and a community with shared future for mankind,mainstream media in the United States such as The Washington Post,The New York Times and The Wall Street Journal have given continuous reports.As the world’s superpower,the United States has a developed media system and a wide range of influence.The study extracted 173 valid texts from May 2015 to March 2020,among which only 5 reports were on a community with shared future for mankind.American media mainly reported from five aspects including economy,politics,cultural,security and environment,although there is no lack of certain sounds,there was more negative reports.It can provide a reference basis for our accurate response and creating a positive international public opinion environment that grasping the reporting trends on the Belt and Road Initiative and a community with shared future for mankind accurately.展开更多
Of the 700,000 people in the United States who experience a new or recurrent stroke each year,more than 500,000 survive(American Stroke Association,2007)[1]. Occupational therapy practitioners are critical rehabilitat...Of the 700,000 people in the United States who experience a new or recurrent stroke each year,more than 500,000 survive(American Stroke Association,2007)[1]. Occupational therapy practitioners are critical rehabilitation professionals for stroke survivors.展开更多
Since the 21 st century, both Chinese Mainland and the United States have formulated foreign language education policiesbased on their national needs. This paper makes a comparative study of the value orientations of ...Since the 21 st century, both Chinese Mainland and the United States have formulated foreign language education policiesbased on their national needs. This paper makes a comparative study of the value orientations of foreign language education poli-cies in Chinese Mainland and the United States in the 21 st century and finds that both China and the United States have regardedtheir national interests as the essential value orientation of their foreign language education policies. To be specific,the core valueorientation of foreign language education policies in China is to enhance its cultural soft power.In contrast,the core value orienta-tion of foreign language education policies in the United States is to safeguard its national security. Through the comparison of thedifferent value orientations of foreign language education policies of the two countries, the paper provides some reference for the for-eign language education policy-making in Chinese Mainland.展开更多
The Yao ethnicity, numbering 2.13 million, are scattered throughout the mountainous regions of Guangxi, Hunan, Yunnan, Guangdong and Guizhou. Most of them, however, have settled in Guangxi Zhuang Autonomous Region.
While your family is sitting down to a delicious dinner of soups,noodles and salads at night,1 people are going without enough food.Read on for some facts about how food banks can make the world different.Second Harve...While your family is sitting down to a delicious dinner of soups,noodles and salads at night,1 people are going without enough food.Read on for some facts about how food banks can make the world different.Second Harvest is one of the 2food banks in America.Every year in展开更多
Today, homosexuality has become legalized. It is one of the human rightsprotected by the U. S. government. Homosexal persons can now openly put ads innewspapers to seek their companions of the same sex. Let’s "e...Today, homosexuality has become legalized. It is one of the human rightsprotected by the U. S. government. Homosexal persons can now openly put ads innewspapers to seek their companions of the same sex. Let’s "enjoy" the展开更多
基金funded by the National Key Research and Development Program of China under Grant No.2020YFC1808102the National Natural Science Foundation of China(Grant Nos.51874328,U1762215)the Strategic Cooperation Technology Projects of CNPC and CUPB(Grant No.ZLZX2020-02).
文摘China began to build its national shale gas demonstration area in 2012.The central exploration,drilling,and development technologies for medium and shallow marine shale reservoirs with less than 3,500m of buried depth in Changning-Weiyuan,Zhaotong,and other regions had matured.In this study,we macroscopically investigated the development history of shale gas in the United States and China and compared the physical and mechanical conditions of deep and shallow reservoirs.The comparative results revealed that themain reasons for the order-ofmagnitude difference between China’s annual shale gas output and the United States could be attributed to three aspects:reservoir buried depth,reservoir physical and mechanical properties,and engineering technology level.The current engineering technology level of China could not meet the requirements of increasing production and reducing costs for deep shale gas reservoirs;they had reached the beneficial threshold development stage and lacked the capacity for large-scale commercial production.We identified several physical and mechanical reasons for this threshold development stage.Deep shale reservoirs were affected by the bedding fracture,low brittleness index,low clay mineral content,and significant areal differences,as well as by the transformation from elasticity to plasticity,difficulty in sanding,and high mechanical and strength parameters.Simultaneously,they were accompanied by six high values of formation temperature,horizontal principal stress difference,pore pressure,fracture pressure,extension pressure,and closure pressure.The key to deep shale gas horizontal well fracturing was to improve the complexity of the hydraulic fracture network,formadequate proppant support of fracture surface,and increase the practical stimulated reservoir volume(SRV),which accompanied visual hydraulic discrete network monitoring.On this basis,we proposed several ideas to improve China’s deep shale gas development involving advanced technology systems,developing tools,and supporting technologies in shale gas exploration and development in the United States.These ideas primarily involved stimulation technologies,such as vertically integrated dessert identification and optimization,horizontal well multistage/multicluster fracturing,staged tools development for horizontal wells,fractures network morphology monitoring by microseismic and distributed optical fiber,shale hydration expansion,soak well,and fracturing fluid flow back.China initially developed the critical technology of horizontal well large-scale and high-strength volume fracturing with a core of“staged fracturing with dense cutting+shorter cluster spacing+fracture reorientation by pitching+forced-sand addition+increasing diameter perforating+proppant combination by high strength and small particle size particles”.We concluded that China should continue to conduct critical research on theories and technical methods of horizontal well fracturing,suitable for domestic deep and ultra-deep marine and marine-continental sedimentary shale,to support and promote the efficient development of shale gas in China in the future.It is essential to balance the relationship between the overall utilization degree of the gas reservoir and associated economic benefits and to localize some essential tools and supporting technologies.These findings can contribute to the flourishing developments of China’s deep shale gas.
基金Postgraduate Innovation Program of Jiangsu Province in 2020:research on the construction of a community of shared future for mankind from the perspective of Marx’s thoery of world history(KYCX20_3060)Key projects in 2017 of The National Social Science Fund of China“The spread of Chinese traditional elementary school among countries in‘the Belt and Road Initiative’”(No.17AZS012)Teaching reform and research topics of Jiangsu University“Research on the construction of the mixed teaching mode of‘Internet+ideological and political courses’”(No.2019JGZD014)。
文摘Since China put forward the Belt and Road Initiative and a community with shared future for mankind,mainstream media in the United States such as The Washington Post,The New York Times and The Wall Street Journal have given continuous reports.As the world’s superpower,the United States has a developed media system and a wide range of influence.The study extracted 173 valid texts from May 2015 to March 2020,among which only 5 reports were on a community with shared future for mankind.American media mainly reported from five aspects including economy,politics,cultural,security and environment,although there is no lack of certain sounds,there was more negative reports.It can provide a reference basis for our accurate response and creating a positive international public opinion environment that grasping the reporting trends on the Belt and Road Initiative and a community with shared future for mankind accurately.
文摘Of the 700,000 people in the United States who experience a new or recurrent stroke each year,more than 500,000 survive(American Stroke Association,2007)[1]. Occupational therapy practitioners are critical rehabilitation professionals for stroke survivors.
文摘Since the 21 st century, both Chinese Mainland and the United States have formulated foreign language education policiesbased on their national needs. This paper makes a comparative study of the value orientations of foreign language education poli-cies in Chinese Mainland and the United States in the 21 st century and finds that both China and the United States have regardedtheir national interests as the essential value orientation of their foreign language education policies. To be specific,the core valueorientation of foreign language education policies in China is to enhance its cultural soft power.In contrast,the core value orienta-tion of foreign language education policies in the United States is to safeguard its national security. Through the comparison of thedifferent value orientations of foreign language education policies of the two countries, the paper provides some reference for the for-eign language education policy-making in Chinese Mainland.
文摘The Yao ethnicity, numbering 2.13 million, are scattered throughout the mountainous regions of Guangxi, Hunan, Yunnan, Guangdong and Guizhou. Most of them, however, have settled in Guangxi Zhuang Autonomous Region.
文摘While your family is sitting down to a delicious dinner of soups,noodles and salads at night,1 people are going without enough food.Read on for some facts about how food banks can make the world different.Second Harvest is one of the 2food banks in America.Every year in
文摘Today, homosexuality has become legalized. It is one of the human rightsprotected by the U. S. government. Homosexal persons can now openly put ads innewspapers to seek their companions of the same sex. Let’s "enjoy" the
