New-type urbanization(NTU)is proposed by China to solve unsustainable issues and improve green development efficiency(GDE)during the process of rapid urbanization.However,the impact mechanism of NTU on GDE is unclear....New-type urbanization(NTU)is proposed by China to solve unsustainable issues and improve green development efficiency(GDE)during the process of rapid urbanization.However,the impact mechanism of NTU on GDE is unclear.Using panel data of 282 prefecture-level cities in China from 2010 to 2019,we measured NTU and GDE to describe their spatiotemporal pattern and relationship evolution.The fixed effects panel model and mediating effect panel model were further utilized to analyze the benchmark impact,mediating mechanism and spatiotem-poral heterogeneity of NTU on GDE.The results showed that NTU improved,with the highest levels observed in the eastern region,while GDE increased with fluctuations,performing better in both the eastern and western regions.With the proportion of double-high cities increasing from 13.83%to 43.62%,the NTU-GDE relationship was upgraded.Overall,every 1%improvement in NTU increased GDE by 0.3111%,and the enterprise effect,resident effect and government effect played a positive mediating role from high to low.During the later stage of NTU,its impact on GDE strengthened significantly,and the mediating role of governments was optimized.The eastern region was the only region with three positive mediating roles of governments,enterprises and residents.These findings will promote GDE through NTU in China and serve as a valuable reference for sustainable global urbanization.展开更多
Green development is a critical component of sustainable tourism, which prioritizes a comprehensive, ecologically-friendly, and people-oriented approach to development. This study presents a case study of the Beijing...Green development is a critical component of sustainable tourism, which prioritizes a comprehensive, ecologically-friendly, and people-oriented approach to development. This study presents a case study of the Beijing–Tianjin–Hebei(BTH) urban agglomeration from 2001 to 2021 to analyze the spatio-temporal evolution characteristics and influencing factors of tourism green development efficiency(TGDE). The study defines the concept of tourism green development and constructs an evaluation system, which is used to explore the internal differences and spatial patterns of TGDE within the urban agglomeration. The methodological approach includes the SBM–Undesirable model, kernel density estimation, Markov chain, and spatial gravity model. The findings indicate that the TGDE in the BTH urban agglomeration is generally favorable, displaying a temporal phase of “rising–declining–rising.” However, the study observes lower TGDE in tourism node cities compared to tourism regional center cities and tourism core hub cities. The non-equilibrium degree of each region indicates significant spatio-temporal evolution patterns and internal differences among the three regions, with a spatially decreasing distribution of “core hub-regional center-node city.” The TGDE in the urban agglomeration experienced an evolutionary trend of “first decreasing and then increasing” with apparent endogenous evolution characteristics. The linkage pattern of green development efficiency in the tourism industry between cities is relatively stable. Furthermore,neighboring cities generally exhibit a higher spatial connectivity strength of green development efficiency in the tourism industry compared to non-neighboring cities. Economic development level, industrial structure, and science and education level are identified as key factors that affect TGDE. However, the study finds that the factors influencing TGDE in tourism core hub cities, tourism regional center cities, and tourism node cities differ somewhat. Economic development level, industrial structure, science and education level, openness, and government regulation impact TGDE in tourism core hub cities and tourism regional center cities, while economic development level, industrial structure, and tourism resource endowment are the primary factors affecting TGDE in tourism node cities. The study provides policymakers and tourism practitioners with valuable insights into enhancing the green development of the tourism industry in the BTH urban agglomeration and other similar regions.Corresponding policy recommendations based on the results are proposed to improve the TGDE of the tourism industry in these regions, promote sustainable tourism development,improve the quality of life of local residents, and protect the ecological environment.展开更多
Suitable spatial morphology of cultivated land is a basic requirement for sustaining agricultural economic development in mountainous areas.Coordinated development efficiency of cultivated land spatial morphology and ...Suitable spatial morphology of cultivated land is a basic requirement for sustaining agricultural economic development in mountainous areas.Coordinated development efficiency of cultivated land spatial morphology and agricultural economy(CECA)is of great practical significance to measure the efficiency of cultivated land use,and thereby promote regional rural revitalization.However,few studies to date have focused on coordinated development efficiency between cultivated land use and agricultural economy in mountainous areas from the perspective of cultivated land spatial morphology.Thus,the present study explores CECA with this focus using the data envelopment analysis method,and analyzes the key influencing factors via a geographical detector model in 16 counties in western Hubei province.The results show the following:(1)CECA exhibits significant spatial heterogeneity that is high in the south of the study area and low in the north;(2)scale efficiency is the primary limiting factor for CECA;(3)the insufficient output of cultivated land use mainly restricts CECA in the south of the study area,while individual county in the north suffered from input redundancy and insufficient output;and(4)population density in the southern region has the most significant effect on CECA,and gross domestic product has the greatest impact in the northern region.The results contribute to the derivation of specific measures by which to promote cultivated land use efficiency and sustainable development of the social economy.展开更多
The traditional data envelopment analysis（DEA）, bootstrap-DEA and Malmquist models are employed to measure different tourism efficiencies and their spatial characteristics of 61 cities in six coastal urban agglomera...The traditional data envelopment analysis（DEA）, bootstrap-DEA and Malmquist models are employed to measure different tourism efficiencies and their spatial characteristics of 61 cities in six coastal urban agglomerations in eastern China. The following conclusions are drawn.（1） The comprehensive efficiency（CE） of urban tourism using the bootstrap-DEA model is lower than the CE level using the DEA-CRS model, which confirms the significant tendency of the DEA-CRS model to overestimate results.（2） The geometric CE averages of urban tourism in the Yangtze River Delta（YRD） and the Pearl River Delta（PRD） have changed from ineffective to effective since 2000, the averages in the Beijing-TianjinHebei（BTH） and the Shandong Peninsula（SDP） have changed from ineffective to moderately effective since 2000, and those in the Central and Southern Liaoning（CSL） and the West Bank of Taiwan Strait（WBTS） have been ineffective since 2000.（3） The CE values of urban tourism in the PRD, the YRD, the BTH and the SDP have been slightly affected by the pure technical efficiency（PTE）, whereas the CE values in the CSL and the WBTS have been slightly affected by the scale efficiency（SE） since 2000.（4） Spatially, the range of geometric averages of the total factor productivity（TFP） for the PRD, the YRD, the BTH, the SDP, the WBTS and the CSL has decreased sequentially, while the one for most cities in six urban agglomerations has exhibited a downward trend since 2000.（5） Collectively, the natural conditions, the economic policies and the tourism capital drive the SE change of urban tourism of the CSL and the WBTS. The tourism enterprises for increasing returns to scale and imitating innovative technology have an effect on the CE change of urban tourism in the BTH and the SDP. The tourism market competition drives the PTE change of urban tourism in the PRD and the YRD. Although the PTE and the SE of urban tourism in six coastal urban agglomerations suffer from uncertain events, the CE maintained overall sound momentum since 2000.展开更多
Green development is an important issue of sustainable development in China.Due to the relatively backward economy and the fragile ecological environment,restricted development zones need to embrace green development....Green development is an important issue of sustainable development in China.Due to the relatively backward economy and the fragile ecological environment,restricted development zones need to embrace green development.Taking 38 counties in Jilin Province as the empirical research objects,and based on cross-sectional data for each county in 2005,2010,and 2015,we accurately depicted the spatiotemporal evolutionary characteristics of green development efficiency(GDE)in restricted development zones of Jilin Province using the slacks-based measure-data envelope analysis(SBM-DEA)model.Moreover,the factors that influence GDE were further analyzed using the Tobit model.We found that:first,GDE showed a V-shaped trend in restricted development zones of Jilin Province.The differences in GDE in the eastern,central,and western Jilin Province increased gradually.Second,76%of counties in the restricted development zones had high or higher efficiencies.The resource-based cities were the main areas with low or lower GDE.Third,the economic development level was the core factor affecting GDE.Urbanization level had a significant negative effect on GDE in the restricted development zones.The effect of technological innovation level on GDE fluctuated,and we found that a‘backward mechanism’of technological innovation was beginning to form.Industrial structure and environmental governance had no significant effects on GDE.展开更多
Under the background of green development,the function direction of technological innovation to green development efficiency,which includes economy,resources and environment,needs to be observed by demonstration.In th...Under the background of green development,the function direction of technological innovation to green development efficiency,which includes economy,resources and environment,needs to be observed by demonstration.In this paper,the green development efficiency of 30 provinces(cities and districts)in China from 2004 to 2017 is measured and its intertemporal changes,regional differences of green development efficiency are analyzed by using the super efficiency SBM model,further through theoretical analysis and empirical study,the influence of technological innovation on regional green development efficiency and its impact mechanism are investigated.The influence mechanisms of the technological innovation on green development efficiency are clarified and empirically tested by spatial econometric models from the perspectives of the growth sources and quantitative analysis.The results show that during the observation period,the green development efficiency in China exhibits a U-shaped variation,but there are huge regional differences with the obvious polarization in Eastern and Midwestern regions,and that technological innovation has some effect in promoting the regional green development efficiency,but not significant enough,which are heterogeneous according to the time periods and regions.展开更多
The green development of Chongqing municipality is crucial in establishing a major ecological shield in the upper reaches of the Yangtze River.By developing a Super-SBM model and using the Malmquist index to analyze a...The green development of Chongqing municipality is crucial in establishing a major ecological shield in the upper reaches of the Yangtze River.By developing a Super-SBM model and using the Malmquist index to analyze and calculate the green development efficiency and its influencing factors in Chongqing from 2011 to 2021,this study reveals an accelerating trend in the overall green development efficiency in Chongqing.The significant enhancement of green development efficiency in Chongqing is primarily attributed to changes in returns to scale.Pure technical efficiency and technological advancements have a considerable potential impact on improving green development efficiency in Chongqing.Furthermore,there are discernible disparities in green development efficiency among districts and counties in Chongqing,with different factors influencing these variations.Chongqing is suggested to promote clean and efficient energy utilization,bolster the application and commercialization of scientific and technological advancements,consistently advance ecological restoration and management,and elevate the quality of green development to a higher level.展开更多
The major cities of every country and region in the world play an important role in the process of global development.The assessment of the development efficiency of these core cities can help governments better under...The major cities of every country and region in the world play an important role in the process of global development.The assessment of the development efficiency of these core cities can help governments better understand their role in globalization and provide some useful information for policy makers.This paper evaluates the development efficiency of 35 major cities around the world during the period 2011-2020.The data used is the Global City Power Index(GPCI)released by the Mori Foundation of Japan,which evaluates each city in a total of 70 indicators from six dimensions:economy,research development(R&D),cultural exchange,livability,environment and accessibility.The development efficiency of the 35 global major cities is evaluated by using data envelopment analysis(DEA)to divide the six dimensions into input and output indexes.The change of development efficiency of the 35 global core cities during 2011-2020 is studied by using Malmquist index.It is found that the absolute strength of each city is not necessarily related to its development efficiency,and the change of development efficiency is affected by both technological efficiency and technological progress.展开更多
With the basic characteristics of conventional horizontal wells,the so-called complex wells including horizontal extended-reach wells,multi-lateral horizontal wells,U-shaped wells,cluster horizontal wells,etc.,are adv...With the basic characteristics of conventional horizontal wells,the so-called complex wells including horizontal extended-reach wells,multi-lateral horizontal wells,U-shaped wells,cluster horizontal wells,etc.,are advanced well types for the efficient development of low-permeability,unconventional,deep-water,and deep oil and gas reservoirs,which have been highly concerned all over the world.Significant progress at home and abroad has been made in relevant researches and practices and is expected to play an important role in the efficient development of shale oil and gas.To meet the basic needs of environment&safety,land conservation,cost reducing and efficiency improving,it is urgent to create a unique and efficient mode for developing shale gas.Therefore,an efficient shale gas development mode for mountainous areas and an engineering and technical support system are presented based on large cluster horizontal-well engineering.An equation is thus obtained for calculating the maximum number of horizontal wells arranged allowably in“Well Factory”on a single platform.The general research and development of large extended-reach well technology are analyzed by expounding the basic concept of an extended-reach well and its drilling extension limit.And a calculation method is thus established to predict the maximum measured depth of open hole in extended-reach drilling.Moreover,some relevant research results and their significance for downhole tubular mechanics&mechanical extension limits in extended-reach drilling are also briefly introduced in this paper.The conclusions are drawn that,by following the idea of“integration of geology and engineering”in oil and gas development,these research results have a foreseeable application prospect in shale gas development in the mountainous areas in the future,and will contribute to new progress in China's“Shale Revolution”.展开更多
Shale gas resources in the Lower Silurian Longmaxi,southern Sichuan Basin,are huge,where,the geological setting,unlike that in North America,is quite complicated and ground surface infrastructure is poor.Therefore,ada...Shale gas resources in the Lower Silurian Longmaxi,southern Sichuan Basin,are huge,where,the geological setting,unlike that in North America,is quite complicated and ground surface infrastructure is poor.Therefore,adaptable key technologies will be essential to achieve commercial exploitation of shale gas there.In the case study of the Changning-Weiyuan National Shale Gas Demonstration Zone,six series of key techniques were summarized in comprehensive geological evaluation,development optimization,fast and superior drilling of horizontal wells,horizontal-well volumetric fracturing,cluster-well and factory-like operation in well blocks,and highly-efficient and clean exploitation.The above techniques were applied in this field after three rounds of adjustment and optimization,the resulted production rates of shale gas wells were getting higher and higher and the single-well estimated ultimate recovery(EUR)was also rising.Compared with that in the first round,the average EUR of wells in the third round was increased by 128%.In conclusion,the application practices prove that the above series of key techniques with adaptation and flexibility provide a robust technical support for the rapid output of shale gas production in South Sichuan Basin.展开更多
The low average single-well production,resulting in low economic benefit,has become the main bottleneck of CBM development in China.In view of this issue,through case study of a CBM gas reservoir in the southern Qinsh...The low average single-well production,resulting in low economic benefit,has become the main bottleneck of CBM development in China.In view of this issue,through case study of a CBM gas reservoir in the southern Qinshui Basin,we summarized the present status of CBM technology and development there and also pointed out some major problems in CBM development:(1)the engineering technology for the CBM development needs to adapt to the particular geological characteristics;(2)a large number of inefficient zones still exist in mature blocks in the southern Qinshui Basin;(3)single-well production can not be effectively enhanced only by increasing the fracturing scale;(4)the production of multi-lateral wells is higher,but the fulfillment rate of production capacity overall is still low;and(5)on-site management lacks scientific evidence.On this basis,we present the following suggestions for subsequent coalbed gas development:(1)the production construction mode should be changed,and the fulfillment rate of production capacity construction should be improved;(2)CBM geological research should be improved and well types and locations should be designed reasonably and scientifically;(3)main technologies should be built in a dialectical thinking mode;(4)horizontal well design should be optimized to improve the applicability of relevant technologies;(5)fracturing mode should be changed to improve single-well production;and(6)the drainage technology should be changed to improve economic efficiency.展开更多
China's shale gas production in 2020 exceeds 200×10^(8) m^(3),which creates a miracle in the history of natural gas development in China.The Sichuan Basin has already been and will be the main battlefield of ...China's shale gas production in 2020 exceeds 200×10^(8) m^(3),which creates a miracle in the history of natural gas development in China.The Sichuan Basin has already been and will be the main battlefield of shale gas exploration and development in China.In order to further promote the large-scale efficient development of shale gas in China,under the new situation of global COVID-19 spread and domestic“carbon peak and carbon neutrality”goal,this paper analyzes the progress and challenges of shale gas exploration and development in the Sichuan Basin from four aspects,including resource exploration,gas reservoir engineering,drilling and production engineering and industry regulation,and puts forward countermeasures and suggestions for achieving large-scale efficient development of shale gas.The following research results are obtained:First,the large-scale efficient development of shale gas in the Sichuan Basin has to take the sustainable and stable production of middle-shallow shale gas and the large-scale productivity construction of deep shale gas as the base.Second,compared with the shale gas exploration and development in the North America,the Sichuan Basin has its own characteristics in terms of geographical setting,geological condition,drilling and production technology and industry regulation,which makes it difficult to copy the development pattern of large scale,high density and continuous well deployment from the North America,so it is necessary to adopt the strategy of“high production with few wells”.On the one hand,continue to apply the geology and engineering integration technology to carry out“integrated research,integrated design,integrated implementation and integrated iteration”in the whole life cycle of shale gas well;and on the other hand,carry out problem-oriented continuous researches from the aspects of geological evaluation,development policy,engineering technology and industry regulation,so as to improve geological evaluation theory and technology,innovate gas reservoir engineering theory and method,research and develop engineering technology for cost reduction and efficiency improvement,improve shale gas industry regulation,and form a new pattern of collaborative promotion of technical and non-technical elements.In conclusion,the research results provide important reference and guidance for the large-scale efficient development of shale gas in the Sichuan Basin and even the whole country.展开更多
The Lower Cambrian Longwangmiao Fm gas reservoir in Moxi block of the Anyue Gas field,Sichuan Basin,is the largest single-sandbody integrated carbonate gas reservoir proved so far in China.Notwithstanding this reservo...The Lower Cambrian Longwangmiao Fm gas reservoir in Moxi block of the Anyue Gas field,Sichuan Basin,is the largest single-sandbody integrated carbonate gas reservoir proved so far in China.Notwithstanding this reservoir's advantages like large-scale reserves and high singlewell productivity,there are multiple complicated factors restricting its efficient development,such as a median content of hydrogen sulfide,low porosity and strong heterogeneity of fractureecave formation,various modes of gasewater occurrences,and close relation between overpressure and stress sensitivity.Up till now,since only a few Cambrian large-scale carbonate gas reservoirs have ever been developed in the world,there still exists some blind spots especially about its exploration and production rules.Besides,as for large-scale sulfur gas reservoirs,the exploration and construction is costly,and production test in the early evaluation stage is severely limited,all of which will bring about great challenges in productivity construction and high potential risks.In this regard,combining with Chinese strategic demand of strengthening clean energy supply security,the PetroChina Southwest Oil&Gas Field Company has carried out researches and field tests for the purpose of providing highproduction wells,optimizing development design,rapidly constructing high-quality productivity and upgrading HSE security in the Longwangmiao Fm gas reservoir in Moxi block.Through the innovations of technology and management mode within 3 years,this gas reservoir has been built into a modern large-scale gas field with high quality,high efficiency and high benefit,and its annual capacity is now up to over 100×10^(8)m^(3),with a desirable production capacity and development indexes gained as originally anticipated.It has become a new model of large-scale gas reservoirs with efficient development,providing a reference for other types of gas reservoirs in China.展开更多
There are abundant high-rank coal bed methane(CBM)resources in China,accounting for one third of total CBM resources.Its efficient development and utilization is of great significance to guarantee the national energy ...There are abundant high-rank coal bed methane(CBM)resources in China,accounting for one third of total CBM resources.Its efficient development and utilization is of great significance to guarantee the national energy strategic security,diminish the hidden danger of coal mine production and reduce carbon dioxide emission.In order to solve the"four lows"problem(i.e.,low effective utilization ratio of proved reserves,low productivity targeting ratio,low single-well production rate and low development profit)restricting the development of high-rank CBM industry in China,this paper deeply analyzes the core problems restricting the development of high-rank CBM.Based on this,several new methods of production control,area selection and evaluation are put forward by taking multiple measures,such as paying the same attention on theoretical research and technological research&development,carrying out laboratory research and field test in parallel and conducting large scale construction and benefit development simultaneously.And the following research results are obtained.First,the geological difference between CBM and coal mine,the difference in reserves recoverability,the adaptability of engineering technology and the scientificity of production are the main factors restricting CBM development effect.Second,"Four-element"production control theory,methane-leading en gineering transformation method and methane-leading production control theory are proposed,which provides guidance for the development of a series of technologies for the efficient development of high-rank CBM.Third,in practice,the control degree of quality reserves is increased from 32%to 80%,the success ratio of development wells is increased from 60%to 95%,the average single-well daily gas production of vertical wells is increased by about 1100 m^(3),the drilling cost of horizontal wells is reduced by 50%,and the operation cost per cubic meter of gas is reduced by 24%.In conclusion,the established technology series for the efficient development of high-rank CBM actively promote the efficient CBMdevelopment in the Qinshui Basin.The yearly CBM production of PetroChina Huabei Oilfield Company is expected to reach 20108 m^(3) in the middle of the"14th Five-Year Plan",which promotes the strategic development of CBM industry in China.展开更多
The Sinian Dengying Formation gas reservoir in the Anyue gas field of the Sichuan Basin is an ultra-deep ancient dolomite karst gas reservoir,whose development is of high difficulty,for the reservoir is thin and scatt...The Sinian Dengying Formation gas reservoir in the Anyue gas field of the Sichuan Basin is an ultra-deep ancient dolomite karst gas reservoir,whose development is of high difficulty,for the reservoir is thin and scattered with strong heterogeneity and is overall characterized by low porosity and low permeability.In order to provide support for the large-scale productivity construction of the gas reservoir of the fourth member of Dengying Formation(Deng 4 Member)in the marginal platform belt of the Anyue gas field,this paper carries out multi-discipline comprehensive researches on the technical bottlenecks based on the geological characteristics of the gas reservoir.In addition,the targeted key technologies for the efficient development of gas reservoirs were developed in the mode of“simultaneous research,application and improvement”.And the following research results are obtained.First,based on the modeling technology of fracturedevuggy dolomite karst reservoirs,accurate modeling of karst reservoirs is realized.Late actual drilling results show that the model's coincidence rate is increased from 63.0% to 90.7% and the“transparency”of gas reservoirs is achieved.Second,based on the reserve mobility evaluation technology of lowporosity and highly-heterogeneous karst reservoirs,the recovery factors of different reservoirs are determined.And consequently,the lower limit of well-controlled reserves and radius for the efficient development of different reservoirs are obtained and type Ⅰ and Ⅱ reservoirs are selected as the main development targets.Third,based on the development optimization design technology of highly-heterogeneous karst gas reservoirs,it is recommended to apply highly-deviated wells(the maximum deviation angle of 75°-84°)in the situations with multiple reservoirs crossed and superimposed.If type Ⅰ and Ⅱ reservoirs are developed intensively,it is recommended to adopt horizontal well drilling with a horizontal section of 800-1100 m.What's more,the reasonable well spacing in type Ⅰ and Ⅱ reservoirs shall be 1.6-3.3 km and 0.9-1.4 km,respectively.Fourth,based on the distinguished drilling technology of highly-deviated wells/horizontal wells in deep carbonate rocks,the fault complexity ratio is decreased from 20.7% to 4.9%,so safe and fast drilling and completion of highly-deviated wells/horizontal wells is realized and well control risks are diminished.What's more,the drilling rates of type Ⅰ and Ⅱ reservoirs are increased from 24.2% to 87.3%,indicating an effective improvement of reservoir drilling rates.Fifth,based on the open-hole segmented accurate acid fracturing technology of highly-deviated and horizontal wells,the difficulty in the highly-heterogeneous reservoir stimulation by horizontal well drilling is solved by conducting the differentiated acid fracturing process of“one segment,one strategy”.Based on the application of these innovative development technologies in the Deng 4 Member gas reservoir in the marginal platform belt of the Anyue gas field,the annual natural gas production capacity and cumulative natural gas production by the end of December 2020 are 60×10^(8) m^(3) and 103×10^(8) m^(3),respectively.In this way,the Sinian Dengying Formation gas reservoir of the Anyue gas field,the economic benefit of which is close to the marginal benefit,becomes the main force of conventional natural gas production increase.展开更多
In recent years,the Sichuan Basin has been the most potential hydrocarbon-bearing basin in China thanks to the great exploration and development breakthroughs of deep large integral carbonate gas reservoirs and shale ...In recent years,the Sichuan Basin has been the most potential hydrocarbon-bearing basin in China thanks to the great exploration and development breakthroughs of deep large integral carbonate gas reservoirs and shale gas in this basin.The Anyue Gas Field located in central Sichuan Basin is not only the largest carbonate gas reservoir,but the most important supergiant gas field discovered in China in recent years.However,it faces a series of major difficulties,e.g.,low reservoir porosity,low permeability,low gas well productivity,thin and vertically and laterally disperse gas layer,strong heterogeneity,quite low structural amplitude and complicated gasewater relationship,which bring great challenges to the rapid conversion of natural gas reserves to production.In this regard,technical researches have been carried out continuously.As a result,many key technologies have been innovatively integrated and great breakthroughs have been realized in many aspects.First,fine development technologies for supergiant,ancient and complex carbonate gas reservoirs are developed innovatively,“transparent gas reservoir”is constructed and the technologies for cultivating high-yield wells are established.By virtue of these technologies,all development wells in the gas reservoir of Lower Cambrian Longwangmiao Formation reach the target of high yield and the single-well gas production rate of the gas reservoir of Lower Sinian Dengying Formation is increased significantly,which provides support for the long-term high production and stable production of Anyue Gas Field.Second,good and fast construction technologies for large-scale gas fields are innovatively integrated.Based on this,the safety of gas wells is under control in the whole life cycle,quality engineering is built up efficiently within 3 years,green mining areas are forged and large-scale safe and clean gas fields are built up efficiently.Third,intelligent control technologies for the development of supergiant gas fields are innovatively integrated.By means of these technologies,internet of everything,depth perception and automatic production are realized.The intelligent technologies of new generation are fused,including AR,VR,robot and unmanned aerial vehicle(UAV).A new intelligent management mode for gas field development is set up,and an intelligent gas field is built up.Fourth,optimization technologies for the overall development of supergiant gas fields are innovatively development,so as to improve the development effects of strong-heterogeneity gas reservoirs and ensure the long-term stable production of supergiant water-bearing gas reservoirs.The research results can be used as reference for the efficient development of similar domestic and foreign gas fields.展开更多
In recent years,deep marine carbonate gas reservoirs have become an important field in increasing conventional gas reserves and production in the Sichuan Basin.Due to complex hydrocarbon accumulation conditions,great ...In recent years,deep marine carbonate gas reservoirs have become an important field in increasing conventional gas reserves and production in the Sichuan Basin.Due to complex hydrocarbon accumulation conditions,great burial depth and complicate gas-water relation,however,this type of gas reservoirs faces huge challenges to realize efficient development.In this paper,the development history of deep marine carbonate gas reservoirs in the Sichuan Basin was analyzed.Then,based on such development characteristics and practices,special technologies were summarized.Finally,the research direction for the coming years was pointed out.And the following research results were obtained.First,the reserves of the deep marine carbonate gas reservoirs in the Sichuan Basin vary greatly in scales and types.The reservoirs are of poor quality and strong heterogeneity with active edge and bottom water.The raw gas generally contains acidic gas.What's more,most development wells are located in mountainous areas,and drilled formations are complicated in vertical distribution.Second,special technologies have been formed in the Sichuan Basin,including the fine description technology for strong-heterogeneity gas reservoirs in deep low-gentle structures,the optimized water control technology for the water-bearing gas reservoirs with developed small-scale fractures and vugs,drilling,completion and stimulation engineering technologies for deep complex gas wells,and the support technology for clean and safe development of sulfur-bearing gas reservoirs,so as to provide support for the efficient productivity construction and optimized development of giant marine carbonate reservoirs in the Sichuan Basin.Third,as the development of the carbonate gas reservoirs in the Sichuan Basin begins to convert into the gas reservoirs in ultra-deep complex structures,the next direction of technological research is the fine structure description and thin reservoir prediction technique,across-scale numerical simulation technique,drilling and completion and gas production engineering technique for deep marine carbonate gas reservoirs.It is concluded that these special technologies for the efficient development of deep marine carbonate gas reservoirs provides powerful support for PetroChina Southwest Company to build up giant gas fields with the reserves of tens of billions of cubic meters and realize the leaping growth of gas production.The research results can provide valuable technical reference for the development of deep marine carbonate gas reservoirs at home and abroad.展开更多
Compared with the United States,Australia,Canada,and other countries,China's coalbed methane reservoir is featured by low formation pressure,low permeability,low gas saturation,and strong heterogeneity,which not o...Compared with the United States,Australia,Canada,and other countries,China's coalbed methane reservoir is featured by low formation pressure,low permeability,low gas saturation,and strong heterogeneity,which not only increases the difficulty of reservoir stimulation but also restricts the single well production and the recovery efficiency of coalbed methane(CBM).In view of this,the research and application of horizontal drilling and completion technology of CBM at home and abroad are reviewed to provide references and theoretical supports for the advancement of the horizontal well engineering technology of CBM in China.This paper introduces a series of horizontal drilling and completion technologies(e.g.,the well type design,well structure optimization,well trajectory control,wellbore stability,completion optimization,reservoir protection,etc.).The advanced technologies and their adaptability,including screen pipe completion and stimulation with dual-layer tubular strings,radial horizontal well screen pipe completion and magnetic steering drilling,are dialectically discussed in this paper.In addition,a novel integrated engineering mode for the efficient and green development of deep CBM and coal through the underground“well factory”is proposed.The conclusions are as follows:(1)In view of the geological conditions and surface environment of the coal seam in China,the horizontal drilling and completion technologies of high rank coalbed methane should be further refined,and an integrated development for the coal measure gas is required;(2)More efforts should be made to strengthen the innovative research on horizontal drilling&completion technology for low-medium rank coals and the broken coal,so as to identify the efficient development mode for the complex coalbed methane reservoir;(3)When encountering major technical challenges during the green and efficient development of unconventional coal mines such as deep coal mines,low grade coal mines and thin coal seams in China,it is necessary to explore the development mode via in-situ conversion process based on underground“well factory”to realize the integrated green and efficient development of deep CBM and coal;(4)The high quality transformation with low-carbon and green energy in China will not only ensure national energy security,but also achieve the goal of“carbon peaking and carbon neutrality”.展开更多
Under the background of the financial crisis and the devaluation of the US dollar brought about by the continuous quantitative easing monetary policy of the Federal Reserve, China has proposed the internationalization...Under the background of the financial crisis and the devaluation of the US dollar brought about by the continuous quantitative easing monetary policy of the Federal Reserve, China has proposed the internationalization of RMB, and at the same time has launched a pilot project of RMB settlement for cross-border trade. It is not difficult to find that the scope and scale of RMB settlement for cross-border trade are gradually expanding under the impetus of financial development and other important factors. Therefore, this paper sorts out the relevant theoretical basis and analyzes the research status quo. On this basis, the paper selects the relevant data from 2016 to 2021 to measure the financial development from three aspects of scale, structure and efficiency. Under the condition of controlling the inflation rate, trade scale and RMB exchange rate, the paper conducts quantitative regression analysis on RMB settlement of cross-border trade, which proves that the financial development has a significant positive effect on RMB settlement of cross-border trade, and puts forward relevant policy recommendations.展开更多
基金supported by the Third Xinjiang Scientific Expedition Program(Grant No.2021xjkk0905)the National Natural Science Foundation of China(Grant No.42121001).
文摘New-type urbanization(NTU)is proposed by China to solve unsustainable issues and improve green development efficiency(GDE)during the process of rapid urbanization.However,the impact mechanism of NTU on GDE is unclear.Using panel data of 282 prefecture-level cities in China from 2010 to 2019,we measured NTU and GDE to describe their spatiotemporal pattern and relationship evolution.The fixed effects panel model and mediating effect panel model were further utilized to analyze the benchmark impact,mediating mechanism and spatiotem-poral heterogeneity of NTU on GDE.The results showed that NTU improved,with the highest levels observed in the eastern region,while GDE increased with fluctuations,performing better in both the eastern and western regions.With the proportion of double-high cities increasing from 13.83%to 43.62%,the NTU-GDE relationship was upgraded.Overall,every 1%improvement in NTU increased GDE by 0.3111%,and the enterprise effect,resident effect and government effect played a positive mediating role from high to low.During the later stage of NTU,its impact on GDE strengthened significantly,and the mediating role of governments was optimized.The eastern region was the only region with three positive mediating roles of governments,enterprises and residents.These findings will promote GDE through NTU in China and serve as a valuable reference for sustainable global urbanization.
基金National Natural Science Foundation of China,No.41771131China Scholarship Council,No.202008110050Key Program for Scientific Research of Beijing Union University,No.SKZD202306。
文摘Green development is a critical component of sustainable tourism, which prioritizes a comprehensive, ecologically-friendly, and people-oriented approach to development. This study presents a case study of the Beijing–Tianjin–Hebei(BTH) urban agglomeration from 2001 to 2021 to analyze the spatio-temporal evolution characteristics and influencing factors of tourism green development efficiency(TGDE). The study defines the concept of tourism green development and constructs an evaluation system, which is used to explore the internal differences and spatial patterns of TGDE within the urban agglomeration. The methodological approach includes the SBM–Undesirable model, kernel density estimation, Markov chain, and spatial gravity model. The findings indicate that the TGDE in the BTH urban agglomeration is generally favorable, displaying a temporal phase of “rising–declining–rising.” However, the study observes lower TGDE in tourism node cities compared to tourism regional center cities and tourism core hub cities. The non-equilibrium degree of each region indicates significant spatio-temporal evolution patterns and internal differences among the three regions, with a spatially decreasing distribution of “core hub-regional center-node city.” The TGDE in the urban agglomeration experienced an evolutionary trend of “first decreasing and then increasing” with apparent endogenous evolution characteristics. The linkage pattern of green development efficiency in the tourism industry between cities is relatively stable. Furthermore,neighboring cities generally exhibit a higher spatial connectivity strength of green development efficiency in the tourism industry compared to non-neighboring cities. Economic development level, industrial structure, and science and education level are identified as key factors that affect TGDE. However, the study finds that the factors influencing TGDE in tourism core hub cities, tourism regional center cities, and tourism node cities differ somewhat. Economic development level, industrial structure, science and education level, openness, and government regulation impact TGDE in tourism core hub cities and tourism regional center cities, while economic development level, industrial structure, and tourism resource endowment are the primary factors affecting TGDE in tourism node cities. The study provides policymakers and tourism practitioners with valuable insights into enhancing the green development of the tourism industry in the BTH urban agglomeration and other similar regions.Corresponding policy recommendations based on the results are proposed to improve the TGDE of the tourism industry in these regions, promote sustainable tourism development,improve the quality of life of local residents, and protect the ecological environment.
基金National Natural Science Foundation of China,No.71804168。
文摘Suitable spatial morphology of cultivated land is a basic requirement for sustaining agricultural economic development in mountainous areas.Coordinated development efficiency of cultivated land spatial morphology and agricultural economy(CECA)is of great practical significance to measure the efficiency of cultivated land use,and thereby promote regional rural revitalization.However,few studies to date have focused on coordinated development efficiency between cultivated land use and agricultural economy in mountainous areas from the perspective of cultivated land spatial morphology.Thus,the present study explores CECA with this focus using the data envelopment analysis method,and analyzes the key influencing factors via a geographical detector model in 16 counties in western Hubei province.The results show the following:(1)CECA exhibits significant spatial heterogeneity that is high in the south of the study area and low in the north;(2)scale efficiency is the primary limiting factor for CECA;(3)the insufficient output of cultivated land use mainly restricts CECA in the south of the study area,while individual county in the north suffered from input redundancy and insufficient output;and(4)population density in the southern region has the most significant effect on CECA,and gross domestic product has the greatest impact in the northern region.The results contribute to the derivation of specific measures by which to promote cultivated land use efficiency and sustainable development of the social economy.
基金National Natural Science Foundation of China,No.41401158No.41140007No.41261035
文摘The traditional data envelopment analysis（DEA）, bootstrap-DEA and Malmquist models are employed to measure different tourism efficiencies and their spatial characteristics of 61 cities in six coastal urban agglomerations in eastern China. The following conclusions are drawn.（1） The comprehensive efficiency（CE） of urban tourism using the bootstrap-DEA model is lower than the CE level using the DEA-CRS model, which confirms the significant tendency of the DEA-CRS model to overestimate results.（2） The geometric CE averages of urban tourism in the Yangtze River Delta（YRD） and the Pearl River Delta（PRD） have changed from ineffective to effective since 2000, the averages in the Beijing-TianjinHebei（BTH） and the Shandong Peninsula（SDP） have changed from ineffective to moderately effective since 2000, and those in the Central and Southern Liaoning（CSL） and the West Bank of Taiwan Strait（WBTS） have been ineffective since 2000.（3） The CE values of urban tourism in the PRD, the YRD, the BTH and the SDP have been slightly affected by the pure technical efficiency（PTE）, whereas the CE values in the CSL and the WBTS have been slightly affected by the scale efficiency（SE） since 2000.（4） Spatially, the range of geometric averages of the total factor productivity（TFP） for the PRD, the YRD, the BTH, the SDP, the WBTS and the CSL has decreased sequentially, while the one for most cities in six urban agglomerations has exhibited a downward trend since 2000.（5） Collectively, the natural conditions, the economic policies and the tourism capital drive the SE change of urban tourism of the CSL and the WBTS. The tourism enterprises for increasing returns to scale and imitating innovative technology have an effect on the CE change of urban tourism in the BTH and the SDP. The tourism market competition drives the PTE change of urban tourism in the PRD and the YRD. Although the PTE and the SE of urban tourism in six coastal urban agglomerations suffer from uncertain events, the CE maintained overall sound momentum since 2000.
基金Under the auspices of National Natural Science Foundation of China(No.41771138,41801105)。
文摘Green development is an important issue of sustainable development in China.Due to the relatively backward economy and the fragile ecological environment,restricted development zones need to embrace green development.Taking 38 counties in Jilin Province as the empirical research objects,and based on cross-sectional data for each county in 2005,2010,and 2015,we accurately depicted the spatiotemporal evolutionary characteristics of green development efficiency(GDE)in restricted development zones of Jilin Province using the slacks-based measure-data envelope analysis(SBM-DEA)model.Moreover,the factors that influence GDE were further analyzed using the Tobit model.We found that:first,GDE showed a V-shaped trend in restricted development zones of Jilin Province.The differences in GDE in the eastern,central,and western Jilin Province increased gradually.Second,76%of counties in the restricted development zones had high or higher efficiencies.The resource-based cities were the main areas with low or lower GDE.Third,the economic development level was the core factor affecting GDE.Urbanization level had a significant negative effect on GDE in the restricted development zones.The effect of technological innovation level on GDE fluctuated,and we found that a‘backward mechanism’of technological innovation was beginning to form.Industrial structure and environmental governance had no significant effects on GDE.
基金This research is supported by Shanxi Province Philosophy and Social Science Project(Grant No.W20191012)Shanxi province Soft Science Project(Grant No.2019041015-1).
文摘Under the background of green development,the function direction of technological innovation to green development efficiency,which includes economy,resources and environment,needs to be observed by demonstration.In this paper,the green development efficiency of 30 provinces(cities and districts)in China from 2004 to 2017 is measured and its intertemporal changes,regional differences of green development efficiency are analyzed by using the super efficiency SBM model,further through theoretical analysis and empirical study,the influence of technological innovation on regional green development efficiency and its impact mechanism are investigated.The influence mechanisms of the technological innovation on green development efficiency are clarified and empirically tested by spatial econometric models from the perspectives of the growth sources and quantitative analysis.The results show that during the observation period,the green development efficiency in China exhibits a U-shaped variation,but there are huge regional differences with the obvious polarization in Eastern and Midwestern regions,and that technological innovation has some effect in promoting the regional green development efficiency,but not significant enough,which are heterogeneous according to the time periods and regions.
文摘The green development of Chongqing municipality is crucial in establishing a major ecological shield in the upper reaches of the Yangtze River.By developing a Super-SBM model and using the Malmquist index to analyze and calculate the green development efficiency and its influencing factors in Chongqing from 2011 to 2021,this study reveals an accelerating trend in the overall green development efficiency in Chongqing.The significant enhancement of green development efficiency in Chongqing is primarily attributed to changes in returns to scale.Pure technical efficiency and technological advancements have a considerable potential impact on improving green development efficiency in Chongqing.Furthermore,there are discernible disparities in green development efficiency among districts and counties in Chongqing,with different factors influencing these variations.Chongqing is suggested to promote clean and efficient energy utilization,bolster the application and commercialization of scientific and technological advancements,consistently advance ecological restoration and management,and elevate the quality of green development to a higher level.
文摘The major cities of every country and region in the world play an important role in the process of global development.The assessment of the development efficiency of these core cities can help governments better understand their role in globalization and provide some useful information for policy makers.This paper evaluates the development efficiency of 35 major cities around the world during the period 2011-2020.The data used is the Global City Power Index(GPCI)released by the Mori Foundation of Japan,which evaluates each city in a total of 70 indicators from six dimensions:economy,research development(R&D),cultural exchange,livability,environment and accessibility.The development efficiency of the 35 global major cities is evaluated by using data envelopment analysis(DEA)to divide the six dimensions into input and output indexes.The change of development efficiency of the 35 global core cities during 2011-2020 is studied by using Malmquist index.It is found that the absolute strength of each city is not necessarily related to its development efficiency,and the change of development efficiency is affected by both technological efficiency and technological progress.
基金supported by National Natural Science Foundation of China(Grant numbers:51821092 and U1762214)。
文摘With the basic characteristics of conventional horizontal wells,the so-called complex wells including horizontal extended-reach wells,multi-lateral horizontal wells,U-shaped wells,cluster horizontal wells,etc.,are advanced well types for the efficient development of low-permeability,unconventional,deep-water,and deep oil and gas reservoirs,which have been highly concerned all over the world.Significant progress at home and abroad has been made in relevant researches and practices and is expected to play an important role in the efficient development of shale oil and gas.To meet the basic needs of environment&safety,land conservation,cost reducing and efficiency improving,it is urgent to create a unique and efficient mode for developing shale gas.Therefore,an efficient shale gas development mode for mountainous areas and an engineering and technical support system are presented based on large cluster horizontal-well engineering.An equation is thus obtained for calculating the maximum number of horizontal wells arranged allowably in“Well Factory”on a single platform.The general research and development of large extended-reach well technology are analyzed by expounding the basic concept of an extended-reach well and its drilling extension limit.And a calculation method is thus established to predict the maximum measured depth of open hole in extended-reach drilling.Moreover,some relevant research results and their significance for downhole tubular mechanics&mechanical extension limits in extended-reach drilling are also briefly introduced in this paper.The conclusions are drawn that,by following the idea of“integration of geology and engineering”in oil and gas development,these research results have a foreseeable application prospect in shale gas development in the mountainous areas in the future,and will contribute to new progress in China's“Shale Revolution”.
基金Project supported by the“Changning-Weiyuan Shale Gas Development Demonstration Project”subordinate to the National Major Science and Technology Project“Development of Large Oil/gas Fields and Coalbed Methane”(No.:2016ZX05062)PetroChina Major Science and Technology Project(No.:2016E-0611).
文摘Shale gas resources in the Lower Silurian Longmaxi,southern Sichuan Basin,are huge,where,the geological setting,unlike that in North America,is quite complicated and ground surface infrastructure is poor.Therefore,adaptable key technologies will be essential to achieve commercial exploitation of shale gas there.In the case study of the Changning-Weiyuan National Shale Gas Demonstration Zone,six series of key techniques were summarized in comprehensive geological evaluation,development optimization,fast and superior drilling of horizontal wells,horizontal-well volumetric fracturing,cluster-well and factory-like operation in well blocks,and highly-efficient and clean exploitation.The above techniques were applied in this field after three rounds of adjustment and optimization,the resulted production rates of shale gas wells were getting higher and higher and the single-well estimated ultimate recovery(EUR)was also rising.Compared with that in the first round,the average EUR of wells in the third round was increased by 128%.In conclusion,the application practices prove that the above series of key techniques with adaptation and flexibility provide a robust technical support for the rapid output of shale gas production in South Sichuan Basin.
基金Special and Significant Project of National Science and Technology“Horizontal Well Development Demonstration Project of Coalbed Methane in Qinshui Basin,Shanxi Province,China”(No.:2011ZX05061)Special and Significant Project of PetroChina“Exploration and Development Demonstration Project of Coal-bed Gas Field in Qinshui Basin”(No.:2010E-2208).
文摘The low average single-well production,resulting in low economic benefit,has become the main bottleneck of CBM development in China.In view of this issue,through case study of a CBM gas reservoir in the southern Qinshui Basin,we summarized the present status of CBM technology and development there and also pointed out some major problems in CBM development:(1)the engineering technology for the CBM development needs to adapt to the particular geological characteristics;(2)a large number of inefficient zones still exist in mature blocks in the southern Qinshui Basin;(3)single-well production can not be effectively enhanced only by increasing the fracturing scale;(4)the production of multi-lateral wells is higher,but the fulfillment rate of production capacity overall is still low;and(5)on-site management lacks scientific evidence.On this basis,we present the following suggestions for subsequent coalbed gas development:(1)the production construction mode should be changed,and the fulfillment rate of production capacity construction should be improved;(2)CBM geological research should be improved and well types and locations should be designed reasonably and scientifically;(3)main technologies should be built in a dialectical thinking mode;(4)horizontal well design should be optimized to improve the applicability of relevant technologies;(5)fracturing mode should be changed to improve single-well production;and(6)the drainage technology should be changed to improve economic efficiency.
基金Project supported by the National Natural Science Foundation of China"Shale Gas Reservoir Dynamic Simulation Research on Coupled Fracture Network E xpansion Mechanism"(No.51874251).
文摘China's shale gas production in 2020 exceeds 200×10^(8) m^(3),which creates a miracle in the history of natural gas development in China.The Sichuan Basin has already been and will be the main battlefield of shale gas exploration and development in China.In order to further promote the large-scale efficient development of shale gas in China,under the new situation of global COVID-19 spread and domestic“carbon peak and carbon neutrality”goal,this paper analyzes the progress and challenges of shale gas exploration and development in the Sichuan Basin from four aspects,including resource exploration,gas reservoir engineering,drilling and production engineering and industry regulation,and puts forward countermeasures and suggestions for achieving large-scale efficient development of shale gas.The following research results are obtained:First,the large-scale efficient development of shale gas in the Sichuan Basin has to take the sustainable and stable production of middle-shallow shale gas and the large-scale productivity construction of deep shale gas as the base.Second,compared with the shale gas exploration and development in the North America,the Sichuan Basin has its own characteristics in terms of geographical setting,geological condition,drilling and production technology and industry regulation,which makes it difficult to copy the development pattern of large scale,high density and continuous well deployment from the North America,so it is necessary to adopt the strategy of“high production with few wells”.On the one hand,continue to apply the geology and engineering integration technology to carry out“integrated research,integrated design,integrated implementation and integrated iteration”in the whole life cycle of shale gas well;and on the other hand,carry out problem-oriented continuous researches from the aspects of geological evaluation,development policy,engineering technology and industry regulation,so as to improve geological evaluation theory and technology,innovate gas reservoir engineering theory and method,research and develop engineering technology for cost reduction and efficiency improvement,improve shale gas industry regulation,and form a new pattern of collaborative promotion of technical and non-technical elements.In conclusion,the research results provide important reference and guidance for the large-scale efficient development of shale gas in the Sichuan Basin and even the whole country.
文摘The Lower Cambrian Longwangmiao Fm gas reservoir in Moxi block of the Anyue Gas field,Sichuan Basin,is the largest single-sandbody integrated carbonate gas reservoir proved so far in China.Notwithstanding this reservoir's advantages like large-scale reserves and high singlewell productivity,there are multiple complicated factors restricting its efficient development,such as a median content of hydrogen sulfide,low porosity and strong heterogeneity of fractureecave formation,various modes of gasewater occurrences,and close relation between overpressure and stress sensitivity.Up till now,since only a few Cambrian large-scale carbonate gas reservoirs have ever been developed in the world,there still exists some blind spots especially about its exploration and production rules.Besides,as for large-scale sulfur gas reservoirs,the exploration and construction is costly,and production test in the early evaluation stage is severely limited,all of which will bring about great challenges in productivity construction and high potential risks.In this regard,combining with Chinese strategic demand of strengthening clean energy supply security,the PetroChina Southwest Oil&Gas Field Company has carried out researches and field tests for the purpose of providing highproduction wells,optimizing development design,rapidly constructing high-quality productivity and upgrading HSE security in the Longwangmiao Fm gas reservoir in Moxi block.Through the innovations of technology and management mode within 3 years,this gas reservoir has been built into a modern large-scale gas field with high quality,high efficiency and high benefit,and its annual capacity is now up to over 100×10^(8)m^(3),with a desirable production capacity and development indexes gained as originally anticipated.It has become a new model of large-scale gas reservoirs with efficient development,providing a reference for other types of gas reservoirs in China.
基金Scientific and Technological Project of China National Petroleum Exploration and Production Corporation"Research on North China Coalbed Methane Reserve Utilization and Beneficial Development Technology"(kt2021-10-07)China National Petroleum North China Technology Project of Oilfield Company"Geological Design Technology of High Coalbed Methane Horizontal Well and Implementation Tracking Research"(2022-HB-M03).
文摘There are abundant high-rank coal bed methane(CBM)resources in China,accounting for one third of total CBM resources.Its efficient development and utilization is of great significance to guarantee the national energy strategic security,diminish the hidden danger of coal mine production and reduce carbon dioxide emission.In order to solve the"four lows"problem(i.e.,low effective utilization ratio of proved reserves,low productivity targeting ratio,low single-well production rate and low development profit)restricting the development of high-rank CBM industry in China,this paper deeply analyzes the core problems restricting the development of high-rank CBM.Based on this,several new methods of production control,area selection and evaluation are put forward by taking multiple measures,such as paying the same attention on theoretical research and technological research&development,carrying out laboratory research and field test in parallel and conducting large scale construction and benefit development simultaneously.And the following research results are obtained.First,the geological difference between CBM and coal mine,the difference in reserves recoverability,the adaptability of engineering technology and the scientificity of production are the main factors restricting CBM development effect.Second,"Four-element"production control theory,methane-leading en gineering transformation method and methane-leading production control theory are proposed,which provides guidance for the development of a series of technologies for the efficient development of high-rank CBM.Third,in practice,the control degree of quality reserves is increased from 32%to 80%,the success ratio of development wells is increased from 60%to 95%,the average single-well daily gas production of vertical wells is increased by about 1100 m^(3),the drilling cost of horizontal wells is reduced by 50%,and the operation cost per cubic meter of gas is reduced by 24%.In conclusion,the established technology series for the efficient development of high-rank CBM actively promote the efficient CBMdevelopment in the Qinshui Basin.The yearly CBM production of PetroChina Huabei Oilfield Company is expected to reach 20108 m^(3) in the middle of the"14th Five-Year Plan",which promotes the strategic development of CBM industry in China.
基金Project supported by the National Science and Technology Major Project“Demonstration Project of Giant Carbonate Gas Field Development in Sichuan Basin”(No.2016ZX05052)the PetroChina Major Technology Special Project“Research and Application of Key Technology for Large-scale Efficient Development of the Fourth Member of Dengying Formation in Central Sichuan”(No.:2016E-0606).
文摘The Sinian Dengying Formation gas reservoir in the Anyue gas field of the Sichuan Basin is an ultra-deep ancient dolomite karst gas reservoir,whose development is of high difficulty,for the reservoir is thin and scattered with strong heterogeneity and is overall characterized by low porosity and low permeability.In order to provide support for the large-scale productivity construction of the gas reservoir of the fourth member of Dengying Formation(Deng 4 Member)in the marginal platform belt of the Anyue gas field,this paper carries out multi-discipline comprehensive researches on the technical bottlenecks based on the geological characteristics of the gas reservoir.In addition,the targeted key technologies for the efficient development of gas reservoirs were developed in the mode of“simultaneous research,application and improvement”.And the following research results are obtained.First,based on the modeling technology of fracturedevuggy dolomite karst reservoirs,accurate modeling of karst reservoirs is realized.Late actual drilling results show that the model's coincidence rate is increased from 63.0% to 90.7% and the“transparency”of gas reservoirs is achieved.Second,based on the reserve mobility evaluation technology of lowporosity and highly-heterogeneous karst reservoirs,the recovery factors of different reservoirs are determined.And consequently,the lower limit of well-controlled reserves and radius for the efficient development of different reservoirs are obtained and type Ⅰ and Ⅱ reservoirs are selected as the main development targets.Third,based on the development optimization design technology of highly-heterogeneous karst gas reservoirs,it is recommended to apply highly-deviated wells(the maximum deviation angle of 75°-84°)in the situations with multiple reservoirs crossed and superimposed.If type Ⅰ and Ⅱ reservoirs are developed intensively,it is recommended to adopt horizontal well drilling with a horizontal section of 800-1100 m.What's more,the reasonable well spacing in type Ⅰ and Ⅱ reservoirs shall be 1.6-3.3 km and 0.9-1.4 km,respectively.Fourth,based on the distinguished drilling technology of highly-deviated wells/horizontal wells in deep carbonate rocks,the fault complexity ratio is decreased from 20.7% to 4.9%,so safe and fast drilling and completion of highly-deviated wells/horizontal wells is realized and well control risks are diminished.What's more,the drilling rates of type Ⅰ and Ⅱ reservoirs are increased from 24.2% to 87.3%,indicating an effective improvement of reservoir drilling rates.Fifth,based on the open-hole segmented accurate acid fracturing technology of highly-deviated and horizontal wells,the difficulty in the highly-heterogeneous reservoir stimulation by horizontal well drilling is solved by conducting the differentiated acid fracturing process of“one segment,one strategy”.Based on the application of these innovative development technologies in the Deng 4 Member gas reservoir in the marginal platform belt of the Anyue gas field,the annual natural gas production capacity and cumulative natural gas production by the end of December 2020 are 60×10^(8) m^(3) and 103×10^(8) m^(3),respectively.In this way,the Sinian Dengying Formation gas reservoir of the Anyue gas field,the economic benefit of which is close to the marginal benefit,becomes the main force of conventional natural gas production increase.
基金supported by the National Major Science and Technology Project“Demonstration Project of Developing Large-Scale Carbonate Gas Field in the Sichuan Basin”(No.:2016ZX05052)PetroChina Major Science and Technology Project“Research and Application of Key Techniques for Put on Production of 30 Billion Cubic Meters of Natural Gas in Southwest Oil and Gas Fields”(No.:2016E-06).
文摘In recent years,the Sichuan Basin has been the most potential hydrocarbon-bearing basin in China thanks to the great exploration and development breakthroughs of deep large integral carbonate gas reservoirs and shale gas in this basin.The Anyue Gas Field located in central Sichuan Basin is not only the largest carbonate gas reservoir,but the most important supergiant gas field discovered in China in recent years.However,it faces a series of major difficulties,e.g.,low reservoir porosity,low permeability,low gas well productivity,thin and vertically and laterally disperse gas layer,strong heterogeneity,quite low structural amplitude and complicated gasewater relationship,which bring great challenges to the rapid conversion of natural gas reserves to production.In this regard,technical researches have been carried out continuously.As a result,many key technologies have been innovatively integrated and great breakthroughs have been realized in many aspects.First,fine development technologies for supergiant,ancient and complex carbonate gas reservoirs are developed innovatively,“transparent gas reservoir”is constructed and the technologies for cultivating high-yield wells are established.By virtue of these technologies,all development wells in the gas reservoir of Lower Cambrian Longwangmiao Formation reach the target of high yield and the single-well gas production rate of the gas reservoir of Lower Sinian Dengying Formation is increased significantly,which provides support for the long-term high production and stable production of Anyue Gas Field.Second,good and fast construction technologies for large-scale gas fields are innovatively integrated.Based on this,the safety of gas wells is under control in the whole life cycle,quality engineering is built up efficiently within 3 years,green mining areas are forged and large-scale safe and clean gas fields are built up efficiently.Third,intelligent control technologies for the development of supergiant gas fields are innovatively integrated.By means of these technologies,internet of everything,depth perception and automatic production are realized.The intelligent technologies of new generation are fused,including AR,VR,robot and unmanned aerial vehicle(UAV).A new intelligent management mode for gas field development is set up,and an intelligent gas field is built up.Fourth,optimization technologies for the overall development of supergiant gas fields are innovatively development,so as to improve the development effects of strong-heterogeneity gas reservoirs and ensure the long-term stable production of supergiant water-bearing gas reservoirs.The research results can be used as reference for the efficient development of similar domestic and foreign gas fields.
基金Project supported by the National Major Science and Technology Project“Demonstration Project of Development of Large Carbonate Gas Fields in the Sichuan Basin”(No.:2016ZX05052)Scientific Research and Technological Development Project of PetroChina Company Limited“Research and Application of Key Technologies for 30 Bcm-level Gas Production in the Southwest Oil&Gas Field”(No.:2016E-06).
文摘In recent years,deep marine carbonate gas reservoirs have become an important field in increasing conventional gas reserves and production in the Sichuan Basin.Due to complex hydrocarbon accumulation conditions,great burial depth and complicate gas-water relation,however,this type of gas reservoirs faces huge challenges to realize efficient development.In this paper,the development history of deep marine carbonate gas reservoirs in the Sichuan Basin was analyzed.Then,based on such development characteristics and practices,special technologies were summarized.Finally,the research direction for the coming years was pointed out.And the following research results were obtained.First,the reserves of the deep marine carbonate gas reservoirs in the Sichuan Basin vary greatly in scales and types.The reservoirs are of poor quality and strong heterogeneity with active edge and bottom water.The raw gas generally contains acidic gas.What's more,most development wells are located in mountainous areas,and drilled formations are complicated in vertical distribution.Second,special technologies have been formed in the Sichuan Basin,including the fine description technology for strong-heterogeneity gas reservoirs in deep low-gentle structures,the optimized water control technology for the water-bearing gas reservoirs with developed small-scale fractures and vugs,drilling,completion and stimulation engineering technologies for deep complex gas wells,and the support technology for clean and safe development of sulfur-bearing gas reservoirs,so as to provide support for the efficient productivity construction and optimized development of giant marine carbonate reservoirs in the Sichuan Basin.Third,as the development of the carbonate gas reservoirs in the Sichuan Basin begins to convert into the gas reservoirs in ultra-deep complex structures,the next direction of technological research is the fine structure description and thin reservoir prediction technique,across-scale numerical simulation technique,drilling and completion and gas production engineering technique for deep marine carbonate gas reservoirs.It is concluded that these special technologies for the efficient development of deep marine carbonate gas reservoirs provides powerful support for PetroChina Southwest Company to build up giant gas fields with the reserves of tens of billions of cubic meters and realize the leaping growth of gas production.The research results can provide valuable technical reference for the development of deep marine carbonate gas reservoirs at home and abroad.
基金Key Project of Natural Science Foundation of China(NSFC)"Basic Research on three-dimensional design&construction of an underground well factory with complex structures"(No.:52234002),and Innovative Research Group Project of NSFC“Basic Research on Drilling and Completion of Critical Oil and Gas Wells”(No.:51821092).
文摘Compared with the United States,Australia,Canada,and other countries,China's coalbed methane reservoir is featured by low formation pressure,low permeability,low gas saturation,and strong heterogeneity,which not only increases the difficulty of reservoir stimulation but also restricts the single well production and the recovery efficiency of coalbed methane(CBM).In view of this,the research and application of horizontal drilling and completion technology of CBM at home and abroad are reviewed to provide references and theoretical supports for the advancement of the horizontal well engineering technology of CBM in China.This paper introduces a series of horizontal drilling and completion technologies(e.g.,the well type design,well structure optimization,well trajectory control,wellbore stability,completion optimization,reservoir protection,etc.).The advanced technologies and their adaptability,including screen pipe completion and stimulation with dual-layer tubular strings,radial horizontal well screen pipe completion and magnetic steering drilling,are dialectically discussed in this paper.In addition,a novel integrated engineering mode for the efficient and green development of deep CBM and coal through the underground“well factory”is proposed.The conclusions are as follows:(1)In view of the geological conditions and surface environment of the coal seam in China,the horizontal drilling and completion technologies of high rank coalbed methane should be further refined,and an integrated development for the coal measure gas is required;(2)More efforts should be made to strengthen the innovative research on horizontal drilling&completion technology for low-medium rank coals and the broken coal,so as to identify the efficient development mode for the complex coalbed methane reservoir;(3)When encountering major technical challenges during the green and efficient development of unconventional coal mines such as deep coal mines,low grade coal mines and thin coal seams in China,it is necessary to explore the development mode via in-situ conversion process based on underground“well factory”to realize the integrated green and efficient development of deep CBM and coal;(4)The high quality transformation with low-carbon and green energy in China will not only ensure national energy security,but also achieve the goal of“carbon peaking and carbon neutrality”.
文摘Under the background of the financial crisis and the devaluation of the US dollar brought about by the continuous quantitative easing monetary policy of the Federal Reserve, China has proposed the internationalization of RMB, and at the same time has launched a pilot project of RMB settlement for cross-border trade. It is not difficult to find that the scope and scale of RMB settlement for cross-border trade are gradually expanding under the impetus of financial development and other important factors. Therefore, this paper sorts out the relevant theoretical basis and analyzes the research status quo. On this basis, the paper selects the relevant data from 2016 to 2021 to measure the financial development from three aspects of scale, structure and efficiency. Under the condition of controlling the inflation rate, trade scale and RMB exchange rate, the paper conducts quantitative regression analysis on RMB settlement of cross-border trade, which proves that the financial development has a significant positive effect on RMB settlement of cross-border trade, and puts forward relevant policy recommendations.
