The significance of coal-derived gas in major gas producing countries

The core of coal-derived gas theory is that coal measure is the gas source, and the hydrocarbon generation of coal measure is dominated by gas and supplemented by oil, so discoveries in related basins are dominated by gas fields. Discovering and developing giant gas fields, especially those super giant gas fields with recoverable reserves more than 1×10^12 m^3, plays a key role in determining whether a country can be a major gas producing country with annual output over 500×10^8 m^3. The coal resource and coal-derived gas reserves are abundant and widespread in the world, and coal-derived gas makes a major contribution to the gas reserves and gas production in the world. By the end of 2017, 13 super giant coal-derived gas fields have been discovered in the world. The total initial recoverable reserves were 49.995 28×10^12 m^3, accounting for 25.8% of the total remaining recoverable reserves (193.5×10^12 m^3) in that year in the world. In 2017, there were 15 giant gas producing countries in the world, with a total gas yield of 28 567×10^8 m^3. Among them, six major coal-derived gas producing countries had a total gas yield of 11 369×10^8 m^3, accounting for 39.8% of total gas yield of major gas producing countries. The Urengoi gas field is a super giant coal-derived gas field with the most cumulative gas production in the world. By the end of 2015, the Urengoi gas field had cumulative gas production of 63 043.96×10^8 m^3, with the highest annual gas yield in the world. Its gas output was 3 300×10^8 m^3 in 1989, accounting for 41.4% and 15.7% of the gas output of Russia and the world, respectively. This study introduces the gas source rocks of the basins with super giant coal-derived gas fields in Russia, Turkmenistan, Netherlands, Mozambique and China, and their significances for these countries becoming giant gas producing countries in the world.

Relationships of the iC4/n C4 and iC5/nC5 ratios with maturity of coal-derived gases of Triassic Xujiahe Formation in central Sichuan Basin, SW China

The original gas reservoirs in different areas and different layers of the Triassic Xujiahe Formation in the central Sichuan Basin are studied to reveal the relationships of iC4/nC4 and iC5/nC5 ratios in coal-derived gas components with maturity using conventional natural gas geochemical research methods. The testing results of 73 gas samples from 8 gas fields show that the iC4/nC4 and iC5/nC5 ratios in coal-derived gas have a good positive correlation, and the correlation coefficient is above 0.8. Both the iC4/nC4 and iC5/nC5 ratios become higher with the increase of natural gas dryness coefficient (C1/C1+) and the methane carbon isotope becoming less negative. These parameters are highly correlated. This study not only reveals characteristics of heavy hydrocarbon isomers generated by coal formation, but also puts forward new identification indicators reflecting the maturity of coal-derived gas, the regression between iC4/nC4, iC5/nC5 and Ro, which can provide an important reference for maturity, migration and accumulation of coal-derived gas, and late stage reformation of coal-derived gas reservoirs.

Geological and Geochemical Characteristics and Exploration Prospect of Coal-Derived Tight Sandstone Gas in China： Case Study of the Ordos, Sichuan, and Tarim Basins

This work extensively investigated global tight sandstone gas, and geologically and geochemically analyzed the tight sandstone gas in China＇s Ordos, Sichuan, and Tarim basins. We compared typical tight sandstone gas in China with that in North America. We proposed six conditions for the formation of China＇s tight sandstone gas, and illustrated the geological characteristics of tight sandstone gas. In China, gas-bearing tight sandstones were mainly deposited in continental lake deltas and marine-terrigenous facies basin environments, associated with coal-measure strata, and were mostly buried deeper than 2000 in under a formation pressure of 20-30 MPa, with pressure coefficients varying from overpressure to negative pressure. In other countries, tight gas bearing sandstones were dominantly deposited in marine to marine-terrigenous facies environments, occurred in coal-measure strata, and were mostly buried shallower than 2000 m in low-pressure systems. We systematically analyzed tight sandstone gas in the Ordos, Sichuan, and Tarim basins in terms of chemical compositions, geochemical characteristics of carbon isotopes, origins, and sources. Tight sandstone gas in China usually has a hydrocarbon content of 〉95%, with CH4 content 〉90%, and a generally higher dry coefficient. In the three above-mentioned large tight sandstone gas regions,δ13C1 and δJ3C2 mainly ranges from -42%o to -28%o and from -28%o to -21%o, respectively. Type III coal-measure source rocks that closely coexist with tight reservoirs are developed extensively in these gas regions. The organic petrology of source rocks and the carbon isotope compositions of gas indicate that tight sandstone gas in China is dominantly coal-derived gas generated by coal-measure strata. Our analysis of carbon isotope series shows that local isotope reversals are mainly caused by the mixing of gases of different maturities and that were generated at different stages. With increasing maturity, the reversal tendency becomes more apparent. Moreover, natural gas with medium-low maturity （e.g., Xujiahe Formation natural gas in the Sichuan Basin） presents an apparent reversal at a low-maturity stage, a normal series at a medium -maturity stage, and a reversal tendency again at a high-maturity stage. Finally, we proposed four conditions for preferred tight sandstone gas ＂sweep spots,＂ and illustrated the recoverable reserves, proven reserves, production, and exploration prospects of tight sandstone gas. The geological and geochemical characteristics, origins, sources, and exploration potential of tight sandstone gas in China from our research will be instructive for the future evaluation, prediction, and exploration of tight sandstone gas in China and abroad.

Flexible coal-derived carbon fibers via electrospinning for self-standing lithium-ion battery anodes

A series of flexible and self-standing coal-derived carbon fibers(CCFs)were fabricated through electro-spinning coupled with carbonization using bituminous coal and polyacrylonitrile(PAN)as the carbon precursors.These CCFs were utilized as free-standing lithium-ion battery(LIB)anodes.Optimizing car-bonization temperature reveals that the CCFs exhibit a one-dimensional solid linear structure with a uni-form distribution of graphite-like microcrystals.These fibers possess a dense structure and smooth surface,with averaging diameter from approximately 125.0 to 210.0 nm at carbonization temperatures ranging from 600 to 900℃.During electrospinning and carbonization,the aromatic rings enriched in bituminous coal crosslink with PAN chains,forming a robust three-dimensional(3D)framework.This 3D microstructure significantly enhances the flexibility and tensile strength of CCFs,while increasing the graphite-like sp^(2)microcrystalline carbon content,thus improving electrical conductivity.The CCFs carbonized at 700℃demonstrate an optimal balance of sp^(3)amorphous and sp^(2)graphite-like carbons.The average diameter of CCFs-700 is 177 nm and the specific surface area(SSA)is 7.2 m^(2)g^(-1).Additionally,the fibers contain oxygen-containing functional groups,as well as nitrogen-containing func-tional groups,including pyridinic nitrogen and pyrrolic nitrogen.Owing to its characteristics,the CCFs-700 showcases remarkable electrochemical performance,delivering a high reversible capacity of 631.4 mAh g^(-1).CCFs-700 also exhibit outstanding cycle stability,which retains approximately all of their first capacity(400.1 mAh g^(-1))after 120 cycles.This research offers an economical yet scalable approach for producing flexible and self-supporting anodes for LIBs that do not require current collectors,binders and conductive additives,thereby simplifying the electrode fabrication process.

益母草碱调节GAS6/Axl信号通路对冠心病大鼠心肌损伤的影响

目的探讨益母草碱对生长停滞特异性蛋白6(GAS6)/酪氨酸蛋白激酶受体(Axl)信号通路的影响,阐明其减轻冠心病大鼠心肌损伤的机制。方法构建冠心病大鼠模型,将造模成功的大鼠按随机抽样方法分为模型组,益母草碱低、高剂量组(分别灌胃25、100 mg/kg益母草碱+腹腔注射75 mg/kg生理盐水),益母草碱高剂量+GAS6/Axl信号通路抑制剂组(灌胃100 mg/kg益母草碱+腹腔注射75 mg/kg的R428),每组12只;另取12只正常大鼠作对照组。各给药组大鼠给予相应药物,对照组和模型组大鼠灌胃并腹腔注射等体积生理盐水,每天1次,连续48 d。给药结束后,检测大鼠心功能和血清中炎症因子及心肌损伤标志物水平;观察其心肌组织病理形态;检测其心肌组织细胞凋亡率和心肌组织中凋亡及GAS6/Axl信号通路相关蛋白表达。结果与对照组比较,模型组大鼠出现心肌细胞与心肌纤维排列紊乱、心肌细胞肥大、细胞核固缩等病变,左室射血分数、左室短轴缩短率、二尖瓣环舒张早期与舒张晚期运动速度之比及GAS6蛋白相对表达量和B细胞淋巴瘤2/B细胞淋巴瘤2相关X蛋白、磷酸化Axl/Axl比值均显著降低(P<0.05),肿瘤坏死因子α、白细胞介素1β、白细胞介素6、肌酸激酶同工酶、肌钙蛋白Ⅰ、肌红蛋白水平以及心肌组织细胞凋亡率和剪切型胱天蛋白酶3/胱天蛋白酶3比值均显著升高(P<0.05);益母草碱各剂量组大鼠上述病理情况及各检测指标均显著改善(P<0.05),且益母草碱高剂量组效果较益母草碱低剂量组明显(P<0.05);R428处理可逆转高剂量益母草碱对冠心病大鼠心肌损伤的改善作用(P<0.05)。结论益母草碱可减轻冠心病大鼠心肌损伤,其作用机制可能与激活GAS6/Axl信号通路相关。

Ammonia-induced CuO/13X for H_(2)S removal from simulated blast furnace gas at low temperature

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.

Smart Gas Sensors:Recent Developments and Future Prospective

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.

Novel Methodologies for Preventing Crack Propagation in Steel Gas Pipelines Considering the Temperature Effect

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.

Mutual regulation of microglia and astrocytes after Gas6 inhibits spinal cord injury

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.

Microstructure characteristics and corrosion behavior of metal inert gas welded dissimilar joints of 6005A modified by Sc and 5083 alloys

The corrosion behavior and microstructure characteristics of metal inert gas(MIG)welded dissimilar joints of the 6005A alloy modified with Sc(designated as 6005A+Sc)and the 5083 alloy were investigated using corrosion tests and microscopy techniques.Results show that the dissimilar joints exhibit strong stress corrosion cracking(SCC)resistance,maintaining substantial strength during slow strain rate tensile tests.Notably,the heat-affected zone(HAZ)and base metal(BM)on the 6005A+Sc side show superior performance in terms of inter-granular corrosion(IGC)and exfoliation corrosion(EXCO)compared to the corresponding zones on the 5083 side.The lower corrosion resistance of the 5083-BM and the 5083-HAZ can be attributed to the presence of numerous Al_(2)Mg_(3)phases and micro-scaled Al_(6)(Mn,Fe)intermetallics,mainly distributed along the rolling direction.Conversely,the enhanced corrosion resistance of the 6005A+Sc-BM and the 6005A+Sc-HAZ can be attributed to the discontinuously distributed grain boundary precipitates(β-Mg_(2)Si),the smaller grain size,and the reduced corrosive current density.

Research on the hazards of gas leakage and explosion in a full-scale residential building

The gas explosion in residential building has always been a highly concerned problem.Explosions in homogeneous mixtures have been extensively studied.However,mixtures are often inhomogeneous in the practical scenarios due to the differences in the densities of methane and air.In order to investigate the effects of gas explosions in inhomogeneous mixtures,experimental studies involving gas leakage and explosion are conducted in a full-scale residential building to reproduce the process of gas explosion.By fitting the dimensionless buoyancy as a function of dimensionless height and dimensionless time,a distribution model of gas in large-scale spaces is established,and the mechanism of inhomogeneous distribution of methane is also be revealed.Furthermore,the stratified reconstruction method(SRM)is introduced for efficiently setting up inhomogeneous concentration fields in FLACS.The simulation results highlight that for the internal overpressure,the distribution of methane has no effect on the first overpressure peak(ΔP1),while it significantly influences the subsequent overpressure peak(ΔP2),and the maximum difference between the overpressure of homogeneous and inhomogeneous distribution is174.3%.Moreover,the initial concentration distribution also has a certain impact on the external overpressure.

Direct ink writing of nickel oxide-based thin films for room temperature gas detection

The rapid industrial growth and increasing population have led to significant pollution and deterioration of the natural atmospheric environment.Major atmospheric pollutants include NO_(2)and CO_(2).Hence,it is imperative to develop NO_(2)and CO_(2)sensors for ambient conditions,that can be used in indoor air quality monitoring,breath analysis,food spoilage detection,etc.In the present study,two thin film nanocomposite(nickel oxide-graphene and nickel oxide-silver nanowires)gas sensors are fabricated using direct ink writing.The nano-composites are investigated for their structural,optical,and electrical properties.Later the nano-composite is deposited on the interdigitated electrode(IDE)pattern to form NO_(2)and CO_(2)sensors.The deposited films are then exposed to NO_(2)and CO_(2)gases separately and their response and recovery times are determined using a custom-built gas sensing setup.Nickel oxide-graphene provides a good response time and recovery time of 10 and 9 s,respectively for NO_(2),due to the higher electron affinity of graphene towards NO_(2).Nickel oxide-silver nanowire nano-composite is suited for CO_(2)gas because silver is an excellent electrocatalyst for CO_(2)by giving response and recovery times of 11 s each.This is the first report showcasing NiO nano-composites for NO_(2)and CO_(2)sensing at room temperature.

Distribution patterns of tight sandstone gas and shale 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.

Characteristics of carbon isotopic composition of alkane gas in large gas fields in China

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.

Study on the basic nitrogen compounds from coal-derived oil

The distillation range analysis and elemental analysis of fractioned direct liquefied oil were conducted. Each fraction of liquefied oil contains some nitrogen compounds. Using the acid extraction method and gas chromatography/mass spectrometry （GC-MS）, the basic nitrogen compounds have been separated and identified. Compared with the nitrogen content of the liquefied oil before and after separation, the basic nitrogen compounds account for more than half of all nitrogen compounds. The basic nitrogen compounds in the light liquefied oil are easily separated, and contain more types of basic nitrogen compounds. The results also show that there are many basic nitrogen compounds in liquefied oil, such as pyrrole, aniline, pyridine, quinoline and so on. However, there are fewer other types of basic nitrogen compounds.

The composition analysis of coal-derived light oil

The composition of coal-derived light oil (IBP-220℃) was separated into 5 fractions by atmospheric distillation and analyzed by gas chromatography/mass spec- trometry (GC/MS).The light oil was made at 0.1 t/d coal direct liquefaction bench scale unit (BSU) at China Coal Research Institute (CCRI).Six groups of organics,including acyclic hydrocarbon,alicyclic hydrocarbon,aromatics,phenols,polynuclear aromatics and heterocyclics,were found and 80 compounds were tentatively identified in total.Alicyclic hydrocarbon is the main component of the light oil compared to other groups whether in relative mass percentage or the number of compounds in group.The predominant oxy- gen-contained compound is phenols,and the nitrogen-containing compound is pyridine. No sulfur-containing compound is detected.

Geochemistry and origins of hydrogen-containing natural gases in deep Songliao Basin,China:Insights from continental scientific drilling

The different reservoirs in deep Songliao Basin have non-homogeneous lithologies and include multiple layers with a high content of hydrogen gas.The gas composition and stable isotope characteristics vary significantly,but the origin analysis of different gas types has previously been weak.Based on the geochemical parameters of gas samples from different depths and the analysis of geological settings,this research covers the diverse origins of natural gas in different strata.The gas components are mainly methane with a small amount of C_(2+),and non-hydrocarbon gases,including nitrogen(N_(2)),hydrogen(H_(2)),carbon dioxide(CO_(2)),and helium(He).At greater depth,the carbon isotope of methane becomes heavier,and the hydrogen isotope points to a lacustrine sedimentary environment.With increasing depth,the origins of N_(2)and CO_(2)change gradually from a mixture of organic and inorganic to inorganic.The origins of hydrogen gas are complex and include organic sources,water radiolysis,water-rock(Fe^(2+)-containing minerals)reactions,and mantle-derived.The shales of Denglouku and Shahezi Formations,as source rocks,provide the premise for generation and occurrence of organic gas.Furthermore,the deep faults and fluid activities in Basement Formation control the generation and migration of mantle-derived gas.The discovery of a high content of H_(2)in study area not only reveals the organic and inorganic association of natural-gas generation,but also provides a scientific basis for the exploration of deep hydrogen-rich gas.

Constraints on Characteristics and Distribution of Gas Hydrate and Free Gas Using Broad-Band Processing of Three-Dimensional Seismic Data

Gas hydrate drilling expeditions in the Pearl River Mouth Basin,South China Sea,have identified concentrated gas hydrates with variable thickness.Moreover,free gas and the coexistence of gas hydrate and free gas have been confirmed by logging,coring,and production tests in the foraminifera-rich silty sediments with complex bottom-simulating reflectors(BSRs).The broad-band processing is conducted on conventional three-dimensional(3D)seismic data to improve the image and detection accuracy of gas hydratebearing layers and delineate the saturation and thickness of gas hydrate-and free gas-bearing sediments.Several geophysical attributes extracted along the base of the gas hydrate stability zone are used to demonstrate the variable distribution and the controlling factors for the differential enrichment of gas hydrate.The inverted gas hydrate saturation at the production zone is over 40% with a thickness of 90 m,showing the interbedded distribution with different boundaries between gas hydrate-and free gas-bearing layers.However,the gas hydrate saturation value at the adjacent canyon is 70%,with 30-m-thick patches and linear features.The lithological and fault controls on gas hydrate and free gas distributions are demonstrated by tracing each gas hydrate-bearing layer.Moreover,the BSR depths based on broad-band reprocessed 3D seismic data not only exhibit variations due to small-scale topographic changes caused by seafloor sedimentation and erosion but also show the upward shift of BSR and the blocky distribution of the coexistence of gas hydrate and free gas in the Pearl River Mouth Basin.

Deep-large faults controlling on the distribution of the venting gas hydrate system in the middle of the Qiongdongnan Basin, South China Sea

Many locations with concentrated hydrates at vents have confirmed the presence of abundant thermogenic gas in the middle of the Qiongdongnan Basin(QDNB).However,the impact of deep structures on gasbearing fluids migration and gas hydrates distribution in tectonically inactive regions is still unclear.In this study,the authors apply high-resolution 3D seismic and logging while drilling(LWD)data from the middle of the QDNB to investigate the influence of deep-large faults on gas chimneys and preferred gasescape pipes.The findings reveal the following:(1)Two significant deep-large faults,F1 and F2,developed on the edge of the Songnan Low Uplift,control the dominant migration of thermogenic hydrocarbons and determine the initial locations of gas chimneys.(2)The formation of gas chimneys is likely related to fault activation and reactivation.Gas chimney 1 is primarily arises from convergent fluid migration resulting from the intersection of the two faults,while the gas chimney 2 benefits from a steeper fault plane and shorter migration distance of fault F2.(3)Most gas-escape pipes are situated near the apex of the two faults.Their reactivations facilitate free gas flow into the GHSZ and contribute to the formation of fracture‐filling hydrates.

GAS6-AS1调节miR-370-3p/SPATA2轴对卵巢癌细胞增殖、迁移、侵袭、凋亡和EMT的影响

目的:探讨长链非编码RNA GAS6反义RNA1(long non-coding RNA GAS6 antisense RNA1, lncRNA GAS6-AS1)调节miR-370-3p/精子发生相关蛋白2 (spermatogenesis-associated protein 2, SPATA2)轴对卵巢癌细胞增殖、迁移、侵袭、凋亡和上皮间质转化(epithelial mesenchymal transformation, EMT)的影响。方法:qRT-PCR、Western blot分别检测癌旁组织、卵巢癌组织、人正常卵巢上皮细胞IOSE80及卵巢癌细胞系HO-8910、SKOV3、A2780中GAS6-AS1、miR-370-3p及SPATA2蛋白表达。将SKOV3细胞分为:对照组(NC组)、 si-NC组、si-GAS6-AS1组、mimic NC组、miR-370-3p mimic组、si-GAS6-AS1+inhibitor NC组、si-GAS6-AS1+miR-370-3p inhibitor组,qRT-PCR检测细胞中GAS6-AS1、miR-370-3p表达;CCK-8法检测细胞增殖;流式细胞术检测细胞凋亡;划痕愈合实验检测细胞迁移;Transwell实验检测细胞侵袭;Western blot检测SPATA2、细胞周期素D1(CyclinD1)、Bcl-2相关X蛋白(Bcl-2-associated X,Bax)、E-钙黏蛋白(E-cadherin)、波形蛋白(Vimentin)、神经钙黏蛋白(N-cadherin)表达;双荧光素酶报告基因实验检测GAS6-AS1与miR-370-3p、 miR-370-3p与SPATA2的关系。结果:在卵巢癌组织和细胞中GAS6-AS1、SPATA2蛋白高表达,miR-370-3p低表达,且在SKOV3细胞中GAS6-AS1、SPATA2蛋白表达量最高,miR-370-3p表达水平最低,因此,选择SKOV3细胞为后续研究对象。与NC组、si-NC组比较,si-GAS6-AS1组GAS6-AS1、OD450值(24 h、48 h、72 h)、划痕愈合率、侵袭细胞数、SPATA2、CyclinD1、Vimentin、N-cadherin蛋白表达降低,miR-370-3p表达、细胞凋亡率、Bax、E-cadherin蛋白表达升高(P<0.05);与NC组、mimic NC组比较,miR-370-3p mimic组OD450值(24 h、48 h、72 h)、划痕愈合率、侵袭细胞数、SPATA2、CyclinD1、Vimentin、N-cadherin蛋白表达降低,miR-370-3p表达、细胞凋亡率、Bax、E-cadherin蛋白表达升高(P<0.05);miR-370-3p inhibitor减弱了沉默GAS6-AS1对SKOV3细胞增殖、迁移、侵袭及EMT的抑制及对细胞凋亡的促进作用。GAS6-AS1与miR-370-3p、miR-370-3p与SPATA2存在靶向调控关系。结论:沉默GAS6-AS1通过上调miR-370-3p来抑制SPATA2表达,从而抑制SKOV3细胞增殖、迁移、侵袭及EMT,并促进细胞凋亡。