Renewable energy storage technologies are critical for transitioning to sustainable energy systems,with salt caverns playing a significant role in large-scale solutions.In water-soluble mining of low-grade salt format...Renewable energy storage technologies are critical for transitioning to sustainable energy systems,with salt caverns playing a significant role in large-scale solutions.In water-soluble mining of low-grade salt formations,insoluble impurities and interlayers detach during salt dissolution and accumulate as sediment at the cavern base,thereby reducing the storage capacity and economic viability of salt cavern gas storage(SCGS).This study investigates sediment formation mechanisms,void distribution,and voidage in the Huai'an low-grade salt mine,introducing a novel self-developed physical simulation device for two butted-well horizontal(TWH)caverns that replicates compressed air injection and brine discharge.Experiments comparing“one injection and one discharge”and“two injections and one discharge”modes revealed that(1)compressed air effectively displaces brine from sediment voids,(2)a 0.5 MPa injection pressure corresponds to a 10.3 MPa operational lower limit in practice,aligning with field data,and(3)sediment voidage is approximately 46%,validated via air-brine interface theory.The“two injections and one discharge”mode outperformed in both discharge volume and rate.Additionally,a mathematical model for brine displacement via compressed air was established.These results provide foundational insights for optimizing compressed air energy storage(CAES)in low-grade salt mines,advancing their role in renewable energy integration.展开更多
Geological storage and utilization of CO_(2)involve complex interactions among Thermo-hydromechanical-chemical(THMC)coupling processes,which significantly affect storage integrity and efficiency.To address the challen...Geological storage and utilization of CO_(2)involve complex interactions among Thermo-hydromechanical-chemical(THMC)coupling processes,which significantly affect storage integrity and efficiency.To address the challenges in accurately simulating these coupled phenomena,this paper systematically reviews recent advances in the mathematical modeling and numerical solution of THMC coupling in CO_(2)geological storage.The study focuses on the derivation and structure of governing and constitutive equations,the classification and comparative performance of fully coupled,iteratively coupled,and explicitly coupled solution methods,and the modeling of dynamic changes in porosity,permeability,and fracture evolution induced by multi-field interactions.Furthermore,the paper evaluates the capabilities,application scenarios,and limitations of major simulation platforms,including TOUGH,CMG-GEM,and COMSOL.By establishing a comparative framework integrating model formulations and solver strategies,this work clarifies the strengths and gaps of current approaches and contributes to the development of robust,scalable,and mechanism-oriented numerical models for long-term prediction of CO_(2)behavior in geological formations.展开更多
Deep and ultra-deep reservoirs have dense matrix and high fracture pressure, which leads to high pressure and difficulty in fracturing construction. Conventional aggravated fracturing fluids have the problems of low a...Deep and ultra-deep reservoirs have dense matrix and high fracture pressure, which leads to high pressure and difficulty in fracturing construction. Conventional aggravated fracturing fluids have the problems of low aggravation efficiency, high friction resistance, etc., and the reduction of construction pressure cannot reach the theoretical effect. In view of the above problems, this paper adopts the weighting agent HD160 and the drag reducing agent JHFR-2 to form a new type of weighted slippery water fracturing fluid system. And the weighting performance, drag reduction performance, corrosion performance, anti-expansion performance and reservoir damage of this system were studied. The results show that the density of the system is adjustable within 1.1 - 1.6 g·cm−3, and the drag reduction rate can be up to 68% at 1.5 g·cm−3, with low corrosion rate, surface tension less than 28 mN·m−1, anti-expansion rate as high as 94.5%, and the damage rate of the reservoir permeability is less than 10%, which is of good application prospect.展开更多
The macromolecular structure of tectonically deformed coals(TDC)may be determined by the deformation mechanisms of coal.Alterations of the macromolecular structure change the pore structure of TDC and thereby impact p...The macromolecular structure of tectonically deformed coals(TDC)may be determined by the deformation mechanisms of coal.Alterations of the macromolecular structure change the pore structure of TDC and thereby impact physical properties such as porosity and permeability.This study focuses on structure and properties of TDC from the Huaibei and Huainan coal mining areas of southern North China.Relationships between the macromolecular structure and the pore structure of TDC were analyzed using techniques such as X-ray diffraction,high-resolution transmission electron microcopy,and the low-temperature nitrogen adsorption.The results indicated that the directional stress condition can cause the arrangement of basic structural units(BSU)more serious and closer.And,the orientation is stronger in ductile deformed coal than in brittle deformed coal.Tectonic deformation directly influences the macromolecular structure of coal and consequently results in dynamic metamorphism.Because the size of BSU in brittle deformed coal increases more slowly than in ductile deformed coal,frictional heating and stress-chemistry of shearing areas might play a more important role,locally altering coal structure under stress,in brittle deformed coal.Strain energy is more significant in increasing the ductile deformation of coal.Furthermore,mesopores account for larger percentage of the nano-scale pore volume in brittle deformed coals,while mesopores volume in ductile deformed coal diminishes rapidly along with an increase in the proportion of micropores and sub-micropores.This research also approved that the deformations of macromolecular structures change nano-scale pore structures,which are very important for gas adsorption and pervasion space for gas.Therefore,the exploration and development potential of coal bed methane is promising for reservoirs that are subjected to a certain degree of brittle deformation(such as schistose structure coal,mortar structure coal and cataclastic structure coal).It also holds promise for TDC resulting from wrinkle structure coal of low ductile deformation and later superimposed by brittle deformation.Other kinds of TDC suffering from strong brittle-ductile and ductile deformation,such as scale structure coal and mylonitic structure coal,are difficult problems to resolve.展开更多
In this study,NiO/SBA-15 was prepared by both direct and post synthesis methods.TEM images revealed that NiO particles aggregated in NiO/SBA-15 obtained with post synthesis method,regardless of NiO loading.However,NiO...In this study,NiO/SBA-15 was prepared by both direct and post synthesis methods.TEM images revealed that NiO particles aggregated in NiO/SBA-15 obtained with post synthesis method,regardless of NiO loading.However,NiO particles were monodispersed in NiO/SBA-15 with a NiO loading of less than 15 wt%by using the direct synthesis method.In this case,NiO particles aggregated when NiO loading was over 20 wt%.TPR analysis verified that with direct synthesis method the location boundary of NiO particles on outer and pore surface could be observed clearly,whereas that could not observed in the case of post synthesis method.This indicates that the type of synthesis method displays significant effect on the location of NiO particles dispersed into the SBA-15.Producer gas conversion was carried out using NiO/SBA-15 as catalysts,which were synthesized with different synthesis methods.The gas conversion including methanation occurred at low temperature(i.e.,300-400℃)and the reverse water gas shift(RWGS)reaction at hightemperature(i.e.,400-900℃).High temperatures facilitated CO conversion to CO with CO selectivity close to 100%,regardless of the synthesis method of the used catalyst.At low temperatures the dispersion type of NiO particles affectedthe CO,conversion reaction,i.e.,monodispersed Ni0 particles gave a CO selectivity of close to 100%,similar to thatobtained at high temperature.The aggregated NiO particles resuled in a CO selectivity of less than 100%owing to CH,formation,regardless of synthesis method of catalyst.Therefore,NiO/SBA-15 obtained with direct synthesis methodfavored RWGS reaction because of high CO selectivity.NiOSBA-15 obtained with post synthesis method is suited formethanation because of high CH selectivity,and the conversion of CO,to CHa through methanation increased withincreasing NiO loading.展开更多
The depositional environment of organic-rich shale and the related tectonic evolution in China are rather different from those in North America. In China, organic-rich shale is not only deposited in marine environment...The depositional environment of organic-rich shale and the related tectonic evolution in China are rather different from those in North America. In China, organic-rich shale is not only deposited in marine environment, but also in non-marine environment： marine-continental transitional environment and lacustrine environment. Through analyzing large amount of outcrops and well cores, the geologic features of organic-rich shale, including mineral composition, organic matter richness and type, and li- thology stratigraphy, were analyzed, indicating very special characteristics. Meanwhile, the more complex and active tectonic movements in China lead to strong deformation and erosion of organic-rich shale, well-development of fractures and faults, and higher thermal maturity and serious heterogeneity. Co-existence of shale gas, tight sand gas, and coal bed methane （CBM） proposes a new topic： whether it is possible to co-produce these gases to reduce cost. Based on the geologic features, the primary pro- duction issues of shale gas in China were discussed with suggestions.展开更多
The deformation of coal is effected by thermal effect, pressures and tectonic stress, and the tectonic stress is the principal influence factor. However, the proposition of a useful quantitative index that responds to...The deformation of coal is effected by thermal effect, pressures and tectonic stress, and the tectonic stress is the principal influence factor. However, the proposition of a useful quantitative index that responds to the degree of deformation of coals quantitatively or semi-quantitatively has been a long-debated issue. The vitrinite reflectance ellipsoid, that is, the reflectance indication surface（RIS） ellipsoid is considered to be a strain ellipsoid that reflects the sum of the strain increment caused by stress in the process of coalification. It has been used to describe the degree of deformation of the coal, but the effect of the anisotropy on the RIS ellipsoid has not yet been considered with regards to non-structural factors. In this paper, Wei＇s parameter（ε） is proposed to express the deformation degree of the strain ellipsoid based on considering the combined influence of thermal effect, pressure and tectonic stress. The equation is as follows： ε=√[（ε_1-ε_0）~2＋（ε_2-ε_0）~2＋（ε_3-ε_0）~2]/3, where ε_1=lnR_（max）, ε_2=lnR_（int）, ε_3=lnR_（min）, and ε_0=（ε_1＋ε_2＋ε_3）/3. Wei＇s parameter represents the distance from the surface to the spindle of the RIS logarithm ellipsoid; thus, the degree of deformation of the strain ellipsoid is indicated quantitatively. The formula itself, meanwhile, represents the absolute value of the degree of relative deformation and is consequently suitable for any type of deformation of the strain ellipsoid. Wei＇s parameter makes it possible to compare degrees of deformation among different deformation types of the strain ellipsoid. This equation has been tested in four types of coal： highly metamorphic but weakly deformed coal of the southern Qinshui Basin, highly metamorphic and strongly deformed coal from the Tianhushan coal mining area of Fujian, and medium metamorphic and weakly or strongly deformed coal from the Huaibei Coalfield. The results of Wei＇s parameters are consistent with the actual deformation degrees of the coal reservoirs determined by other methods, which supports the effectiveness of this method. In addition, Wei＇s parameter is an important complement to the indicators of the degrees of deformation of coals, which possess certain theoretical significance and practical values.展开更多
Decoding the tectono-sedimentary history of the oldest cratons is essential for understanding Earth’s evolution and habitability.Unlike the lithosphere of orogenic belts,which is more easily reactivated and reworked,...Decoding the tectono-sedimentary history of the oldest cratons is essential for understanding Earth’s evolution and habitability.Unlike the lithosphere of orogenic belts,which is more easily reactivated and reworked,the lithosphere and sedimentary cover of cratons are relatively stable and thus better reflect the tectono-sedimentary events during Earth’s evolution[1,2].Continental deformation at Earth’s surface is an extremely complex geological process,in which the formation and evolution of sedimentary basins are closely linked to plate motions and mantle activities,representing an intrinsic manifestation of plate-mantle coupling[1,3].The North China Craton,one of the oldest cratons on Earth,is primarily composed of an Archean-Paleoproterozoic crystalline basement and a Mesoproterozoic-Quaternary sedimentary cover[2,4].展开更多
Continental deformation on the Earth's surface is an extremely complex geological process,in which the formation and evolution of sedimentary basins are closely related to plate motions and mantle activities.Combi...Continental deformation on the Earth's surface is an extremely complex geological process,in which the formation and evolution of sedimentary basins are closely related to plate motions and mantle activities.Combining sedimentary basins with orogenic belts and sedimentary responses with tectonic activities can comprehensively elucidate the geological processes during the Earth's evolution.This paper focuses on the multi-stage evolution of the Ordos Basin,the coupled basin-mountain systems and energy resources,discusses the evolution of the Ordos Basin and its coupling relationship with the peripheral tectonic belts,and further reveals the intrinsic connections and influencing factors of the energy resources in the basin.The conclusions are as follows:There are three large sedimentary hiatuses(Neoproterozoic-Early Cambrian,Late Ordovician-Early Carboniferous,and Late Cretaceous-Paleogene)and many small minor sedimentary hiatuses in the Ordos Block,which are mainly related to the tectonic activities,but also affected by the changes of the sea level and the climate.The Ordos Basin is a Meso-Cenozoic superposition basin formed by the contraction and reworking of the remnants of the Paleozoic cratonic basin,and its depositional extent and subsidence center have undergone multi-stage evolution,which was mainly influenced by the subduction of the Paleo-Pacific Plate.Influenced by the multi-directional convergence of peripheral plates in the North China Craton and the transformation of its own deep tectono-thermal regime,many coupled basin-mountain systems were formed with the Ordos Basin and the Yinshan orogenic belt,the Qinling orogenic belt,the Lvliangshan tectonic belt,the Helanshan tectonic belt or the Liupanshan tectonic belt as the core.The formation and enrichment of energy resources in the Ordos Basin are controlled by the tectono-sedimentary response,basin-mountain coupling evolution,and Early Cretaceous tectono-thermal events.All of them were gradually enriched into deposits during the formation,evolution,and reworking of the basin,and have a certain relationship of generation and coexistence,so they should belong to the same reservoir-forming(ore-forming)system.This study not only is helpful for revealing the coupling relationship between peripheral plate motions and internal mantle activities of the North China Craton,but also is of great significance for establishing the Earth's multi-layer coupling model and super energy system.展开更多
The generation mechanism and enrichment patterns of shale gas in coal measure in the southern part of the North China Craton hold significant guiding implications for deep energy exploration.Taking the Huaibei mining ...The generation mechanism and enrichment patterns of shale gas in coal measure in the southern part of the North China Craton hold significant guiding implications for deep energy exploration.Taking the Huaibei mining area in the southern part of the North China Craton as the study object,this study systematically reveals the enrichment mechanism of shale gas in coal measure in the context of the destruction of the North China Craton through basin simulation,rock pyrolysis,and geochemical analyses of magmatic rocks.The results indicate that coal measures of the southern part of the North China Craton mainly developed three episodes of Early Cretaceous magmatism(143-104 Ma)after their formation.Their whole-rock arc-type geochemical signatures,adakitic affinity indicative of subducted slab melting origins,and Sr-Nd isotopic characteristics[(^(87)Sr/^(86)Sr)_(i)=0.707-0.712,ε_(Nd)(t)=−12.63 to−9.18]suggest they were controlled by the retreat of the subducting Western Pacific Plate,consistent with the background of North China Craton destruction.This thermal event caused the regional heat flow to surge to 130 mW m^(−2),significantly accelerating the thermal evolution of the Permian coal measure shales.The vitrinite reflectance(R)of shales in the Shanxi Formation and Lower Shihezi Formation reached 1.10%and 1.33%,respectively,promoting the thermal cracking of heavy oil into light oil and wet gas,forming the main hydrocarbon generation stage for shale gas.However,craton destruction was also accompanied by intense tectonic uplift;the cumulative erosion in the study area exceeded 2000 m.Reduced formation pressure led to the desorption and escape of some gases,highlighting the dual effects of promoting hydrocarbon generation while limiting preservation.Integrating the intensity of structural deformation with the spatiotemporal distribution of magmatic activity,the study proposes that regions with weak structural deformation superimposed with Early Cretaceous magmatic intrusions represent favorable targets for shale gas enrichment.These results elucidate the shale gas accumulation model of“thermal evolution controlling generation and tectonic activity controlling preservation”under craton destruction,providing crucial guidance for shale gas exploration in the North China region and other complex structural areas with similar settings.展开更多
基金financial support from the National Key Research and Development Program of China(No.2024YFB4007100)the Basic ForwardLooking Project of the Sinopec Science and Technology Department,“Research on the Long-Term Sealing Mechanism of Multi-layer Salt Cavern Hydrogen Storage”(No.P24197-4)。
文摘Renewable energy storage technologies are critical for transitioning to sustainable energy systems,with salt caverns playing a significant role in large-scale solutions.In water-soluble mining of low-grade salt formations,insoluble impurities and interlayers detach during salt dissolution and accumulate as sediment at the cavern base,thereby reducing the storage capacity and economic viability of salt cavern gas storage(SCGS).This study investigates sediment formation mechanisms,void distribution,and voidage in the Huai'an low-grade salt mine,introducing a novel self-developed physical simulation device for two butted-well horizontal(TWH)caverns that replicates compressed air injection and brine discharge.Experiments comparing“one injection and one discharge”and“two injections and one discharge”modes revealed that(1)compressed air effectively displaces brine from sediment voids,(2)a 0.5 MPa injection pressure corresponds to a 10.3 MPa operational lower limit in practice,aligning with field data,and(3)sediment voidage is approximately 46%,validated via air-brine interface theory.The“two injections and one discharge”mode outperformed in both discharge volume and rate.Additionally,a mathematical model for brine displacement via compressed air was established.These results provide foundational insights for optimizing compressed air energy storage(CAES)in low-grade salt mines,advancing their role in renewable energy integration.
基金supported by the China Postdoctoral Science Foundation(No.2024M752803)the National Natural Science Foundation of China(No.52179112)the Open Fund of National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation(Southwest Petroleum University)(No.PLN2023-02)。
文摘Geological storage and utilization of CO_(2)involve complex interactions among Thermo-hydromechanical-chemical(THMC)coupling processes,which significantly affect storage integrity and efficiency.To address the challenges in accurately simulating these coupled phenomena,this paper systematically reviews recent advances in the mathematical modeling and numerical solution of THMC coupling in CO_(2)geological storage.The study focuses on the derivation and structure of governing and constitutive equations,the classification and comparative performance of fully coupled,iteratively coupled,and explicitly coupled solution methods,and the modeling of dynamic changes in porosity,permeability,and fracture evolution induced by multi-field interactions.Furthermore,the paper evaluates the capabilities,application scenarios,and limitations of major simulation platforms,including TOUGH,CMG-GEM,and COMSOL.By establishing a comparative framework integrating model formulations and solver strategies,this work clarifies the strengths and gaps of current approaches and contributes to the development of robust,scalable,and mechanism-oriented numerical models for long-term prediction of CO_(2)behavior in geological formations.
文摘Deep and ultra-deep reservoirs have dense matrix and high fracture pressure, which leads to high pressure and difficulty in fracturing construction. Conventional aggravated fracturing fluids have the problems of low aggravation efficiency, high friction resistance, etc., and the reduction of construction pressure cannot reach the theoretical effect. In view of the above problems, this paper adopts the weighting agent HD160 and the drag reducing agent JHFR-2 to form a new type of weighted slippery water fracturing fluid system. And the weighting performance, drag reduction performance, corrosion performance, anti-expansion performance and reservoir damage of this system were studied. The results show that the density of the system is adjustable within 1.1 - 1.6 g·cm−3, and the drag reduction rate can be up to 68% at 1.5 g·cm−3, with low corrosion rate, surface tension less than 28 mN·m−1, anti-expansion rate as high as 94.5%, and the damage rate of the reservoir permeability is less than 10%, which is of good application prospect.
基金supported by the National Natural Science Foundation of China(Grant No.40772135,4097213141030422)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA05030100)National Science and Technology Major Project(No.2011ZX05060-005).
文摘The macromolecular structure of tectonically deformed coals(TDC)may be determined by the deformation mechanisms of coal.Alterations of the macromolecular structure change the pore structure of TDC and thereby impact physical properties such as porosity and permeability.This study focuses on structure and properties of TDC from the Huaibei and Huainan coal mining areas of southern North China.Relationships between the macromolecular structure and the pore structure of TDC were analyzed using techniques such as X-ray diffraction,high-resolution transmission electron microcopy,and the low-temperature nitrogen adsorption.The results indicated that the directional stress condition can cause the arrangement of basic structural units(BSU)more serious and closer.And,the orientation is stronger in ductile deformed coal than in brittle deformed coal.Tectonic deformation directly influences the macromolecular structure of coal and consequently results in dynamic metamorphism.Because the size of BSU in brittle deformed coal increases more slowly than in ductile deformed coal,frictional heating and stress-chemistry of shearing areas might play a more important role,locally altering coal structure under stress,in brittle deformed coal.Strain energy is more significant in increasing the ductile deformation of coal.Furthermore,mesopores account for larger percentage of the nano-scale pore volume in brittle deformed coals,while mesopores volume in ductile deformed coal diminishes rapidly along with an increase in the proportion of micropores and sub-micropores.This research also approved that the deformations of macromolecular structures change nano-scale pore structures,which are very important for gas adsorption and pervasion space for gas.Therefore,the exploration and development potential of coal bed methane is promising for reservoirs that are subjected to a certain degree of brittle deformation(such as schistose structure coal,mortar structure coal and cataclastic structure coal).It also holds promise for TDC resulting from wrinkle structure coal of low ductile deformation and later superimposed by brittle deformation.Other kinds of TDC suffering from strong brittle-ductile and ductile deformation,such as scale structure coal and mylonitic structure coal,are difficult problems to resolve.
文摘In this study,NiO/SBA-15 was prepared by both direct and post synthesis methods.TEM images revealed that NiO particles aggregated in NiO/SBA-15 obtained with post synthesis method,regardless of NiO loading.However,NiO particles were monodispersed in NiO/SBA-15 with a NiO loading of less than 15 wt%by using the direct synthesis method.In this case,NiO particles aggregated when NiO loading was over 20 wt%.TPR analysis verified that with direct synthesis method the location boundary of NiO particles on outer and pore surface could be observed clearly,whereas that could not observed in the case of post synthesis method.This indicates that the type of synthesis method displays significant effect on the location of NiO particles dispersed into the SBA-15.Producer gas conversion was carried out using NiO/SBA-15 as catalysts,which were synthesized with different synthesis methods.The gas conversion including methanation occurred at low temperature(i.e.,300-400℃)and the reverse water gas shift(RWGS)reaction at hightemperature(i.e.,400-900℃).High temperatures facilitated CO conversion to CO with CO selectivity close to 100%,regardless of the synthesis method of the used catalyst.At low temperatures the dispersion type of NiO particles affectedthe CO,conversion reaction,i.e.,monodispersed Ni0 particles gave a CO selectivity of close to 100%,similar to thatobtained at high temperature.The aggregated NiO particles resuled in a CO selectivity of less than 100%owing to CH,formation,regardless of synthesis method of catalyst.Therefore,NiO/SBA-15 obtained with direct synthesis methodfavored RWGS reaction because of high CO selectivity.NiOSBA-15 obtained with post synthesis method is suited formethanation because of high CH selectivity,and the conversion of CO,to CHa through methanation increased withincreasing NiO loading.
基金financially supported by the National Natural Science Foundation of China (Grant Nos. 41372213, 41030422)Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA05030100)
文摘The depositional environment of organic-rich shale and the related tectonic evolution in China are rather different from those in North America. In China, organic-rich shale is not only deposited in marine environment, but also in non-marine environment： marine-continental transitional environment and lacustrine environment. Through analyzing large amount of outcrops and well cores, the geologic features of organic-rich shale, including mineral composition, organic matter richness and type, and li- thology stratigraphy, were analyzed, indicating very special characteristics. Meanwhile, the more complex and active tectonic movements in China lead to strong deformation and erosion of organic-rich shale, well-development of fractures and faults, and higher thermal maturity and serious heterogeneity. Co-existence of shale gas, tight sand gas, and coal bed methane （CBM） proposes a new topic： whether it is possible to co-produce these gases to reduce cost. Based on the geologic features, the primary pro- duction issues of shale gas in China were discussed with suggestions.
基金financial supported by National Natural Science Foundation of China(Nos.41372213,41030422)Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA05030100)
文摘The deformation of coal is effected by thermal effect, pressures and tectonic stress, and the tectonic stress is the principal influence factor. However, the proposition of a useful quantitative index that responds to the degree of deformation of coals quantitatively or semi-quantitatively has been a long-debated issue. The vitrinite reflectance ellipsoid, that is, the reflectance indication surface（RIS） ellipsoid is considered to be a strain ellipsoid that reflects the sum of the strain increment caused by stress in the process of coalification. It has been used to describe the degree of deformation of the coal, but the effect of the anisotropy on the RIS ellipsoid has not yet been considered with regards to non-structural factors. In this paper, Wei＇s parameter（ε） is proposed to express the deformation degree of the strain ellipsoid based on considering the combined influence of thermal effect, pressure and tectonic stress. The equation is as follows： ε=√[（ε_1-ε_0）~2＋（ε_2-ε_0）~2＋（ε_3-ε_0）~2]/3, where ε_1=lnR_（max）, ε_2=lnR_（int）, ε_3=lnR_（min）, and ε_0=（ε_1＋ε_2＋ε_3）/3. Wei＇s parameter represents the distance from the surface to the spindle of the RIS logarithm ellipsoid; thus, the degree of deformation of the strain ellipsoid is indicated quantitatively. The formula itself, meanwhile, represents the absolute value of the degree of relative deformation and is consequently suitable for any type of deformation of the strain ellipsoid. Wei＇s parameter makes it possible to compare degrees of deformation among different deformation types of the strain ellipsoid. This equation has been tested in four types of coal： highly metamorphic but weakly deformed coal of the southern Qinshui Basin, highly metamorphic and strongly deformed coal from the Tianhushan coal mining area of Fujian, and medium metamorphic and weakly or strongly deformed coal from the Huaibei Coalfield. The results of Wei＇s parameters are consistent with the actual deformation degrees of the coal reservoirs determined by other methods, which supports the effectiveness of this method. In addition, Wei＇s parameter is an important complement to the indicators of the degrees of deformation of coals, which possess certain theoretical significance and practical values.
基金supported by the National Key Research and Development Program of China(2023YFF0804300)the National Natural Science Foundation of China(42372153 and 41530315)the National Science and Technology Major Project of China(2016ZX05066 and 2017ZX05064).
文摘Decoding the tectono-sedimentary history of the oldest cratons is essential for understanding Earth’s evolution and habitability.Unlike the lithosphere of orogenic belts,which is more easily reactivated and reworked,the lithosphere and sedimentary cover of cratons are relatively stable and thus better reflect the tectono-sedimentary events during Earth’s evolution[1,2].Continental deformation at Earth’s surface is an extremely complex geological process,in which the formation and evolution of sedimentary basins are closely linked to plate motions and mantle activities,representing an intrinsic manifestation of plate-mantle coupling[1,3].The North China Craton,one of the oldest cratons on Earth,is primarily composed of an Archean-Paleoproterozoic crystalline basement and a Mesoproterozoic-Quaternary sedimentary cover[2,4].
基金supported by the National Key Research and Development Program of China(Grant No.2023YFF0804300)the National Natural Science Foundation of China(Grant No.41530315)the National Science and Technology Major Project of China(Grant Nos.2016ZX05066,2017ZX05064)。
文摘Continental deformation on the Earth's surface is an extremely complex geological process,in which the formation and evolution of sedimentary basins are closely related to plate motions and mantle activities.Combining sedimentary basins with orogenic belts and sedimentary responses with tectonic activities can comprehensively elucidate the geological processes during the Earth's evolution.This paper focuses on the multi-stage evolution of the Ordos Basin,the coupled basin-mountain systems and energy resources,discusses the evolution of the Ordos Basin and its coupling relationship with the peripheral tectonic belts,and further reveals the intrinsic connections and influencing factors of the energy resources in the basin.The conclusions are as follows:There are three large sedimentary hiatuses(Neoproterozoic-Early Cambrian,Late Ordovician-Early Carboniferous,and Late Cretaceous-Paleogene)and many small minor sedimentary hiatuses in the Ordos Block,which are mainly related to the tectonic activities,but also affected by the changes of the sea level and the climate.The Ordos Basin is a Meso-Cenozoic superposition basin formed by the contraction and reworking of the remnants of the Paleozoic cratonic basin,and its depositional extent and subsidence center have undergone multi-stage evolution,which was mainly influenced by the subduction of the Paleo-Pacific Plate.Influenced by the multi-directional convergence of peripheral plates in the North China Craton and the transformation of its own deep tectono-thermal regime,many coupled basin-mountain systems were formed with the Ordos Basin and the Yinshan orogenic belt,the Qinling orogenic belt,the Lvliangshan tectonic belt,the Helanshan tectonic belt or the Liupanshan tectonic belt as the core.The formation and enrichment of energy resources in the Ordos Basin are controlled by the tectono-sedimentary response,basin-mountain coupling evolution,and Early Cretaceous tectono-thermal events.All of them were gradually enriched into deposits during the formation,evolution,and reworking of the basin,and have a certain relationship of generation and coexistence,so they should belong to the same reservoir-forming(ore-forming)system.This study not only is helpful for revealing the coupling relationship between peripheral plate motions and internal mantle activities of the North China Craton,but also is of great significance for establishing the Earth's multi-layer coupling model and super energy system.
基金supported by the National Key Research and Development Program of China(Grant No.2023YFF0804300)the National Natural Science Foundation of China(Grant Nos.42372153,41530315)+1 种基金the National Science and Technology Major Project of China(Grant Nos.2016ZX05066,2017ZX05064)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA05030100)。
文摘The generation mechanism and enrichment patterns of shale gas in coal measure in the southern part of the North China Craton hold significant guiding implications for deep energy exploration.Taking the Huaibei mining area in the southern part of the North China Craton as the study object,this study systematically reveals the enrichment mechanism of shale gas in coal measure in the context of the destruction of the North China Craton through basin simulation,rock pyrolysis,and geochemical analyses of magmatic rocks.The results indicate that coal measures of the southern part of the North China Craton mainly developed three episodes of Early Cretaceous magmatism(143-104 Ma)after their formation.Their whole-rock arc-type geochemical signatures,adakitic affinity indicative of subducted slab melting origins,and Sr-Nd isotopic characteristics[(^(87)Sr/^(86)Sr)_(i)=0.707-0.712,ε_(Nd)(t)=−12.63 to−9.18]suggest they were controlled by the retreat of the subducting Western Pacific Plate,consistent with the background of North China Craton destruction.This thermal event caused the regional heat flow to surge to 130 mW m^(−2),significantly accelerating the thermal evolution of the Permian coal measure shales.The vitrinite reflectance(R)of shales in the Shanxi Formation and Lower Shihezi Formation reached 1.10%and 1.33%,respectively,promoting the thermal cracking of heavy oil into light oil and wet gas,forming the main hydrocarbon generation stage for shale gas.However,craton destruction was also accompanied by intense tectonic uplift;the cumulative erosion in the study area exceeded 2000 m.Reduced formation pressure led to the desorption and escape of some gases,highlighting the dual effects of promoting hydrocarbon generation while limiting preservation.Integrating the intensity of structural deformation with the spatiotemporal distribution of magmatic activity,the study proposes that regions with weak structural deformation superimposed with Early Cretaceous magmatic intrusions represent favorable targets for shale gas enrichment.These results elucidate the shale gas accumulation model of“thermal evolution controlling generation and tectonic activity controlling preservation”under craton destruction,providing crucial guidance for shale gas exploration in the North China region and other complex structural areas with similar settings.
