By analyzing the characteristics of development, structural evolution and reservoir beds of the residual carbonate strata, this study shows that the residual carbonate strata in the Yingmaili low uplift are favorable ...By analyzing the characteristics of development, structural evolution and reservoir beds of the residual carbonate strata, this study shows that the residual carbonate strata in the Yingmaili low uplift are favorable oil and gas accumulation series in the Tabei （northern Tarim uplift） uplift. There are different patterns of hydrocarbon accumulation on the northern and southern slopes of the Yingmaili low uplift. The north-south differentiation of oil reservoirs were caused by different lithologies of the residual carbonate strata and the key constraints on the development of the reservoir beds. The Mesozoic terrestrial organic matter in the Kuqa depression and the Palaeozoic marine organic matter in the Manjiaer sag of the Northern depression are the major hydrocarbon source rocks for the northern slope and southern slope respectively. The hydrocarbon accumulation on the northern and southern slopes is controlled by differences in maturity and thermal evolution history of these two kinds of organic matter. On the southern slope, the oil accumulation formed in the early stage was destroyed completely, and the period from the late Hercynian to the Himalayian is the most important time for hydrocarbon accumulation. However, the time of hydrocarbon accumulation on the northern slope began 5 Ma B.P. Carbonate inner buried anticlines reservoirs are present on the southern slope, while weathered crust and paleo-buried hill karst carbonate reservoirs are present on the northern slope. The northern and southern slopes had different controlling factors of hydrocarbon accumulation respectively. Fracture growth in the reservoir beds is the most important controlling factor on the southern slope; while hydrocarbon accumulation on the northern slope is controlled by weathered crust and cap rock.展开更多
Although significant progress has been made in the geological theory and exploration and development of shale gas in China,the research on the geological particularity and enrichment regularity associated with shale g...Although significant progress has been made in the geological theory and exploration and development of shale gas in China,the research on the geological particularity and enrichment regularity associated with shale gas accumulation remains weak.With this in mind,we analyzed the shale gas accumulation patterns in China.The findings show that:(1)A variety of organic-rich shales were deposited in the continental margintype marine and transitional environments during the Pre-Mesozoic period and the basin-type terrestrial environment during the Mesozoic and Cenozoic eras.(2)The basins dominated by Mesozoic and Cenozoic terrestrial sediments superimpose on the Pre-Mesozoic continental margintype marineeor transitional-facies sediments.The former developed the terrestrial shales with large thickness,high organic matter abundance,new age,and low thermal maturity;meanwhile,the deep parts of the basins are favorable for shale gas enrichment.However,the latter preserves the shale with old age,high thermal maturity,and undergoing multiphase tectonic movements;and the tectonically stable regions are favorable for shale gas enrichment.(3)The aulacogens mainly formed in the Meso-Neoproterozoic,Sinian-Ordovician,and Devon-Triassic periods are favorable for marine organic-rich shale deposition;moreover,this type of shale and other types including transitional facies shales with favorable reservoir-forming assemblages,coal-measure shales in small and medium-sized basins,and low-medium mature shales affected by magma intrusion,have jointly constituted the various shale gas accumulation patterns in China.(4)Based on the drilling discoveries in China,shale gas accumulation patterns can be categorized into two types:tectonic-controlled and stratigraphic-controlled.The former is mainly related to structural features,whereas the latter is mainly related to the variation of lithology and strata.(5)Shale development and gas content are mainly affected and controlled by geological factors including sedimentation,diagenesis,and later tectonic movements.Favorable sedimentary environments,appropriate thermal maturity,good sealing capacity of caprock,and excellent structural preservation are the necessary conditions for shale gas enrichment.展开更多
Based on the achievements and research advances in oil and gas exploration in the Persian Gulf Basin,this study analyzes the orderliness of oil and gas distribution and main controlling factors of hydrocarbon accumula...Based on the achievements and research advances in oil and gas exploration in the Persian Gulf Basin,this study analyzes the orderliness of oil and gas distribution and main controlling factors of hydrocarbon accumulation with reservoir-forming assemblage as the unit.In the Persian Gulf Basin,the hydrocarbon-generating centers of source rocks of different geological ages and the hydrocarbon rich zones migrate in a clockwise direction around the Ghawar Oilfield in the Central Arabian Subbasin.Horizontally,the overall distribution pattern is orderly,showing“oil in the west and gas in the east”,and“large oil and gas fields dense in the basin center and sparse at the basin edges”.Vertically,the extents of petroleum system compounding and sources mixing increase from west to east,the pattern of tectonic strength(weak in the west and strong in the east)forming the distribution characteristics of“gas rich in the Paleozoic,oil rich in the Mesozoic,and both oil and gas rich in the Cenozoic”.The large scale accumulation and orderly distribution of oil and gas in the Persian Gulf Basin are controlled by three factors:(1)Multiple sets of giant hydrocarbon kitchens provide a resource base for near-source reservoir-forming assemblages.The short-distance lateral migration determines the oil and gas enrichment in and around the distribution area of effective source rocks.(2)The anhydrite caprocks in the platform area are thin but have experienced weak late-stage tectonic activities.Their good sealing performance makes it difficult for oil and gas to migrate vertically to shallow layers through them.The thrust faults and high-angle fractures formed by intense tectonic activities of the Zagros Orogenic Belt connect multiple source-reservoir assemblages.However,the Neogene Gachsaran Formation gypsum-salt rocks are thick and highly plastic,generally with good sealing performance,so large-scale oil and gas accumulations are still formed beneath the salt;(3)Each set of reservoir-forming assemblages is well matched in time and space in terms of the development of source rocks and reservoir-caprock assemblages,the maturation and hydrocarbon generation of source rocks,and the formation of traps,thus resulting in abundant multi layer hydrocarbon accumulations.At present,the Persian Gulf Basin is still in the stage of structural trap exploration.The pre-salt prospective traps in effective hydrocarbon kitchens remain the first choice.The areas with significant changes in Mesozoic sedimentary facies have the conditions to form large scale lithologic oil and gas reservoirs.The deep Paleozoic conventional oil and gas reservoirs and the Lower Silurian Qusaiba Member shale gas have great exploration potential and are expected to become important reserve growth areas in the future.展开更多
The Pinghu slope belt in the Xihu sag of the East China Sea Shelf Basin(ECSSB) is a crucial hydrocarbon production area in eastern China. However, due to the complex geological conditions, publications have lacked com...The Pinghu slope belt in the Xihu sag of the East China Sea Shelf Basin(ECSSB) is a crucial hydrocarbon production area in eastern China. However, due to the complex geological conditions, publications have lacked comprehensive research on the spatial-temporal coupling relationships of primary factors that impact hydrocarbon accumulation in the Pinghu slope belt. Furthermore, the hydrocarbon distribution patterns and the controlling factors across different study areas within the same slope belt are not yet fully understood. This study extensively utilized three-dimensional seismic data, well logging data,geochemical analysis, fluorescence analysis, and oil testing and production data to address these issues.Following a “stratification and differentiation” approach, the study identified seven distinct hydrocarbon migration and accumulation units(HMAU) in the Pinghu slope area based on the structural morphology characteristics, hydrocarbon source-reservoir-cap rock patterns, hydrocarbon migration pathways, and hydrocarbon supply range. Detailed analysis was conducted to examine the hydrocarbon distribution patterns and controlling factors within each migration and accumulation unit across different structural units, including high, medium, and low structural components. All data sources support a “southern-northern sub-area division, eastern-western sub-belt division, and variations in hydrocarbon accumulation” pattern in the Pinghu slope belt. The degree of hydrocarbon accumulation is controlled by the factors of structural morphology, hydrocarbon generation potential of source rocks, the spatial position of source slopes, fault sealing capacity, and sand body distribution. Furthermore, different coupling patterns of faults and sand bodies play a pivotal role in governing hydrocarbon enrichment systems across various migration and accumulation units. These observations indicate that three hydrocarbon accumulation patterns have been established within the slope belt, including near-source to far-source gentle slope with multiple hydrocarbon kitchens in the XP1-XP4 zones, near-source to middle-source gentle slope with dual-hydrocarbon kitchens in the XP5 zone, and near-source steep slope with a single hydrocarbon kitchen in the XP6-XP7 zones. These findings contribute to enhancing the theoretical system of hydrocarbon accumulation in the slope belt.展开更多
Purpose:The study aimed to describe youth time-use compositions,focusing on time spent in shorter and longer bouts of sedentary behavior and physical activity(PA),and to examine associations of these time-use composit...Purpose:The study aimed to describe youth time-use compositions,focusing on time spent in shorter and longer bouts of sedentary behavior and physical activity(PA),and to examine associations of these time-use compositions with cardiometabolic biomarkers.Methods:Accelerometer and cardiometabolic biomarker data from 2 Australian studies involving youths 7-13 years old were pooled(complete cases with accelerometry and adiposity marker data,n=782).A 9-component time-use composition was formed using compositional data analysis:time in shorter and longer bouts of sedentary behavior;time in shorter and longer bouts of light-,moderate-,or vigorous-intensity PA;and"other time"(i.e.,non-wear/sleep).Shorter and longer bouts of sedentary time were defined as<5 min and>5 min,respectively.Shorter bouts of light-,moderate-,and vigorous-intensity PA were defined as<1 min;longer bouts were defined as≥1 min.Regression models examined associations between overall time-use composition and cardiometabolic biomarkers.Then,associations were derived between ratios of longer activity patterns relative to shorter activity patterns,and of each intensity level relative to the other intensity levels and"other time",and cardiometabolic biomarkers.Results:Confounder-adjusted models showed that the overall time-use composition was associated with adiposity,blood pressure,lipids,and the summary score.Specifically,more time in longer bouts of light-intensity PA relative to shorter bouts of light-intensity PA was significantly associated with greater body mass index z-score(zBMI)(β=1.79;SE=0.68)and waist circumference(β=18.35,SE=4.78).When each activity intensity was considered relative to all higher intensities and"other time",more time in light-and vigorous-intensity PA,and less time in sedentary behavior and moderate-intensity PA,were associated with lower waist circumference.Conclusion:Accumulating PA,particularly light-intensity PA,in frequent short bursts may be more beneficial for limiting adiposity compared to accumulating the same amount of PA at these intensities in longer bouts.展开更多
Cumulative effects on wetland soils under different cultivation patterns were analyzed in the experimental fields of the Ecological Experimental Station of Mire-wetlands in Sanjiang Plain. The results suggested that t...Cumulative effects on wetland soils under different cultivation patterns were analyzed in the experimental fields of the Ecological Experimental Station of Mire-wetlands in Sanjiang Plain. The results suggested that the paddy field combined with the glebe to act on the soil environment. Under the combination of natural and anthropological factors, the cultivation of the paddy field and the glebe obviously related with different kinds of fertility factors of soil. The remarkable relation among organic matter, total nitrogen and available nitrogen reflected the fertilization of the soil at some extent.展开更多
Baise basin is a semi-graben type , pan-shaped faulted basin of Early Tertiary , in which carbonate lacustrine deposits and elastic lacustrine deposits developed . The assemblages of Gilbert-type delta-lakes ,littoral...Baise basin is a semi-graben type , pan-shaped faulted basin of Early Tertiary , in which carbonate lacustrine deposits and elastic lacustrine deposits developed . The assemblages of Gilbert-type delta-lakes ,littoral ,shallow and deep water fades are recognized . Based on grain size , the clastic lacustrine deposit systems can be grouped in three kinds of depositional sequences of progressive deposition : (1)from coarse to fine , (2)from fine to coarse and (3) from fine to coarse and then to fine agan . This was controlled mainly by hydrodynamic factor of lake bottom type .Lake shore was an important place for coal accumulation and peatmoor development . It had long time for coal accumulation and there was a very little amount of minerals into the basin ,and the thick coal layer and high quality coal developed m the zone where initial lake bottom was plan-like and the surface stream flow was weak .Peat accumulation advanced from the margin to the center of basin .Carbonate lakes contained much water ,very high preponderant contenis of coagel ,low inert contents and no fusinite in the coal .展开更多
This paper expounds the basic principles and structures of the whole petroleum system to reveal the pattern of conventional oil/gas-tight oil/gas-shale oil/gas sequential accumulation and the hydrocarbon accumulation ...This paper expounds the basic principles and structures of the whole petroleum system to reveal the pattern of conventional oil/gas-tight oil/gas-shale oil/gas sequential accumulation and the hydrocarbon accumulation models and mechanisms of the whole petroleum system.It delineates the geological model,flow model,and production mechanism of shale and tight reservoirs,and proposes future research orientations.The main structure of the whole petroleum system includes three fluid dynamic fields,three types of oil and gas reservoirs/resources,and two types of reservoir-forming processes.Conventional oil/gas,tight oil/gas,and shale oil/gas are orderly in generation time and spatial distribution,and sequentially rational in genetic mechanism,showing the pattern of sequential accumulation.The whole petroleum system involves two categories of hydrocarbon accumulation models:hydrocarbon accumulation in the detrital basin and hydrocarbon accumulation in the carbonate basin/formation.The accumulation of unconventional oil/gas is self-containment,which is microscopically driven by the intermolecular force(van der Waals force).The unconventional oil/gas production has proved that the geological model,flow model,and production mechanism of shale and tight reservoirs represent a new and complex field that needs further study.Shale oil/gas must be the most important resource replacement for oil and gas resources of China.Future research efforts include:(1)the characteristics of the whole petroleum system in carbonate basins and the source-reservoir coupling patterns in the evolution of composite basins;(2)flow mechanisms in migration,accumulation,and production of shale oil/gas and tight oil/gas;(3)geological characteristics and enrichment of deep and ultra-deep shale oil/gas,tight oil/gas and coalbed methane;(4)resource evaluation and new generation of basin simulation technology of the whole petroleum system;(5)research on earth system-earth organic rock and fossil fuel system-whole petroleum system.展开更多
Deep shale gas has become an important frontier for future shale gas exploration and development.The Wufeng-Longmaxi formations in southern China have undergone complex tectonic and transformation through multi-stage ...Deep shale gas has become an important frontier for future shale gas exploration and development.The Wufeng-Longmaxi formations in southern China have undergone complex tectonic and transformation through multi-stage tectonic movements.Deep shale gas enrichment conditions are complex,which greatly restricts the exploration and development of deep shale gas.In this study,based on systematic analysis of basic geological characteristics and gas reservoir characteristics of deep shales,the main factors controlling deep shale gas enrichment in southern China were investigated,and enrichment modes were established.The results show that high-quality shales were developed in the deep-water continental shelf facies,characterized by moderate thermal maturity,high silica content,and abundant organic matter.These characteristics provide a good basis for the formation and enrichment of shale gas.The deep shale gas reservoir is featured by overpressure,high porosity and high gas content.The development and maintenance of high porosity,favorable roof and floor sealing conditions,and weak tectonic activity during uplift stage are the main factors to control deep shale gas enrichment.Based on a comprehensive analysis,the enrichment modes of deep shale gas under three different tectonic patterns were established,namely overpressure enrichment within the basin,overpressure enrichment in the faulted nose or slope of the margin,and overpressure enrichment in the remnant syncline outside the basin.This study provides a reference for exploration and development of deep shale gas in Sichuan Basin and other areas.展开更多
There are known brown coal deposits in Primorsky Krai(Russian Federation),where coals contain rare elements(Ge,U,REE,etc.)up to industrial concentrations.One of the known metalliferous coals is the Rakovka coal-bearin...There are known brown coal deposits in Primorsky Krai(Russian Federation),where coals contain rare elements(Ge,U,REE,etc.)up to industrial concentrations.One of the known metalliferous coals is the Rakovka coal-bearing depression,located on the southern edge of the Khanka(Prikhankaiskaya)Lowland,with an area of about 70 km2.Rare-metal granites with a developed weathering crust are spread in its basement and flanks.The structural conditions forming the depression were studied using measurements of orientations of structural elements(layering,contacts,veins,and dikes)with regard to kinematic conditions of faulting.The coal and host rocks were sampled in sections in the cross strike of the coal seam.Granites and dikes cutting them were sampled by separate rock chip samples.The chemical composition and element content were determined for all samples.It was found that the adjacent rocks played a major role in the formation of the Rakovka rare-metal-coal deposit.The rare-elements enrichment is not associated with active tectonics,faults,and hydrothermal sources,as was previously assumed.Rather,it was caused by the hydrogenic and clastogenic removal of these metals from the weathering crust of granites of the depression's flanks and argillated basite dikes cutting the granites.The hydrogenic nature of the anomalous accumulation of U in sorbed form on organic matter of coals is confirmed by the predominant enrichment of low-ash beds.Rare earth elements entered coal seams both in mineral and dissolved forms.A model of REE and uranium input into the coal-bearing sediments of the Rakovka depression was proposed.展开更多
The hydrocarbon accumulation pattern of the Mesozoic covered Archean buried hill in the Bohai Oilfield was not clarified before,which restricts the oil and gas exploration progress in this area.In recent years,reservo...The hydrocarbon accumulation pattern of the Mesozoic covered Archean buried hill in the Bohai Oilfield was not clarified before,which restricts the oil and gas exploration progress in this area.In recent years,reservoir development modes and reservoir prediction technologies have been researched after the structural evolution and stratigraphic distribution characteristics of the buried hill in the Bozhong sag were investigated based on new 3D seismic data and a large number of cores and logging data of newly drilling wells.Then,the hydrocarbon accumulation pattern of covered type Archean buried hill was analyzed.Finally,this pattern was applied to guide the oil and gas exploration deployment in Bozhong 13-2 structure,and a significant discovery of Bozhong 13-2 large monoblock volatile buried hill oilfield was realized.And the following research results were obtained.First,the structure in this area mainly experienced multi-period tectonic movements,such as Indosinian,Yanshanian and Himalayan,and it is characterized by compression and thrusting to form a hill during Indosinian-early Yanshanian,extension and inversion transformation during middle Yanshanian,and burial and finalization during Himalayan,forming Bozhong 13-2 Mesozoic covered Archean large buried hill trap.Second,under the effect of Mesozoic cover and the control of multi-stage stress superposition,the reservoir development in this area has the distribution characteristics of“different vertical top,internal lateral continuity”.Third,the fracture prediction technology based on smooth reflection strength filter is developed.And by means of this technology,multi-scale fractured reservoirs inside buried hills can be predicted effectively.Fourth,the hydrocarbon accumulation pattern of“overpressure injection-relay migration”for covered type buried hills is established,which provides a basis for long-distance migration and large-scale accumulation of oil and gas in covered type buried hills.In conclusion,these understandings guide the discovery of Bozhong 13-2 Oilfield,achieve a breakthrough in the oil and exploration of Mesozoic covered buried hill in the Bohai Oilfield and can be used as the reference for the oil and gas exploration in the similar covered type buried hills of the Bohai Bay Basin and other areas.展开更多
Tofigure out the process and controlling factors of gas reservoir formation in deep-waters,based on an analysis of geological features,source of natural gas and process of reservoir formation in the Liwan 3-1 gasfield...Tofigure out the process and controlling factors of gas reservoir formation in deep-waters,based on an analysis of geological features,source of natural gas and process of reservoir formation in the Liwan 3-1 gasfield,physical simulation experiment of the gas reservoir formation process has been performed,consequently,pattern and features of gas reservoir formation in the Baiyun sag has been found out.The results of the experiment show that:①the formation of the Liwan 3-1 faulted anticline gasfield is closely related to the longstanding active large faults,where natural gas is composed of a high proportion of hydrocarbons,a small amount of non-hydrocarbons,and the wet gas generated during highly mature stage shows obvious vertical migration signs;②liquid hydrocarbons associated with natural gas there are derived from source rock of the Enping&Zhuhai Formation,whereas natural gas comes mainly from source rock of the Enping Formation,and source rock of the Wenchang Formation made a little contribution during the early Eocene period as well;③although there was gas migration and accumulation,yet most of the natural gas mainly scattered and dispersed due to the stronger activity of faults in the early period;later as fault activity gradually weakened,gas started to accumulate into reservoirs in the Baiyun sag;④there is stronger vertical migration of oil and gas than lateral migration,and the places where fault links effective source rocks with reservoirs are most likely for gas accumulation;⑤effective temporal-spatial coupling of source-fault-reservoir in late stage is the key to gas reservoir formation in the Baiyun sag;⑥the nearer the distance from a trap to a large-scale fault and hydrocarbon source kitchen,the more likely gas may accumulate in the trap in late stage,therefore gas accumulation efficiency is much lower for the traps which are far away from large-scale faults and hydrocarbon source kitchens.展开更多
Based on analyses of characteristics,hydrocarbon charging history and geological conditions for the formation of Sinian-Cambrian reservoirs in the north slope area of central Sichuan paleo-uplift,the natural gas origi...Based on analyses of characteristics,hydrocarbon charging history and geological conditions for the formation of Sinian-Cambrian reservoirs in the north slope area of central Sichuan paleo-uplift,the natural gas origin,accumulation evolution,accumulation pattern and formation conditions of large lithologic gas reservoirs have been investigated.Through comprehensive analyses of natural gas composition,carbon and hydrogen isotopic compositions,fluid inclusions,reservoir bitumen,and geological conditions such as lithofacies paleogeography and beach body characterization,it is concluded that:(1)The natural gas in the Sinian-Cambrian of the north slope area is mainly oil cracking gas,and different contribution ratios of multiple sets of source rocks lead to different geochemical characteristics of natural gas in different reservoirs.(2)Although the both Sinian and Cambrian gas reservoirs in this area are lithologic gas reservoirs under monocline background,the former has normal-pressure and the latter has high-pressure.There are three types of source-reservoir-caprock combinations:single source with lower generation and upper reservoir,double sources with lower generation and upper reservoir or with side source and lateral reservoir,double sources with lower generation and upper reservoir or with upper generation and lower reservoir.The Permian-Triassic is the main generation period of oil,Early-Middle Jurassic is the main generation period of oil cracking gas and wet gas,and Late Jurassic-Cretaceous is the main generation period of dry gas.(3)The Sinian-Cambrian system of the north slope area has two favorable conditions for formation of large lithologic gas reservoirs,one is that the large scale beach facies reservoirs are located in the range of ancient oil reservoirs or near the source rocks,which is conducive to the"in-situ"large-scale accumulation of cracked gas in the paleo-oil reservoirs,the other is that the large scale mound-beach complex reservoirs and sealing layers of inter beach tight zones match effectively to form large lithologic traps under the slope background.The research results confirm that the north slope area has large multi-layer lithologic gas reservoirs with more than one trillion cubic meters of natural gas resources and great exploration potential.展开更多
基金part of the National Key Fundamental Research Program(No.2005CB422108)the National Natural Science Foundation of China(Grant No.40672092).
文摘By analyzing the characteristics of development, structural evolution and reservoir beds of the residual carbonate strata, this study shows that the residual carbonate strata in the Yingmaili low uplift are favorable oil and gas accumulation series in the Tabei （northern Tarim uplift） uplift. There are different patterns of hydrocarbon accumulation on the northern and southern slopes of the Yingmaili low uplift. The north-south differentiation of oil reservoirs were caused by different lithologies of the residual carbonate strata and the key constraints on the development of the reservoir beds. The Mesozoic terrestrial organic matter in the Kuqa depression and the Palaeozoic marine organic matter in the Manjiaer sag of the Northern depression are the major hydrocarbon source rocks for the northern slope and southern slope respectively. The hydrocarbon accumulation on the northern and southern slopes is controlled by differences in maturity and thermal evolution history of these two kinds of organic matter. On the southern slope, the oil accumulation formed in the early stage was destroyed completely, and the period from the late Hercynian to the Himalayian is the most important time for hydrocarbon accumulation. However, the time of hydrocarbon accumulation on the northern slope began 5 Ma B.P. Carbonate inner buried anticlines reservoirs are present on the southern slope, while weathered crust and paleo-buried hill karst carbonate reservoirs are present on the northern slope. The northern and southern slopes had different controlling factors of hydrocarbon accumulation respectively. Fracture growth in the reservoir beds is the most important controlling factor on the southern slope; while hydrocarbon accumulation on the northern slope is controlled by weathered crust and cap rock.
基金supported by the National Natural Science Foundation of China“Key parameter testing and intelligent evaluation system of shale gas potential”(No.41927801)the China Postdoctoral Science Foundation“Formation mechanism of organic matter related uranium in Niutitang Formation and its helium geological significance”(No.2022M712968)the Major Science and Technology Special Project of China“Shale gas exploration,development and demonstration application in Henan Province”(No.151100311000).
文摘Although significant progress has been made in the geological theory and exploration and development of shale gas in China,the research on the geological particularity and enrichment regularity associated with shale gas accumulation remains weak.With this in mind,we analyzed the shale gas accumulation patterns in China.The findings show that:(1)A variety of organic-rich shales were deposited in the continental margintype marine and transitional environments during the Pre-Mesozoic period and the basin-type terrestrial environment during the Mesozoic and Cenozoic eras.(2)The basins dominated by Mesozoic and Cenozoic terrestrial sediments superimpose on the Pre-Mesozoic continental margintype marineeor transitional-facies sediments.The former developed the terrestrial shales with large thickness,high organic matter abundance,new age,and low thermal maturity;meanwhile,the deep parts of the basins are favorable for shale gas enrichment.However,the latter preserves the shale with old age,high thermal maturity,and undergoing multiphase tectonic movements;and the tectonically stable regions are favorable for shale gas enrichment.(3)The aulacogens mainly formed in the Meso-Neoproterozoic,Sinian-Ordovician,and Devon-Triassic periods are favorable for marine organic-rich shale deposition;moreover,this type of shale and other types including transitional facies shales with favorable reservoir-forming assemblages,coal-measure shales in small and medium-sized basins,and low-medium mature shales affected by magma intrusion,have jointly constituted the various shale gas accumulation patterns in China.(4)Based on the drilling discoveries in China,shale gas accumulation patterns can be categorized into two types:tectonic-controlled and stratigraphic-controlled.The former is mainly related to structural features,whereas the latter is mainly related to the variation of lithology and strata.(5)Shale development and gas content are mainly affected and controlled by geological factors including sedimentation,diagenesis,and later tectonic movements.Favorable sedimentary environments,appropriate thermal maturity,good sealing capacity of caprock,and excellent structural preservation are the necessary conditions for shale gas enrichment.
基金Supported by the CNPC Major Science and Technology Project(2023ZZ07).
文摘Based on the achievements and research advances in oil and gas exploration in the Persian Gulf Basin,this study analyzes the orderliness of oil and gas distribution and main controlling factors of hydrocarbon accumulation with reservoir-forming assemblage as the unit.In the Persian Gulf Basin,the hydrocarbon-generating centers of source rocks of different geological ages and the hydrocarbon rich zones migrate in a clockwise direction around the Ghawar Oilfield in the Central Arabian Subbasin.Horizontally,the overall distribution pattern is orderly,showing“oil in the west and gas in the east”,and“large oil and gas fields dense in the basin center and sparse at the basin edges”.Vertically,the extents of petroleum system compounding and sources mixing increase from west to east,the pattern of tectonic strength(weak in the west and strong in the east)forming the distribution characteristics of“gas rich in the Paleozoic,oil rich in the Mesozoic,and both oil and gas rich in the Cenozoic”.The large scale accumulation and orderly distribution of oil and gas in the Persian Gulf Basin are controlled by three factors:(1)Multiple sets of giant hydrocarbon kitchens provide a resource base for near-source reservoir-forming assemblages.The short-distance lateral migration determines the oil and gas enrichment in and around the distribution area of effective source rocks.(2)The anhydrite caprocks in the platform area are thin but have experienced weak late-stage tectonic activities.Their good sealing performance makes it difficult for oil and gas to migrate vertically to shallow layers through them.The thrust faults and high-angle fractures formed by intense tectonic activities of the Zagros Orogenic Belt connect multiple source-reservoir assemblages.However,the Neogene Gachsaran Formation gypsum-salt rocks are thick and highly plastic,generally with good sealing performance,so large-scale oil and gas accumulations are still formed beneath the salt;(3)Each set of reservoir-forming assemblages is well matched in time and space in terms of the development of source rocks and reservoir-caprock assemblages,the maturation and hydrocarbon generation of source rocks,and the formation of traps,thus resulting in abundant multi layer hydrocarbon accumulations.At present,the Persian Gulf Basin is still in the stage of structural trap exploration.The pre-salt prospective traps in effective hydrocarbon kitchens remain the first choice.The areas with significant changes in Mesozoic sedimentary facies have the conditions to form large scale lithologic oil and gas reservoirs.The deep Paleozoic conventional oil and gas reservoirs and the Lower Silurian Qusaiba Member shale gas have great exploration potential and are expected to become important reserve growth areas in the future.
基金funded by the Natural Science Foundation of Heilongjiang Province (LH 2022D013)supported by the Central Support Program for Young Talents in Local Universities in Heilongjiang Province (14011202101)Key Research and Development Plan Project of Heilongjiang Province (JD22A022)。
文摘The Pinghu slope belt in the Xihu sag of the East China Sea Shelf Basin(ECSSB) is a crucial hydrocarbon production area in eastern China. However, due to the complex geological conditions, publications have lacked comprehensive research on the spatial-temporal coupling relationships of primary factors that impact hydrocarbon accumulation in the Pinghu slope belt. Furthermore, the hydrocarbon distribution patterns and the controlling factors across different study areas within the same slope belt are not yet fully understood. This study extensively utilized three-dimensional seismic data, well logging data,geochemical analysis, fluorescence analysis, and oil testing and production data to address these issues.Following a “stratification and differentiation” approach, the study identified seven distinct hydrocarbon migration and accumulation units(HMAU) in the Pinghu slope area based on the structural morphology characteristics, hydrocarbon source-reservoir-cap rock patterns, hydrocarbon migration pathways, and hydrocarbon supply range. Detailed analysis was conducted to examine the hydrocarbon distribution patterns and controlling factors within each migration and accumulation unit across different structural units, including high, medium, and low structural components. All data sources support a “southern-northern sub-area division, eastern-western sub-belt division, and variations in hydrocarbon accumulation” pattern in the Pinghu slope belt. The degree of hydrocarbon accumulation is controlled by the factors of structural morphology, hydrocarbon generation potential of source rocks, the spatial position of source slopes, fault sealing capacity, and sand body distribution. Furthermore, different coupling patterns of faults and sand bodies play a pivotal role in governing hydrocarbon enrichment systems across various migration and accumulation units. These observations indicate that three hydrocarbon accumulation patterns have been established within the slope belt, including near-source to far-source gentle slope with multiple hydrocarbon kitchens in the XP1-XP4 zones, near-source to middle-source gentle slope with dual-hydrocarbon kitchens in the XP5 zone, and near-source steep slope with a single hydrocarbon kitchen in the XP6-XP7 zones. These findings contribute to enhancing the theoretical system of hydrocarbon accumulation in the slope belt.
文摘Purpose:The study aimed to describe youth time-use compositions,focusing on time spent in shorter and longer bouts of sedentary behavior and physical activity(PA),and to examine associations of these time-use compositions with cardiometabolic biomarkers.Methods:Accelerometer and cardiometabolic biomarker data from 2 Australian studies involving youths 7-13 years old were pooled(complete cases with accelerometry and adiposity marker data,n=782).A 9-component time-use composition was formed using compositional data analysis:time in shorter and longer bouts of sedentary behavior;time in shorter and longer bouts of light-,moderate-,or vigorous-intensity PA;and"other time"(i.e.,non-wear/sleep).Shorter and longer bouts of sedentary time were defined as<5 min and>5 min,respectively.Shorter bouts of light-,moderate-,and vigorous-intensity PA were defined as<1 min;longer bouts were defined as≥1 min.Regression models examined associations between overall time-use composition and cardiometabolic biomarkers.Then,associations were derived between ratios of longer activity patterns relative to shorter activity patterns,and of each intensity level relative to the other intensity levels and"other time",and cardiometabolic biomarkers.Results:Confounder-adjusted models showed that the overall time-use composition was associated with adiposity,blood pressure,lipids,and the summary score.Specifically,more time in longer bouts of light-intensity PA relative to shorter bouts of light-intensity PA was significantly associated with greater body mass index z-score(zBMI)(β=1.79;SE=0.68)and waist circumference(β=18.35,SE=4.78).When each activity intensity was considered relative to all higher intensities and"other time",more time in light-and vigorous-intensity PA,and less time in sedentary behavior and moderate-intensity PA,were associated with lower waist circumference.Conclusion:Accumulating PA,particularly light-intensity PA,in frequent short bursts may be more beneficial for limiting adiposity compared to accumulating the same amount of PA at these intensities in longer bouts.
基金Supported by Chinese Youth Natural Sciences Fund Project(40501030)
文摘Cumulative effects on wetland soils under different cultivation patterns were analyzed in the experimental fields of the Ecological Experimental Station of Mire-wetlands in Sanjiang Plain. The results suggested that the paddy field combined with the glebe to act on the soil environment. Under the combination of natural and anthropological factors, the cultivation of the paddy field and the glebe obviously related with different kinds of fertility factors of soil. The remarkable relation among organic matter, total nitrogen and available nitrogen reflected the fertilization of the soil at some extent.
文摘Baise basin is a semi-graben type , pan-shaped faulted basin of Early Tertiary , in which carbonate lacustrine deposits and elastic lacustrine deposits developed . The assemblages of Gilbert-type delta-lakes ,littoral ,shallow and deep water fades are recognized . Based on grain size , the clastic lacustrine deposit systems can be grouped in three kinds of depositional sequences of progressive deposition : (1)from coarse to fine , (2)from fine to coarse and (3) from fine to coarse and then to fine agan . This was controlled mainly by hydrodynamic factor of lake bottom type .Lake shore was an important place for coal accumulation and peatmoor development . It had long time for coal accumulation and there was a very little amount of minerals into the basin ,and the thick coal layer and high quality coal developed m the zone where initial lake bottom was plan-like and the surface stream flow was weak .Peat accumulation advanced from the margin to the center of basin .Carbonate lakes contained much water ,very high preponderant contenis of coagel ,low inert contents and no fusinite in the coal .
基金Supported by the National Natural Science Foundation of China(U22B6002)PetroChina Science Research and Technology Development Project(2021DJ0101)。
文摘This paper expounds the basic principles and structures of the whole petroleum system to reveal the pattern of conventional oil/gas-tight oil/gas-shale oil/gas sequential accumulation and the hydrocarbon accumulation models and mechanisms of the whole petroleum system.It delineates the geological model,flow model,and production mechanism of shale and tight reservoirs,and proposes future research orientations.The main structure of the whole petroleum system includes three fluid dynamic fields,three types of oil and gas reservoirs/resources,and two types of reservoir-forming processes.Conventional oil/gas,tight oil/gas,and shale oil/gas are orderly in generation time and spatial distribution,and sequentially rational in genetic mechanism,showing the pattern of sequential accumulation.The whole petroleum system involves two categories of hydrocarbon accumulation models:hydrocarbon accumulation in the detrital basin and hydrocarbon accumulation in the carbonate basin/formation.The accumulation of unconventional oil/gas is self-containment,which is microscopically driven by the intermolecular force(van der Waals force).The unconventional oil/gas production has proved that the geological model,flow model,and production mechanism of shale and tight reservoirs represent a new and complex field that needs further study.Shale oil/gas must be the most important resource replacement for oil and gas resources of China.Future research efforts include:(1)the characteristics of the whole petroleum system in carbonate basins and the source-reservoir coupling patterns in the evolution of composite basins;(2)flow mechanisms in migration,accumulation,and production of shale oil/gas and tight oil/gas;(3)geological characteristics and enrichment of deep and ultra-deep shale oil/gas,tight oil/gas and coalbed methane;(4)resource evaluation and new generation of basin simulation technology of the whole petroleum system;(5)research on earth system-earth organic rock and fossil fuel system-whole petroleum system.
基金support from a project of the Basic Research Program on Deep Petroleum Resource Accumulation and Key Engineering Technologies(U19B6003).
文摘Deep shale gas has become an important frontier for future shale gas exploration and development.The Wufeng-Longmaxi formations in southern China have undergone complex tectonic and transformation through multi-stage tectonic movements.Deep shale gas enrichment conditions are complex,which greatly restricts the exploration and development of deep shale gas.In this study,based on systematic analysis of basic geological characteristics and gas reservoir characteristics of deep shales,the main factors controlling deep shale gas enrichment in southern China were investigated,and enrichment modes were established.The results show that high-quality shales were developed in the deep-water continental shelf facies,characterized by moderate thermal maturity,high silica content,and abundant organic matter.These characteristics provide a good basis for the formation and enrichment of shale gas.The deep shale gas reservoir is featured by overpressure,high porosity and high gas content.The development and maintenance of high porosity,favorable roof and floor sealing conditions,and weak tectonic activity during uplift stage are the main factors to control deep shale gas enrichment.Based on a comprehensive analysis,the enrichment modes of deep shale gas under three different tectonic patterns were established,namely overpressure enrichment within the basin,overpressure enrichment in the faulted nose or slope of the margin,and overpressure enrichment in the remnant syncline outside the basin.This study provides a reference for exploration and development of deep shale gas in Sichuan Basin and other areas.
基金The reported study was funded by RFBR and NSFC,Project Number 21-55-53013.
文摘There are known brown coal deposits in Primorsky Krai(Russian Federation),where coals contain rare elements(Ge,U,REE,etc.)up to industrial concentrations.One of the known metalliferous coals is the Rakovka coal-bearing depression,located on the southern edge of the Khanka(Prikhankaiskaya)Lowland,with an area of about 70 km2.Rare-metal granites with a developed weathering crust are spread in its basement and flanks.The structural conditions forming the depression were studied using measurements of orientations of structural elements(layering,contacts,veins,and dikes)with regard to kinematic conditions of faulting.The coal and host rocks were sampled in sections in the cross strike of the coal seam.Granites and dikes cutting them were sampled by separate rock chip samples.The chemical composition and element content were determined for all samples.It was found that the adjacent rocks played a major role in the formation of the Rakovka rare-metal-coal deposit.The rare-elements enrichment is not associated with active tectonics,faults,and hydrothermal sources,as was previously assumed.Rather,it was caused by the hydrogenic and clastogenic removal of these metals from the weathering crust of granites of the depression's flanks and argillated basite dikes cutting the granites.The hydrogenic nature of the anomalous accumulation of U in sorbed form on organic matter of coals is confirmed by the predominant enrichment of low-ash beds.Rare earth elements entered coal seams both in mineral and dissolved forms.A model of REE and uranium input into the coal-bearing sediments of the Rakovka depression was proposed.
基金Project supported by the National Major Science and Technology Project“Comprehensive study on hydrocarbon accumulation in buried hills and exploration prospects in Bohai Bay Basin”(No.:2016ZX05024-003-010)CNOOC(China)Limited Science and Technology Project“Geological characteristics,typical hydrocarbon accumulation mechanisms and prospect prediction in buried hill reservoirs in Bohai Bay Basin”(No.:CCL2014TJXZSS0870).
文摘The hydrocarbon accumulation pattern of the Mesozoic covered Archean buried hill in the Bohai Oilfield was not clarified before,which restricts the oil and gas exploration progress in this area.In recent years,reservoir development modes and reservoir prediction technologies have been researched after the structural evolution and stratigraphic distribution characteristics of the buried hill in the Bozhong sag were investigated based on new 3D seismic data and a large number of cores and logging data of newly drilling wells.Then,the hydrocarbon accumulation pattern of covered type Archean buried hill was analyzed.Finally,this pattern was applied to guide the oil and gas exploration deployment in Bozhong 13-2 structure,and a significant discovery of Bozhong 13-2 large monoblock volatile buried hill oilfield was realized.And the following research results were obtained.First,the structure in this area mainly experienced multi-period tectonic movements,such as Indosinian,Yanshanian and Himalayan,and it is characterized by compression and thrusting to form a hill during Indosinian-early Yanshanian,extension and inversion transformation during middle Yanshanian,and burial and finalization during Himalayan,forming Bozhong 13-2 Mesozoic covered Archean large buried hill trap.Second,under the effect of Mesozoic cover and the control of multi-stage stress superposition,the reservoir development in this area has the distribution characteristics of“different vertical top,internal lateral continuity”.Third,the fracture prediction technology based on smooth reflection strength filter is developed.And by means of this technology,multi-scale fractured reservoirs inside buried hills can be predicted effectively.Fourth,the hydrocarbon accumulation pattern of“overpressure injection-relay migration”for covered type buried hills is established,which provides a basis for long-distance migration and large-scale accumulation of oil and gas in covered type buried hills.In conclusion,these understandings guide the discovery of Bozhong 13-2 Oilfield,achieve a breakthrough in the oil and exploration of Mesozoic covered buried hill in the Bohai Oilfield and can be used as the reference for the oil and gas exploration in the similar covered type buried hills of the Bohai Bay Basin and other areas.
基金National High Technology Research and Development Program of China“Fundamental Study on Formation and Distribution of Hydrocarbon Resources in Deep-water Basins,South China Sea”(No.2009CB219400).
文摘Tofigure out the process and controlling factors of gas reservoir formation in deep-waters,based on an analysis of geological features,source of natural gas and process of reservoir formation in the Liwan 3-1 gasfield,physical simulation experiment of the gas reservoir formation process has been performed,consequently,pattern and features of gas reservoir formation in the Baiyun sag has been found out.The results of the experiment show that:①the formation of the Liwan 3-1 faulted anticline gasfield is closely related to the longstanding active large faults,where natural gas is composed of a high proportion of hydrocarbons,a small amount of non-hydrocarbons,and the wet gas generated during highly mature stage shows obvious vertical migration signs;②liquid hydrocarbons associated with natural gas there are derived from source rock of the Enping&Zhuhai Formation,whereas natural gas comes mainly from source rock of the Enping Formation,and source rock of the Wenchang Formation made a little contribution during the early Eocene period as well;③although there was gas migration and accumulation,yet most of the natural gas mainly scattered and dispersed due to the stronger activity of faults in the early period;later as fault activity gradually weakened,gas started to accumulate into reservoirs in the Baiyun sag;④there is stronger vertical migration of oil and gas than lateral migration,and the places where fault links effective source rocks with reservoirs are most likely for gas accumulation;⑤effective temporal-spatial coupling of source-fault-reservoir in late stage is the key to gas reservoir formation in the Baiyun sag;⑥the nearer the distance from a trap to a large-scale fault and hydrocarbon source kitchen,the more likely gas may accumulate in the trap in late stage,therefore gas accumulation efficiency is much lower for the traps which are far away from large-scale faults and hydrocarbon source kitchens.
基金Chinese Academy of Sciences Strategic Pilot Science and Technology Project(Class A)(XDA14010403)National Science and Technology Major Project(2016ZX05007)PetroChina Science and Technology Project(2021DJ0604,kt2020-01-03)。
文摘Based on analyses of characteristics,hydrocarbon charging history and geological conditions for the formation of Sinian-Cambrian reservoirs in the north slope area of central Sichuan paleo-uplift,the natural gas origin,accumulation evolution,accumulation pattern and formation conditions of large lithologic gas reservoirs have been investigated.Through comprehensive analyses of natural gas composition,carbon and hydrogen isotopic compositions,fluid inclusions,reservoir bitumen,and geological conditions such as lithofacies paleogeography and beach body characterization,it is concluded that:(1)The natural gas in the Sinian-Cambrian of the north slope area is mainly oil cracking gas,and different contribution ratios of multiple sets of source rocks lead to different geochemical characteristics of natural gas in different reservoirs.(2)Although the both Sinian and Cambrian gas reservoirs in this area are lithologic gas reservoirs under monocline background,the former has normal-pressure and the latter has high-pressure.There are three types of source-reservoir-caprock combinations:single source with lower generation and upper reservoir,double sources with lower generation and upper reservoir or with side source and lateral reservoir,double sources with lower generation and upper reservoir or with upper generation and lower reservoir.The Permian-Triassic is the main generation period of oil,Early-Middle Jurassic is the main generation period of oil cracking gas and wet gas,and Late Jurassic-Cretaceous is the main generation period of dry gas.(3)The Sinian-Cambrian system of the north slope area has two favorable conditions for formation of large lithologic gas reservoirs,one is that the large scale beach facies reservoirs are located in the range of ancient oil reservoirs or near the source rocks,which is conducive to the"in-situ"large-scale accumulation of cracked gas in the paleo-oil reservoirs,the other is that the large scale mound-beach complex reservoirs and sealing layers of inter beach tight zones match effectively to form large lithologic traps under the slope background.The research results confirm that the north slope area has large multi-layer lithologic gas reservoirs with more than one trillion cubic meters of natural gas resources and great exploration potential.
