By investigating the evolution of shale gas generation,storage,adjustment and accumulation under different structural settings in superimposed basins,this study elucidates the differential accumulation mechanisms of s...By investigating the evolution of shale gas generation,storage,adjustment and accumulation under different structural settings in superimposed basins,this study elucidates the differential accumulation mechanisms of shale gas.An improved evaluation method of shale gas content evolution in superimposed basins is proposed.This method incorporates the coupling effect of key geological factors such as temperature,pressure,organic matter abundance,maturity,and pore characteristics on the content and occurrence state of shale gas,as well as the configuration relationship between shale gas generation and storage throughout geological history.Using this approach,the gas evolution histories of the Longmaxi Formation shales in wells N201 and PY1 are reconstructed under varying geological conditions.The Longmaxi Formation shales in these wells are dominated by typeⅠkerogen,with original total organic carbon(TOC_(o))contents of 6.20 wt% and 4.92 wt%,respectively,indicating differences in the initial material basis for gas generation.At the maximum burial depth of approximately 5000 m,the Longmaxi Formation shale in well N201 exhibits a formation pressure coefficient of 2.05,an organic matter maturity of 2.2%,and organic pores accounting for 68%of the total porosity.The gas generation quantity(Q_(g))reaches 19.24 m^(3)/t,while the gas storage capacity(Q_(s))is 4.30 m^(3)/t.The actual total gas content(Q_(a)),constrained by Q_(s),is 4.30 m^(3)/t,with free gas comprising 94%.Following relatively moderate tectonic uplift,the Q_(a) in well N201 decreases to 4.03 m^(3)/t,with free gas accounting for 63%.In contrast,the Longmaxi Formation shale in well PY1 reached a maximum burial depth of 6300 m,associated with a formation pressure coefficient of 1.62,organic matter maturity of 2.5%,and organic pore proportion of 67%.Here,Q_(g) is 16.87 m^(3)/t,and both Q_(s) and Q_(a) are 3.65 m^(3)/t,with free gas accounting for 98%.After intense tectonic uplift,Q_(a) declines to 2.72 m^(3)/t,and the proportion of free gas drops to51%.Finally,a four-stage differential accumulation model of shale gas is established:Slow gas generation and only adsorbed gas occur in stageⅠ,which is primarily controlled by TOC content;both adsorbed gas and free gas present in stageⅡ,with free gas becoming dominant;rapid gas generation and free gas predominance are controlled by temperature and porosity in stageⅢ;and gas adjustment and accumulation are primarily controlled by temperature and pressure in stageⅣ.展开更多
For the next exploration direction and integrated evaluation and optimization of targets for the northern continental margin of the South China Sea,this paper proposes the concept of the“total natural gas play system...For the next exploration direction and integrated evaluation and optimization of targets for the northern continental margin of the South China Sea,this paper proposes the concept of the“total natural gas play system”based on the principles of systems theory.Integrating over 60 years of exploration achievements in the four major basins,the paper studies the basic geological conditions,hydrocarbon accumulation models and distribution characteristics of the system.With the core principle of“source-heat controlling natural gas and play-stratigraphy controlling accumulation”,it analyzes the distribution law of natural gas reservoirs covering“intra-sag,sag margin,extra-sag”and multi-stratigraphic sequences.The study shows that under the joint control of source and heat,the northern continental margin of the South China Sea can be divided into two major gas areas:the southern area dominated by coal-type gas and the northern area dominated by oil-type gas,with the former as the main body.Based on the distribution location of hydrocarbon kitchen,the total gas plays are classified into three types:intra-sag,sag margin and extra-sag.In the oil-type gas area of the northern coastal zone,the proportion of intra-sag natural gas is relatively high;in the coal-type gas area of the southern offshore zone,the proportions of intra-sag and sag margin natural gas are relatively large;while the scale of gas accumulation in the extra-sag plays is relatively small.Finally,it is clearly pointed out that the southern offshore zone is the main direction for the next natural gas exploration in the northern South China Sea.Specifically,in the offshore zone,the intra-sag play and middle-deep layers of the sag margin play in the Yingzhong sag should be focused for the Yinggehai Basin;the intra-sag play and sag margin play in the central depression are targets for the Qiongdongnan Basin;the middle-deep layers of the intra-sag play are targets for the Baiyun sag of the Pearl River Mouth Basin.Furthermore,in the northern depression zone of the Pearl River Mouth Basin within the coastal zone,the main exploration directions include the middle-deep layers of the intra-sag play in the Huizhou sag and the middle-deep layers of the intra-sag play in the Enping sag;in the Beibu Gulf Basin,the main directions are the middle-deep layers of the intra-sag play in the Weixinan sag and the middle-deep layers of the intra-sag play in the Haizhong sag.展开更多
Based on the data of regional geology,seismic,drilling,logging and production performance obtained from 94 major petroliferous basins worldwide,the global coal resources were screened and statistically analyzed.Then,u...Based on the data of regional geology,seismic,drilling,logging and production performance obtained from 94 major petroliferous basins worldwide,the global coal resources were screened and statistically analyzed.Then,using established definition methods and evaluation criteria for coal-rock gas in China,and by analogy with the tectono-sedimentary and burial-thermal evolution conditions of coal rocks in sedimentary basins within China,the geological resource potential of global coal-rock gas was estimated mainly by the volume method,partly by the volumetric method in selected regions.According to the evaluation indicator system comprising 14 parameters under 5 categories and the associated scoring criteria,the target basins were ranked,and the future research targets for these basins were proposed.The results reveal that,globally,coal rocks are primarily formed in four types of swamp environments within four categories of prototype basins,and distributed across five major coal-forming periods and eight coal-accumulation belts.The total geological coal resources are estimated at approximately 42×10^(12)t,including 22×10^(12)t in the strata deeper than 1500 m.The global geological coal-rock gas resources in deep strata are roughly 232×10^(12)m^(3),of which over 90%are endowed in Russia,Canada,the United States,China and Australia,with China contributing 24%.The top 10 basins by coal-rock gas resource endowment,i.e.Alberta,Kuznetsk,Ordos,East Siberian,Bowen,West Siberian,Sichuan,South Turgay,Lena-Vilyuy and Tarim,collectively hold 75%of the global total.The Permian,Cretaceous,Carboniferous,Jurassic,and Paleogene-Neogene account for 32%,30%,18%,10%,and 7%of total coal-rock gas resources,respectively.The 10 most practical basins for future coal-rock gas exploration and development are identified as Alberta,Ordos,Kuznetsk,San Juan,Sichuan,East Siberian,Rocky Mountain,Bowen,Junggar and Qinshui.Propelled by successful development practices in China,coal-rock gas is now entering a phase of theoretical breakthrough,technological innovation,and rapid production growth,positioning it to spearhead the next wave of the global unconventional oil and gas revolution.展开更多
Gas sensors are valuable tools for human applications,and extensive research has been conducted in this field.However,practical implementation has yet to be fully realized.In response,efforts have been made to explore...Gas sensors are valuable tools for human applications,and extensive research has been conducted in this field.However,practical implementation has yet to be fully realized.In response,efforts have been made to explore metal-organic frameworks(MOFs),a novel class of porous materials,as potential solutions.MOFs exhibit exceptional porosity and highly tunable chemical compositions and structures,giving rise to a wide range of unique physical and chemical properties.Significant progress has been achieved in developing MOF-based gas sensors,improving sensing performance for various gases.This review aims to provide a comprehensive understanding of MOF-based gas sensors,even for readers unfamiliar with MOFs and gas sensors.It covers the working principles of these sensors,fundamental concepts of MOFs,strategies for tuning MOF properties,fabrication techniques for MOF films,and recent studies on MOF and MOF-derivative gas sensors.Finally,current challenges,overlooked aspects,and future directions for fully exploiting the potential of MOFs in gas sensor development are discussed.展开更多
Oil and gas resources serve as the driving force for economic and social development.This rapid development of science and technology has accelerated the exploration,development,and utilization of oil and gas resource...Oil and gas resources serve as the driving force for economic and social development.This rapid development of science and technology has accelerated the exploration,development,and utilization of oil and gas resources,and thus led to spurts in related research.However,the research trends in global oil and gas exploration vary with the progress of science and technology as well as social demands.Accordingly,they are not easily captured.This study explores the research trends in global oil and gas exploration through the bibliometric analysis of 3460 articles on oil and gas exploration collected from the Web of Science database and published from 2013 to 2023.The research hotspots,objects,regional distribution,methods,and evaluation methods in oil and gas exploration are analyzed,and the direction of development of oil and gas exploration is presented on this basis.The research characteristics of four major countries or regions related to oil and gas exploration were further investigated and compared.The results show that the number of publications on oil and gas exploration research has been continuously increasing in the past decade,with China ranking the top in terms of publications.Given the continuously evolving global energy demand,exploration of unconventional oil and gas,application of digital technology,deep and emerging regional resource exploration,and environmentally friendly and low-carbon source exploration will be future research hotspots.展开更多
This paper examines how natural gas disperses vertically when high-pressure pipelines with large openings fail in unconfined environments,providing insight into hazardous gas cloud development and behavior.A comprehen...This paper examines how natural gas disperses vertically when high-pressure pipelines with large openings fail in unconfined environments,providing insight into hazardous gas cloud development and behavior.A comprehensive study was conducted using a full-scale field experiment(1,219 mm diameter,12 MPa pressure,100 mm aperture)combined with a validated computational fluid dynamics(CFD)numerical simulation model to systematically analyze the coupling effects of pipeline pressure and ambient wind speed.The results indicate that:(1)Pipeline pressure determines the vertical jet scale,where jet height is positively correlated with pressure;at 12 MPa,the maximum jet height reaches 69.4 m(approximately 2.65 times that at 4 MPa),and the lower explosive limit(LEL)cloud area follows a quadratic polynomial trend.(2)Ambient wind speed significantly alters the diffusion trajectory;at a wind speed of 10 m/s,the LEL gas cloud area expands by 1.69 times compared to calm conditions,while the jet height is suppressed to 29.9%of the calm wind value.(3)Our developed dynamic prediction model for the hazardous gas-cloud region achieves a determination coefficient of 0.975 and maintaining prediction errors maintained within approximately 12%.The proposed empirical correlations and dynamic prediction model provide essential quantitative data support for safety-distance design and emergency-response decision-making for high-pressure natural gas pipelines.展开更多
Understanding gas generation in lithium-ion batteries during thermal runaway is critical to designing safer electric vehicles.We developed an in situ gas analysis system capable of measuring gases as they are generate...Understanding gas generation in lithium-ion batteries during thermal runaway is critical to designing safer electric vehicles.We developed an in situ gas analysis system capable of measuring gases as they are generated inside a lab-scale battery cell during thermal abuse.Two phases of gas-generating reactions were observed in charged Lithium Nickel Cobalt Manganese Aluminum Oxide(NCMA)-graphite cells.By adding a lithium iron phosphate(LFP)-based reference electrode inside the cell,we find that reactions occurring between the anode and electrolyte generate H_(2) and CO_(2) in the 80–130℃ temperature range.These reactions are correlated with the self-heating onset observed in accelerated rate calorimetry(ARC)and involve both solid electrolyte interphase(SEI)and intercalated lithium.Above 160℃,reactions occurring due to cathode decomposition accelerate thermal runaway and generate large amounts of carbon dioxide,and to a lesser extent,hydrogen and ethylene.The methods presented herein can be used to evaluate cell thermal stability for the design of safer batteries.展开更多
Aqueous hydrogen(H_(2))gas batteries with unmatched lifespan are ideal for grid-scale energy storage,yet their deployment remains limited by the lack of low-cost,efficient,and durable hydrogen electrodes.Here,we repor...Aqueous hydrogen(H_(2))gas batteries with unmatched lifespan are ideal for grid-scale energy storage,yet their deployment remains limited by the lack of low-cost,efficient,and durable hydrogen electrodes.Here,we report a high-throughput and durable gas diffusion electrode(GDE)based on a simply preparable carbon-coated nickel(Ni@C)catalyst and the design of H_(2) diffusion channels.By optimizing the carbon layer structure,a balance between the intrinsic activity and stability of the catalyst can be achieved.This Ni@C catalyst exhibits a hydrogen oxidation reaction(HOR)activity of 44 A g^(-1) as well as remarkable hydrogen evolution reaction(HER)performance.Experimental results and theoretical calculations confirm the electronic interaction between the carbon shell and Ni.In combination with a hydrophobic design,a robust and durable Ni@C-GDE has been fabricated.This electrode achieves a low HOR polarization of only 91 mV at 30 mA cm^(-2),outperforming Pt/C-GDE(154 mV),and operates stably over 4500cycles(3200 h)for HOR/HER reversing.Enabled by this electrode,a 10 Ah Ni-H_(2) battery with an energy density of 156.3 Wh kg^(-1) and cost of 62.2$kWh^(-1) is demonstrated.This work offers a viable strategy for practical and scalable hydrogen gas batteries.展开更多
To address the persistent challenge of dynamic mismatch between wellbore lifting capacity and reservoir fluid supply,and to establish a robust optimization framework for drainage operations in high-water-cut tight san...To address the persistent challenge of dynamic mismatch between wellbore lifting capacity and reservoir fluid supply,and to establish a robust optimization framework for drainage operations in high-water-cut tight sandstone gas reservoirs,this study systematically investigates the graded optimization and dynamic adaptation of drainage gas recovery technologies.Production data from a representative tight gas field were first employed to forecast reservoir performance.The predictive reliability was rigorously validated through high-precision history matching,thereby providing a quantitatively consistent foundation for subsequent wellbore optimization.Building on this characterization,a coupled simulation framework was developed that integrates wellbore multiphase flow modeling with nodal analysis based on the Inflow Performance Relationship,IPR,and the Vertical Lift Performance,VLP.This coordinated approach enables comprehensive evaluation of process adaptability and dynamic optimization of foam-assisted drainage,mechanical pumping,and jet pumping systems under evolving water-gas ratio,WGR conditions.The results reveal that a progressively increasing water-gas ratio is the dominant factor driving the transition from chemically assisted drainage methods to mechanically enhanced lifting technologies.A distinct quantitative threshold is identified at WGR≈0.002,beyond which mechanical intervention becomes more effective and economically justified.For mechanical pumping and jet pumping systems,a parameter inversion optimization strategy constrained by the target bottomhole flowing pressure,Pwf,is proposed to ensure stable production while maintaining reservoir drawdown control.In particular,the nozzle-to-throat area ratio of the jet pump is identified as the key governing parameter influencing entrainment capacity and lifting efficiency.Moreover,a configuration characterized by small pump diameter,long stroke length,and low operating speed is demonstrated to satisfy drainage requirements while mitigating torque fluctuations,enhancing volumetric efficiency,and improving pump fillage stability.展开更多
Natural gas hydrate in Class Ⅰ reservoirs holds significant commercial potential,as demonstrated by production trials in the South China Sea.However,experimental studies have focused largely on Class Ⅲ systems,with ...Natural gas hydrate in Class Ⅰ reservoirs holds significant commercial potential,as demonstrated by production trials in the South China Sea.However,experimental studies have focused largely on Class Ⅲ systems,with Class Ⅰ/Ⅱ reservoirs remaining underrepresented due to the difficulties in simulating the geothermal gradient and interlayer interactions.This study investigates depressurization performance across all three classes using a novel 360°rotatable reactor with segmented temperature control,enabling precise simulation of reservoir conditions.Results reveal:(i)Class Ⅰ shows two-stage gas production,with 50%from early free gas enabling rapid depressurization,followed by dissociated gas dominance.They achieve 38.4%-78.3%higher cumulative production and superior gas-to-water ratios due to efficient energy use.(ii)The free gas layer in Class Ⅰ accelerates pressure and heat transfer.Class Ⅱ’s water layer provides sensible heat but causes water blocking,impairing heat flow.Class Ⅲ exhibits rapid initial dissociation but a quick decline without fluid support.(iii)Low temperature,low hydrate saturation,and high production pressure collectively reduce efficiency by increasing flow resistance,limiting gas supply,and reducing dissociation drive.Over-depressurization risks hydrate reformation and ice blockage.This work bridges experimental gaps for Class Ⅰ/Ⅱ reservoirs,offering key insights for optimizing recovery.展开更多
The Ordovician Majiagou Formation(O1m)in the Ordos Basin is a crucial exploration field for natural gas,and exploration of the Ordovician middle assemblage(O_(1)m_(5)^(5-7))has recently yielded great breakthrough.The ...The Ordovician Majiagou Formation(O1m)in the Ordos Basin is a crucial exploration field for natural gas,and exploration of the Ordovician middle assemblage(O_(1)m_(5)^(5-7))has recently yielded great breakthrough.The Daniudi gas field provides a good case study to determine the gas source for the strata.The O_(1)m_(5)^(5-7)gas displays C1/C1-5 ratios of 0.932-0.985 and CO_(2)contents of 1.56%-11.75%,and the detectable H2S content ranges from 0.0002%to 1.8617%.Theδ^(13)C1,δ^(13)C2,δ^(13)CCO_(2),andδD_(1)values are−39.7‰to−35.6‰,−30.4‰to−23.7‰,−12.4‰to−4.6‰,and−204‰to−185‰,respectively.Identification of the gas origin and source indicates that the gaseous alkanes are commonly coal-derived gas.The gas was generated from the coal measures in the Taiyuan Formation(C_(3t))and subsequently migrated.A small amount of oil-associated gas,mainly from O1m carbonate source rocks,has been incorporated into the gas reservoir.The natural gas has experienced insignificant alteration by thermochemical sulfate reduction,and the relatively high levels of CO_(2)are probably associated with corrosion alteration of carbonate reservoirs by injected fluid during acid fracturing.展开更多
Although extensive research has been conducted on CO_(2)-enhanced coalbed methane(CO_(2)-ECBM)recovery,most prior studies have focused on the impact of gas adsorption-induced swelling on coal permeability under equili...Although extensive research has been conducted on CO_(2)-enhanced coalbed methane(CO_(2)-ECBM)recovery,most prior studies have focused on the impact of gas adsorption-induced swelling on coal permeability under equilibrium conditions.This paper presents a comprehensive thermo-hydro-mechanical-chemical(THMC)model that integrates thermal expansion and heat conduction(T),gas diffusion in the matrix and gas-water two-phase flow in the fractures(H),matrix and fracture deformation due to poroelasticity(M),and non-equilibrium binary gas adsorption-induced matrix swelling(C)during CO_(2)-ECBM recovery.The accuracy of the proposed model was verified through experimental data,and the model was simulated using finite element method(FEM)software.Simulation results indicate that the permeability evolution can be categorized into three stages.Ignoring the impact of water on gas adsorption properties would lead to an overestimation of the influence of adsorption-induced swelling,while disregarding non-equilibrium adsorption underestimates it.An examination of five designed cases identified critical factors influencing permeability.Parametric analysis shows that increases in the injection pressure,the injection temperature,and the initial permeability promote the competitive adsorption-induced swelling between CH_(4)and CO_(2),leading to increased CH_(4)production and CO_(2)storage.Conversely,an increase in initial water saturation reduces available gas flow space,decreasing both CH_(4)production and CO_(2)storage.Higher irreducible water saturation favors early gas recovery,while lower irreducible water saturation is more advantageous for long-term recovery.展开更多
It is crucial to develop arsenic removal adsorbents with strong sulfur resistance under middle-low-temperature flue gas conditions(<400℃).In this work,five Fe-Ce-La oxides were prepared by co-precipitation method,...It is crucial to develop arsenic removal adsorbents with strong sulfur resistance under middle-low-temperature flue gas conditions(<400℃).In this work,five Fe-Ce-La oxides were prepared by co-precipitation method,and FeCeLaO/SiO_(2)-Al_(2)O_(3) composite adsorbents were prepared by coupling fly ash-based Si-Al carriers.The active components Fe-Ce-La oxides and Si-Al carriers were characterized by TPD,TG,XRF,BET and XPS,respectively.The effects of temperature,Si/Al ratio and FeCeLaO loading rate on the sulfur resistance were investigated.Results show that the SO_(2) promotes the arsenic removal of Fe_(2)O_(3),CeLaO and FeCeLaO.At 400℃,the arsenic removal efficiencies of the three oxides increase from 45.3%,72.5% and 81.3% without SO_(2) to 62.6%,80.5%and 91.0%,respectively.The SO_(2) inhibits the arsenic removal of La_(2)O_(2)CO_(3) and FeLaO,and the inhibition effect is pronounced at high temperatures.The sulfur poisoning resistance of Si-Al carriers increases with the increase of Si/Al ratio.When the Si/Al ratio is increased to 9.74,the arsenic removal efficiency in the SO_(2) environment is 13.9% higher than that in the absence of SO_(2).Introducing FeCeLaO active components is beneficial for enhancing the SO_(2) poisoning resistance of Si-Al carriers.The strong sulfur resistance of the FeCeLaO/SiO_(2)-Al_(2)O_(3) composite adsorbent results from multiple factors:protective effects of Ce on Fe,La and Al;sulfation-induced generation of Ce^(3+)and surface-adsorbed oxygen;and strong surface acidity of SiO_(2).展开更多
The Savitzky-Golay(SG)filter,which employs polynomial least-squares approximations to smooth data and estimate derivatives,is widely used for processing noisy data.However,noise suppression by the SG filter is recogni...The Savitzky-Golay(SG)filter,which employs polynomial least-squares approximations to smooth data and estimate derivatives,is widely used for processing noisy data.However,noise suppression by the SG filter is recognized to be limited at data boundaries and high frequencies,which can significantly reduce the signal-to-noise ratio(SNR).To solve this problem,a novel method synergistically integrating Principal Component Analysis(PCA)with SG filtering is proposed in this paper.This approach avoids the is-sue of excessive smoothing associated with larger window sizes.The proposed PCA-SG filtering algorithm was applied to a CO gas sensing system based on Cavity Ring-Down Spectroscopy(CRDS).The perform-ance of the PCA-SG filtering algorithm is demonstrated through comparison with Moving Average Filtering(MAF),Wavelet Transformation(WT),Kalman Filtering(KF),and the SG filter.The results demonstrate that the proposed algorithm exhibits superior noise reduction capabilities compared to the other algorithms evaluated.The SNR of the ring-down signal was improved from 11.8612 dB to 29.0913 dB,and the stand-ard deviation of the extracted ring-down time constant was reduced from 0.037μs to 0.018μs.These results confirm that the proposed PCA-SG filtering algorithm effectively improves the smoothness of the ring-down curve data,demonstrating its feasibility.展开更多
Gas wells often encounter blockages in gas recovery channels owing to fluid accumulation during the later stages of extraction,which adversely affects subsequent recovery efforts.These undesirable conditions(e.g.,high...Gas wells often encounter blockages in gas recovery channels owing to fluid accumulation during the later stages of extraction,which adversely affects subsequent recovery efforts.These undesirable conditions(e.g.,high condensate content,high temperature,and high salinity)often affect foaming agent performance.In this study,surfactants were screened using an airflow method that closely resembles field treatment method.Notably,alcohol ether sulfates(AE_(n)S)with various polyoxyethylene(EO)units demonstrated exceptional performance in terms of liquid unloading efficiency and foam stability.At 80℃,the unloading efficiency of AE_(n)S with two EO units(AE_(2)S)in a high NaCl mass concentration(up to 200 g/L)and high condensate volume fraction(up to 20%)reached 84%.The dynamic surface tension and interfacial tension measured at the same temperature were used to analyze the influence of the diffusion rate and interfacial characteristics on the AE_(n)S foam,while the viscosity and liquid film thickness measurements reflected the mechanical strength and liquid-carrying capacity.In addition,transmission electron microscopy(TEM)revealed that AE_(2)S formed“dendritic”micellar aggregates at a high NaCl mass concentration,which significantly enhanced the viscosity and stability of the foam.The interactions among AE_(n)S,NaCl,and H2O were analyzed using molecular dynamics,and it was confirmed from a molecular mechanics perspective that a stable structure can form among the three,contributing to the foam stability.These findings demonstrate the significant potential of the AE_(2)S foam for gas well deliquification.展开更多
基金funded by the Sinopec Science and Technology Project(No.P23132)the AAPG Foundation Grants-inAid Program(No.18644937)。
文摘By investigating the evolution of shale gas generation,storage,adjustment and accumulation under different structural settings in superimposed basins,this study elucidates the differential accumulation mechanisms of shale gas.An improved evaluation method of shale gas content evolution in superimposed basins is proposed.This method incorporates the coupling effect of key geological factors such as temperature,pressure,organic matter abundance,maturity,and pore characteristics on the content and occurrence state of shale gas,as well as the configuration relationship between shale gas generation and storage throughout geological history.Using this approach,the gas evolution histories of the Longmaxi Formation shales in wells N201 and PY1 are reconstructed under varying geological conditions.The Longmaxi Formation shales in these wells are dominated by typeⅠkerogen,with original total organic carbon(TOC_(o))contents of 6.20 wt% and 4.92 wt%,respectively,indicating differences in the initial material basis for gas generation.At the maximum burial depth of approximately 5000 m,the Longmaxi Formation shale in well N201 exhibits a formation pressure coefficient of 2.05,an organic matter maturity of 2.2%,and organic pores accounting for 68%of the total porosity.The gas generation quantity(Q_(g))reaches 19.24 m^(3)/t,while the gas storage capacity(Q_(s))is 4.30 m^(3)/t.The actual total gas content(Q_(a)),constrained by Q_(s),is 4.30 m^(3)/t,with free gas comprising 94%.Following relatively moderate tectonic uplift,the Q_(a) in well N201 decreases to 4.03 m^(3)/t,with free gas accounting for 63%.In contrast,the Longmaxi Formation shale in well PY1 reached a maximum burial depth of 6300 m,associated with a formation pressure coefficient of 1.62,organic matter maturity of 2.5%,and organic pore proportion of 67%.Here,Q_(g) is 16.87 m^(3)/t,and both Q_(s) and Q_(a) are 3.65 m^(3)/t,with free gas accounting for 98%.After intense tectonic uplift,Q_(a) declines to 2.72 m^(3)/t,and the proportion of free gas drops to51%.Finally,a four-stage differential accumulation model of shale gas is established:Slow gas generation and only adsorbed gas occur in stageⅠ,which is primarily controlled by TOC content;both adsorbed gas and free gas present in stageⅡ,with free gas becoming dominant;rapid gas generation and free gas predominance are controlled by temperature and porosity in stageⅢ;and gas adjustment and accumulation are primarily controlled by temperature and pressure in stageⅣ.
基金Supported by the NSFC-Industry Joint Fund for Innovative Development(U24B2016)China National Science and Technology Major Project(2025ZD1402700)。
文摘For the next exploration direction and integrated evaluation and optimization of targets for the northern continental margin of the South China Sea,this paper proposes the concept of the“total natural gas play system”based on the principles of systems theory.Integrating over 60 years of exploration achievements in the four major basins,the paper studies the basic geological conditions,hydrocarbon accumulation models and distribution characteristics of the system.With the core principle of“source-heat controlling natural gas and play-stratigraphy controlling accumulation”,it analyzes the distribution law of natural gas reservoirs covering“intra-sag,sag margin,extra-sag”and multi-stratigraphic sequences.The study shows that under the joint control of source and heat,the northern continental margin of the South China Sea can be divided into two major gas areas:the southern area dominated by coal-type gas and the northern area dominated by oil-type gas,with the former as the main body.Based on the distribution location of hydrocarbon kitchen,the total gas plays are classified into three types:intra-sag,sag margin and extra-sag.In the oil-type gas area of the northern coastal zone,the proportion of intra-sag natural gas is relatively high;in the coal-type gas area of the southern offshore zone,the proportions of intra-sag and sag margin natural gas are relatively large;while the scale of gas accumulation in the extra-sag plays is relatively small.Finally,it is clearly pointed out that the southern offshore zone is the main direction for the next natural gas exploration in the northern South China Sea.Specifically,in the offshore zone,the intra-sag play and middle-deep layers of the sag margin play in the Yingzhong sag should be focused for the Yinggehai Basin;the intra-sag play and sag margin play in the central depression are targets for the Qiongdongnan Basin;the middle-deep layers of the intra-sag play are targets for the Baiyun sag of the Pearl River Mouth Basin.Furthermore,in the northern depression zone of the Pearl River Mouth Basin within the coastal zone,the main exploration directions include the middle-deep layers of the intra-sag play in the Huizhou sag and the middle-deep layers of the intra-sag play in the Enping sag;in the Beibu Gulf Basin,the main directions are the middle-deep layers of the intra-sag play in the Weixinan sag and the middle-deep layers of the intra-sag play in the Haizhong sag.
基金Supported by the China National Science and Technology Major Project on New-Type Oil and Gas Exploration and Development(2025ZD1404200,2025ZD1400800)PetroChina Science and Technology Project(2023ZZ07)。
文摘Based on the data of regional geology,seismic,drilling,logging and production performance obtained from 94 major petroliferous basins worldwide,the global coal resources were screened and statistically analyzed.Then,using established definition methods and evaluation criteria for coal-rock gas in China,and by analogy with the tectono-sedimentary and burial-thermal evolution conditions of coal rocks in sedimentary basins within China,the geological resource potential of global coal-rock gas was estimated mainly by the volume method,partly by the volumetric method in selected regions.According to the evaluation indicator system comprising 14 parameters under 5 categories and the associated scoring criteria,the target basins were ranked,and the future research targets for these basins were proposed.The results reveal that,globally,coal rocks are primarily formed in four types of swamp environments within four categories of prototype basins,and distributed across five major coal-forming periods and eight coal-accumulation belts.The total geological coal resources are estimated at approximately 42×10^(12)t,including 22×10^(12)t in the strata deeper than 1500 m.The global geological coal-rock gas resources in deep strata are roughly 232×10^(12)m^(3),of which over 90%are endowed in Russia,Canada,the United States,China and Australia,with China contributing 24%.The top 10 basins by coal-rock gas resource endowment,i.e.Alberta,Kuznetsk,Ordos,East Siberian,Bowen,West Siberian,Sichuan,South Turgay,Lena-Vilyuy and Tarim,collectively hold 75%of the global total.The Permian,Cretaceous,Carboniferous,Jurassic,and Paleogene-Neogene account for 32%,30%,18%,10%,and 7%of total coal-rock gas resources,respectively.The 10 most practical basins for future coal-rock gas exploration and development are identified as Alberta,Ordos,Kuznetsk,San Juan,Sichuan,East Siberian,Rocky Mountain,Bowen,Junggar and Qinshui.Propelled by successful development practices in China,coal-rock gas is now entering a phase of theoretical breakthrough,technological innovation,and rapid production growth,positioning it to spearhead the next wave of the global unconventional oil and gas revolution.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(RS-2024-00333650)supported by basic science research program through the National Research Foundation of Korea funded by the Ministry of Education(NRF-2019R1A6A1A11055660)+1 种基金supported by the Technology Innovation Program(“20013621”,Center for Super Critical Material Industrial Technology)funded By the Ministry of Trade,Industry&Energy(MOTIE,Korea)supported by Strategic Networking&Development Program funded by the Ministry of Science and ICT through the National Research Foundation of Korea(RS-2023-00268523)。
文摘Gas sensors are valuable tools for human applications,and extensive research has been conducted in this field.However,practical implementation has yet to be fully realized.In response,efforts have been made to explore metal-organic frameworks(MOFs),a novel class of porous materials,as potential solutions.MOFs exhibit exceptional porosity and highly tunable chemical compositions and structures,giving rise to a wide range of unique physical and chemical properties.Significant progress has been achieved in developing MOF-based gas sensors,improving sensing performance for various gases.This review aims to provide a comprehensive understanding of MOF-based gas sensors,even for readers unfamiliar with MOFs and gas sensors.It covers the working principles of these sensors,fundamental concepts of MOFs,strategies for tuning MOF properties,fabrication techniques for MOF films,and recent studies on MOF and MOF-derivative gas sensors.Finally,current challenges,overlooked aspects,and future directions for fully exploiting the potential of MOFs in gas sensor development are discussed.
文摘Oil and gas resources serve as the driving force for economic and social development.This rapid development of science and technology has accelerated the exploration,development,and utilization of oil and gas resources,and thus led to spurts in related research.However,the research trends in global oil and gas exploration vary with the progress of science and technology as well as social demands.Accordingly,they are not easily captured.This study explores the research trends in global oil and gas exploration through the bibliometric analysis of 3460 articles on oil and gas exploration collected from the Web of Science database and published from 2013 to 2023.The research hotspots,objects,regional distribution,methods,and evaluation methods in oil and gas exploration are analyzed,and the direction of development of oil and gas exploration is presented on this basis.The research characteristics of four major countries or regions related to oil and gas exploration were further investigated and compared.The results show that the number of publications on oil and gas exploration research has been continuously increasing in the past decade,with China ranking the top in terms of publications.Given the continuously evolving global energy demand,exploration of unconventional oil and gas,application of digital technology,deep and emerging regional resource exploration,and environmentally friendly and low-carbon source exploration will be future research hotspots.
基金supported by the National Natural Science Foundation of China(Grant No.52574278)the Xinjiang Uygur Autonomous Region Key R&D Program Project(Grant No.2024B01003).
文摘This paper examines how natural gas disperses vertically when high-pressure pipelines with large openings fail in unconfined environments,providing insight into hazardous gas cloud development and behavior.A comprehensive study was conducted using a full-scale field experiment(1,219 mm diameter,12 MPa pressure,100 mm aperture)combined with a validated computational fluid dynamics(CFD)numerical simulation model to systematically analyze the coupling effects of pipeline pressure and ambient wind speed.The results indicate that:(1)Pipeline pressure determines the vertical jet scale,where jet height is positively correlated with pressure;at 12 MPa,the maximum jet height reaches 69.4 m(approximately 2.65 times that at 4 MPa),and the lower explosive limit(LEL)cloud area follows a quadratic polynomial trend.(2)Ambient wind speed significantly alters the diffusion trajectory;at a wind speed of 10 m/s,the LEL gas cloud area expands by 1.69 times compared to calm conditions,while the jet height is suppressed to 29.9%of the calm wind value.(3)Our developed dynamic prediction model for the hazardous gas-cloud region achieves a determination coefficient of 0.975 and maintaining prediction errors maintained within approximately 12%.The proposed empirical correlations and dynamic prediction model provide essential quantitative data support for safety-distance design and emergency-response decision-making for high-pressure natural gas pipelines.
基金supported by General Motors Research and Development。
文摘Understanding gas generation in lithium-ion batteries during thermal runaway is critical to designing safer electric vehicles.We developed an in situ gas analysis system capable of measuring gases as they are generated inside a lab-scale battery cell during thermal abuse.Two phases of gas-generating reactions were observed in charged Lithium Nickel Cobalt Manganese Aluminum Oxide(NCMA)-graphite cells.By adding a lithium iron phosphate(LFP)-based reference electrode inside the cell,we find that reactions occurring between the anode and electrolyte generate H_(2) and CO_(2) in the 80–130℃ temperature range.These reactions are correlated with the self-heating onset observed in accelerated rate calorimetry(ARC)and involve both solid electrolyte interphase(SEI)and intercalated lithium.Above 160℃,reactions occurring due to cathode decomposition accelerate thermal runaway and generate large amounts of carbon dioxide,and to a lesser extent,hydrogen and ethylene.The methods presented herein can be used to evaluate cell thermal stability for the design of safer batteries.
基金financially supported by the“National Natural Science Foundation of China”(No.22279082)the“Natural Science Foundation of Sichuan”(2025YFHZ0056)。
文摘Aqueous hydrogen(H_(2))gas batteries with unmatched lifespan are ideal for grid-scale energy storage,yet their deployment remains limited by the lack of low-cost,efficient,and durable hydrogen electrodes.Here,we report a high-throughput and durable gas diffusion electrode(GDE)based on a simply preparable carbon-coated nickel(Ni@C)catalyst and the design of H_(2) diffusion channels.By optimizing the carbon layer structure,a balance between the intrinsic activity and stability of the catalyst can be achieved.This Ni@C catalyst exhibits a hydrogen oxidation reaction(HOR)activity of 44 A g^(-1) as well as remarkable hydrogen evolution reaction(HER)performance.Experimental results and theoretical calculations confirm the electronic interaction between the carbon shell and Ni.In combination with a hydrophobic design,a robust and durable Ni@C-GDE has been fabricated.This electrode achieves a low HOR polarization of only 91 mV at 30 mA cm^(-2),outperforming Pt/C-GDE(154 mV),and operates stably over 4500cycles(3200 h)for HOR/HER reversing.Enabled by this electrode,a 10 Ah Ni-H_(2) battery with an energy density of 156.3 Wh kg^(-1) and cost of 62.2$kWh^(-1) is demonstrated.This work offers a viable strategy for practical and scalable hydrogen gas batteries.
基金supported by the Major Science and Technology Project of PetroChina Company Limited“Research on Key Technologies for Enhancing Recovery in Tight Sandstone Gas Reservoirs”,specifically under its third sub-project:“Research on Integrated Fracturing,Drainage,and Production Technology to Enhance Single-Well Production in Water-Bearing Gas Reservoirs”(Grant number:2023ZZ25YJ03).
文摘To address the persistent challenge of dynamic mismatch between wellbore lifting capacity and reservoir fluid supply,and to establish a robust optimization framework for drainage operations in high-water-cut tight sandstone gas reservoirs,this study systematically investigates the graded optimization and dynamic adaptation of drainage gas recovery technologies.Production data from a representative tight gas field were first employed to forecast reservoir performance.The predictive reliability was rigorously validated through high-precision history matching,thereby providing a quantitatively consistent foundation for subsequent wellbore optimization.Building on this characterization,a coupled simulation framework was developed that integrates wellbore multiphase flow modeling with nodal analysis based on the Inflow Performance Relationship,IPR,and the Vertical Lift Performance,VLP.This coordinated approach enables comprehensive evaluation of process adaptability and dynamic optimization of foam-assisted drainage,mechanical pumping,and jet pumping systems under evolving water-gas ratio,WGR conditions.The results reveal that a progressively increasing water-gas ratio is the dominant factor driving the transition from chemically assisted drainage methods to mechanically enhanced lifting technologies.A distinct quantitative threshold is identified at WGR≈0.002,beyond which mechanical intervention becomes more effective and economically justified.For mechanical pumping and jet pumping systems,a parameter inversion optimization strategy constrained by the target bottomhole flowing pressure,Pwf,is proposed to ensure stable production while maintaining reservoir drawdown control.In particular,the nozzle-to-throat area ratio of the jet pump is identified as the key governing parameter influencing entrainment capacity and lifting efficiency.Moreover,a configuration characterized by small pump diameter,long stroke length,and low operating speed is demonstrated to satisfy drainage requirements while mitigating torque fluctuations,enhancing volumetric efficiency,and improving pump fillage stability.
基金partially funded by Shenzhen Science and Technology Program(No.JCYJ20240813112038050)the National Natural Science Foundation of China(No.52404059)+1 种基金the Economy Trade and Information Commission of Shenzhen Municipality,China(No.HYCYPT20140507010002)the Key Program of Marine Economy Development(Six Marine Industries)Special Foundation of the Department of Natural Resources of Guangdong Province,China(No.GDOE[2021]55).
文摘Natural gas hydrate in Class Ⅰ reservoirs holds significant commercial potential,as demonstrated by production trials in the South China Sea.However,experimental studies have focused largely on Class Ⅲ systems,with Class Ⅰ/Ⅱ reservoirs remaining underrepresented due to the difficulties in simulating the geothermal gradient and interlayer interactions.This study investigates depressurization performance across all three classes using a novel 360°rotatable reactor with segmented temperature control,enabling precise simulation of reservoir conditions.Results reveal:(i)Class Ⅰ shows two-stage gas production,with 50%from early free gas enabling rapid depressurization,followed by dissociated gas dominance.They achieve 38.4%-78.3%higher cumulative production and superior gas-to-water ratios due to efficient energy use.(ii)The free gas layer in Class Ⅰ accelerates pressure and heat transfer.Class Ⅱ’s water layer provides sensible heat but causes water blocking,impairing heat flow.Class Ⅲ exhibits rapid initial dissociation but a quick decline without fluid support.(iii)Low temperature,low hydrate saturation,and high production pressure collectively reduce efficiency by increasing flow resistance,limiting gas supply,and reducing dissociation drive.Over-depressurization risks hydrate reformation and ice blockage.This work bridges experimental gaps for Class Ⅰ/Ⅱ reservoirs,offering key insights for optimizing recovery.
基金sponsored by National Natural Science Foundation of China(Grant Nos.U2244209,42172149,42488101,and 42141021).
文摘The Ordovician Majiagou Formation(O1m)in the Ordos Basin is a crucial exploration field for natural gas,and exploration of the Ordovician middle assemblage(O_(1)m_(5)^(5-7))has recently yielded great breakthrough.The Daniudi gas field provides a good case study to determine the gas source for the strata.The O_(1)m_(5)^(5-7)gas displays C1/C1-5 ratios of 0.932-0.985 and CO_(2)contents of 1.56%-11.75%,and the detectable H2S content ranges from 0.0002%to 1.8617%.Theδ^(13)C1,δ^(13)C2,δ^(13)CCO_(2),andδD_(1)values are−39.7‰to−35.6‰,−30.4‰to−23.7‰,−12.4‰to−4.6‰,and−204‰to−185‰,respectively.Identification of the gas origin and source indicates that the gaseous alkanes are commonly coal-derived gas.The gas was generated from the coal measures in the Taiyuan Formation(C_(3t))and subsequently migrated.A small amount of oil-associated gas,mainly from O1m carbonate source rocks,has been incorporated into the gas reservoir.The natural gas has experienced insignificant alteration by thermochemical sulfate reduction,and the relatively high levels of CO_(2)are probably associated with corrosion alteration of carbonate reservoirs by injected fluid during acid fracturing.
基金the support from the National Natural Science Foundation of China(No.52079077)Natural Science Foundation of Hubei Provincial(2025AFB358).
文摘Although extensive research has been conducted on CO_(2)-enhanced coalbed methane(CO_(2)-ECBM)recovery,most prior studies have focused on the impact of gas adsorption-induced swelling on coal permeability under equilibrium conditions.This paper presents a comprehensive thermo-hydro-mechanical-chemical(THMC)model that integrates thermal expansion and heat conduction(T),gas diffusion in the matrix and gas-water two-phase flow in the fractures(H),matrix and fracture deformation due to poroelasticity(M),and non-equilibrium binary gas adsorption-induced matrix swelling(C)during CO_(2)-ECBM recovery.The accuracy of the proposed model was verified through experimental data,and the model was simulated using finite element method(FEM)software.Simulation results indicate that the permeability evolution can be categorized into three stages.Ignoring the impact of water on gas adsorption properties would lead to an overestimation of the influence of adsorption-induced swelling,while disregarding non-equilibrium adsorption underestimates it.An examination of five designed cases identified critical factors influencing permeability.Parametric analysis shows that increases in the injection pressure,the injection temperature,and the initial permeability promote the competitive adsorption-induced swelling between CH_(4)and CO_(2),leading to increased CH_(4)production and CO_(2)storage.Conversely,an increase in initial water saturation reduces available gas flow space,decreasing both CH_(4)production and CO_(2)storage.Higher irreducible water saturation favors early gas recovery,while lower irreducible water saturation is more advantageous for long-term recovery.
文摘It is crucial to develop arsenic removal adsorbents with strong sulfur resistance under middle-low-temperature flue gas conditions(<400℃).In this work,five Fe-Ce-La oxides were prepared by co-precipitation method,and FeCeLaO/SiO_(2)-Al_(2)O_(3) composite adsorbents were prepared by coupling fly ash-based Si-Al carriers.The active components Fe-Ce-La oxides and Si-Al carriers were characterized by TPD,TG,XRF,BET and XPS,respectively.The effects of temperature,Si/Al ratio and FeCeLaO loading rate on the sulfur resistance were investigated.Results show that the SO_(2) promotes the arsenic removal of Fe_(2)O_(3),CeLaO and FeCeLaO.At 400℃,the arsenic removal efficiencies of the three oxides increase from 45.3%,72.5% and 81.3% without SO_(2) to 62.6%,80.5%and 91.0%,respectively.The SO_(2) inhibits the arsenic removal of La_(2)O_(2)CO_(3) and FeLaO,and the inhibition effect is pronounced at high temperatures.The sulfur poisoning resistance of Si-Al carriers increases with the increase of Si/Al ratio.When the Si/Al ratio is increased to 9.74,the arsenic removal efficiency in the SO_(2) environment is 13.9% higher than that in the absence of SO_(2).Introducing FeCeLaO active components is beneficial for enhancing the SO_(2) poisoning resistance of Si-Al carriers.The strong sulfur resistance of the FeCeLaO/SiO_(2)-Al_(2)O_(3) composite adsorbent results from multiple factors:protective effects of Ce on Fe,La and Al;sulfation-induced generation of Ce^(3+)and surface-adsorbed oxygen;and strong surface acidity of SiO_(2).
文摘The Savitzky-Golay(SG)filter,which employs polynomial least-squares approximations to smooth data and estimate derivatives,is widely used for processing noisy data.However,noise suppression by the SG filter is recognized to be limited at data boundaries and high frequencies,which can significantly reduce the signal-to-noise ratio(SNR).To solve this problem,a novel method synergistically integrating Principal Component Analysis(PCA)with SG filtering is proposed in this paper.This approach avoids the is-sue of excessive smoothing associated with larger window sizes.The proposed PCA-SG filtering algorithm was applied to a CO gas sensing system based on Cavity Ring-Down Spectroscopy(CRDS).The perform-ance of the PCA-SG filtering algorithm is demonstrated through comparison with Moving Average Filtering(MAF),Wavelet Transformation(WT),Kalman Filtering(KF),and the SG filter.The results demonstrate that the proposed algorithm exhibits superior noise reduction capabilities compared to the other algorithms evaluated.The SNR of the ring-down signal was improved from 11.8612 dB to 29.0913 dB,and the stand-ard deviation of the extracted ring-down time constant was reduced from 0.037μs to 0.018μs.These results confirm that the proposed PCA-SG filtering algorithm effectively improves the smoothness of the ring-down curve data,demonstrating its feasibility.
文摘Gas wells often encounter blockages in gas recovery channels owing to fluid accumulation during the later stages of extraction,which adversely affects subsequent recovery efforts.These undesirable conditions(e.g.,high condensate content,high temperature,and high salinity)often affect foaming agent performance.In this study,surfactants were screened using an airflow method that closely resembles field treatment method.Notably,alcohol ether sulfates(AE_(n)S)with various polyoxyethylene(EO)units demonstrated exceptional performance in terms of liquid unloading efficiency and foam stability.At 80℃,the unloading efficiency of AE_(n)S with two EO units(AE_(2)S)in a high NaCl mass concentration(up to 200 g/L)and high condensate volume fraction(up to 20%)reached 84%.The dynamic surface tension and interfacial tension measured at the same temperature were used to analyze the influence of the diffusion rate and interfacial characteristics on the AE_(n)S foam,while the viscosity and liquid film thickness measurements reflected the mechanical strength and liquid-carrying capacity.In addition,transmission electron microscopy(TEM)revealed that AE_(2)S formed“dendritic”micellar aggregates at a high NaCl mass concentration,which significantly enhanced the viscosity and stability of the foam.The interactions among AE_(n)S,NaCl,and H2O were analyzed using molecular dynamics,and it was confirmed from a molecular mechanics perspective that a stable structure can form among the three,contributing to the foam stability.These findings demonstrate the significant potential of the AE_(2)S foam for gas well deliquification.
