（U-Th）/He dating is a newly developed low temperature thermochronometry, and it elaborately reflects cooling history of geologic body under low temperature. It can be applied to analyze thermal evolution of the sedi...（U-Th）/He dating is a newly developed low temperature thermochronometry, and it elaborately reflects cooling history of geologic body under low temperature. It can be applied to analyze thermal evolution of the sedimentary basin, combining with vitrinite reflectance and fission track. （U-Th）/He dating of apatite and zircon from drilling cores in Puguang （普光）-Maoba （毛坝） area and outcrops in Tongjiang （通江） area indicates that the Northeast Sichuan （四川） basin underwent great uplift and denudation during the Tertiary and the Quaternary. During the period, denudation rates changed from 74.8 to 172.5 m/Ma and denudation thickness was between 2 800 and 3 000 m, geotemperature gradually declined into the current temperature, passing through helium closure temperature of apatite. The uplift and denudation relate to new tectonic movement response in the Sichuan basin aroused by the Qinghai （青海）-Tibet plateau. Drilling samples above 4 000 m did not undergo closure temperature of zircon, but the samples nearly 4 000 m might approach closure temperature of zircon and all the samples underwent closure temperature of apatite. According to （U-Th）/He ages of zircon, it is concluded that the Northeast Sichuan basin began to uplift in the Late Jurassic. From the Late Jurassic to the Paleogene, Northeast Sichuan basin was in slow uplift and denudation, but the denudation of Puguang-Maoba area was earlier than that of Tongjiang area. （U-Th）/He ages of zircon indicate the denudation time of provenance areas. On the basis of paleodrainage characteristics, provenance transport and other related data, provenance areas of the clastie rocks are decided, which is worthy to be investigated further.展开更多
The metamorphism and hydrocarbon generation from the Upper Paleozoic coal-bearing strata in Northern China have been widely studied by Chinese geologists since the 1990s. Based on a large amount of data of Ro values,c...The metamorphism and hydrocarbon generation from the Upper Paleozoic coal-bearing strata in Northern China have been widely studied by Chinese geologists since the 1990s. Based on a large amount of data of Ro values,combined with geological background,we have systematically analyzed the thermal evolutionary characteristics of or-ganic matter and the stages of hydrocarbon generation from the Permo-Carboniferous coal deposits and discussed the condition of secondary hydrocarbon generation. The distribution range of secondary hydrocarbon generation in North-ern China is thus determined. It is shown that the coal ranks of the Upper Paleozoic coal deposits are higher in the southern and western belts than those in the northern and eastern belts. Really significant secondary hydrocarbon gen-eration is mainly related to the thermal evolution of organic matter during the Himalayan Period. Profitable areas for secondary hydrocarbon generation should be buried at 3000-4000 m up to the present. Maturity of the Permo-Carbon-iferous source rocks is not very high. It is suggested that the Bohai Bay depression is favourable for secondary hydro-carbon generation and has good oil and gas prospects.展开更多
Thermal diffusivity(D)and thermal conductivity(κ)of harzburgite and dunite from Luobusha ophiolite were simultaneously measured up to 3 GPa and 823 K using the transient plane-source method in a multi anvil apparatus...Thermal diffusivity(D)and thermal conductivity(κ)of harzburgite and dunite from Luobusha ophiolite were simultaneously measured up to 3 GPa and 823 K using the transient plane-source method in a multi anvil apparatus.The results show that the values of D andκof both samples systematically decrease with increasing temperature and increase with increasing pressure.By combination of the thermal physical data of rocks and minerals and geophysical constraints,we performed numerical simulation on the thermal evolution of Tibet vary over depth,distance and geologic ages.The present results provide new constraints on occurrence of partial melting and its geophysical significance beneath Tibetan crust.展开更多
The Tianshan orogenic belt is a major part of the southern Central Asian Orogenic Belt（CAOB）,extending from west to east for over 2500 km through Uzbekistan,Tajikistan,Kyrgyzstan and Kazakhstan to Xinjiang in NW Chi...The Tianshan orogenic belt is a major part of the southern Central Asian Orogenic Belt（CAOB）,extending from west to east for over 2500 km through Uzbekistan,Tajikistan,Kyrgyzstan and Kazakhstan to Xinjiang in NW China,and contains the record of multi-phase tectonothermal evolution.Till now.展开更多
Abstract: Thermochronological dating was used to study the thermal evolution of the Mesozoic plutons and uplift history of the Yanshan orogenic belt. The results show that the cooling history of the plutons is complic...Abstract: Thermochronological dating was used to study the thermal evolution of the Mesozoic plutons and uplift history of the Yanshan orogenic belt. The results show that the cooling history of the plutons is complicated, corresponding to the inhomogeneous uplift process of the Yanshan orogenic belt. The Panshan granite cooled fast during 226.48–204.95 Ma at a rate of 10.22°C/Ma after its emplacement at a depth of about 10 km, and its fast uplift occurred in about 96–35 Ma at an average rate of 0.115 mm/a. The Wulingshan pluton cooled fast during 132–127.23 Ma at a rate of 94.34°C/Ma, and its rapid uplift occurred in 86–45 Ma at an average rate of 0.186 mm/a. The Yunmengshan granite cooled fast during 143–120.99 Ma at a rate of 19.51°C/Ma, and its rapid uplift occurred in 106–103.95 Ma and 20–0.0 Ma at a rate of 1.06 mm/a and 0.15 mm/a respectively. The Sihetang granite-gneiss uplifted rapidly since 13 Ma at an average rate of 0.256 mm/a. The Badaling granite uplifted rapidly since 6 Ma at an average rate of 0.556 mm/a. The Cenozoic uplift of the Yanshan Mountains can be well correlated to the rifting process of the surrounding basins.展开更多
Chuxiong Basin in Yunnan is a typical Mesozoic foreland basin which is enriched in widely distributed Triassic coal resources with thick deposits and of important strategic significance. By applying vitrinite reflecta...Chuxiong Basin in Yunnan is a typical Mesozoic foreland basin which is enriched in widely distributed Triassic coal resources with thick deposits and of important strategic significance. By applying vitrinite reflectance measurement, inclusion thermometry, fission track dating and EASY% Ro numerical simulation, the Triassic coal thermal evolution history of the Chuxiong Basin was analyzed, and the results were concluded. The vitrinite reflectance of Chuxiong Basin is higher in the west and south in general.Vertically, in the east, west, and north of the basin, the vitrinite reflectance increases with increasing depth, and in the northern part, exceptionally high values occur, and there is no significant regularity in the east. The formation of inclusions inside quartz veins in Chuxiong Basin Triassic coal are unrelated with magmatic hydrothermal fluid, and there are multi-phase inclusions formed in three or four sections of tectonic movements. The main heating period(apparent age) of the Triassic coal is concentrated in the late Cenozoic, during which the coal was subjected to repeated thermal disturbance, resulting in a multimodal distribution of the fission track data, which reveals mild burial features of the early stages of the Late Cenozoic. The Triassic coal of Chuxiong Basin has experienced two major temperature increasing processes, which occurred in the early-mid Yanshan and the early Himalayan, respectively. The first hydrocarbon generation period of coal organic matter occurred in the formation stage of the foreland basin, during which the south and west of the basin generated large amounts of hydrocarbon, but little was preserved. The second generation stage in the Early Himalayan had conditions suitable for high gas accumulation, especially in the western and southern regions. The upper Triassic coal is of moderate burial depth and is less affected by the strike-slip effect. There are key areas of Chuxiong Basin oil and gas exploration, such as the Yanfeng Basin in the north-central, Yongren and Yunlong areas.展开更多
Reconstructing the thermal evolution of the eastern Qaidam Basin is important for gaining a deeper understanding of its lithospheric geodynamics and for more accurate hydrocarbon evaluation and prediction.This article...Reconstructing the thermal evolution of the eastern Qaidam Basin is important for gaining a deeper understanding of its lithospheric geodynamics and for more accurate hydrocarbon evaluation and prediction.This article presents a set of new apatite and zircon(U-Th)/He thermochronological ages.Combined with 336 vitrinite reflectance(R_(o))data,the thermal history of the Ouanan Sag in the eastern Qaidam Basin has been reconstructed using inversion models.Three detrital samples from the Ounan Sag shows that the apatite(U-Th)/He ages are primarily concentrated in the range of 17.0 Ma to 76.5 Ma and that the zircon(U-Th)/He ages range from 200 Ma to 289.3 Ma.The time-temperature models demonstrate that the Ounan Sag experienced rapid subsidence and heating from the Carboniferous to late Permian,and exhumation/cooling events from the end of Permian to the Triassic.This thermal evolution was influenced by the widespread intrusion of plutons,and the collision and orogenesis caused by asthenosphere upwelling below the Qaidam arc,and slab rollback of the Southern Kunlun oceanic lithosphere,respectively.Additionally,our models depict the main exhumation/cooling stages since the Paleogene and a reheating event in the Miocene as a result of the intensifying growth of the Qinghai-Tibet Plateau and local sedimentary loading,followed by the initial India-Eurasia collision.Furthermore,the eastern Qaidam Basin experienced consistent heating during the late Paleozoic,reaching the maximum paleotemperature and geothermal gradient in the late Permian,with values of~230℃and~43-44℃/km,respectively.This study suggests that the source rocks in the most upper member of upper Carboniferous Keluke(C_(2)k)Formations in the Ounan Sag reached the gas generation stage in the late Permian.展开更多
The Liwan Sag, with an area of 4 000 km-2, is one of the deepwater sags in the Zhujiang River（Pearl River） Mouth Basin, northern South China Sea. Inspired by the exploration success in oil and gas resources in the d...The Liwan Sag, with an area of 4 000 km-2, is one of the deepwater sags in the Zhujiang River（Pearl River） Mouth Basin, northern South China Sea. Inspired by the exploration success in oil and gas resources in the deepwater sags worldwide, we conducted the thermal modeling to investigate the tectono-thermal history of the Liwan Sag,which has been widely thought to be important to understand tectonic activities as well as hydrocarbon potential of a basin. Using the multi-stage finite stretching model, the tectonic subsidence history and the thermal history have been obtained for 12 artificial wells, which were constructed on basis of one seismic profile newly acquired in the study area. Two stages of rifting during the time periods of 49–33.9 Ma and 33.9–23 Ma can be recognized from the tectonic subsidence pattern, and there are two phases of heating processes corresponding to the rifting.The reconstructed average basal paleo-heat flow values at the end of the rifting events are -70.5 and -94.2 mW/m^2 respectively. Following the heating periods, the study area has undergone a persistent thermal attenuation phase since 23 Ma and the basal heat flow cooled down to -71.8–82.5 mW/m^2 at present.展开更多
Deep and ultra-deep layers in the petroliferous basins of China are characterized by large temperature difference and complicated thermal evolution history.The control effects of temperature and thermal evolution hist...Deep and ultra-deep layers in the petroliferous basins of China are characterized by large temperature difference and complicated thermal evolution history.The control effects of temperature and thermal evolution history on the differences of hydrocarbon phase states and the hydrocarbon generation history in deep and ultra-deep layers are researched less and unsystematically.To deal with this situation,based on a large number of temperature and pressure data of deeplayers and combined with the complicated historical situation of deep layer evolution in the oil and gas basins of China,the effects of temperature,heating time and pressure on the hydrocarbon formation temperature and phase state were analyzed,and the types of temperature and pressure relationships were classified.Finally,based on the classification of thermal evolution history of deep and ultra-deep layers,We discussed the control effects of basin thermal evolution history on the hydrocarbon generation and phase state,and the following research results were obtained.First,the hydrocarbon phase states of deep layers in different basins and regions are greatly different,and they are mainly affected by temperature,heating time,heating rate,pressure,source rock types and other factors.And temperature is the most important factor controlling hydrocarbon generation and phase state distribution.Second,under the conditions of rapid temperature increasing and short heating time,there still maybe oil reservoirs and condensate gas reservoirs in deep and ultra-deep layersin thecase ofhigh temperature.Third,overpressureinhibitshydrocarbon generationand pyrolysis.Fourth,thereis a closerelationship betweentemperature and formation pressure of deeplayers,whichcan be divided into three types,i.e.,lowemedium temperature and high pressure type,high temperature and high pressure type,and medium temperature and lowemedium pressure type.Fifth,the thermal evolution history of deep and ultra-deep layers can be divided into four types,namely the late rapid subsidence,heating and low geothermal gradient type,the late rapid subsidence,heating and high geothermal gradient type,the middleelate rapid heating and late uplifting and cooling type,and the early great subsidence and rapid heating and middleelate great uplift erosion and cooling type.In conclusion,deep and ultra-deep layers in the basins with different types of thermal history are different in hydrocarbon phase states,accumulation stages and prospects.展开更多
The Earth’s core is composed of iron,nickel,and a small amount of light elements(e.g.,Si,S,O,C,N,H and P).The thermal conductivities of these components dominate the adiabatic heat flow in the core,which is highly co...The Earth’s core is composed of iron,nickel,and a small amount of light elements(e.g.,Si,S,O,C,N,H and P).The thermal conductivities of these components dominate the adiabatic heat flow in the core,which is highly correlated to geodynamo.Here we review a large number of studies on the electrical and thermal conductivity of iron and iron alloys and discuss their implications on the thermal evolution of the Earth’s core.In summary,we suggest that the Wiedemann-Franz law,commonly used to convert the electrical resistivity to thermal conductivity for metals and alloys,should be cautiously applied under extremely high pressure-temperature(P-T)conditions(e.g.,Earth’s core)because the Lorentz number may be P-T dependent.To date,the discrepancy in the thermal conductivity of iron and iron alloys remains between those from the resistivity measurements and the thermal diffusivity modeling,where the former is systematically larger.Recent studies reconcile the electrical resistivity by first-principles calculation and direct measurements,and this is a good start in resolving this discrepancy.Due to an overall higher thermal conductivity than previously thought,the inner core age is presently constrained at~1.0 Ga.However,light elements in the core would likely lower the thermal conductivity and prolong the crystallization of the inner core.Meanwhile,whether thermal convection can power the dynamo before the inner core formation depends on the amounts of the proper light elements in the core.More works are needed to establish the thermal evolution model of the core.展开更多
By means of the vitrinite reflectance and U-Th/He dating of apatite and zircon in cut- ting samples from the T3x-K1j formations in the Yuanba （元坝） area of Northeast Sichuan （四川） Basin, a correlation has been e...By means of the vitrinite reflectance and U-Th/He dating of apatite and zircon in cut- ting samples from the T3x-K1j formations in the Yuanba （元坝） area of Northeast Sichuan （四川） Basin, a correlation has been established between the He-derived age and depth/temperature in this area assuming helium closure temperature of apatite in this area being 95 ℃. Mesozoic strata （T3x-Kd＇） experienced helium closure temperature of apatite approaching 95 ℃, but didn＇t reach the helium closure temperature of zircon （ca. 170-190 ℃） although some reached the highest pa- laeogeothermal temperature of about 170 ℃. The Mesozoic strata in the Yuanba area experienced an important uplift and denudation during Paleogene-Neogene periods （0.2-36.4 Ma）, the erosion rate being about 109.9 m/Ma. The K1] Formation and overlying strata experienced a maximum de- nudation loss of about 4 000 m. Geotemperatures gradually fell to the helium closure temperature of apatite and then fell further to the current temperature. The thermal evolution history of this area indicates that the maximum palaeogeothermal temperature of Mesozoic strata was close to 170- 190 ℃, prior to the strata being uplifted. During the period between 176 and 36 Ma, the palaeogeo- thermal temperature fell to 95-170 ℃. and after 36 Ma, it continued to fall to the present geotem- perature of less than 95 ℃.展开更多
The Fukushima nuclear accident in Japan on March 11,2011,produced large amounts of Cs-polluted soil which must be controlled to prevent the spread of hazardous Cs into the environment.In this paper,the effects of heat...The Fukushima nuclear accident in Japan on March 11,2011,produced large amounts of Cs-polluted soil which must be controlled to prevent the spread of hazardous Cs into the environment.In this paper,the effects of heat treatment on the structure and properties of Cs-containing glass-ceramics,as a simulated nuclear waste form,were systematically investigated.Cesium atoms are chemically bonded in the pollucite structure,and the amorphous phase further encapsulates the pollucite crystals in the glassceramics,thus providing an extra protective layer for the immobilized Cs.XRD analysis,Raman and FT-IR studies on the glass-ceramics synergistically indicated that the optimum crystallization temperature for pollucite is around 1000℃.The pollucite is predominantly the main crystalline phase with a narrow crystal size distribution between 0.5 and 2 mm.Standard leaching test results show that the leaching rate of Cs was very low(3.0×10^(-3) g/(m^(2)·d)).The study offers a practical method for immobilizing Cs in pollucite-base glass-ceramics.Moreover,the experimentally obtained data may provide some important references for converting Cs-polluted soil into pollucite-base glass-ceramics waste form.展开更多
Pulsars are rapidly spinning, strongly magnetized neutron stars. Their electromagnetic dipole radiation is usually assumed to be at the expense of the rotational energy. In this work, we consider a new channel through...Pulsars are rapidly spinning, strongly magnetized neutron stars. Their electromagnetic dipole radiation is usually assumed to be at the expense of the rotational energy. In this work, we consider a new channel through which rotational energy could be radiated away directly via neutrinos. With this new energy conversion channel, we can improve the chemical heating mechanism that originates in the deviation from β equilibrium due to spin-down compression. The improved chemical and thermal evolution equations with different magnetic field strengths are solved numerically. The results show that the new energy conversion channel could raise the surface temperature of neutron stars, especially for weak field stars at later stages of their evolution. Moreover, our results indicate that the new energy conversion channel induced by the non-equilibrium reaction processes should be taken into account in the study of thermal evolution.展开更多
The interaction of hydrogen with interface between the precipitates and the martensitie matrix in 18Ni maraging steel has been studied by means of thermal evolution hydrogen technique us- ing gas chromatograph as hydr...The interaction of hydrogen with interface between the precipitates and the martensitie matrix in 18Ni maraging steel has been studied by means of thermal evolution hydrogen technique us- ing gas chromatograph as hydrogen detector.An evolution rate peak has been observed at 451 K.The height of the peak relates to the amount and distribution of the precipitates.The activation energy for hydrogen escaping from the trap sites is 23.2 kJ/mol.展开更多
The conventional biomarkers are limited due to the extremely high thermal stresses in ultra-deep hydrocarbon reservoirs.The diamondoid with cage structure has excellent thermal stability and is an effective tool for c...The conventional biomarkers are limited due to the extremely high thermal stresses in ultra-deep hydrocarbon reservoirs.The diamondoid with cage structure has excellent thermal stability and is an effective tool for characterizing the ultra-deep hydrocarbon and linking its source.We investigated the distribution of diamondoids in ultra-deep reservoirs including black oils,volatile oils,and condensates.The source-related diamondoids indicate that crude oils are mainly sourced from marine siliceous shale.The bulk characteristics(e.g.color,density,Sat/Aro)of crude oils reveal the variations of thermal maturity:low maturity for black oils,moderate maturity for volatile oils,and high maturity for condensates.Based on regular variations in the thermal maturity of crude oils,the thermal evolution of diamondoids is characterized.The abundance of C_(1)-and C_(2)-alkylated diamantanes increases with increasing maturity,and hydrothermal activity may lead to an abnormal increase in the percentage of C_(3)-alkylated adamantanes.Despite the higher thermal stability of 4-methyldiamantane(4-MD),a more sensitive change in relative abundance with maturity for 1-methyldiamantane(1-MD)among all methyldiamantanes(MDs)is observed.Ethyl diamondoids are thermally less stable and their derived indices can effectively indicate the thermal maturity of ultra-deep hydrocarbons.The applications of commonly maturity-related indices should be cautious(e.g.MDI),whereas the novel methyl-ethyl diamantane index(MEDI)is highly recommended.The combination of high MAI values and low MEDI values most likely reflects the influence of late-charged light hydrocarbons.Overall,multiple charging and in-reservoir mixing of light hydrocarbons and oils with various maturities constrained the present phase states of ultra-deep oil reservoirs.This study gives a new perspective to understanding the fate of molecular evolution and phase states of hydrocarbons in the ultra-deep basins.展开更多
The Xihu Depression,situated in the northeastern East China Sea Basin,represents the most significant natural gas-producing region in Eastern China.An insufficient understanding of reservoir heterogeneity in petroleum...The Xihu Depression,situated in the northeastern East China Sea Basin,represents the most significant natural gas-producing region in Eastern China.An insufficient understanding of reservoir heterogeneity in petroleum geological conditions―particularly within structural zones beyond the well-explored Pinghu Slope and Ningbo Anticline Belt―has hindered comprehensive hydrocarbon exploration across the sag.Critical knowledge gaps persist in characterizing the geothermal field,reconstructing thermal evolution histories,and constraining hydrocarbon generation phases.These limitations directly impede systematic evaluations of basin selection criteria,reservoir delineation,and their dynamic relationships within petroleum systems.This study analyzes the present geothermal gradient at a unified depth(4000-5000 m),the geothermal heat flow,the geothermal temperature at a unified depth(3000-6000 m),and the plan distribution characteristics of the geothermal temperatures of the exploration strata in the key study area in the Xihu Depression―the Western Slope and the Central Anticlinal Belt.The research in this study is based on present bottom-hole temperature measurements and temperature data for testing for oil,using a one-dimensional steady-state heat conduction equation and the Bullard method.The results indicate that the present geothermal gradient in the Xihu Depression,between a unified depth of 4000 m and 5000 m,ranges from 16.7◦C/km to 44.6℃/km,with an average of 30.6℃/km.The present geothermal heat flow is between 32.23 mW/m^(2)and 90.13 mW/m^(2),with an average of 52.03 mW/m^(2),indicating a typical cold basin.The formation temperature gradually increases with burial depth,from 3000 m to 6000 m.In the plane,the formation temperature gradually increases from the south to the north and from the edge of the depression to the center of the depression.The burial history and thermal evolution of the key plays of the Xihu Depression were reconstructed using apatite fission tracks and zircon U-Th/He data,combined with vitrinite reflectance,which revealed that the tectonic uplift that occurred during the Late Miocene Longjing Movement was a critical event in trap formation and hydrocarbon filling.The thermal-hydrocarbon generation history indicates that the Xihu Depression has mostly entered a high maturity stage,with gas condensate and condensate charging occurring between 16.4 Ma and 13 Ma and natural gas filling occurring at 5.3 Ma up to now.Hydrocarbon generation and expulsion in the Xihu Depression occurred early in the north and late in the south,with two stages in the north and one stage in the south.A study of the burial history-thermal history-hydrocarbon generation history based on the reconstruction of geothermal fields demonstrates the matching relationship between hydrocarbon generation,distribution,and accumulation in the Xihu Depression―an understanding that is vital for oil and gas exploration in the Xihu Depression.展开更多
Greenstone basalts and komatiites provide a means to track both mantle composition and magma generation temperature with time. Four types of mantle are characterized from incompatible element distributions in basalts ...Greenstone basalts and komatiites provide a means to track both mantle composition and magma generation temperature with time. Four types of mantle are characterized from incompatible element distributions in basalts and komatiites： depleted, hydrated, enriched and mantle from which komatiites are derived. Our most important observation is the recognition for the first time of what we refer to as a Great Thermal Divergence within the mantle beginning near the end of the Archean, which we ascribe to thermal and convective evolution. Prior to 2.5 Ga, depleted and enriched mantle have indistinguishable thermal histories, whereas at 2.5-2.0 Ga a divergence in mantle magma generation temperature begins between these two types of mantle. Major and incompatible element distributions and calculated magma generation temperatures suggest that Archean enriched mantle did not come from mantle plumes, but was part of an undifferentiated or well-mixed mantle similar in composition to calculated primitive mantle. During this time, however, high-temperature mantle plumes from dominantly depleted sources gave rise to komatiites and associated basalts. Recycling of oceanic crust into the deep mantle after the Archean may have contributed to enrichment ofTi, A1, Ca and Na in basalts derived from enriched mantle sources. After 2.5 Ga, increases in Mg# in basalts from depleted mantle and decreases in Fe and Mn reflect some combination of growing depletion and cooling of depleted mantle with time. A delay in cooling of depleted mantle until after the Archean probably reflects a combination of greater radiogenic heat sources in the Archean mantle and the propagation of plate tectonics after 3 Ga.展开更多
Here,the geological factors controlling deep geothermal anomalies in mines were studied based on the geotemperature,lithologic thermal conductivity,and related geological data collected from the Qianjiaying Mine,China...Here,the geological factors controlling deep geothermal anomalies in mines were studied based on the geotemperature,lithologic thermal conductivity,and related geological data collected from the Qianjiaying Mine,China.A simulation of the change in magma waste heat,conducted using the ANSYS Workbench,revealed the distribution characteristics of geothermal anomalies in this mine and the corresponding geological control factors.The results revealed the following points.(1)First-degree heat hazard level(temperature=31-37℃)occurred in the central and southwestern parts of the mine at an^600-m depth,while second-degree heat hazard level(temperature≥37℃)occurred at an^800-m depth.The geotemperature and geothermal gradient in the southwestern part of the mine were anomalously high.(2)The geotemperatures measured in the mine generally reflected a standard increase with depth,while the geothermal gradient remained unchanged with depth.The geothermal gradient and its average value in the study area were 0.70-4.23 and 2.12C·hm^-1,respectively.(3)A combination of stratum characteristics,geological structure,and groundwater characteristics led to geothermal anomalies in mines;additionally,the waste heat from magma had no significant effect on the geothermal field.展开更多
The thermal effect caused by deep magma intrusion can not only accelerate the metamorphism of coal body,but also bring additional thermal field that changes the mechanical environment of coal seams,thereby affecting t...The thermal effect caused by deep magma intrusion can not only accelerate the metamorphism of coal body,but also bring additional thermal field that changes the mechanical environment of coal seams,thereby affecting the permeability of coal seams.Different from shallow coal resources,deep coal resources are in a mechanical environment characterized by limited stress and strain.Thus,the thermal effect has a more significant influence on the distribution and permeability characteristics of deep coal seams.In this study,the evolution history of highly metamorphic coal seams in Yangquan mining area was analyzed,and the main effect of magmatic activity on coal seams was obtained.Based on the determined vitrinite reflectance data of typical mines in Yangquan mining area,the maximum paleotemperature was calculated by adopting the Barker’s method.Furthermore,the paleotemperature distribution in Yangquan mining area was summarized,and its relationship with the metamorphic degree was acquired.Then,a new permeability model considering the thermal strain was proposed to analyze the permeability evolution in deep coal seams at different ground temperatures.Finally,through a combination of the results of gas pressure and outburst number in Sijiazhuang Mine,Yangquan No.5 Mine and Xinjing Mine,the influence of ground temperature on the gas outburst risk in Yangquan mining area was explored.The following conclusions were drawn:The maximum paleotemperature in Yangquan area can be 303C.In addition,the paleotemperature in the south is higher than that in the north of Yangquan mining area.The various temperatures at different depths bring about different degrees of thermal stress to different coal seams,leading to different strains.Under the fixed displacement boundary conditions in the deep,the coal seam folds and bends to varying degrees.Moreover,the difference in the ground temperature raises the a value of coal seams and lowers the permeability,which promotes the formation of gas-rich zones and increases the risk of coal seam outburst.The research results can help mines to make proper gas disaster prevention plan for different zones.展开更多
In shale reservoirs,the organic pores with various structures formed during the thermal evolution of organic matter are the main storage site for adsorbed methane.However,in the process of thermal evolution,the adsorp...In shale reservoirs,the organic pores with various structures formed during the thermal evolution of organic matter are the main storage site for adsorbed methane.However,in the process of thermal evolution,the adsorption characteristics of methane in multi type and multi-scale organic matter pores have not been sufficiently studied.In this study,the molecular simulation method was used to study the adsorption characteristics of methane based on the geological conditions of Longmaxi Formation shale reservoir in Sichuan Basin,China.The results show that the characteristics of pore structure will affect the methane adsorption characteristics.The adsorption capacity of slit-pores for methane is much higher than that of cylindrical pores.The groove space inside the pore will change the density distribution of methane molecules in the pore,greatly improve the adsorption capacity of the pore,and increase the pressure sensitivity of the adsorption process.Although the variation of methane adsorption characteristics of different shapes is not consistent with pore size,all pores have the strongest methane adsorption capacity when the pore size is about 2 nm.In addition,the changes of temperature and pressure during the thermal evolution are also important factors to control the methane adsorption characteristics.The pore adsorption capacity first increases and then decreases with the increase of pressure,and increases with the increase of temperature.In the early stage of thermal evolution,pore adsorption capacity is strong and pressure sensitivity is weak;while in the late stage,it is on the contrary.展开更多
基金supported by the National Basic Research Pro-gram of China (No. 2005CB422102)China Petroleum and Chemical Corporation Program (P06083)
文摘（U-Th）/He dating is a newly developed low temperature thermochronometry, and it elaborately reflects cooling history of geologic body under low temperature. It can be applied to analyze thermal evolution of the sedimentary basin, combining with vitrinite reflectance and fission track. （U-Th）/He dating of apatite and zircon from drilling cores in Puguang （普光）-Maoba （毛坝） area and outcrops in Tongjiang （通江） area indicates that the Northeast Sichuan （四川） basin underwent great uplift and denudation during the Tertiary and the Quaternary. During the period, denudation rates changed from 74.8 to 172.5 m/Ma and denudation thickness was between 2 800 and 3 000 m, geotemperature gradually declined into the current temperature, passing through helium closure temperature of apatite. The uplift and denudation relate to new tectonic movement response in the Sichuan basin aroused by the Qinghai （青海）-Tibet plateau. Drilling samples above 4 000 m did not undergo closure temperature of zircon, but the samples nearly 4 000 m might approach closure temperature of zircon and all the samples underwent closure temperature of apatite. According to （U-Th）/He ages of zircon, it is concluded that the Northeast Sichuan basin began to uplift in the Late Jurassic. From the Late Jurassic to the Paleogene, Northeast Sichuan basin was in slow uplift and denudation, but the denudation of Puguang-Maoba area was earlier than that of Tongjiang area. （U-Th）/He ages of zircon indicate the denudation time of provenance areas. On the basis of paleodrainage characteristics, provenance transport and other related data, provenance areas of the clastie rocks are decided, which is worthy to be investigated further.
基金Projects 40572085 supported by the National Natural Science Foundation of ChinaNCET-06 by the New-Century Excellent Talent Program of the Min- istry of Education
文摘The metamorphism and hydrocarbon generation from the Upper Paleozoic coal-bearing strata in Northern China have been widely studied by Chinese geologists since the 1990s. Based on a large amount of data of Ro values,combined with geological background,we have systematically analyzed the thermal evolutionary characteristics of or-ganic matter and the stages of hydrocarbon generation from the Permo-Carboniferous coal deposits and discussed the condition of secondary hydrocarbon generation. The distribution range of secondary hydrocarbon generation in North-ern China is thus determined. It is shown that the coal ranks of the Upper Paleozoic coal deposits are higher in the southern and western belts than those in the northern and eastern belts. Really significant secondary hydrocarbon gen-eration is mainly related to the thermal evolution of organic matter during the Himalayan Period. Profitable areas for secondary hydrocarbon generation should be buried at 3000-4000 m up to the present. Maturity of the Permo-Carbon-iferous source rocks is not very high. It is suggested that the Bohai Bay depression is favourable for secondary hydro-carbon generation and has good oil and gas prospects.
基金Key Research Program of Frontier Sciences of CAS(ZDBS-LY-DQC015)National Natural Science Foundation of China(Nos.41973056,41773056,41303048)Science Foundation of Guizhou Province(2017-1196,2018-1176).
文摘Thermal diffusivity(D)and thermal conductivity(κ)of harzburgite and dunite from Luobusha ophiolite were simultaneously measured up to 3 GPa and 823 K using the transient plane-source method in a multi anvil apparatus.The results show that the values of D andκof both samples systematically decrease with increasing temperature and increase with increasing pressure.By combination of the thermal physical data of rocks and minerals and geophysical constraints,we performed numerical simulation on the thermal evolution of Tibet vary over depth,distance and geologic ages.The present results provide new constraints on occurrence of partial melting and its geophysical significance beneath Tibetan crust.
基金supported by the Major Basic Research Project of the Ministry of Science and Technology of China(Grant No.2014CB448000)National Science Foundation of China(Grant Nos..41473053 and 41573045)a grant of Chinese Ministry of Land and Resources(Grant No.201211074–05)
文摘The Tianshan orogenic belt is a major part of the southern Central Asian Orogenic Belt（CAOB）,extending from west to east for over 2500 km through Uzbekistan,Tajikistan,Kyrgyzstan and Kazakhstan to Xinjiang in NW China,and contains the record of multi-phase tectonothermal evolution.Till now.
文摘Abstract: Thermochronological dating was used to study the thermal evolution of the Mesozoic plutons and uplift history of the Yanshan orogenic belt. The results show that the cooling history of the plutons is complicated, corresponding to the inhomogeneous uplift process of the Yanshan orogenic belt. The Panshan granite cooled fast during 226.48–204.95 Ma at a rate of 10.22°C/Ma after its emplacement at a depth of about 10 km, and its fast uplift occurred in about 96–35 Ma at an average rate of 0.115 mm/a. The Wulingshan pluton cooled fast during 132–127.23 Ma at a rate of 94.34°C/Ma, and its rapid uplift occurred in 86–45 Ma at an average rate of 0.186 mm/a. The Yunmengshan granite cooled fast during 143–120.99 Ma at a rate of 19.51°C/Ma, and its rapid uplift occurred in 106–103.95 Ma and 20–0.0 Ma at a rate of 1.06 mm/a and 0.15 mm/a respectively. The Sihetang granite-gneiss uplifted rapidly since 13 Ma at an average rate of 0.256 mm/a. The Badaling granite uplifted rapidly since 6 Ma at an average rate of 0.556 mm/a. The Cenozoic uplift of the Yanshan Mountains can be well correlated to the rifting process of the surrounding basins.
基金support of the Fundamental Research Funds for the Central Universities (No. 2015XKZD07) of Chinathe Foundation Research Project of Jiangsu province (Youth Fund Project) of China (No. BK20150179)A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions of China (PAPD)
文摘Chuxiong Basin in Yunnan is a typical Mesozoic foreland basin which is enriched in widely distributed Triassic coal resources with thick deposits and of important strategic significance. By applying vitrinite reflectance measurement, inclusion thermometry, fission track dating and EASY% Ro numerical simulation, the Triassic coal thermal evolution history of the Chuxiong Basin was analyzed, and the results were concluded. The vitrinite reflectance of Chuxiong Basin is higher in the west and south in general.Vertically, in the east, west, and north of the basin, the vitrinite reflectance increases with increasing depth, and in the northern part, exceptionally high values occur, and there is no significant regularity in the east. The formation of inclusions inside quartz veins in Chuxiong Basin Triassic coal are unrelated with magmatic hydrothermal fluid, and there are multi-phase inclusions formed in three or four sections of tectonic movements. The main heating period(apparent age) of the Triassic coal is concentrated in the late Cenozoic, during which the coal was subjected to repeated thermal disturbance, resulting in a multimodal distribution of the fission track data, which reveals mild burial features of the early stages of the Late Cenozoic. The Triassic coal of Chuxiong Basin has experienced two major temperature increasing processes, which occurred in the early-mid Yanshan and the early Himalayan, respectively. The first hydrocarbon generation period of coal organic matter occurred in the formation stage of the foreland basin, during which the south and west of the basin generated large amounts of hydrocarbon, but little was preserved. The second generation stage in the Early Himalayan had conditions suitable for high gas accumulation, especially in the western and southern regions. The upper Triassic coal is of moderate burial depth and is less affected by the strike-slip effect. There are key areas of Chuxiong Basin oil and gas exploration, such as the Yanfeng Basin in the north-central, Yongren and Yunlong areas.
基金financially supported by grants from the Geological Survey Projects of China Geological Survey(grant nos.20242065,20230260)the Fundamental Research Fund of Chinese Academy of Geological Sciences(grant no.JKYQN202342)the National Natural Science Foundation of China(grant no.41772272)。
文摘Reconstructing the thermal evolution of the eastern Qaidam Basin is important for gaining a deeper understanding of its lithospheric geodynamics and for more accurate hydrocarbon evaluation and prediction.This article presents a set of new apatite and zircon(U-Th)/He thermochronological ages.Combined with 336 vitrinite reflectance(R_(o))data,the thermal history of the Ouanan Sag in the eastern Qaidam Basin has been reconstructed using inversion models.Three detrital samples from the Ounan Sag shows that the apatite(U-Th)/He ages are primarily concentrated in the range of 17.0 Ma to 76.5 Ma and that the zircon(U-Th)/He ages range from 200 Ma to 289.3 Ma.The time-temperature models demonstrate that the Ounan Sag experienced rapid subsidence and heating from the Carboniferous to late Permian,and exhumation/cooling events from the end of Permian to the Triassic.This thermal evolution was influenced by the widespread intrusion of plutons,and the collision and orogenesis caused by asthenosphere upwelling below the Qaidam arc,and slab rollback of the Southern Kunlun oceanic lithosphere,respectively.Additionally,our models depict the main exhumation/cooling stages since the Paleogene and a reheating event in the Miocene as a result of the intensifying growth of the Qinghai-Tibet Plateau and local sedimentary loading,followed by the initial India-Eurasia collision.Furthermore,the eastern Qaidam Basin experienced consistent heating during the late Paleozoic,reaching the maximum paleotemperature and geothermal gradient in the late Permian,with values of~230℃and~43-44℃/km,respectively.This study suggests that the source rocks in the most upper member of upper Carboniferous Keluke(C_(2)k)Formations in the Ounan Sag reached the gas generation stage in the late Permian.
基金The Program of the Key Technologies for Petroleum Exploration in Deep Oceanic Areas under contract No.2011ZX05025-006-05the Chinese Postdoc Fund,No.58 General Fund,2015 under contract No.2015M582636the National Natural Science Foundation of China under contract No.41602251
文摘The Liwan Sag, with an area of 4 000 km-2, is one of the deepwater sags in the Zhujiang River（Pearl River） Mouth Basin, northern South China Sea. Inspired by the exploration success in oil and gas resources in the deepwater sags worldwide, we conducted the thermal modeling to investigate the tectono-thermal history of the Liwan Sag,which has been widely thought to be important to understand tectonic activities as well as hydrocarbon potential of a basin. Using the multi-stage finite stretching model, the tectonic subsidence history and the thermal history have been obtained for 12 artificial wells, which were constructed on basis of one seismic profile newly acquired in the study area. Two stages of rifting during the time periods of 49–33.9 Ma and 33.9–23 Ma can be recognized from the tectonic subsidence pattern, and there are two phases of heating processes corresponding to the rifting.The reconstructed average basal paleo-heat flow values at the end of the rifting events are -70.5 and -94.2 mW/m^2 respectively. Following the heating periods, the study area has undergone a persistent thermal attenuation phase since 23 Ma and the basal heat flow cooled down to -71.8–82.5 mW/m^2 at present.
基金supported by the National Key Rescarch and Development Program of China"Accumulation patem and exploration direction of ultra-deep and middle Ncoprotierozoic oil and gas"(No.2017YFC0603106)Key Project of Natural Science Foundation of China"Constraints of hate Mesoznic palcogoothermal fiekd on litho sphenic dynamic evolution andoil and gas occ urrence inOrdosand Qinshui sedimentary basins"(No.41630312)MajorNational Science and Technology Project of the 13th FYP"Structural evolution and preservation conditions of the southwest of Ordos Basin in the middle-upper Proterozoic and lower Palcozoic"(No.2017ZX05005-002-008).
文摘Deep and ultra-deep layers in the petroliferous basins of China are characterized by large temperature difference and complicated thermal evolution history.The control effects of temperature and thermal evolution history on the differences of hydrocarbon phase states and the hydrocarbon generation history in deep and ultra-deep layers are researched less and unsystematically.To deal with this situation,based on a large number of temperature and pressure data of deeplayers and combined with the complicated historical situation of deep layer evolution in the oil and gas basins of China,the effects of temperature,heating time and pressure on the hydrocarbon formation temperature and phase state were analyzed,and the types of temperature and pressure relationships were classified.Finally,based on the classification of thermal evolution history of deep and ultra-deep layers,We discussed the control effects of basin thermal evolution history on the hydrocarbon generation and phase state,and the following research results were obtained.First,the hydrocarbon phase states of deep layers in different basins and regions are greatly different,and they are mainly affected by temperature,heating time,heating rate,pressure,source rock types and other factors.And temperature is the most important factor controlling hydrocarbon generation and phase state distribution.Second,under the conditions of rapid temperature increasing and short heating time,there still maybe oil reservoirs and condensate gas reservoirs in deep and ultra-deep layersin thecase ofhigh temperature.Third,overpressureinhibitshydrocarbon generationand pyrolysis.Fourth,thereis a closerelationship betweentemperature and formation pressure of deeplayers,whichcan be divided into three types,i.e.,lowemedium temperature and high pressure type,high temperature and high pressure type,and medium temperature and lowemedium pressure type.Fifth,the thermal evolution history of deep and ultra-deep layers can be divided into four types,namely the late rapid subsidence,heating and low geothermal gradient type,the late rapid subsidence,heating and high geothermal gradient type,the middleelate rapid heating and late uplifting and cooling type,and the early great subsidence and rapid heating and middleelate great uplift erosion and cooling type.In conclusion,deep and ultra-deep layers in the basins with different types of thermal history are different in hydrocarbon phase states,accumulation stages and prospects.
基金financial support from the National Natural Science Foundation of China(Grant Nos.41804082 and 41873073)the Special Research Assistant Funding Program provided by the Chinese Academy of Sciences。
文摘The Earth’s core is composed of iron,nickel,and a small amount of light elements(e.g.,Si,S,O,C,N,H and P).The thermal conductivities of these components dominate the adiabatic heat flow in the core,which is highly correlated to geodynamo.Here we review a large number of studies on the electrical and thermal conductivity of iron and iron alloys and discuss their implications on the thermal evolution of the Earth’s core.In summary,we suggest that the Wiedemann-Franz law,commonly used to convert the electrical resistivity to thermal conductivity for metals and alloys,should be cautiously applied under extremely high pressure-temperature(P-T)conditions(e.g.,Earth’s core)because the Lorentz number may be P-T dependent.To date,the discrepancy in the thermal conductivity of iron and iron alloys remains between those from the resistivity measurements and the thermal diffusivity modeling,where the former is systematically larger.Recent studies reconcile the electrical resistivity by first-principles calculation and direct measurements,and this is a good start in resolving this discrepancy.Due to an overall higher thermal conductivity than previously thought,the inner core age is presently constrained at~1.0 Ga.However,light elements in the core would likely lower the thermal conductivity and prolong the crystallization of the inner core.Meanwhile,whether thermal convection can power the dynamo before the inner core formation depends on the amounts of the proper light elements in the core.More works are needed to establish the thermal evolution model of the core.
基金supported by the National Basic Research Program of China(No.2012CB214801)China Petroleum and Chemical Corporation Program(No.P120009)
文摘By means of the vitrinite reflectance and U-Th/He dating of apatite and zircon in cut- ting samples from the T3x-K1j formations in the Yuanba （元坝） area of Northeast Sichuan （四川） Basin, a correlation has been established between the He-derived age and depth/temperature in this area assuming helium closure temperature of apatite in this area being 95 ℃. Mesozoic strata （T3x-Kd＇） experienced helium closure temperature of apatite approaching 95 ℃, but didn＇t reach the helium closure temperature of zircon （ca. 170-190 ℃） although some reached the highest pa- laeogeothermal temperature of about 170 ℃. The Mesozoic strata in the Yuanba area experienced an important uplift and denudation during Paleogene-Neogene periods （0.2-36.4 Ma）, the erosion rate being about 109.9 m/Ma. The K1] Formation and overlying strata experienced a maximum de- nudation loss of about 4 000 m. Geotemperatures gradually fell to the helium closure temperature of apatite and then fell further to the current temperature. The thermal evolution history of this area indicates that the maximum palaeogeothermal temperature of Mesozoic strata was close to 170- 190 ℃, prior to the strata being uplifted. During the period between 176 and 36 Ma, the palaeogeo- thermal temperature fell to 95-170 ℃. and after 36 Ma, it continued to fall to the present geotem- perature of less than 95 ℃.
基金The work was supported by the Anhui emphatic research and developmental projects(201904a05020079).
文摘The Fukushima nuclear accident in Japan on March 11,2011,produced large amounts of Cs-polluted soil which must be controlled to prevent the spread of hazardous Cs into the environment.In this paper,the effects of heat treatment on the structure and properties of Cs-containing glass-ceramics,as a simulated nuclear waste form,were systematically investigated.Cesium atoms are chemically bonded in the pollucite structure,and the amorphous phase further encapsulates the pollucite crystals in the glassceramics,thus providing an extra protective layer for the immobilized Cs.XRD analysis,Raman and FT-IR studies on the glass-ceramics synergistically indicated that the optimum crystallization temperature for pollucite is around 1000℃.The pollucite is predominantly the main crystalline phase with a narrow crystal size distribution between 0.5 and 2 mm.Standard leaching test results show that the leaching rate of Cs was very low(3.0×10^(-3) g/(m^(2)·d)).The study offers a practical method for immobilizing Cs in pollucite-base glass-ceramics.Moreover,the experimentally obtained data may provide some important references for converting Cs-polluted soil into pollucite-base glass-ceramics waste form.
基金Supported by National Natural Science Foundation of China(11373006)the West Light Foundation of Chinese Academy of Sciences(ZD201302)
文摘Pulsars are rapidly spinning, strongly magnetized neutron stars. Their electromagnetic dipole radiation is usually assumed to be at the expense of the rotational energy. In this work, we consider a new channel through which rotational energy could be radiated away directly via neutrinos. With this new energy conversion channel, we can improve the chemical heating mechanism that originates in the deviation from β equilibrium due to spin-down compression. The improved chemical and thermal evolution equations with different magnetic field strengths are solved numerically. The results show that the new energy conversion channel could raise the surface temperature of neutron stars, especially for weak field stars at later stages of their evolution. Moreover, our results indicate that the new energy conversion channel induced by the non-equilibrium reaction processes should be taken into account in the study of thermal evolution.
文摘The interaction of hydrogen with interface between the precipitates and the martensitie matrix in 18Ni maraging steel has been studied by means of thermal evolution hydrogen technique us- ing gas chromatograph as hydrogen detector.An evolution rate peak has been observed at 451 K.The height of the peak relates to the amount and distribution of the precipitates.The activation energy for hydrogen escaping from the trap sites is 23.2 kJ/mol.
基金supported by the National Natural Science Foundation of China(Grant No.U20B6001,41472108)。
文摘The conventional biomarkers are limited due to the extremely high thermal stresses in ultra-deep hydrocarbon reservoirs.The diamondoid with cage structure has excellent thermal stability and is an effective tool for characterizing the ultra-deep hydrocarbon and linking its source.We investigated the distribution of diamondoids in ultra-deep reservoirs including black oils,volatile oils,and condensates.The source-related diamondoids indicate that crude oils are mainly sourced from marine siliceous shale.The bulk characteristics(e.g.color,density,Sat/Aro)of crude oils reveal the variations of thermal maturity:low maturity for black oils,moderate maturity for volatile oils,and high maturity for condensates.Based on regular variations in the thermal maturity of crude oils,the thermal evolution of diamondoids is characterized.The abundance of C_(1)-and C_(2)-alkylated diamantanes increases with increasing maturity,and hydrothermal activity may lead to an abnormal increase in the percentage of C_(3)-alkylated adamantanes.Despite the higher thermal stability of 4-methyldiamantane(4-MD),a more sensitive change in relative abundance with maturity for 1-methyldiamantane(1-MD)among all methyldiamantanes(MDs)is observed.Ethyl diamondoids are thermally less stable and their derived indices can effectively indicate the thermal maturity of ultra-deep hydrocarbons.The applications of commonly maturity-related indices should be cautious(e.g.MDI),whereas the novel methyl-ethyl diamantane index(MEDI)is highly recommended.The combination of high MAI values and low MEDI values most likely reflects the influence of late-charged light hydrocarbons.Overall,multiple charging and in-reservoir mixing of light hydrocarbons and oils with various maturities constrained the present phase states of ultra-deep oil reservoirs.This study gives a new perspective to understanding the fate of molecular evolution and phase states of hydrocarbons in the ultra-deep basins.
基金the National Natural Science Foundation of China(No.42430806)CNOOC(China)Co.,Ltd+1 种基金‘14th Five-Year'science and technology major project offshore deep/ultra-deep oil and gas exploration technology(KJGG2022-0402)‘14th Five-Year'national oil and gas resources evaluation CNOOC mining rights area and surrounding blank area oil and gas resources evaluation project(QGYQZYPJ2022-3).
文摘The Xihu Depression,situated in the northeastern East China Sea Basin,represents the most significant natural gas-producing region in Eastern China.An insufficient understanding of reservoir heterogeneity in petroleum geological conditions―particularly within structural zones beyond the well-explored Pinghu Slope and Ningbo Anticline Belt―has hindered comprehensive hydrocarbon exploration across the sag.Critical knowledge gaps persist in characterizing the geothermal field,reconstructing thermal evolution histories,and constraining hydrocarbon generation phases.These limitations directly impede systematic evaluations of basin selection criteria,reservoir delineation,and their dynamic relationships within petroleum systems.This study analyzes the present geothermal gradient at a unified depth(4000-5000 m),the geothermal heat flow,the geothermal temperature at a unified depth(3000-6000 m),and the plan distribution characteristics of the geothermal temperatures of the exploration strata in the key study area in the Xihu Depression―the Western Slope and the Central Anticlinal Belt.The research in this study is based on present bottom-hole temperature measurements and temperature data for testing for oil,using a one-dimensional steady-state heat conduction equation and the Bullard method.The results indicate that the present geothermal gradient in the Xihu Depression,between a unified depth of 4000 m and 5000 m,ranges from 16.7◦C/km to 44.6℃/km,with an average of 30.6℃/km.The present geothermal heat flow is between 32.23 mW/m^(2)and 90.13 mW/m^(2),with an average of 52.03 mW/m^(2),indicating a typical cold basin.The formation temperature gradually increases with burial depth,from 3000 m to 6000 m.In the plane,the formation temperature gradually increases from the south to the north and from the edge of the depression to the center of the depression.The burial history and thermal evolution of the key plays of the Xihu Depression were reconstructed using apatite fission tracks and zircon U-Th/He data,combined with vitrinite reflectance,which revealed that the tectonic uplift that occurred during the Late Miocene Longjing Movement was a critical event in trap formation and hydrocarbon filling.The thermal-hydrocarbon generation history indicates that the Xihu Depression has mostly entered a high maturity stage,with gas condensate and condensate charging occurring between 16.4 Ma and 13 Ma and natural gas filling occurring at 5.3 Ma up to now.Hydrocarbon generation and expulsion in the Xihu Depression occurred early in the north and late in the south,with two stages in the north and one stage in the south.A study of the burial history-thermal history-hydrocarbon generation history based on the reconstruction of geothermal fields demonstrates the matching relationship between hydrocarbon generation,distribution,and accumulation in the Xihu Depression―an understanding that is vital for oil and gas exploration in the Xihu Depression.
基金funding from the European Research Council(ERC StG 279828)
文摘Greenstone basalts and komatiites provide a means to track both mantle composition and magma generation temperature with time. Four types of mantle are characterized from incompatible element distributions in basalts and komatiites： depleted, hydrated, enriched and mantle from which komatiites are derived. Our most important observation is the recognition for the first time of what we refer to as a Great Thermal Divergence within the mantle beginning near the end of the Archean, which we ascribe to thermal and convective evolution. Prior to 2.5 Ga, depleted and enriched mantle have indistinguishable thermal histories, whereas at 2.5-2.0 Ga a divergence in mantle magma generation temperature begins between these two types of mantle. Major and incompatible element distributions and calculated magma generation temperatures suggest that Archean enriched mantle did not come from mantle plumes, but was part of an undifferentiated or well-mixed mantle similar in composition to calculated primitive mantle. During this time, however, high-temperature mantle plumes from dominantly depleted sources gave rise to komatiites and associated basalts. Recycling of oceanic crust into the deep mantle after the Archean may have contributed to enrichment ofTi, A1, Ca and Na in basalts derived from enriched mantle sources. After 2.5 Ga, increases in Mg# in basalts from depleted mantle and decreases in Fe and Mn reflect some combination of growing depletion and cooling of depleted mantle with time. A delay in cooling of depleted mantle until after the Archean probably reflects a combination of greater radiogenic heat sources in the Archean mantle and the propagation of plate tectonics after 3 Ga.
基金the financial support of the National Natural Science Foundation of China(Grants Nos.41702167 and 41972169)。
文摘Here,the geological factors controlling deep geothermal anomalies in mines were studied based on the geotemperature,lithologic thermal conductivity,and related geological data collected from the Qianjiaying Mine,China.A simulation of the change in magma waste heat,conducted using the ANSYS Workbench,revealed the distribution characteristics of geothermal anomalies in this mine and the corresponding geological control factors.The results revealed the following points.(1)First-degree heat hazard level(temperature=31-37℃)occurred in the central and southwestern parts of the mine at an^600-m depth,while second-degree heat hazard level(temperature≥37℃)occurred at an^800-m depth.The geotemperature and geothermal gradient in the southwestern part of the mine were anomalously high.(2)The geotemperatures measured in the mine generally reflected a standard increase with depth,while the geothermal gradient remained unchanged with depth.The geothermal gradient and its average value in the study area were 0.70-4.23 and 2.12C·hm^-1,respectively.(3)A combination of stratum characteristics,geological structure,and groundwater characteristics led to geothermal anomalies in mines;additionally,the waste heat from magma had no significant effect on the geothermal field.
基金The authors are grateful to the financial support from National Science and Technology Major Project of China:Demonstration project of coordinated exploitation of coalbed methane and coal in key coal mines of Shanxi province(2016ZX05067)National Natural Science Foundation of China(5187431451904311).
文摘The thermal effect caused by deep magma intrusion can not only accelerate the metamorphism of coal body,but also bring additional thermal field that changes the mechanical environment of coal seams,thereby affecting the permeability of coal seams.Different from shallow coal resources,deep coal resources are in a mechanical environment characterized by limited stress and strain.Thus,the thermal effect has a more significant influence on the distribution and permeability characteristics of deep coal seams.In this study,the evolution history of highly metamorphic coal seams in Yangquan mining area was analyzed,and the main effect of magmatic activity on coal seams was obtained.Based on the determined vitrinite reflectance data of typical mines in Yangquan mining area,the maximum paleotemperature was calculated by adopting the Barker’s method.Furthermore,the paleotemperature distribution in Yangquan mining area was summarized,and its relationship with the metamorphic degree was acquired.Then,a new permeability model considering the thermal strain was proposed to analyze the permeability evolution in deep coal seams at different ground temperatures.Finally,through a combination of the results of gas pressure and outburst number in Sijiazhuang Mine,Yangquan No.5 Mine and Xinjing Mine,the influence of ground temperature on the gas outburst risk in Yangquan mining area was explored.The following conclusions were drawn:The maximum paleotemperature in Yangquan area can be 303C.In addition,the paleotemperature in the south is higher than that in the north of Yangquan mining area.The various temperatures at different depths bring about different degrees of thermal stress to different coal seams,leading to different strains.Under the fixed displacement boundary conditions in the deep,the coal seam folds and bends to varying degrees.Moreover,the difference in the ground temperature raises the a value of coal seams and lowers the permeability,which promotes the formation of gas-rich zones and increases the risk of coal seam outburst.The research results can help mines to make proper gas disaster prevention plan for different zones.
基金This work was supported by the National Natural Science Foundation of China(Nos.41772141,41972171)the Natural Science Foundation of Jiangsu Province(BK20181362),the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘In shale reservoirs,the organic pores with various structures formed during the thermal evolution of organic matter are the main storage site for adsorbed methane.However,in the process of thermal evolution,the adsorption characteristics of methane in multi type and multi-scale organic matter pores have not been sufficiently studied.In this study,the molecular simulation method was used to study the adsorption characteristics of methane based on the geological conditions of Longmaxi Formation shale reservoir in Sichuan Basin,China.The results show that the characteristics of pore structure will affect the methane adsorption characteristics.The adsorption capacity of slit-pores for methane is much higher than that of cylindrical pores.The groove space inside the pore will change the density distribution of methane molecules in the pore,greatly improve the adsorption capacity of the pore,and increase the pressure sensitivity of the adsorption process.Although the variation of methane adsorption characteristics of different shapes is not consistent with pore size,all pores have the strongest methane adsorption capacity when the pore size is about 2 nm.In addition,the changes of temperature and pressure during the thermal evolution are also important factors to control the methane adsorption characteristics.The pore adsorption capacity first increases and then decreases with the increase of pressure,and increases with the increase of temperature.In the early stage of thermal evolution,pore adsorption capacity is strong and pressure sensitivity is weak;while in the late stage,it is on the contrary.
