The Zhujiang River Mouth Basin,a primary depocenter for terrigenous sediments in the western Pacific,presents a semienclosed tectonic setting with limited exchange with the open ocean.This unique feature enables syste...The Zhujiang River Mouth Basin,a primary depocenter for terrigenous sediments in the western Pacific,presents a semienclosed tectonic setting with limited exchange with the open ocean.This unique feature enables systematic linkages among sedimentary processes,climate change,regional sea-level fluctuations,and tectonic events.To explore these linkages,this study focuses on Well PY35 in the Baiyun Sag of the Zhujiang River Mouth Basin.By integrating microfossil analysis with Milankovitch cycle analysis of well log data,an astronomical time scale(ATS)(17.54-7.80 Ma)and a high-resolution stratigraphic framework were established,allowing for the calculation of sedimentation rates across different hierarchical sequences and time intervals.The results indicate that between 17.54 Ma and 7.80 Ma,the sedimentation rate initially increased and then decreased,ranging from 6.1 cm/ka to 45.7 cm/ka,with an average rate of 22.2 cm/ka.During the Middle Miocene Climatic Optimum(MMCO),sedimentation rates were moderate and exhibited an increasing trend,largely driven by increased sediment input due to enhanced weathering from rising temperatures and by expanded accommodation space resulting from tectonic subsidence.Meanwhile,the Middle Miocene Climate Transition(MMCT)was marked by a notable rise in sedimentation rates,consistent with a major sea-level fall due to global cooling,which promoted the direct seaward progradation of marginal sediments.The Late Middle Miocene to Late Miocene had the lowest sedimentation rates,which can be attributed to reduced weathering under cold and arid conditions,along with a sea-level rise induced by regional tectonics.The short-term increase in the sedimentation rate observed at 10.4 Ma may have been driven by sea-level fluctuations.This study provides both theoretical and empirical support for understanding the influence of abrupt climate changes on sedimentary processes.展开更多
As oil and gas development increasingly targets unconventional reservoirs,the limitations of conventional hydraulic fracturing,namely high water consumption and significant reservoir damage,have become more pronounced...As oil and gas development increasingly targets unconventional reservoirs,the limitations of conventional hydraulic fracturing,namely high water consumption and significant reservoir damage,have become more pronounced.This has driven growing interest in the development of clean fracturing fluids that minimize both water usage and formation impairment.In this study,a low-liquid-content viscoelastic surfactant(VES)foam fracturing fluid system was formulated and evaluated through laboratory experiments.The optimized formulation comprises 0.2%foaming agent CTAB(cetyltrimethylammonium bromide)and 2%foam stabilizer EAPB(erucamidopropyl betaine).Laboratory tests demonstrated that the VES foam system achieved a composite foam value of 56,700 mL・s,reflecting excellent foaming performance.Proppant transport experiments revealed minimal variation in suspended sand volume over 120 min across different sand ratios,indicating robust sand-carrying capacity even at high proppant concentrations.Rheological measurements showed that the fluid maintained a viscosity above 120 mPa・s after 120 min of shearing at 70℃ and a shear rate of 170 s−1,with the elastic modulus exceeding the viscous modulus,confirming the system’s exceptional stability and resilience.Furthermore,core damage tests indicated that the VES foam caused only 4.42%formation damage,highlighting its potential for efficient and low-damage stimulation of tight reservoirs.Overall,the findings demonstrate that this low-liquid-content VES foam provides a highly effective,environmentally considerate alternative for hydraulic fracturing in unconventional formations,combining superior proppant transport,rheological stability,and minimal reservoir impairment.展开更多
The Sichuan Basin is a major target for shale gas exploration in present China because of its rich gas stored in abundant black shales with multiple bed series.For further guidance or reference,field exploration and d...The Sichuan Basin is a major target for shale gas exploration in present China because of its rich gas stored in abundant black shales with multiple bed series.For further guidance or reference,field exploration and development practices in the shale reservoirs Upper Ordovician WufengeLower Silurian Longmaxi shale reservoirs were studied in terms of development stages and progress,favorable conditions for shale gas accumulation,bottlenecking issues on theories and technologies related to shale gas development,and so on.The following findings were obtained.(1)Shale with rich organic matters originated from the deep shelf has a good quality and great thickness in the continuous beds.The relatively stable wide buffer zones in synclines(anticlines)provides favorable conditions for shale gas accumulation and preservation with well developed micro-fractures and overpressure as necessary factors for a great potential of high shale gas productivity.(2)The bottlenecking technical issues restricting the shale gas industrial development in this study area include the following aspects:understandings of rich-organic matter shale sedimentary facies and modes,shale reservoir diagenetic process and evaluation systems,shale gas generation and accumulation mechanism,geophysical logging identification and prediction of shale gas layers,low resource utilization rate,great uncertainty of shale gas development,no technological breakthrough in the exploration of shale gas reservoirs buried deeper than 3500 m.In conclusion,this study area will be the major target for the shale gas exploration and development in China in a rather long period in the future.展开更多
The global sustained low oil prices have a significant impact on China's oil and gas industry system and the national energy security.This paper aims to find solutions in order to guarantee the smooth development ...The global sustained low oil prices have a significant impact on China's oil and gas industry system and the national energy security.This paper aims to find solutions in order to guarantee the smooth development of China's oil and gas industry system and its survival in such a severe environment.First,the origins of sustained low oil prices were analyzed.Then,based on those published data from IEA,government and some other authorities,this study focused on the development status,energy policies and the future developing trend of those main oil&gas producing countries.Investigations show that the low-price running is primarily contributed to the so-called oil and gas policies in the USA.It is predicted that national petroleum consumption will reach up to 6.0×10^(8) t(oil)&3300×10^(8) m^(3)(gas)in 2020 and 6.8×10^(8) t(oil)&5200×10^(8) m^(3)(gas)in 2030.For reducing the dependence on foreign oil and gas,the investment in the upstream of oil and gas industry should be maintained and scientific research should be intensified to ensure the smooth operation of the oil and gas production system.Considering China's national energy security strategy,the following suggestions were proposed herein.First,ensure that in China the yearly oil output reaches 2×10^(8) t,while natural gas yield will be expected to be up to 2700×10^(8) m^(3)in 2030,both of which should become the“bottom line”in the long term.Second,focus on the planning of upstream business with insistence on risk exploration investment,scientific and technological innovation and pilot area construction especially for low-permeability tight oil&gas,shale oil&gas reservoir development techniques.Third,encourage the in-depth reform and further growth especially in the three major state-owned oil&gas companies under adverse situations,and create more companies competent to offer overseas technical services by taking the opportunity of the“One Belt and One Road”policy.Finally,promote the new energy business and find solutions to turning those oil companies to integrated energy companies.展开更多
Accurate identification of water sources is crucial for effective water management and safety in mining operations.However,imbalanced water sample datasets often lead to suboptimal classification accuracy.To address t...Accurate identification of water sources is crucial for effective water management and safety in mining operations.However,imbalanced water sample datasets often lead to suboptimal classification accuracy.To address this challenge,this study proposes a novel water source identification method integrating Synthetic Minority Over-Sampling Technique(SMOTE),Zebra Optimization Algorithm(ZOA),and Light Gradient Boosting Machine(LightGBM).Initially,SMOTE is utilized to synthesize samples for the minority class within the imbalanced dataset,thereby generating a balanced water sample dataset and mitigating class distribution disparities.Subsequently,an efficient water source identification model is constructed by combining ZOA with LightGBM,leveraging the strengths of both algorithms.The model’s performance is validated using a test set and compared with other common classification models.Results demonstrate that SMOTE significantly alleviates class imbalance and enhances the classification accuracy of LightGBM for minority class water samples.ZOA parameter tuning accelerates model convergence and further improves classification accuracy,optimizing the model’s overall performance.In experimental validation,the proposed SMOTE-ZOA-LightGBM model achieved an accuracy of 88.41%and a F1 score of 88.24%,outperforming six other classification models.The method proposed in this paper can accurately identify water source types,effectively addressing the issue of low classification accuracy caused by imbalanced water sample data.It provides reliable technical support and scientific basis for identifying and preventing water inrush sources in mines.展开更多
The boosting development of artificial intelligence(AI)is contributing to rapid exponential surge of computing power demand,which results in the concerns on the increased energy consumption and carbon emission.To high...The boosting development of artificial intelligence(AI)is contributing to rapid exponential surge of computing power demand,which results in the concerns on the increased energy consumption and carbon emission.To highlight the environmental impact of AI,a quantified analysis on the carbon emission associated with AI systems was conducted in this study,with the hope of offering guidelines for police maker to setup emission limits or studies interested in this issue and beyond.It has been discovered that both industry and academia play pivotal roles in driving AI development forward.The carbon emissions from 79 prominent AI systems released between 2020 and 2024 were quantified.The projected total carbon footprint from the AI systems in the top 20 of carbon emissions could reach up to 102.6 Mt of CO_(2) equivalent per year.This could potentially have a substantial impact on the environmental market,exceeding$10 billion annually,especially considering potential carbon penalties in the near future.Hence,it is appealed to take proactive measures to develop quantitative analysis methodologies and establish appropriate standards for measuring carbon emissions associated with AI systems.Emission cap is also crucial to drive the industry to adopt more environmentally friendly practices and technologies,in order to build a more sustainable future for AI.展开更多
基金The National Natural Science Foundation of China under contract Nos 42372170,42472055,42272177,and 42077410the Safety Discipline“double first-class”to found Project of China under contract No.AQ20240305.
文摘The Zhujiang River Mouth Basin,a primary depocenter for terrigenous sediments in the western Pacific,presents a semienclosed tectonic setting with limited exchange with the open ocean.This unique feature enables systematic linkages among sedimentary processes,climate change,regional sea-level fluctuations,and tectonic events.To explore these linkages,this study focuses on Well PY35 in the Baiyun Sag of the Zhujiang River Mouth Basin.By integrating microfossil analysis with Milankovitch cycle analysis of well log data,an astronomical time scale(ATS)(17.54-7.80 Ma)and a high-resolution stratigraphic framework were established,allowing for the calculation of sedimentation rates across different hierarchical sequences and time intervals.The results indicate that between 17.54 Ma and 7.80 Ma,the sedimentation rate initially increased and then decreased,ranging from 6.1 cm/ka to 45.7 cm/ka,with an average rate of 22.2 cm/ka.During the Middle Miocene Climatic Optimum(MMCO),sedimentation rates were moderate and exhibited an increasing trend,largely driven by increased sediment input due to enhanced weathering from rising temperatures and by expanded accommodation space resulting from tectonic subsidence.Meanwhile,the Middle Miocene Climate Transition(MMCT)was marked by a notable rise in sedimentation rates,consistent with a major sea-level fall due to global cooling,which promoted the direct seaward progradation of marginal sediments.The Late Middle Miocene to Late Miocene had the lowest sedimentation rates,which can be attributed to reduced weathering under cold and arid conditions,along with a sea-level rise induced by regional tectonics.The short-term increase in the sedimentation rate observed at 10.4 Ma may have been driven by sea-level fluctuations.This study provides both theoretical and empirical support for understanding the influence of abrupt climate changes on sedimentary processes.
文摘As oil and gas development increasingly targets unconventional reservoirs,the limitations of conventional hydraulic fracturing,namely high water consumption and significant reservoir damage,have become more pronounced.This has driven growing interest in the development of clean fracturing fluids that minimize both water usage and formation impairment.In this study,a low-liquid-content viscoelastic surfactant(VES)foam fracturing fluid system was formulated and evaluated through laboratory experiments.The optimized formulation comprises 0.2%foaming agent CTAB(cetyltrimethylammonium bromide)and 2%foam stabilizer EAPB(erucamidopropyl betaine).Laboratory tests demonstrated that the VES foam system achieved a composite foam value of 56,700 mL・s,reflecting excellent foaming performance.Proppant transport experiments revealed minimal variation in suspended sand volume over 120 min across different sand ratios,indicating robust sand-carrying capacity even at high proppant concentrations.Rheological measurements showed that the fluid maintained a viscosity above 120 mPa・s after 120 min of shearing at 70℃ and a shear rate of 170 s−1,with the elastic modulus exceeding the viscous modulus,confirming the system’s exceptional stability and resilience.Furthermore,core damage tests indicated that the VES foam caused only 4.42%formation damage,highlighting its potential for efficient and low-damage stimulation of tight reservoirs.Overall,the findings demonstrate that this low-liquid-content VES foam provides a highly effective,environmentally considerate alternative for hydraulic fracturing in unconventional formations,combining superior proppant transport,rheological stability,and minimal reservoir impairment.
基金supported by the National Major Science and Technology Project“A Study on Formation and Enrichment Law,Selection Evaluation Technology and Application of Shale Gas in the Sichuan Basin and Its Periphery”(No.2017ZX05035).
文摘The Sichuan Basin is a major target for shale gas exploration in present China because of its rich gas stored in abundant black shales with multiple bed series.For further guidance or reference,field exploration and development practices in the shale reservoirs Upper Ordovician WufengeLower Silurian Longmaxi shale reservoirs were studied in terms of development stages and progress,favorable conditions for shale gas accumulation,bottlenecking issues on theories and technologies related to shale gas development,and so on.The following findings were obtained.(1)Shale with rich organic matters originated from the deep shelf has a good quality and great thickness in the continuous beds.The relatively stable wide buffer zones in synclines(anticlines)provides favorable conditions for shale gas accumulation and preservation with well developed micro-fractures and overpressure as necessary factors for a great potential of high shale gas productivity.(2)The bottlenecking technical issues restricting the shale gas industrial development in this study area include the following aspects:understandings of rich-organic matter shale sedimentary facies and modes,shale reservoir diagenetic process and evaluation systems,shale gas generation and accumulation mechanism,geophysical logging identification and prediction of shale gas layers,low resource utilization rate,great uncertainty of shale gas development,no technological breakthrough in the exploration of shale gas reservoirs buried deeper than 3500 m.In conclusion,this study area will be the major target for the shale gas exploration and development in China in a rather long period in the future.
基金Project supported by the National Basic Research Program of China(973 Program)“Basic Research on Efficient Development of Marine Shale Gas in Southern China”(Grant No.2013CB228000)the National Major Science and Technology Program during the“12th Five-Year Plan”“Key Techniques for Shale Gas Exploration and Development”(Grant No.2011ZX05018).
文摘The global sustained low oil prices have a significant impact on China's oil and gas industry system and the national energy security.This paper aims to find solutions in order to guarantee the smooth development of China's oil and gas industry system and its survival in such a severe environment.First,the origins of sustained low oil prices were analyzed.Then,based on those published data from IEA,government and some other authorities,this study focused on the development status,energy policies and the future developing trend of those main oil&gas producing countries.Investigations show that the low-price running is primarily contributed to the so-called oil and gas policies in the USA.It is predicted that national petroleum consumption will reach up to 6.0×10^(8) t(oil)&3300×10^(8) m^(3)(gas)in 2020 and 6.8×10^(8) t(oil)&5200×10^(8) m^(3)(gas)in 2030.For reducing the dependence on foreign oil and gas,the investment in the upstream of oil and gas industry should be maintained and scientific research should be intensified to ensure the smooth operation of the oil and gas production system.Considering China's national energy security strategy,the following suggestions were proposed herein.First,ensure that in China the yearly oil output reaches 2×10^(8) t,while natural gas yield will be expected to be up to 2700×10^(8) m^(3)in 2030,both of which should become the“bottom line”in the long term.Second,focus on the planning of upstream business with insistence on risk exploration investment,scientific and technological innovation and pilot area construction especially for low-permeability tight oil&gas,shale oil&gas reservoir development techniques.Third,encourage the in-depth reform and further growth especially in the three major state-owned oil&gas companies under adverse situations,and create more companies competent to offer overseas technical services by taking the opportunity of the“One Belt and One Road”policy.Finally,promote the new energy business and find solutions to turning those oil companies to integrated energy companies.
基金funding from the Natural Science Foundation of Henan Province(252300421852)the State Key Laboratory of Development and Comprehensive Utilization of Coking Coal Resources(41040220201308)+4 种基金the National Natural Science Foundation of China(41972254)the China Postdoctoral Science Foundation(2019M662494)Supported by the Key Scientific Research Projects of Higher Education Institutions of Henan Province(19A170005)the Fundamental Research Funds for the Universities of Henan Province(NSFRF200337,NSFRF200103)Key Research and Development Project of Henan Province(251111322300).
文摘Accurate identification of water sources is crucial for effective water management and safety in mining operations.However,imbalanced water sample datasets often lead to suboptimal classification accuracy.To address this challenge,this study proposes a novel water source identification method integrating Synthetic Minority Over-Sampling Technique(SMOTE),Zebra Optimization Algorithm(ZOA),and Light Gradient Boosting Machine(LightGBM).Initially,SMOTE is utilized to synthesize samples for the minority class within the imbalanced dataset,thereby generating a balanced water sample dataset and mitigating class distribution disparities.Subsequently,an efficient water source identification model is constructed by combining ZOA with LightGBM,leveraging the strengths of both algorithms.The model’s performance is validated using a test set and compared with other common classification models.Results demonstrate that SMOTE significantly alleviates class imbalance and enhances the classification accuracy of LightGBM for minority class water samples.ZOA parameter tuning accelerates model convergence and further improves classification accuracy,optimizing the model’s overall performance.In experimental validation,the proposed SMOTE-ZOA-LightGBM model achieved an accuracy of 88.41%and a F1 score of 88.24%,outperforming six other classification models.The method proposed in this paper can accurately identify water source types,effectively addressing the issue of low classification accuracy caused by imbalanced water sample data.It provides reliable technical support and scientific basis for identifying and preventing water inrush sources in mines.
基金financially supported by the Fundamental Research Funds for the Central Universities(No.226-2024-00010)the National Key Research and Development Program of China(No.2022YFC3203003)the Key Project of Natural Science Foundation of Zhejiang Province(No.LZ23E080004).
文摘The boosting development of artificial intelligence(AI)is contributing to rapid exponential surge of computing power demand,which results in the concerns on the increased energy consumption and carbon emission.To highlight the environmental impact of AI,a quantified analysis on the carbon emission associated with AI systems was conducted in this study,with the hope of offering guidelines for police maker to setup emission limits or studies interested in this issue and beyond.It has been discovered that both industry and academia play pivotal roles in driving AI development forward.The carbon emissions from 79 prominent AI systems released between 2020 and 2024 were quantified.The projected total carbon footprint from the AI systems in the top 20 of carbon emissions could reach up to 102.6 Mt of CO_(2) equivalent per year.This could potentially have a substantial impact on the environmental market,exceeding$10 billion annually,especially considering potential carbon penalties in the near future.Hence,it is appealed to take proactive measures to develop quantitative analysis methodologies and establish appropriate standards for measuring carbon emissions associated with AI systems.Emission cap is also crucial to drive the industry to adopt more environmentally friendly practices and technologies,in order to build a more sustainable future for AI.
