Progress and development directions of stimulation techniques for ultra-deep oil and gas reservoirs

By reviewing the development history of stimulation techniques for deep/ultra-deep oil and gas reservoirs,the new progress in this field in China and abroad has been summed up,including deeper understanding on formation mechanisms of fracture network in deep/ultra-deep oil and gas reservoir,performance improvement of fracturing fluid materials,fine stratification of ultra-deep vertical wells,and mature staged multi-cluster fracturing technique for ultra-deep and highly deviated wells/horizontal wells.In light of the exploration and development trend of ultra-deep oil and gas reservoirs in China,the requirements and technical difficulties in ultra-deep oil and gas reservoir stimulation are discussed:(1)The research and application of integrated geological engineering technology is difficult.(2)The requirements on fracturing materials for stimulation are high.(3)It is difficult to further improve the production in vertical profile of the ultra-deep and hugely thick reservoirs.(4)The requirements on tools and supporting high-pressure equipment on the ground for stimulation are high.(5)It is difficult to achieve efficient stimulation of ultra-deep,high-temperature and high-pressure wells.(6)It is difficult to monitor directly the reservoir stimulation and evaluate the stimulation effect accurately after stimulation.In line with the complex geological characteristics of ultra-deep oil and gas reservoirs in China,seven technical development directions are proposed:(1)To establish systematic new techniques for basic research and evaluation experiments;(2)to strengthen geological research and improve the operational mechanism of integrating geological research and engineering operation;(3)to develop high-efficiency fracturing materials for ultra-deep reservoirs;(4)to research separated layer fracturing technology for ultra-deep and hugely thick reservoirs;(5)to explore fracture-control stimulation technology for ultra-deep horizontal well;(6)to develop direct monitoring technology for hydraulic fractures in ultra-deep oil and gas reservoirs;(7)to develop downhole fracturing tools with high temperature and high pressure tolerance and supporting wellhead equipment able to withstand high pressure.

Discussion on the development direction of hydropower in China

Hydropower is the second largest conventional energy resource in China.It is a renewable energy with mature technology,flexible operation,cleanliness and low carbon.A hydropower project has flood control,a water supply,navigation,irrigation and other comprehensive utilization functions.The new era in China is guided by the new energy-security strategy of‘four revolutions and one cooperation’and the new development concept of‘innovation,coordination,green development,openness and sharing’.According to the dual nature of water and electricity,this paper deepens the basic understanding of hydropower from the experience of the world,the difficult problems of hydropower in China and the long-term development of hydropower enterprises.The future direction of hydropower development is explored from the following aspects:high-quality development of follow-up hydropower projects,innovative utilization of existing hydropower value,creative pursuit of hydropower-benefit growth and high-level promotion of hydropower international cooperation.

Forecast for Six Development Directions of the Chinese Aluminium Industry

1.Implement energy saving and emission reduction Adopt the applicable advanced new cathode structure aluminium electricity,aluminium oxide energy saving and aluminum processing technology to carry out technical transformation of existing processing capacity of electrolytic aluminium,aluminium oxide。

Progress and Developmental Direction of Post-harvest Component Detection and Preservation Techniques of Nanfeng Citrus in China

This paper was summarized the research status and the development tendency of post-harvest component detection and preservation techniques of Nanfeng citrus in China, also analyzed the characteristics of various techniques, and proposed the developmental direction of novel techniques for post-harvest component detection and preservation of Nanfeng citrus.

Research Progress and Prospect of Road Dust Suppressants

Road dust has great adverse effects on traffic quality,traffic safety,atmospheric environment quality,and human health.Therefore,with the continuous development of modern science and technology,the research of road dust suppressants is also progressing.To promote the rational application and development of road dust suppressants,the research progress and prospects of them are analyzed in this paper.It includes a basic overview of road dust suppressants,the main types,the usage and precautions,and the main development direction.It is hoped that this analysis can provide some reference for further research and development of road dust suppressants.

RECENT DEVELOPMENTS OF DIRECT BONDED COPPER(DBC)SUBSTRATES FOR POWER MODULES

DBC substrates are the standard circuit boardsfor power modules. Using the DBC technologythick copper foils (0.125mm - 0.Tmm) arecladded to Alumina or Aluminum Nitride,The strong adhesion of the copper to ceramicbond reduces the thermal expansion coefficientin horizontal direction only slightly above theTEC of the ceramic itself. This allows directsilicon attach of large dies without using TECcontrolling layers.As DBC technology is using copper foils,integralleads overhanging the ceramic can be realized...

Grouting theories and technologies for the reinforcement of fractured rocks surrounding deep roadways

Grouting is an effective method to improve the integrity and stability of fractured rocks that surround deep roadways.After years of research and practice,various theories and a complete set of grouting technologies for deep roadways with fractured rocks have been developed and are widely applied in Chinese coal mining production.This paper systematically summarizes and analyzes the research results concerning the theory,design,materials,processes,and equipment for the grouting and reinforcement of fractured rocks surrounding deep roadways.Specifically,in terms of grouting methods,pregrouting,groutingwhile-excavation,and postgrouting methods are explored;in terms of grouting theory,backfill grouting,compaction grouting,infiltration grouting,and fracture grouting theories are studied.In addition,this paper also studies grouting borehole arrangement,water-cement ratio,grouting pressure,grouting volume,grout diffusion radius,and other grouting parameters and their determination methods.On this basis,this paper explores the physical and mechanical properties of organic and organic-inorganic composite grouting materials,and assess grouting reinforcement quality testing methods and instruments.Taken as the field cases,the application of pregrouting in front of heading faces,groutingwhile-excavation,and postgrouting in the Kouzidong coal mine are then introduced,and the effects of the grouting reinforcements are evaluated.This paper proposes a development direction for grouting technology based on problems existing in the grouting reinforcement of fractured rocks surrounding deep roadways.

Current Situation and Trend of the Technology Development of China’s Oral Care Products

This paper details the latest situation and features of the technology development in terms of China’s oral care products industry and proposes the following development direction in this sector. Meanwhile, the paper analyzes the popular products in the international market of oral care products and also predicts the trend of the product future in China’s market.

Review:Research Progress for Electric Vehicle Hub Motor Driving Technology

Due to high efficiency,high controllability,high integration,lightweight,and other advantages,electric vehicle with hub motor driving technology has become an emerging trend of chassis technology.This paper concludes the current state⁃of⁃the⁃art of hub motor drive technologies.Firstly,it summarizes recent hub motor drive products and makes suggestions for hub motor drive schemes in different application scenarios.Then research on hub motor drive key technologies such as integrated design,thermal optimization,lightweight,and intensity optimization is investigated.Considering the high response accuracy and zero delay characteristic of hub motor driving system combined with advanced distributed dynamics control technology that can further improve vehicle performance,this paper also analyzes existing chassis dynamics control technologies of hub motor driving system.Considering the development trend of vehicle electrification,intelligentization,network connection,and current research,this paper makes some forecasts for hub motor drive technologies development in the conclusion.

Advances in Researches of Functional Rice

Functional rice has functions of adjusting human physiological functions of and preventing diseases. At present,there are researches both at home and abroad about the relationship between nutritional quality and physiological active substances of rice and human physiological activities. Through conventional breeding,gene mutation technology,and molecular-assisted selection( MAS) technology,it is feasible to select and breed new rice varieties and plants with certain health care functions.

Wellbore Engineering Technologies for Ultra-deep Oil and Gas Exploration：Challenges and Trend

Ultra-deep formations hold abundant oil and gas resources.As the demand for oil and gas increases with economic development,more and more efforts are putting into the exploration and development of oil and gas reservoirs in deep formations around the world.In China,the exploration and development of deep oil and gas are pacing up,especially in ultra-deep formations in the Sichuan Basin,Tarim Basin and Ordos Basin.The reservoirs in these basins feature extremely large depth(over 7000 m),super high temperature(150°C-210°C),super high pressure(over 150 MPa),high acid gas content(H_2S and CO_2),strong heterogeneity,and multiple pressure systems,which pose a series of challenges to wellbore engineering technologies including drilling,drilling fluid,cementing,logging,and completion testing.Therefore,it is necessary to delve into core drilling and testing technologies for deep formations.

Progress and prospects of graphene-based materials in lithium batteries

Reasonable design and applications of graphene-based materials are supposed to be promising ways to tackle many fundamental problems emerging in lithium batteries,including suppression of electrode/electrolyte side reactions,stabilization of electrode architecture,and improvement of conductive component.Therefore,extensive fundamental research on this aspect has been performed so far.However,when it comes to large-scale industrial applications,the utilization of graphene-based materials progresses at a very slow pace.Namely,there presents a severe technological decoupling between academic research and industrial application,and there is an urgent need to link them.Herein,in order to address current issues of graphene-based materials used in lithium batteries,we present their latest advancements with stateof-the-art technologies.Potential applications of graphenebased materials in practical lithium batteries are highlighted and predicted to bridge the gap between the academic progress and industrial manufacture,thereby paving the way for accelerating the development of graphenebased material as well as lithium battery industry.

Important progress and future direction of studies on China＇s urban agglomerations

Urban agglomerations are an inevitable outcome of China＇s new national industrialization and urbanization reaching relatively advanced stages of development over the past 30 years. In the early 2000 s, urban agglomerations became new geographical units for participating in global competition and the international division of labor, and China has spent the past decade promoting them as the main spaces for pushing forward its new form of urbanization. The convening of the first Central Work Conference on Urbanization and the National New-type Urbanization Plan（2014–2020） further defined the status of urban agglomerations as the main players in promoting China＇s new type of national urbanization. Nevertheless, urban agglomerations remain a weak link in Chinese academia and are in urgent need of study. Only 19 articles on the theme of urban agglomerations were published in the journal Acta Geographica Sinica between 1934 and 2013, accounting for only 0.55% of all articles written during that period. Not only are there very few, they have also all been published within a relatively short period of time, with the first having been published only 10 years ago. The studies are also concentrated among only a few authors and institutions, and research is aimed at national requirements but is rather divergent. Even so, some studies on urban agglomerations have played a leading role and made important contributions to dictating the overall formation of urban agglomerations nationwide. Specifically, a proposed spatial pattern for urban agglomerations formed the basic framework for the spatial structure of China＇s urban agglomerations and guided the government to make urban agglomerations the main urban pattern when promoting the new type of urbanization; proposed standards and technologies for identifying the spatial dimensions of urban agglomerations played an important role in defining the scope of national urban agglomerations; a series of studies in the area of urban agglomerations spurred more in-depth and practical studies in the field; and studies on issues related to the formation and growth of urban agglomerations provided warnings on the future selection and development of urban agglomerations. Taking the progress and results of these studies as a foundation, the foci of selecting and developing urban agglomerations in China are as follows： to be problem-oriented and profoundly reflect on and review new problems exposed in the selection and development of urban agglomerations; to concentrate on urban agglomerations and lay importance on the formation of a new “5＋9＋6” spatial structure for China＇s urban agglomerations; to rely on urban agglomerations and promote the formation of a new pattern of national urbanization along the main axes highlighted by urban agglom-erations; to be guided by national strategic demand and continue to deepen understanding of major scientific issues in the course of the formation and development of urban agglomerations, including studying the resource and environmental effects of high-density urban agglomerations, scientifically examining resource and environmental carrying capacities of high-density urban agglomerations, creating new management systems and government coordination mechanisms for the formation and development of urban agglomerations, studying the establishment of public finance systems and public finance reserve mechanisms for urban agglomerations, and studying and formulating technical specifications for urban agglomeration planning and standards for delineating urban agglomeration boundaries.

Green tribology:Fundamentals and future development

As green tribology is a new field of tribology still in its infancy,understanding its fundamentals is essential for its further development.In this article,a brief historical retrospective on the emergence of green tribology is introduced first,and then the definition,objectives,and disciplinary features of green tribology are clarified.In particular,the technological connotations of green tribology are expounded comprehensively.Also,the developing directions of this new area are envisaged.These findings may contribute to laying the foundation of further advancement in green tribology.

Review of research progress on soil moisture sensor technology

Soil moisture is directly related to the amount of irrigation in agriculture and influences the yield of crops.Accordingly,a soil moisture sensor is an important tool for measuring soil moisture content.In this study,the previous research conducted in recent 2-3 decades on soil moisture sensors was reviewed and the principles of commonly used soil moisture sensor and their various applications were summarized.Furthermore,the advantages,disadvantages,and influencing factors of various measurement methods employed were compared and analyzed.The improvements were presented by several scholars have established the major applications and performance levels of soil moisture sensors,thereby setting the course for future development.These studies indicated that soil moisture sensors in the future should be developed to achieve high-precision,low-cost,non-destructive,automated,and highly integrated systems.Also,it was indicated that future studies should involve the development of specialized sensors for different applications and scenarios.This review research aimed to provide a certain reference for application departments and scientific researchers in the process of selecting soil moisture sensor products and measuring soil moisture.

A review on pavement distress and structural defects detection and quantification technologies using imaging approaches

Pavement distress detection(PDD)plays a vital role in planning timely pavement maintenance that improves pavement service life.In order to promote the development of PDD technologies and find out the insufficiencies in PDD field,this paper reviews the technical development history and characteristics of various PDD technologies,which contributes to the current state of research on PDD.First,processes of PDD are briefly introduced.The PDD technologies based on radar ranging,2D image,laser ranging and 3 D structured light are illustrated.The newest 3D PDD technology based on interference fringe,which has better accuracy,is in progress.The principles and implementation processes of these methods are discussed.Finally,the shortcomings of these technologies in the field of PDD are concluded.Recommendations for future development are provided.The research results show that various PDD technologies have been continuously improved,developed,over the past decade,and have achieved a series of results.However,the measurements from existing PDD technologies can not be metrological traced to acquire the true dimensions of pavement distresses.The lack of metrological traceability technology in the PDD field needs to be further solved.In order to achieve more accurate and efficient PDD,the metrological traceability technology of PDD systems has become the future development direction in this field.