Exploration and development of large gas fields is an important way for a country to rapidly develop its natural gas industry.From 1991 to 2020,China discovered 68 new large gas fields,boosting its annual gas output t...Exploration and development of large gas fields is an important way for a country to rapidly develop its natural gas industry.From 1991 to 2020,China discovered 68 new large gas fields,boosting its annual gas output to 1925×108m3in 2020,making it the fourth largest gas-producing country in the world.Based on 1696 molecular components and carbon isotopic composition data of alkane gas in 70 large gas fields in China,the characteristics of carbon isotopic composition of alkane gas in large gas fields in China were obtained.The lightest and average values ofδ^(13)C_(1),δ13C2,δ13C3andδ13C4become heavier with increasing carbon number,while the heaviest values ofδ^(13)C_(1),δ13C2,δ13C3andδ13C4become lighter with increasing carbon number.Theδ^(13)C_(1)values of large gas fields in China range from-71.2‰to-11.4‰(specifically,from-71.2‰to-56.4‰for bacterial gas,from-54.4‰to-21.6‰for oil-related gas,from-49.3‰to-18.9‰for coal-derived gas,and from-35.6‰to-11.4‰for abiogenic gas).Based on these data,theδ^(13)C_(1)chart of large gas fields in China was plotted.Moreover,theδ^(13)C_(1)values of natural gas in China range from-107.1‰to-8.9‰,specifically,from-1071%o to-55.1‰for bacterial gas,from-54.4‰to-21.6‰for oil-related gas,from-49.3‰to-13.3‰for coal-derived gas,and from-36.2‰to-8.9‰for abiogenic gas.Based on these data,theδ^(13)C_(1)chart of natural gas in China was plotted.展开更多
The extraction of coal measure gas has been shifted toward thin gas reservoirs due to the depletion of medium-thick gas reservoirs.The coproduction of coalbed gas,shale gas,and tight sandstone gas(called a multisuperp...The extraction of coal measure gas has been shifted toward thin gas reservoirs due to the depletion of medium-thick gas reservoirs.The coproduction of coalbed gas,shale gas,and tight sandstone gas(called a multisuperposed gas system)is a key low-cost technology for the enhancement of natural gas production from thin gas reservoirs in coal measure.As an emerging engineering exploitation technology at its early stage of development,gas coproduction confronts various engineering challenges in hydraulic fracturing,bottom-hole pressure regulation,well network arrangement,and extraction sequence.The current understanding of the opportunities and challenges in the gas coproduction from the multisuperposed gas system is not comprehensive enough.In this case,the previous achievements in the field of gas coproduction should be urgently reviewed to provide valuable guidance and recommendations for further development.This review first discusses the regional and spatial distribution characteristics and possible reservoir combinations of gas reservoirs in coal measure.Then,the basic properties of different reservoirs,engineering challenges,and interlayer interference are comparatively analyzed and discussed.The current simulation models for gas coproduction and potential future research directions are further explored.The results indicate that the coupling effects of reservoir heterogeneity,interwell interference,and geological structure for increasing coproduction prediction accuracy should be included in future simulation models for gas coproduction.Careful investigation is required to explore the mechanisms and their further quantifications on the effects of interlayer interference in gas coproduction.The fractal dimension as a scale can play an important role in the characterization of the gas and water transport in different reservoirs.The machine learning methods have tremendous potential to provide accurate and fast predictions for gas coproduction and interlayer interference.展开更多
This study investigates the application of carbon dioxide (CO2) sequestration to address challenges in water-drive gas reservoirs, specifically focusing on improving gas recovery and mitigating water invasion. Traditi...This study investigates the application of carbon dioxide (CO2) sequestration to address challenges in water-drive gas reservoirs, specifically focusing on improving gas recovery and mitigating water invasion. Traditional methods like blow-down and co-production have limitations, including sand production, water coning, and inefficiency in strong aquifers. To overcome these issues, this research explores CO2 injection near the edge aquifer, aiming to reduce water influx and enhance gas recovery through the propagation of a CO2 plume in the gas-water contact zone. Both synthetic and real compositional reservoir models were studied, with CO2 injection performed while maintaining reservoir pressure below 90% of the initial level. Results show that CO2 sequestration significantly improved recovery, particularly in higher permeability reservoirs, where it reduced aquifer influx and increased gas production by 26% under challenging conditions. While CO2 dissolution in water decreased aquifer influx by 39%, its adverse effect on sweep efficiency led to a reduction in gas and water production by 4.2% and 10%, respectively. The method's effectiveness was not significantly impacted by aquifer permeability, but it was sensitive to vertical-to-horizontal permeability ratios. When applied to a real gas reservoir, the proposed method increased gas production by 14% compared to conventional techniques, with minimal CO2 production over a 112-year period. This study demonstrates the potential of CO2 sequestration as a comprehensive solution for enhancing gas recovery, reducing water production, and mitigating environmental impacts in water-drive gas reservoirs.展开更多
The precision of dynamic reserve calculations in gas reservoirs is crucial for the rational and efficient development of oil and gas fields and the formulation of gas well production plans.The Shaximiao gas reservoir ...The precision of dynamic reserve calculations in gas reservoirs is crucial for the rational and efficient development of oil and gas fields and the formulation of gas well production plans.The Shaximiao gas reservoir in the ZT block of northwestern Sichuan is densely packed and highly heterogeneous,featuring complex gas-water distribution,substantial variations in test production among gas wells,and a rapid decline rate.To precisely determine the dynamic reserves of these tight water-bearing gas wells,this study focuses on the water-tight gas reservoirs in the ZT block of northwestern Sichuan,conducting core X-ray diffraction,constant-rate mercury injection,and reservoir rock stress sensitivity experiments.Utilizing the experimental findings,the porosity and permeability of the rock samples under effective stress conditions are adjusted via binary linear regression.These adjusted parameters are then incorporated into the water-sealed gas material balance method,thereby establishing a novel approach for calculating dynamic reserves in water-tight gas reservoirs under stress sensitivity conditions.The results show that:(1)the rock porosity ranges from 6.08%to 10.22%,permeability ranges from 0.035 mD to 0.547 mD,clay mineral content ranges from 6.58%to 19.14%,pore radius distribution ranges from 90μm to 180μm,throat radius distribution ranges from 0.61μm to 3.41μm,with significant differences in throat distribution,indicating poor reservoir fluid flow capacity and strong tightness;(2)after aging experiments,rock samples exhibit plastic deformation,with porosity and permeability unable to fully recover after pressure relief.The stress sensitivity curve of rock samples shows a two-stage characteristic,with moderate to strong stress sensitivity;(3)porosity stress sensitivity is mainly influenced by pore radius and mineral composition-larger pore radius and higher clay content lead to stronger stress sensitivity,with porosity loss rates ranging from 8.26%to 23.69%.Permeability stress sensitivity is mainly influenced by throat radius and mineral composition-smaller throat radius and higher clay content result in stronger stress sensitivity,with permeability loss rates ranging from 47.91%to 62.03%;(4)a comparative analysis between the traditional dynamic reserve calculation method for gas wells and the new method considering stress sensitivity shows a relative error between 0.90%and 2.41%,with the new method demonstrating better accuracy.This study combines physical experimental results with an effective stress model of reservoir rocks to develop a new method for calculating dynamic reserves of water-bearing tight gas reservoirs under effective stress conditions,providing experimental data and example calculation results to support subsequent dynamic evaluation of gas reservoirs and the establishment of rational well allocation plans.展开更多
In this study,to better decide the effect of coal seam dip angle upon the dynamic change of the crossfusion in gas transport and storage areas during the progress of working face in the high gas thick coal seam,a two-...In this study,to better decide the effect of coal seam dip angle upon the dynamic change of the crossfusion in gas transport and storage areas during the progress of working face in the high gas thick coal seam,a two-dimensional physical simulation experiment regarded as the theoretical research was conducted to properly explore the variation law of overburden fracture.The results demonstrated that the boundary of the gas transport zone was located in the region of fracture separation.The boundary of the gas storage area was located in the abrupt penetration zone.Also,according to the information theory,the state of the gas transport and storage areas was determined by the changing trend of the fracture rate and fracture entropy.The mathematical representation model of the dip effect in gas transport and storage areas was established.The criteria upon which the regional location of the gas transport area and gas storage area can be based were put forward.The cross-fusion evolution process of the dip effect in gas transport and storage areas was revealed as well.The research results could provide guidance for realising directional and accurate gas extraction.展开更多
Blast furnace gas(BFG)is an important by-product energy for the iron and steel industry and has been widely used for heating or electricity generation.However,the undesirable contaminants in BFG(especially H_(2)S)gene...Blast furnace gas(BFG)is an important by-product energy for the iron and steel industry and has been widely used for heating or electricity generation.However,the undesirable contaminants in BFG(especially H_(2)S)generate harmful environmental emissions.The desulfurization of BFG is urgent for integrated steel plants due to the stringent ultra-low emission standards.Compared with other desulfurization materials,zeolite-based adsorbents represent a viable option with low costs and long service life.In this study,an ammonia-induced CuO modified 13X adsorbent(NH_(3)–CuO/13X)was prepared for H_(2)S removal from simulated BFG at low temperature.The XRD,H_(2)-TPR and TEM analysis proved that smaller CuO particles were formed and the dispersion of Cu on the surface of 13X zeolite was improved via the induction of ammonia.Evaluation on H_(2)S adsorption performance of the adsorbent was carried out using simulated BFG,and the results showed that NH_(3)–CuO/13X-3 has better breakthrough sulfur capacity,which was more than twice the sulfur capacity of CuO/13X.It is proposed that the enhanced desulfurization performance of NH_(3)–CuO/13X is attributed to an abundant pore of 13X,and combined action of 13X and CuO.This work provided an effective way to improve the sulfur capacity of zeolite-based adsorbents via impregnation method by ammonia induction.展开更多
Gas sensor is an indispensable part of modern society withwide applications in environmental monitoring,healthcare,food industry,public safety,etc.With the development of sensor technology,wireless communication,smart...Gas sensor is an indispensable part of modern society withwide applications in environmental monitoring,healthcare,food industry,public safety,etc.With the development of sensor technology,wireless communication,smart monitoring terminal,cloud storage/computing technology,and artificial intelligence,smart gas sensors represent the future of gassensing due to their merits of real-time multifunctional monitoring,earlywarning function,and intelligent and automated feature.Various electronicand optoelectronic gas sensors have been developed for high-performancesmart gas analysis.With the development of smart terminals and the maturityof integrated technology,flexible and wearable gas sensors play an increasingrole in gas analysis.This review highlights recent advances of smart gassensors in diverse applications.The structural components and fundamentalprinciples of electronic and optoelectronic gas sensors are described,andflexible and wearable gas sensor devices are highlighted.Moreover,sensorarray with artificial intelligence algorithms and smart gas sensors in“Internet of Things”paradigm are introduced.Finally,the challengesand perspectives of smart gas sensors are discussed regarding the future need of gas sensors for smart city and healthy living.展开更多
Invasive inflammation and excessive scar formation are the main reasons for the difficulty in repairing nervous tissue after spinal cord injury.Microglia and astrocytes play key roles in the spinal cord injury micro-e...Invasive inflammation and excessive scar formation are the main reasons for the difficulty in repairing nervous tissue after spinal cord injury.Microglia and astrocytes play key roles in the spinal cord injury micro-environment and share a close interaction.However,the mechanisms involved remain unclear.In this study,we found that after spinal cord injury,resting microglia(M0)were polarized into pro-inflammatory phenotypes(MG1 and MG3),while resting astrocytes were polarized into reactive and scar-forming phenotypes.The expression of growth arrest-specific 6(Gas6)and its receptor Axl were significantly down-regulated in microglia and astrocytes after spinal cord injury.In vitro experiments showed that Gas6 had negative effects on the polarization of reactive astrocytes and pro-inflammatory microglia,and even inhibited the cross-regulation between them.We further demonstrated that Gas6 can inhibit the polarization of reactive astrocytes by suppressing the activation of the Yes-associated protein signaling pathway.This,in turn,inhibited the polarization of pro-inflammatory microglia by suppressing the activation of the nuclear factor-κB/p65 and Janus kinase/signal transducer and activator of transcription signaling pathways.In vivo experiments showed that Gas6 inhibited the polarization of pro-inflammatory microglia and reactive astrocytes in the injured spinal cord,thereby promoting tissue repair and motor function recovery.Overall,Gas6 may play a role in the treatment of spinal cord injury.It can inhibit the inflammatory pathway of microglia and polarization of astrocytes,attenuate the interaction between microglia and astrocytes in the inflammatory microenvironment,and thereby alleviate local inflammation and reduce scar formation in the spinal cord.展开更多
BACKGROUND Acute mesenteric ischemia is a life-threatening disease.Intrasplenic gas is an extremely rare finding in such cases.CASE SUMMARY We report a case of a 79-year-old woman with a history of end-stage renal dis...BACKGROUND Acute mesenteric ischemia is a life-threatening disease.Intrasplenic gas is an extremely rare finding in such cases.CASE SUMMARY We report a case of a 79-year-old woman with a history of end-stage renal disease on hemodialysis for approximately 20 years,type 2 diabetes mellitus,and atrial fibrillation who presented with two days of epigastric pain.A computed tomography scan of the abdomen revealed intraperitoneal free air and significant intrasplenic gas.Laparoscopy revealed diffuse intestinal gangrene,and acute superior mesenteric ischemia was diagnosed.The patient died within 24 hours owing to profound shock.CONCLUSION Intrasplenic gas is an extremely rare finding on computed tomography imaging in cases of acute mesenteric ischemia.展开更多
Using the software ANSYS-19.2/Explicit Dynamics,this study performedfinite-element modeling of the large-diameter steel pipeline cross-section for the Beineu-Bozoy-Shymkent gas pipeline with a non-through straight crac...Using the software ANSYS-19.2/Explicit Dynamics,this study performedfinite-element modeling of the large-diameter steel pipeline cross-section for the Beineu-Bozoy-Shymkent gas pipeline with a non-through straight crack,strengthened by steel wire wrapping.The effects of the thread tensile force of the steel winding in the form of single rings at the crack edges and the wires with different winding diameters and pitches were also studied.The results showed that the strengthening was preferably executed at a minimum value of the thread tensile force,which was 6.4%more effective than that at its maximum value.The analysis of the influence of the winding dia-meters showed that the equivalent stresses increased by 32%from the beginning of the crack growth until the wire broke.The increment in winding diameter decelerated the disclosure of the edge crack and reduced its length by 8.2%.The analysis of the influence of the winding pitch showed that decreasing the distance between the winding turns also led to a 33.6%reduction in the length of the straight crack and a 7.9%reduction in the maximum stres-ses on the strengthened pipeline cross-section.The analysis of the temperature effect on the pipeline material,within a range from-40℃ to+50℃,resulted in a crack length change of up to 5.8%.As the temperature dropped,the crack length decreased.Within such a temperature range,the maximum stresses were observed along the cen-tral area of the crack,which were equal to 413 MPa at+50℃ and 440 MPa at-40℃.The results also showed that the presence of the steel winding in the pipeline significantly reduced the length of crack propagation up to 8.4 times,depending on the temperature effect and design parameters of prestressing.This work integrated the existing methods for crack localization along steel gas pipelines.展开更多
Mercury removal from coal combustion flue gas remains a significant challenge for environmental protection due to the lack of cost-effective sorbents.In this study,a series of red mud(RM)-based sorbents impregnated wi...Mercury removal from coal combustion flue gas remains a significant challenge for environmental protection due to the lack of cost-effective sorbents.In this study,a series of red mud(RM)-based sorbents impregnated with sodium halides(NaBr and NaI)are presented to capture elemental mercury(Hg^(0))from flue gas.The modified RM underwent comprehensive characterization,including analysis of its textural qualities,crystal structure,chemical composition,and thermal properties.The results indicate that the halide impregnation substantially impacts the surface area and pore size of the RM.Hg^(0) removal performance was evaluated on a fixed-bed reactor in simulated flue gas(consisting of N_(2),O_(2),CO_(2),NO and SO_(2),etc.)on a modified RM.At an optimal adsorption temperature of 160℃,NaI-modified sorbent(RMI5)offers a removal efficiency of 98%in a mixture of gas,including O_(2),NO and HCl.Furthermore,pseudo-second-order model fitting results demonstrate the chemisorption mechanism for the adsorption of Hg^(0) in kinetic investigations.展开更多
Based on an elaboration of the resource potential and annual production of tight sandstone gas and shale gas in the United States and China,this paper reviews the researches on the distribution of tight sandstone gas ...Based on an elaboration of the resource potential and annual production of tight sandstone gas and shale gas in the United States and China,this paper reviews the researches on the distribution of tight sandstone gas and shale gas reservoirs,and analyzes the distribution characteristics and genetic types of tight sandstone gas reservoirs.In the United States,the proportion of tight sandstone gas in the total gas production declined from 20%-35%in 2008 to about 8%in 2023,and the shale gas production was 8310×10^(8)m^(3)in 2023,about 80%of the total gas production,in contrast to the range of 5%-17%during 2000-2008.In China,the proportion of tight sandstone gas in the total gas production increased from 16%in 2010 to 28%or higher in 2023.China began to produce shale gas in 2012,with the production reaching 250×10^(8)m^(3)in 2023,about 11%of the total gas production of the country.The distribution of shale gas reservoirs is continuous.According to the fault presence,fault displacement and gas layer thickness,the continuous shale gas reservoirs can be divided into two types:continuity and intermittency.Most previous studies believed that both tight sandstone gas reservoirs and shale gas reservoirs are continuous,but this paper holds that the distribution of tight sandstone gas reservoirs is not continuous.According to the trap types,tight sandstone gas reservoirs can be divided into lithologic,anticlinal,and synclinal reservoirs.The tight sandstone gas is coal-derived in typical basins in China and Egypt,but oil-type gas in typical basins in the United States and Oman.展开更多
In recent years, the world has faced rising global temperatures, accumulative pollution, and energy crises, stimulating scientists worldwide to strive for eco-friendly and cost-effective solutions. Biochar has materia...In recent years, the world has faced rising global temperatures, accumulative pollution, and energy crises, stimulating scientists worldwide to strive for eco-friendly and cost-effective solutions. Biochar has materialized as a favorable tool for environmental remediation, indicating efficacy as an efficient sorbent substance for both inorganic and organic pollutants in environmental field. These unique properties exclude improved surface functionality, porous morphology, large specific surface area (SSA), cation exchange capacity (CEC), robust adsorption capabilities, environmental stability, and embedded micronutrients. Biochar exhibited potential characteristics for environmental oversight, greenhouse gas (GHG) emission reduction, and soil fertility improvement. This review explores the impact of fundamental factors such as retention time, pyrolysis temperature, gas flow rate, and reactor design on biochar yield and properties. Collected data revealed the various applications of biochar, ranging from waste management and construction materials to the adsorptive removal of hydrocarbon lubricants from aqueous media, contaminant immobilization, and carbon sequestration. It has played mostly a significant share in climate change mitigation and an important role in soil amendments. Biochar improves soil improvement by increasing water retention (10%–30%), carbon sequestration, soil surface functionality, and providing high surface area with chemical stability. The assessment also reports the prospects and contests associated with biochar application uses in various agriculture cropping ecosystems. Inclusive, this review highlights the multifaceted characteristics of biochar as an adjustable on top of a sustainable solution addressing greenhouse gas emission, carbon sequestration, and environmental stresses. However, further research is needed to understand its long-term impacts and optimal applications fully.展开更多
In the production of castings,intrusive gas pore represents a kind of common defects which can lead to leakage in high gas-tightness requirement castings,such as cylinder blocks and cylinder heads for engines.It occur...In the production of castings,intrusive gas pore represents a kind of common defects which can lead to leakage in high gas-tightness requirement castings,such as cylinder blocks and cylinder heads for engines.It occurs due to the intrusion of gases generated during the resin burning of the sand core into castings during the casting process.Therefore,a gas generation and flow constitution model was established,in which the gas generation rate is a function of temperature and time,and the flow of gas is controlled by the gas release,conservation,and Darcy's law.The heat transfer and gas flow during casting process was numerically simulated.The dangerous point of cores is firstly identified by a virtual heat transfer method based on the similarity between heat transfer and gas flow in the sand core.The gas pores in castings are predicted by the gas pressure,the viscosity and state of the melt for these dangerous points.Three distinct sand core structures were designed and used for the production of iron castings,and the simulated gas pore results were validated by the obtained castings.展开更多
In view of the increased focus on“green”and sustainable development and compliance with the national strategy for“carbon peak and carbon neutrality,”this study investigated the effect of replacing cement(0-20%)wit...In view of the increased focus on“green”and sustainable development and compliance with the national strategy for“carbon peak and carbon neutrality,”this study investigated the effect of replacing cement(0-20%)with limestone powder(stone powder)as a mineral admixture on the micro,meso,and macro properties of mortar.First,the applicability of stone powder was examined based on the physical filling and heat of hydration of stone powder-cement.Second,micro-meso testing methods,such as X-ray diffraction,scanning electron microscopy,thermogravimetry-differential scanning calorimetry,and nuclear magnetic resonance,were utilized to reveal the influencing mechanisms of stone powder on the microstructure of the mortar.Furthermore,the effect of stone powder on the compressive strength and gas permeability of the mortar was analyzed.Additionally,the time-dependent variations in the gas permeability and its functional relationship with the mechanical properties were determined.Finally,the correlation between the compressive strength and gas permeability with respect to the pore size of stone powder-doped mortar was established via gray-correlation analysis.The results show that an appropriate amount of stone powder(5%)can effectively improve the particle gradation,decelerate the release of the heat of hydration,increase the amount of hydration products,and improve the pore structure,thereby increasing the compressive strength and reducing the gas permeability coefficient.The gas permeability of stone powder-doped mortar was found to exhibit good time-dependent characteristics as well as a quadratic linear correlation with the compressive strength.The gray-correlation analysis results indicate that air pores exhibit the highest influence on the compressive strength and that the gas permeability coefficient is most significantly affected by large pores.展开更多
Natural gas hydrate is a clean energy source with substantial resource potential.In contrast to conventional oil and gas,natural gas hydrate exists as a multi-phase system consisting of solids,liquids,and gases,which ...Natural gas hydrate is a clean energy source with substantial resource potential.In contrast to conventional oil and gas,natural gas hydrate exists as a multi-phase system consisting of solids,liquids,and gases,which presents unique challenges and complicates the mechanisms of seepage and exploitation.Both domestic and international natural gas hydrate production tests typically employ a single-well production model.Although this approach has seen some success,it continues to be hindered by low production rates and short production cycles.Therefore,there is an urgent need to explore a new well network to significantly increase the production of a single well.This paper provides a comprehensive review of the latest advancements in natural gas hydrate research,including both laboratory studies and field tests.It further examines the gas production processes and development outcomes for single wells,dual wells,multi-branch wells,and multi-well systems under conditions of depressurization,thermal injection,and CO_(2) replacement.On this basis,well types and well networks suitable for commercial exploitation of natural gas hydrate were explored,and the technical direction of natural gas hydrate development was proposed.The study shows that fully exploiting the flexibility of complex structural wells and designing a well network compatible with the reservoir is the key to improving production from a single well.Moreover,multi-well joint exploitation is identified as an effective strategy for achieving large-scale,efficient development of natural gas hydrate.展开更多
In this work,we realized a room-temperature nitrogen dioxide(NO_(2))gas sensor based on a platinum(Pt)-loaded nanoporous gallium nitride(NP-GaN)sensing material using the thermal reduction method and coreduction with ...In this work,we realized a room-temperature nitrogen dioxide(NO_(2))gas sensor based on a platinum(Pt)-loaded nanoporous gallium nitride(NP-GaN)sensing material using the thermal reduction method and coreduction with the catalysis of polyols.The gas sensor gained excellent sensitivity to NO_(2) at a concentration range of 200 ppm to 100 ppb,benefiting from the loading of Pt nanoparticles,and exhibited a short response time(22 s)and recovery time(170 s)to 100 ppm of NO_(2) at room temperature with excellent selectivity to NO_(2) compared with other gases.This phenomenon was attributed to the spillover effect and the synergic electronic interaction with semiconductor materials of Pt,which not only provided more electrons for the adsorption of NO_(2) molecules but also occupied effective sites,causing poor sites for other gases.The low detection limit of Pt/NP-GaN was 100 ppb,and the gas sensor still had a fast response 70 d after fabrication.Besides,the gas-sensing mechanism of the gas sensor was further elaborated to determine the reason leading to its improved properties.The significant spillover impact and oxygen dissociation of Pt provided advantages to its synergic electronic interaction with semiconductor materials,leading to the improvement of the gas properties of gas sensors.展开更多
基金Supported by the National Natural Science Foundation of China(41472120)General Project of National Natural Science Foundation of China(42272188)+1 种基金Special Fund of PetroChina and New Energy Branch(2023YQX10101)Petrochemical Joint Fund of Fund Committee(U20B6001)。
文摘Exploration and development of large gas fields is an important way for a country to rapidly develop its natural gas industry.From 1991 to 2020,China discovered 68 new large gas fields,boosting its annual gas output to 1925×108m3in 2020,making it the fourth largest gas-producing country in the world.Based on 1696 molecular components and carbon isotopic composition data of alkane gas in 70 large gas fields in China,the characteristics of carbon isotopic composition of alkane gas in large gas fields in China were obtained.The lightest and average values ofδ^(13)C_(1),δ13C2,δ13C3andδ13C4become heavier with increasing carbon number,while the heaviest values ofδ^(13)C_(1),δ13C2,δ13C3andδ13C4become lighter with increasing carbon number.Theδ^(13)C_(1)values of large gas fields in China range from-71.2‰to-11.4‰(specifically,from-71.2‰to-56.4‰for bacterial gas,from-54.4‰to-21.6‰for oil-related gas,from-49.3‰to-18.9‰for coal-derived gas,and from-35.6‰to-11.4‰for abiogenic gas).Based on these data,theδ^(13)C_(1)chart of large gas fields in China was plotted.Moreover,theδ^(13)C_(1)values of natural gas in China range from-107.1‰to-8.9‰,specifically,from-1071%o to-55.1‰for bacterial gas,from-54.4‰to-21.6‰for oil-related gas,from-49.3‰to-13.3‰for coal-derived gas,and from-36.2‰to-8.9‰for abiogenic gas.Based on these data,theδ^(13)C_(1)chart of natural gas in China was plotted.
基金China Scholarship Council,Grant/Award Number:202206420091National Natural Science Foundation of China,Grant/Award Numbers:42030810,51674246。
文摘The extraction of coal measure gas has been shifted toward thin gas reservoirs due to the depletion of medium-thick gas reservoirs.The coproduction of coalbed gas,shale gas,and tight sandstone gas(called a multisuperposed gas system)is a key low-cost technology for the enhancement of natural gas production from thin gas reservoirs in coal measure.As an emerging engineering exploitation technology at its early stage of development,gas coproduction confronts various engineering challenges in hydraulic fracturing,bottom-hole pressure regulation,well network arrangement,and extraction sequence.The current understanding of the opportunities and challenges in the gas coproduction from the multisuperposed gas system is not comprehensive enough.In this case,the previous achievements in the field of gas coproduction should be urgently reviewed to provide valuable guidance and recommendations for further development.This review first discusses the regional and spatial distribution characteristics and possible reservoir combinations of gas reservoirs in coal measure.Then,the basic properties of different reservoirs,engineering challenges,and interlayer interference are comparatively analyzed and discussed.The current simulation models for gas coproduction and potential future research directions are further explored.The results indicate that the coupling effects of reservoir heterogeneity,interwell interference,and geological structure for increasing coproduction prediction accuracy should be included in future simulation models for gas coproduction.Careful investigation is required to explore the mechanisms and their further quantifications on the effects of interlayer interference in gas coproduction.The fractal dimension as a scale can play an important role in the characterization of the gas and water transport in different reservoirs.The machine learning methods have tremendous potential to provide accurate and fast predictions for gas coproduction and interlayer interference.
文摘This study investigates the application of carbon dioxide (CO2) sequestration to address challenges in water-drive gas reservoirs, specifically focusing on improving gas recovery and mitigating water invasion. Traditional methods like blow-down and co-production have limitations, including sand production, water coning, and inefficiency in strong aquifers. To overcome these issues, this research explores CO2 injection near the edge aquifer, aiming to reduce water influx and enhance gas recovery through the propagation of a CO2 plume in the gas-water contact zone. Both synthetic and real compositional reservoir models were studied, with CO2 injection performed while maintaining reservoir pressure below 90% of the initial level. Results show that CO2 sequestration significantly improved recovery, particularly in higher permeability reservoirs, where it reduced aquifer influx and increased gas production by 26% under challenging conditions. While CO2 dissolution in water decreased aquifer influx by 39%, its adverse effect on sweep efficiency led to a reduction in gas and water production by 4.2% and 10%, respectively. The method's effectiveness was not significantly impacted by aquifer permeability, but it was sensitive to vertical-to-horizontal permeability ratios. When applied to a real gas reservoir, the proposed method increased gas production by 14% compared to conventional techniques, with minimal CO2 production over a 112-year period. This study demonstrates the potential of CO2 sequestration as a comprehensive solution for enhancing gas recovery, reducing water production, and mitigating environmental impacts in water-drive gas reservoirs.
基金supported by CNPC Southwest Oil and Gas Field Branch's 2023 Scientific Research Program Project(20230303-14).
文摘The precision of dynamic reserve calculations in gas reservoirs is crucial for the rational and efficient development of oil and gas fields and the formulation of gas well production plans.The Shaximiao gas reservoir in the ZT block of northwestern Sichuan is densely packed and highly heterogeneous,featuring complex gas-water distribution,substantial variations in test production among gas wells,and a rapid decline rate.To precisely determine the dynamic reserves of these tight water-bearing gas wells,this study focuses on the water-tight gas reservoirs in the ZT block of northwestern Sichuan,conducting core X-ray diffraction,constant-rate mercury injection,and reservoir rock stress sensitivity experiments.Utilizing the experimental findings,the porosity and permeability of the rock samples under effective stress conditions are adjusted via binary linear regression.These adjusted parameters are then incorporated into the water-sealed gas material balance method,thereby establishing a novel approach for calculating dynamic reserves in water-tight gas reservoirs under stress sensitivity conditions.The results show that:(1)the rock porosity ranges from 6.08%to 10.22%,permeability ranges from 0.035 mD to 0.547 mD,clay mineral content ranges from 6.58%to 19.14%,pore radius distribution ranges from 90μm to 180μm,throat radius distribution ranges from 0.61μm to 3.41μm,with significant differences in throat distribution,indicating poor reservoir fluid flow capacity and strong tightness;(2)after aging experiments,rock samples exhibit plastic deformation,with porosity and permeability unable to fully recover after pressure relief.The stress sensitivity curve of rock samples shows a two-stage characteristic,with moderate to strong stress sensitivity;(3)porosity stress sensitivity is mainly influenced by pore radius and mineral composition-larger pore radius and higher clay content lead to stronger stress sensitivity,with porosity loss rates ranging from 8.26%to 23.69%.Permeability stress sensitivity is mainly influenced by throat radius and mineral composition-smaller throat radius and higher clay content result in stronger stress sensitivity,with permeability loss rates ranging from 47.91%to 62.03%;(4)a comparative analysis between the traditional dynamic reserve calculation method for gas wells and the new method considering stress sensitivity shows a relative error between 0.90%and 2.41%,with the new method demonstrating better accuracy.This study combines physical experimental results with an effective stress model of reservoir rocks to develop a new method for calculating dynamic reserves of water-bearing tight gas reservoirs under effective stress conditions,providing experimental data and example calculation results to support subsequent dynamic evaluation of gas reservoirs and the establishment of rational well allocation plans.
基金supported by the National Natural Science Foundation of China(No.5217-4205)Shaanxi Provincial Outstanding Youth Science Fund Project(No.2023-JC-JQ-40)+4 种基金National Key Research and Development Project(No.2023YFC3009004)Key Project of Shaanxi Provincial Department of Education(No.22JY040)Xinjiang Uygur Autonomous Region Key Research and Development Task Special Project(No.2022B01034-3)Key Laboratory of Green Coal Mining in Xinjiang,Ministry of Education(No.KLXGY-KA2404)Shaanxi Provincial Key Research and Development Task General Project(No.2024GX–YBXM-490)。
文摘In this study,to better decide the effect of coal seam dip angle upon the dynamic change of the crossfusion in gas transport and storage areas during the progress of working face in the high gas thick coal seam,a two-dimensional physical simulation experiment regarded as the theoretical research was conducted to properly explore the variation law of overburden fracture.The results demonstrated that the boundary of the gas transport zone was located in the region of fracture separation.The boundary of the gas storage area was located in the abrupt penetration zone.Also,according to the information theory,the state of the gas transport and storage areas was determined by the changing trend of the fracture rate and fracture entropy.The mathematical representation model of the dip effect in gas transport and storage areas was established.The criteria upon which the regional location of the gas transport area and gas storage area can be based were put forward.The cross-fusion evolution process of the dip effect in gas transport and storage areas was revealed as well.The research results could provide guidance for realising directional and accurate gas extraction.
基金financially supported by National Natural Science Foundation of China(Grant.22076189)National Key Research and Development Program of China(No.2023YFC3707003)the Joint Fund of Yulin University and Dalian National Laboratory for Clean Energy(Grant.YLU-DNL Fund 2022003).
文摘Blast furnace gas(BFG)is an important by-product energy for the iron and steel industry and has been widely used for heating or electricity generation.However,the undesirable contaminants in BFG(especially H_(2)S)generate harmful environmental emissions.The desulfurization of BFG is urgent for integrated steel plants due to the stringent ultra-low emission standards.Compared with other desulfurization materials,zeolite-based adsorbents represent a viable option with low costs and long service life.In this study,an ammonia-induced CuO modified 13X adsorbent(NH_(3)–CuO/13X)was prepared for H_(2)S removal from simulated BFG at low temperature.The XRD,H_(2)-TPR and TEM analysis proved that smaller CuO particles were formed and the dispersion of Cu on the surface of 13X zeolite was improved via the induction of ammonia.Evaluation on H_(2)S adsorption performance of the adsorbent was carried out using simulated BFG,and the results showed that NH_(3)–CuO/13X-3 has better breakthrough sulfur capacity,which was more than twice the sulfur capacity of CuO/13X.It is proposed that the enhanced desulfurization performance of NH_(3)–CuO/13X is attributed to an abundant pore of 13X,and combined action of 13X and CuO.This work provided an effective way to improve the sulfur capacity of zeolite-based adsorbents via impregnation method by ammonia induction.
基金supported by the National Natural Science Foundation of China(No.22376159)the Fundamental Research Funds for the Central Universities.
文摘Gas sensor is an indispensable part of modern society withwide applications in environmental monitoring,healthcare,food industry,public safety,etc.With the development of sensor technology,wireless communication,smart monitoring terminal,cloud storage/computing technology,and artificial intelligence,smart gas sensors represent the future of gassensing due to their merits of real-time multifunctional monitoring,earlywarning function,and intelligent and automated feature.Various electronicand optoelectronic gas sensors have been developed for high-performancesmart gas analysis.With the development of smart terminals and the maturityof integrated technology,flexible and wearable gas sensors play an increasingrole in gas analysis.This review highlights recent advances of smart gassensors in diverse applications.The structural components and fundamentalprinciples of electronic and optoelectronic gas sensors are described,andflexible and wearable gas sensor devices are highlighted.Moreover,sensorarray with artificial intelligence algorithms and smart gas sensors in“Internet of Things”paradigm are introduced.Finally,the challengesand perspectives of smart gas sensors are discussed regarding the future need of gas sensors for smart city and healthy living.
基金supported by the National Natural Science Foundation of China, Nos.81971151 (to YW), 82102528 (to XL), 82102583 (to LW)the Natural Science Foundation of Guangdong Province, China, Nos.2020A1515010265 (to YW), 2020A1515110679 (to XL), and 2021A1515010358 (to XL)
文摘Invasive inflammation and excessive scar formation are the main reasons for the difficulty in repairing nervous tissue after spinal cord injury.Microglia and astrocytes play key roles in the spinal cord injury micro-environment and share a close interaction.However,the mechanisms involved remain unclear.In this study,we found that after spinal cord injury,resting microglia(M0)were polarized into pro-inflammatory phenotypes(MG1 and MG3),while resting astrocytes were polarized into reactive and scar-forming phenotypes.The expression of growth arrest-specific 6(Gas6)and its receptor Axl were significantly down-regulated in microglia and astrocytes after spinal cord injury.In vitro experiments showed that Gas6 had negative effects on the polarization of reactive astrocytes and pro-inflammatory microglia,and even inhibited the cross-regulation between them.We further demonstrated that Gas6 can inhibit the polarization of reactive astrocytes by suppressing the activation of the Yes-associated protein signaling pathway.This,in turn,inhibited the polarization of pro-inflammatory microglia by suppressing the activation of the nuclear factor-κB/p65 and Janus kinase/signal transducer and activator of transcription signaling pathways.In vivo experiments showed that Gas6 inhibited the polarization of pro-inflammatory microglia and reactive astrocytes in the injured spinal cord,thereby promoting tissue repair and motor function recovery.Overall,Gas6 may play a role in the treatment of spinal cord injury.It can inhibit the inflammatory pathway of microglia and polarization of astrocytes,attenuate the interaction between microglia and astrocytes in the inflammatory microenvironment,and thereby alleviate local inflammation and reduce scar formation in the spinal cord.
文摘BACKGROUND Acute mesenteric ischemia is a life-threatening disease.Intrasplenic gas is an extremely rare finding in such cases.CASE SUMMARY We report a case of a 79-year-old woman with a history of end-stage renal disease on hemodialysis for approximately 20 years,type 2 diabetes mellitus,and atrial fibrillation who presented with two days of epigastric pain.A computed tomography scan of the abdomen revealed intraperitoneal free air and significant intrasplenic gas.Laparoscopy revealed diffuse intestinal gangrene,and acute superior mesenteric ischemia was diagnosed.The patient died within 24 hours owing to profound shock.CONCLUSION Intrasplenic gas is an extremely rare finding on computed tomography imaging in cases of acute mesenteric ischemia.
基金funded by the Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan(Grant No.AP19680589).
文摘Using the software ANSYS-19.2/Explicit Dynamics,this study performedfinite-element modeling of the large-diameter steel pipeline cross-section for the Beineu-Bozoy-Shymkent gas pipeline with a non-through straight crack,strengthened by steel wire wrapping.The effects of the thread tensile force of the steel winding in the form of single rings at the crack edges and the wires with different winding diameters and pitches were also studied.The results showed that the strengthening was preferably executed at a minimum value of the thread tensile force,which was 6.4%more effective than that at its maximum value.The analysis of the influence of the winding dia-meters showed that the equivalent stresses increased by 32%from the beginning of the crack growth until the wire broke.The increment in winding diameter decelerated the disclosure of the edge crack and reduced its length by 8.2%.The analysis of the influence of the winding pitch showed that decreasing the distance between the winding turns also led to a 33.6%reduction in the length of the straight crack and a 7.9%reduction in the maximum stres-ses on the strengthened pipeline cross-section.The analysis of the temperature effect on the pipeline material,within a range from-40℃ to+50℃,resulted in a crack length change of up to 5.8%.As the temperature dropped,the crack length decreased.Within such a temperature range,the maximum stresses were observed along the cen-tral area of the crack,which were equal to 413 MPa at+50℃ and 440 MPa at-40℃.The results also showed that the presence of the steel winding in the pipeline significantly reduced the length of crack propagation up to 8.4 times,depending on the temperature effect and design parameters of prestressing.This work integrated the existing methods for crack localization along steel gas pipelines.
基金supported by the National Natural Science Foundation of China(22278066,21776039)the National Key R&D Program of China(2023YFB4103001)The Fundamental Research Funds for the Central Universities(DUT2021TB03).
文摘Mercury removal from coal combustion flue gas remains a significant challenge for environmental protection due to the lack of cost-effective sorbents.In this study,a series of red mud(RM)-based sorbents impregnated with sodium halides(NaBr and NaI)are presented to capture elemental mercury(Hg^(0))from flue gas.The modified RM underwent comprehensive characterization,including analysis of its textural qualities,crystal structure,chemical composition,and thermal properties.The results indicate that the halide impregnation substantially impacts the surface area and pore size of the RM.Hg^(0) removal performance was evaluated on a fixed-bed reactor in simulated flue gas(consisting of N_(2),O_(2),CO_(2),NO and SO_(2),etc.)on a modified RM.At an optimal adsorption temperature of 160℃,NaI-modified sorbent(RMI5)offers a removal efficiency of 98%in a mixture of gas,including O_(2),NO and HCl.Furthermore,pseudo-second-order model fitting results demonstrate the chemisorption mechanism for the adsorption of Hg^(0) in kinetic investigations.
基金Supported by the National Key R&D Project(2019YFC1805505)National Natural Science Foundation of China(42272188,42172149,U2244209)+2 种基金Science and Technology Special Project of China National Petroleum Corporation(2023YQX10101)Petrochemical Joint Fund Integration Project of National Natural Science Foundation of China(U20B6001)Shale Gas Academician Workstation Project of Guizhou Energy Industry Research Institute Co.,Ltd.([2021]45-2)。
文摘Based on an elaboration of the resource potential and annual production of tight sandstone gas and shale gas in the United States and China,this paper reviews the researches on the distribution of tight sandstone gas and shale gas reservoirs,and analyzes the distribution characteristics and genetic types of tight sandstone gas reservoirs.In the United States,the proportion of tight sandstone gas in the total gas production declined from 20%-35%in 2008 to about 8%in 2023,and the shale gas production was 8310×10^(8)m^(3)in 2023,about 80%of the total gas production,in contrast to the range of 5%-17%during 2000-2008.In China,the proportion of tight sandstone gas in the total gas production increased from 16%in 2010 to 28%or higher in 2023.China began to produce shale gas in 2012,with the production reaching 250×10^(8)m^(3)in 2023,about 11%of the total gas production of the country.The distribution of shale gas reservoirs is continuous.According to the fault presence,fault displacement and gas layer thickness,the continuous shale gas reservoirs can be divided into two types:continuity and intermittency.Most previous studies believed that both tight sandstone gas reservoirs and shale gas reservoirs are continuous,but this paper holds that the distribution of tight sandstone gas reservoirs is not continuous.According to the trap types,tight sandstone gas reservoirs can be divided into lithologic,anticlinal,and synclinal reservoirs.The tight sandstone gas is coal-derived in typical basins in China and Egypt,but oil-type gas in typical basins in the United States and Oman.
基金Deanship of Scientific Research(DSR)at King Faisal University,Saudi Arabia,under project number KFU241939.
文摘In recent years, the world has faced rising global temperatures, accumulative pollution, and energy crises, stimulating scientists worldwide to strive for eco-friendly and cost-effective solutions. Biochar has materialized as a favorable tool for environmental remediation, indicating efficacy as an efficient sorbent substance for both inorganic and organic pollutants in environmental field. These unique properties exclude improved surface functionality, porous morphology, large specific surface area (SSA), cation exchange capacity (CEC), robust adsorption capabilities, environmental stability, and embedded micronutrients. Biochar exhibited potential characteristics for environmental oversight, greenhouse gas (GHG) emission reduction, and soil fertility improvement. This review explores the impact of fundamental factors such as retention time, pyrolysis temperature, gas flow rate, and reactor design on biochar yield and properties. Collected data revealed the various applications of biochar, ranging from waste management and construction materials to the adsorptive removal of hydrocarbon lubricants from aqueous media, contaminant immobilization, and carbon sequestration. It has played mostly a significant share in climate change mitigation and an important role in soil amendments. Biochar improves soil improvement by increasing water retention (10%–30%), carbon sequestration, soil surface functionality, and providing high surface area with chemical stability. The assessment also reports the prospects and contests associated with biochar application uses in various agriculture cropping ecosystems. Inclusive, this review highlights the multifaceted characteristics of biochar as an adjustable on top of a sustainable solution addressing greenhouse gas emission, carbon sequestration, and environmental stresses. However, further research is needed to understand its long-term impacts and optimal applications fully.
基金funded by the Beijing Nature Sciences Fund Haidian Originality Cooperation Project (Grant No. L212002)。
文摘In the production of castings,intrusive gas pore represents a kind of common defects which can lead to leakage in high gas-tightness requirement castings,such as cylinder blocks and cylinder heads for engines.It occurs due to the intrusion of gases generated during the resin burning of the sand core into castings during the casting process.Therefore,a gas generation and flow constitution model was established,in which the gas generation rate is a function of temperature and time,and the flow of gas is controlled by the gas release,conservation,and Darcy's law.The heat transfer and gas flow during casting process was numerically simulated.The dangerous point of cores is firstly identified by a virtual heat transfer method based on the similarity between heat transfer and gas flow in the sand core.The gas pores in castings are predicted by the gas pressure,the viscosity and state of the melt for these dangerous points.Three distinct sand core structures were designed and used for the production of iron castings,and the simulated gas pore results were validated by the obtained castings.
基金Funded by the National Natural Science Foundation of China project(Nos.52108219 and U21A20150)the Lanzhou University of Technology Hongliu Outstanding Young Talent Program,China(No.04-062407)the Research on Quality Control Technology of High-performance Concrete Prepared by Manufactured Sand(No.2020Y21)。
文摘In view of the increased focus on“green”and sustainable development and compliance with the national strategy for“carbon peak and carbon neutrality,”this study investigated the effect of replacing cement(0-20%)with limestone powder(stone powder)as a mineral admixture on the micro,meso,and macro properties of mortar.First,the applicability of stone powder was examined based on the physical filling and heat of hydration of stone powder-cement.Second,micro-meso testing methods,such as X-ray diffraction,scanning electron microscopy,thermogravimetry-differential scanning calorimetry,and nuclear magnetic resonance,were utilized to reveal the influencing mechanisms of stone powder on the microstructure of the mortar.Furthermore,the effect of stone powder on the compressive strength and gas permeability of the mortar was analyzed.Additionally,the time-dependent variations in the gas permeability and its functional relationship with the mechanical properties were determined.Finally,the correlation between the compressive strength and gas permeability with respect to the pore size of stone powder-doped mortar was established via gray-correlation analysis.The results show that an appropriate amount of stone powder(5%)can effectively improve the particle gradation,decelerate the release of the heat of hydration,increase the amount of hydration products,and improve the pore structure,thereby increasing the compressive strength and reducing the gas permeability coefficient.The gas permeability of stone powder-doped mortar was found to exhibit good time-dependent characteristics as well as a quadratic linear correlation with the compressive strength.The gray-correlation analysis results indicate that air pores exhibit the highest influence on the compressive strength and that the gas permeability coefficient is most significantly affected by large pores.
基金This work was supported by the projects of the China Geological Survey(DD 20221703).
文摘Natural gas hydrate is a clean energy source with substantial resource potential.In contrast to conventional oil and gas,natural gas hydrate exists as a multi-phase system consisting of solids,liquids,and gases,which presents unique challenges and complicates the mechanisms of seepage and exploitation.Both domestic and international natural gas hydrate production tests typically employ a single-well production model.Although this approach has seen some success,it continues to be hindered by low production rates and short production cycles.Therefore,there is an urgent need to explore a new well network to significantly increase the production of a single well.This paper provides a comprehensive review of the latest advancements in natural gas hydrate research,including both laboratory studies and field tests.It further examines the gas production processes and development outcomes for single wells,dual wells,multi-branch wells,and multi-well systems under conditions of depressurization,thermal injection,and CO_(2) replacement.On this basis,well types and well networks suitable for commercial exploitation of natural gas hydrate were explored,and the technical direction of natural gas hydrate development was proposed.The study shows that fully exploiting the flexibility of complex structural wells and designing a well network compatible with the reservoir is the key to improving production from a single well.Moreover,multi-well joint exploitation is identified as an effective strategy for achieving large-scale,efficient development of natural gas hydrate.
基金supported by the National Natural Science Foundation of China(Nos.62031022 and 52375572)the Key R&D Program of Shanxi Province,China(No.202102030201003)+1 种基金Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering,China(No.2022SXAT001)Key Core Technological Breakthrough Program of Taiyuan City,China(No.2024TYJB0126).
文摘In this work,we realized a room-temperature nitrogen dioxide(NO_(2))gas sensor based on a platinum(Pt)-loaded nanoporous gallium nitride(NP-GaN)sensing material using the thermal reduction method and coreduction with the catalysis of polyols.The gas sensor gained excellent sensitivity to NO_(2) at a concentration range of 200 ppm to 100 ppb,benefiting from the loading of Pt nanoparticles,and exhibited a short response time(22 s)and recovery time(170 s)to 100 ppm of NO_(2) at room temperature with excellent selectivity to NO_(2) compared with other gases.This phenomenon was attributed to the spillover effect and the synergic electronic interaction with semiconductor materials of Pt,which not only provided more electrons for the adsorption of NO_(2) molecules but also occupied effective sites,causing poor sites for other gases.The low detection limit of Pt/NP-GaN was 100 ppb,and the gas sensor still had a fast response 70 d after fabrication.Besides,the gas-sensing mechanism of the gas sensor was further elaborated to determine the reason leading to its improved properties.The significant spillover impact and oxygen dissociation of Pt provided advantages to its synergic electronic interaction with semiconductor materials,leading to the improvement of the gas properties of gas sensors.
