The Zhujiang(Pearl)River Mouth Basin(PRMB)is located in the northern part of the South China Sea,and it is one of China’s three major offshore hydrocarbon-rich basins,playing an indispensable role in meeting the coun...The Zhujiang(Pearl)River Mouth Basin(PRMB)is located in the northern part of the South China Sea,and it is one of China’s three major offshore hydrocarbon-rich basins,playing an indispensable role in meeting the country’s energy needs.Exploration for oil in the PRMB started early and has achieved remarkable results in some sags,but many sags have yet to yield significant discoveries,necessitating the search for new favorable exploration areas.The aim of this study is to analyze the deep structural characteristics of various sags in the PRMB and predict favorable exploration areas,providing corresponding support for the next strategic breakthrough in oil exploration.Some studies indicate a certain relationship between the Moho depth and crustal thickness and the occurrence of oil.In this paper,based on satellite altimetry gravity anomaly data,we utilize a Moho depth inversion method based on variable residual crustal density to obtain the Moho depth in the PRMB,from which the crustal thickness and crustal stretching factor of the basin are calculated.The results show that the Moho depth in the PRMB ranges from 10 km to 37 km,the crustal thickness ranges from 7 km to 35 km,and the crustal stretching factor ranges from 0.9 to 3.0.Finally,we propose a comprehensive evaluation scheme for oil resoureces based on the CRiteria Importance Through Intercriteria Correlation(CRITIC)method,which comprehensively evaluates multiple factors,such as the Cenozoic sedimentary filling scale,Cenozoic thickness,Moho depth,crustal thickness,and crustal stretching factor,and provides evaluation criteria for identifying hydrocarbon-rich sags.According to this evaluation scheme,the exploration potential is relatively high in the Liwan Sag,Jinghai Sag,Heshan Sag,and Jieyang Sag,which are favorable exploration areas.展开更多
1 Introduction The huize Zn-Pb ore district in Yunnan province is locatedinthecentralsouthernofthe Sichuan—Yunnan—GuizhouPb-ZnPoly-metallic Mineralization Area in the southwestern margin of the Yangtze Block,and is ...1 Introduction The huize Zn-Pb ore district in Yunnan province is locatedinthecentralsouthernofthe Sichuan—Yunnan—GuizhouPb-ZnPoly-metallic Mineralization Area in the southwestern margin of the Yangtze Block,and is strictly controlled by fault structures.It has developed to one of the famous production bases of lead&zinc and germanium in China.展开更多
Based on the analysis of surface geological survey,exploratory well,gravity-magnetic-electric and seismic data,and through mapping the sedimentary basin and its peripheral orogenic belts together,this paper explores s...Based on the analysis of surface geological survey,exploratory well,gravity-magnetic-electric and seismic data,and through mapping the sedimentary basin and its peripheral orogenic belts together,this paper explores systematically the boundary,distribution,geological structure,and tectonic attributes of the Ordos prototype basin in the geological historical periods.The results show that the Ordos block is bounded to the west by the Engorwusu Fault Zone,to the east by the Taihangshan Mountain Piedmont Fault Zone,to the north by the Solonker-Xilamuron Suture Zone,and to the south by the Shangnan-Danfeng Suture Zone.The Ordos Basin boundary was the plate tectonic boundary during the Middle Proterozoic to Paleozoic,and the intra-continental deformation boundary in the Meso-Cenozoic.The basin survived as a marine cratonic basin covering the entire Ordos block during the Middle Proterozoic to Ordovician,a marine-continental transitional depression basin enclosed by an island arc uplift belt at the plate margin during the Carboniferous to Permian,a unified intra-continental lacustrine depression basin in the Triassic,and an intra-continental cratonic basin circled by a rift system in the Cenozoic.The basin scope has been decreasing till the present.The large,widespread prototype basin controlled the exploration area far beyond the present-day sedimentary basin boundary,with multiple target plays vertically.The Ordos Basin has the characteristics of a whole petroleum(or deposition)system.The Middle Proterozoic wide-rift system as a typical basin under the overlying Phanerozoic basin and the Cambrian-Ordovician passive margin basin and intra-cratonic depression in the deep-sited basin will be the important successions for oil and gas exploration in the coming years.展开更多
An integrated geologic study was performed in the Baiyun–Liwan deep water areas,Pearl River Mouth Basin,based on the achievements obtained during the past five exploration stages.The following understandings were obt...An integrated geologic study was performed in the Baiyun–Liwan deep water areas,Pearl River Mouth Basin,based on the achievements obtained during the past five exploration stages.The following understandings were obtained.(1)The Baiyun Sag has superior source rock conditions and has experienced three tectonic evaluation stages like rifting,rifting-depression and depression.The Wenchang–Enping Fms deposited during the rifting stage have large hydrocarbon generation potentials.During the rifting-depression and depression stages,the deposition in the study area was controlled by the Oligocene and Miocene shelf slope break zones.The Oligocene Zhuhai Fm shallow marine delta-longshore depositional system and the Miocene Zhujiang–Hanjiang Fms deep fan depositional system were formed,and they are the most favorable reservoir-caprock assemblages in the study area.(2)The Hydrocarbon accumulation pattern in the deep waters is different from that in the northern shallow waters.Shelf slope break zone,composite conduction system consisting of structural ridge,fault,sandbody,unconformity and fluid diapir as well as late tectonic movement are the three major factors controlling hydrocarbon migration and accumulation in the study area.(3)The Liwan 3-1 gas field is a typical example.The superior trapping conditions,high-quality reservoirs of delta distributary channel controlled by shelf slope break zone,vertical conduction system consisting of fault and diapir,as well as the overlying massive marine mudstone caprock provide favorable geologic conditions for the formation of large gas fields.Four areas were identified as the targets of gas exploration in the near future:the deep water fan system in the central sag,the structural-stratigraphic traps in the uplifted areas on both sides of the main sag of Baiyun,a series of large structural traps on the fault terrace to the southwest of the main sag,and the ultra-deep frontiers in sags such as Liwan to the south of the main sag.展开更多
In 2001, the International Seabed Authority （ISBA） initiated the consideration relating to the Regulations for Prospecting and Exploration for Hydrothermal Polymetallic Sulphides and Cobalt-rich Ferromanganese Crust...In 2001, the International Seabed Authority （ISBA） initiated the consideration relating to the Regulations for Prospecting and Exploration for Hydrothermal Polymetallic Sulphides and Cobalt-rich Ferromanganese Crusts in the Area at its 7th session. Since then, the consideration of the Regulations has been mainly focused on the size of areas to be allocated for exploration and exploitation of the crusts. This paper, based on the investigation data and the analysis of the distribution characteristics of the crusts, suggests a model for determining the size of areas for exploration and exploitation of the crusts, taking into account various factors such as production scale, crust thickness and grade, mineable area proportion, recovery efficiency, exploration venture, and so on. Through the modeling, the paper suggests that the exploration area （the area covered by each application for approval of a plan of work for exploration of cobalt-rich crusts） shall be 4 856 km2 and the exploitation area （the mine site area） shall be 1 214 km2, for 20 years of 1 million wet tonnes annual production.展开更多
The geothermal resources in Fujian Province are mainly hydrothermal resources of medium-low temperature.To better understand the whole process and conditions of heat control in the middle and deep crust,this study foc...The geothermal resources in Fujian Province are mainly hydrothermal resources of medium-low temperature.To better understand the whole process and conditions of heat control in the middle and deep crust,this study focuses on the analysis of heat accumulation model in Hongtang Area of Xiamen,and the main conditions of the model such as faults and sags are explored and interpreted in detail by using gravity and wide-field electromagnetic methods.4 main faults(F33,F2,F12 and HT-F1)and 10 secondary faults(HT-F2,HT-F3,HT-F4,HT-F5,HT-F6,HT-F7,HT-F8,HT-F9,HT-F10 and HT-F11)were inferred,and the distribution range of sags was delineated.The convective geothermal system is composed of four components:Heat source,geothermal reservoir,heat-conductive fault and heat retaining cover,which form a quaternary heat accumulation model.According to the model,the intersection of the main faults F12,HTF1 and F33 can be delineated as the primary target area of geothermal exploration,while the intersection of the secondary faults(F12 and HT-F6;F12 and HT-F2;HT-F9,HT-F10 and F12;F12 and HT-F11;F33 and HT-F3;HT-F8 and HT-F3;HT-F2,HT-F10 and HT-F1)can be delineated as the secondary target area.Borehole DR01,which is located in the primary target area,shows that the water temperature increases from fast to slow in the depth range of 0–500 m,and stays at 36℃below 500 m.The reliability of the heat accumulation model and the target area was tested via geothermal boreholes,which is of great significance to the exploitation and utilization of geothermal resources in Hongtang Area of Xiamen.展开更多
The global trends in deepwater oil and gas exploration,characteristics of deepwater oil and gas discovery,and layout of deepwater oil and gas exploration business by seven major international oil companies are systema...The global trends in deepwater oil and gas exploration,characteristics of deepwater oil and gas discovery,and layout of deepwater oil and gas exploration business by seven major international oil companies are systematically analyzed using commercial databases(e.g.S&P Global and Rystad)and public information of oil companies.The deepwater area is currently the most important domain for global oil and gas exploration and discovery,with the most discoveries and reserves in passive continental margin basins.The deepwater discoveries have the greatest contribution to the total newly discovered oil and gas reserves in the sea areas,with an increasing number of lithological reservoirs discovered,and oil and gas discoveries mainly distributed in the Mesozoic–Cenozoic.The seven major international oil companies are widely active in various aspects of deepwater oil and gas exploration and development,and play a leading role.Based on years of theoretical understanding of global oil and gas geology and resource evaluation,it is proposed that favorable deepwater exploration areas in the future will mainly focus on three major areas:the Atlantic coast,the Indian Ocean periphery,and the Arctic Ocean periphery.Six suggestions are put forward for expanding overseas deepwater oil and gas exploration business:first,expand the sources for obtaining multi-user seismic data and improve the scientific selection of deepwater exploration areas;second,increase efforts to obtain deepwater exploration projects in key areas;third,adopt various methods to access into/exit from resource licenses flexibly;fourth,acquire licenses with large equity and operate in“dual-exploration”model;fifth,strengthen cooperation with leading international oil companies in deepwater technology;and sixth,improve business operation capabilities and gradually transform from“non-operators”to“operators”.展开更多
The global exploration investment, new oil and gas discoveries, exploration business adjustment strategies of oil companies in 2021, and future favorable exploration domains are systematically analyzed using commercia...The global exploration investment, new oil and gas discoveries, exploration business adjustment strategies of oil companies in 2021, and future favorable exploration domains are systematically analyzed using commercial databases such as IHS and public information of oil companies. It has been found that the world oil and gas exploration situation in 2021 has continued the downturn since the outbreak of COVID-19. The investment and drilling workload decreased slightly, but the success rate of exploration wells, especially deepwater exploration wells, increased significantly, and the newly discovered reserves increased slightly compared with last year. Deep waters of the passive continental margin basins are still the leading sites for discovering conventional large and medium-sized oil and gas fields. The conventional oil and gas exploration in deep formations of onshore petroliferous basins has been keeping a good state, with tight/shale oil and gas discoveries made in Saudi Arabia, Russia, and other countries. While strengthening the exploration and development of local resources, national, international, and independent oil companies have been focusing on major overseas frontiers using their advantages, including risk exploration in deep waters and natural gas. Future favorable exploration directions in the three major frontiers, the global deep waters, deep onshore formations, and unconventional resources, have been clarified. Four suggestions are put forward for the global exploration business of Chinese oil companies: first, a farm in global deepwater frontier basins in advance through bidding at a low cost and adopt the “dual exploration model” after making large-scale discoveries;second, enter new blocks of emerging hot basins in the world through farm-in and other ways, to find large oil and gas fields quickly;third, cooperate with national oil companies of the resource host countries in the form of joint research and actively participate exploration of deep onshore formations of petroliferous basins;fourth, track tight/shale oil and gas cooperation opportunities in a few countries such as Saudi Arabia and Russia, and take advantage of mature domestic theories and technologies to farm in at an appropriate time.展开更多
The Carboniferous shale in the Guizhong Depression of central Guangxi presents good exploration potential of shale gas,but its exploration effectiveness is restricted by the unclear distribution,quality and potential ...The Carboniferous shale in the Guizhong Depression of central Guangxi presents good exploration potential of shale gas,but its exploration effectiveness is restricted by the unclear distribution,quality and potential of high-quality shale.In this paper,the Lower Carboniferous Luzhai shale was taken as the research object in order to guide the exploration of Carboniferous shale gas in the Guizhong Depression.Based on the field outcrops,well drilling,well logging and test data of the Guizhong Depression and its surrounding areas,the shale formation was studied systematically based on the characteristics of distribution,organic geochemistry and reservoir,and the preservation conditions.Then,the development characteristics of black shale were confirmed and the distribution laws of high-quality shale were summarized.Finally,shale gas exploration was analyzed and the favorable exploration areas were defined.And the following research results were obtained.First,the Luzhai shale in the Guizhong Depression is mainly carbonaceous shale and siliceous shale of deepwater continental shelf facies.Second,the high-quality Luzhai shale is 20-60 m thick and it is characterized by high total organic carbon,good type of organic matters,moderate maturity of organic matter,high content of brittle minerals,good reservoir property and developed pores of organic matters.Third,regional caprocks and roofs&floors are well developed in the Liucheng Slope and the Yishan Sag.They are weakly deformed,suffer from less uplift and denudation,and are far away from the strong strikeeslip reverse fault,so they have good preservation conditions.Fourth,shallow wells which were drilled in the surface structures of the Guizhong Depression in the early stage present abundant gas shows,and most of them produce gas flow,which reveals a promising prospect of shale gas exploration in this area.In conclusion,the wide and gentle synclines with large burial depth in the Liucheng Slope and the Yishan Sag are the favorable areas for shale gas exploration in the Guizhong Depression.展开更多
To accelerate the petroleum exploration in deep sea of China,since the period of“the 11th Five-Year Plan”,the sedimentary process,source rock formation and hydrocarbon generation and expulsion process in deep-water ...To accelerate the petroleum exploration in deep sea of China,since the period of“the 11th Five-Year Plan”,the sedimentary process,source rock formation and hydrocarbon generation and expulsion process in deep-water area of the Qiongdongnan Basin in the western South China Sea have been studied systematically using the data like large-area 3D seismic survey,logging,drill core(cuttings)and geochemical analysis,providing three innovative understandings,i.e.excellent hydrocarbon source conditions,good accumulation conditions,and grouping and zonal distribution of large exploration targets.From the study,the following conclusions are drawn.First,the deep-water area located in the southern and central parts of the Qiongdongnan Basin was formed under the control of such tectonic events as IndosinianeEurasian Plate collision,Himalayan uplifting and South China Sea expansion,and experienced Paleogene lift and Neogene depression stages.Second,accompanied by lacustrine deposition,faulting activity was violent in Eocene;whereas in Early Oligocene,rift continued to develop under a sedimentary environment of marineeterrestrial transitional facies and littoral-neritic facies.Third,oil generation predominated Eocene lacustrine mudstone and gas generation predominated Lower Oligocene marineeterrestrial transitional facies coal-measure strata compose two sets of major source rocks.Fourth,analysis in respect of thermal evolution level,hydrocarbon generation volume and hydrocarbon generation intensity shows that Ledong,Lingshui,Baodao and Changchang sags belong to potential hydrocarbon-rich kitchens,among which Ledong and Lingshui sags have been proved to have great hydrocarbon generation potential by drilling.Fifth,researches of deep-water sedimentology and hydrocarbon accumulation dynamics reveal that Paleogene and Neogene plays are developed vertically,and favorable hydrocarbon accumulation zones like the Central Canyon lithologic trap zone(group),Changchang circum-sag trap zone(group)and southern Baodao fault terrace zone are developed horizontally in the area.Sixth,with its excellent petroleum accumulation conditions and great exploration potential,the Central Canyon lithologic trap zone should be taken as the preferred drilling target,which has been verified correct by the discovery of the Central Canyon Gas Field d the largest gas field in the northern South China Sea.展开更多
The gold concentration areas in the northwestern Jiaodong Peninsula constituted an important gold metallogenetic region in Eastern China during the Mesozoic. The deep geological bodies＇ texture characteristic is impo...The gold concentration areas in the northwestern Jiaodong Peninsula constituted an important gold metallogenetic region in Eastern China during the Mesozoic. The deep geological bodies＇ texture characteristic is important for exploring the resources thoroughly and understanding the metallogenic process. The detailed textures were revealed using high-resolution seismic profiles through the three major ore-controlling structures-Sanshandao fault zone, Jiaojia fault zone and Zhaoping fault zone. This study aims to establish a deep structural framework of this area. Based on their formation mechanism, the fault structures developed in the area can be divided into regional and local fault structures. The structural styles are characterised by superimposing their compressional, strike-slip and extensional multi-stage activities. The crust is cut by vertical structures corresponding to a left-lateral strike-slip fault system on the surface. Nearby these structures are the arc-shape structures formed by multi-stage magma intrusions into the upper crust. Bounded by the Tancheng–Lujiang and Muping–Jimo fault zones, the current Jiaodong block, developed a series of NE-trending strike-slip fault systems, was probably formed by the assemblage of several obliquely aligned blocks. The intensive magmatism and hydrothermal activity between the blocks induced large-scale mineralisation. It provides a new angle of view for understanding the cratonic destruction and large ore-concentration formed during the Mesozoic.展开更多
Large amounts of gas hydrate are distributed in the northern slope of the South China Sea,which is a potential threat of methane leakage.Aerobic methane oxidation by methanotrophs,significant methane biotransformation...Large amounts of gas hydrate are distributed in the northern slope of the South China Sea,which is a potential threat of methane leakage.Aerobic methane oxidation by methanotrophs,significant methane biotransformation that occurs in sediment surface and water column,can effectively reduce atmospheric emission of hydrate-decomposed methane.To identify active aerobic methanotrophs and their methane oxidation potential in sediments from the Shenhu Area in the South China Sea,multi-day enrichment incubations were conducted in this study.The results show that the methane oxidation rates in the studied sediments were 2.03‒2.36μmol/gdw/d,which were higher than those obtained by sediment incubations from other areas in marine ecosystems.Thus the authors suspect that the methane oxidation potential of methanotrophs was relatively higher in sediments from the Shenhu Area.After the incubations family Methylococcaea(type I methanotrophs)mainly consisted of genus Methylobacter and Methylococcaea_Other were predominant with an increased proportion of 70.3%,whereas Methylocaldum decreased simultaneously in the incubated sediments.Collectively,this study may help to gain a better understanding of the methane biotransformation in the Shenhu Area.展开更多
Natural gas resources in China are abundant. The undiscovered recoverable natural gas resources in China are estimated to be 19.27 ×10^12 m^3. Natural gas is mainly distributed in the middle and west China and of...Natural gas resources in China are abundant. The undiscovered recoverable natural gas resources in China are estimated to be 19.27 ×10^12 m^3. Natural gas is mainly distributed in the middle and west China and offshore areas of China. The Tarim Basin, Sichuan Basin, Ordos Basin, East China Sea Basin, Tsaidam Basin, Yinggehai Basin, and Qiongdongnan Basin are the main gas-bearing basins. The natural gas resources are not distributed evenly and are under-explored in China. The deeper horizons in east China, foreland basins and craton paleo-uplifts in the middle and west China, and the offshore basins are the main exploration areas in the future.展开更多
The Caledonian Palaeohigh is an important gas exploration domain of Sinian and Lower Paleozoic in western Central Sichuan Basin where gas discoveries have been made successively in recent years.In order to sort out th...The Caledonian Palaeohigh is an important gas exploration domain of Sinian and Lower Paleozoic in western Central Sichuan Basin where gas discoveries have been made successively in recent years.In order to sort out the relationship between the tectonic evolution of this Palaeohigh and hydrocarbon accumulation there,we carried out a new round of research based on previous study results.The evolution history of this Palaeohigh can be divided into seven episodes:the Late Sinian overall tilting and the youth form development of this Palaeohigh,the Cambrian-Ordovician syndepositional uplifting,the Silurian joint uplifting,the Devonian-Carboniferous uplifting and erosion,the Permian overall subsidence and deposition of regional caprock,the Triassic-Jurassic migration of structural high of the eastern segment of this Palaeohigh,and Cretaceous-Neogene strong deformation of the western segment of this Palaeohigh.The hydrocarbon accumulation in the Sinian-Lower Paleozoic experienced three evolution stages,namely the formation of ancient oil reservoirs in the Silurian-Triassic period,the development of the paleo-gas reservoirs in the Jurassic-Oligocene period,and differential evolution of gas reservoirs since the Miocene era.The Sinian-Lower Paleozoic paleo-reservoirs mainly occur in the Leshan-Ziyang-Gaoshiti-Longnǚsi zone and in the area to its north.The tectonic movement of the western segment of the Palaeohigh was strong,while its eastern segment was relatively stable since the later Himalayan epoch,which is favorable for gas accumulation and preservation.It is believed that the Gaoshiti-Moxi-Longnǚsi structural belt and its northern flank are not only favorable for the development of structural gas reservoirs in the Lower Paleozoic but also for gas reservoirs of karstic-lithologic type on the top of the Cambrian and Ordovician.The later type will be the major exploration target of this area in the future.展开更多
Oil-cracked gas,as the main type of high-over mature marine natural gas in China,is mainly derived from occluded hydrocarbon.So it is significant to carry out quantitative study on occluded hydrocarbon.In this paper,t...Oil-cracked gas,as the main type of high-over mature marine natural gas in China,is mainly derived from occluded hydrocarbon.So it is significant to carry out quantitative study on occluded hydrocarbon.In this paper,the occluded hydrocarbon volume of the main basins in China was calculated depending on their types,abundances and evolution stages by means of the forward method(experimental simulation)and the inversion method(geologic profile dissection).And then,occluded hydrocarbon evolution models were established for five types of source rocks(sapropelic,sapropelic prone hybrid,humic prone hybrid,humic and coal).It is shown that the hydrocarbon expulsion efficiency of sapropelic and sapropelic prone hybrid excellent source rocks is lower than 30%at the low-maturity stage,30%e60%at the principal oil generation stage,and 50%e80%at the high-maturity stage,which are all about 10%higher than that of humic prone hybrid and humic source rocks at the corresponding stages.The resource distribution and cracked gas expulsion of occluded hydrocarbon since the high-maturity stage of marine source rocks in the Sichuan Basin were preliminarily calculated on the basis of the evolution models.The cracked gas expulsion is 230.4×10^(12) m^(3) at the high evolution stage of occluded hydrocarbon of the Lower Cambrian Qiongzhusi Fm in this basin,and 12.3×10^(12) m^(3) from the source rocks of Sinian Doushantuo Fm,indicating good potential for natural gas resources.It is indicated that the favorable areas of occluded hydrocarbon cracked gas in the Qiongzhusi Fm source rocks in the Sichuan Basin include GaoshitieMoxi,Ziyang and Weiyuan,covering a favorable area of 4.3×10^(4) km^(2).展开更多
Various types of paleo-uplifts with different characteristics are developed in the Tarim Basin.Previously,there were multiple opinions on the pale-uplifts origins and structural evolution,so the oil and gas exploratio...Various types of paleo-uplifts with different characteristics are developed in the Tarim Basin.Previously,there were multiple opinions on the pale-uplifts origins and structural evolution,so the oil and gas exploration ideas and deployment in the Tarim Basin were not developed smoothly.In this paper,regional seismic interpretation and structural analysis were carried out on the deep marine carbonate rocks in this basin based on the new seismic and drilling data.Then combined with the structural denudation results,the paleo-structural frameworks were reconstructed.And finally,the formation stage and main controlling factors of paleo-uplifts were discussed.It is shown that the Middle Ordovician is the key period when regional extension was converted to compression in this basin,so stratigraphic,sedimentary and structural differences occurred.Before the deposition of Yijianfang Fm in late Middle Ordovician,three carbonate paleo-uplifts(i.e.,the Northern,Central and SW Tarim paleo-uplifts)begun to appear,and they were all broad-folded paleo-uplifts of nearly E-W striking and were formed at the same stage.The distribution and development of the Phanerozoic uplifts in this basin are restricted by the Northern and Southern Tarim basement paleuplifts of nearly E-W striking which were developed during the Precambrian.It is indicated that all the three paleo-uplifts are compressional paleo-uplifts originated from the convergence of the southern plate margin based on the basement paleo-uplifts and they are all characterized by similar structural characteristics and inherited formation and evolution.The current differences of paleo-uplifts are controlled by multi-stage intense structural reformation since the Silurian.It is concluded that the oil and gas exploration potential is immense in the carbonate reservoirs of well-preserved deep paleo-structural zones in a larger area.展开更多
Owing to the characteristics of chemical inertness,low molecular weight,low boiling point,strong permeability and high heat conductivity,helium is extensively used in the fields of aerospace,low-temperature supercondu...Owing to the characteristics of chemical inertness,low molecular weight,low boiling point,strong permeability and high heat conductivity,helium is extensively used in the fields of aerospace,low-temperature superconductivity,medicine and high tech,and it is a kind of irreplaceable strategic rare resource.So far,however,less research has been conducted on the enrichment of helium in natural gas reservoirs.To solve this problem,this paper discusses the classification standard of helium-rich gas reservoirs.Based on this,the origin,source and enrichment process of helium in typical helium-rich gas reservoirs are studied,highlighting the contribution of main helium sources to helium-rich gas reservoirs.In addition,helium enrichment models of helium-rich gas reservoir in petroliferous basins are established.And the following research results are obtained.First,6 helium enrichment models of two categories(crust-source helium enrichment and crust-mantle mixing helium enrichment)are established for different petroliferous basins in China.Second,helium-rich gas reservoirs are characterized by using the multiple helium supply and diverse helium enrichment model.And no matter what enrichment model it is,the contribution of the main helium source to gas reservoirs is indispensable.Third,the helium in the gas reservoirs of central and western basins is mainly crust-source helium,and its enrichment models include ancient formation water moving upward along the fault to dilute helium,helium enrichment in the process of natural gas migration along ancient reservoirs,and helium enrichment of shale gas.Fourth,the helium in the helium-rich gas reservoirs of eastern basins is of crust-mantle mixing origin and its enrichment models are mainly hydrocarbon gas based,carbon dioxide based and nitrogen based.In conclusion,the establishment of the helium enrichment models of helium-rich gas reservoirs in petroliferous basins provides reference and guidance for studying helium enrichment laws and main controlling factors and is of great significance to the evaluation of favorable helium exploration areas.展开更多
Taking a hydrocarbon zone or a basin group as a unit,this paper analyzed the vertical hydrocarbon generation regularity of onshore and offshore oil and gasfields in China,based on the theory of co-control of source an...Taking a hydrocarbon zone or a basin group as a unit,this paper analyzed the vertical hydrocarbon generation regularity of onshore and offshore oil and gasfields in China,based on the theory of co-control of source and heat.The results demonstrated that the hydrocarbon generation modes of oil and gasfields in China are orderly.First,the hydrocarbon zones in southeastern China offshore area,including the East and South China Sea basins,are dominated by single hydrocarbon generation mode,which displays as either single oil generation in the near shore or single gas generation in the offshore controlled by both source and heat.Second,the eastern hydrocarbon zones,including the Bohai Bay,Songliao and Jianghan basins and the North and South Yellow Sea basins,are dominated by a two-layer hydrocarbon generation mode,which performs as“upper oil and lower gas”.Third,the central hydrocarbon zones,including the Ordos,Sichuan and Chuxiong basins,are also dominated by the“upper oil and lower gas”two-layer hydrocarbon generation mode.In the Ordos Basin,gas is mainly generated in the Triassic,and oil is predominantly generated in the Paleozoic.In the Sichuan Basin,oil was discovered in the Jurassic,and gas was mostly discovered in the Sinian and Triassic.Fourth,the western hydrocarbon zones are dominated by a“sandwich”multi-layer mode,such as the Junggar,Tarim,Qaidam basins.In summary,the theory of co-control of source and heat will be widely applied to oil and gas exploration all over China.Oil targets should be focused on the near shore areas in the southeastern China sea,the upper strata in the eastern and middle hydrocarbon zones,and the Ordovician,Permian and Paleogene strata in the western hydrocarbon zone,while gas targets should be focused on the off-shore areas in the southeastern China sea,the Cambrian,Carboniferous,Jurassic,and Quaternary strata in the western hydrocarbon zone.A pattern of exploring gasfields under or outside oilfields and oilfields under or outside gasfields is presented.Therefore,there is still a great prospect for oil and gas exploration in China.展开更多
基金The Fundamental Research Funds for the Central Universities,CHD,under contract No.300102264106the Shaanxi Natural Science Basic Research Program under contract No.2025JC-YBQN-370the Scientific and Technological Project of CNOOC Research Institute Co.,Ltd.under contract No.CCL2021RCPS0167KQN.
文摘The Zhujiang(Pearl)River Mouth Basin(PRMB)is located in the northern part of the South China Sea,and it is one of China’s three major offshore hydrocarbon-rich basins,playing an indispensable role in meeting the country’s energy needs.Exploration for oil in the PRMB started early and has achieved remarkable results in some sags,but many sags have yet to yield significant discoveries,necessitating the search for new favorable exploration areas.The aim of this study is to analyze the deep structural characteristics of various sags in the PRMB and predict favorable exploration areas,providing corresponding support for the next strategic breakthrough in oil exploration.Some studies indicate a certain relationship between the Moho depth and crustal thickness and the occurrence of oil.In this paper,based on satellite altimetry gravity anomaly data,we utilize a Moho depth inversion method based on variable residual crustal density to obtain the Moho depth in the PRMB,from which the crustal thickness and crustal stretching factor of the basin are calculated.The results show that the Moho depth in the PRMB ranges from 10 km to 37 km,the crustal thickness ranges from 7 km to 35 km,and the crustal stretching factor ranges from 0.9 to 3.0.Finally,we propose a comprehensive evaluation scheme for oil resoureces based on the CRiteria Importance Through Intercriteria Correlation(CRITIC)method,which comprehensively evaluates multiple factors,such as the Cenozoic sedimentary filling scale,Cenozoic thickness,Moho depth,crustal thickness,and crustal stretching factor,and provides evaluation criteria for identifying hydrocarbon-rich sags.According to this evaluation scheme,the exploration potential is relatively high in the Liwan Sag,Jinghai Sag,Heshan Sag,and Jieyang Sag,which are favorable exploration areas.
基金supported by the Funds for the program of the National Natural Science Foundation (Noes. 41572060, U1133602)Projects of YM Lab (2011)Innovation Team of Yunnan province and KMUST (2008,2012)
文摘1 Introduction The huize Zn-Pb ore district in Yunnan province is locatedinthecentralsouthernofthe Sichuan—Yunnan—GuizhouPb-ZnPoly-metallic Mineralization Area in the southwestern margin of the Yangtze Block,and is strictly controlled by fault structures.It has developed to one of the famous production bases of lead&zinc and germanium in China.
基金Supported by the National Natural Science Foundation of China(42330810)Major Science and Technology Project of PetroChina Changqing Oilfield Company(ZDZX2021-01).
文摘Based on the analysis of surface geological survey,exploratory well,gravity-magnetic-electric and seismic data,and through mapping the sedimentary basin and its peripheral orogenic belts together,this paper explores systematically the boundary,distribution,geological structure,and tectonic attributes of the Ordos prototype basin in the geological historical periods.The results show that the Ordos block is bounded to the west by the Engorwusu Fault Zone,to the east by the Taihangshan Mountain Piedmont Fault Zone,to the north by the Solonker-Xilamuron Suture Zone,and to the south by the Shangnan-Danfeng Suture Zone.The Ordos Basin boundary was the plate tectonic boundary during the Middle Proterozoic to Paleozoic,and the intra-continental deformation boundary in the Meso-Cenozoic.The basin survived as a marine cratonic basin covering the entire Ordos block during the Middle Proterozoic to Ordovician,a marine-continental transitional depression basin enclosed by an island arc uplift belt at the plate margin during the Carboniferous to Permian,a unified intra-continental lacustrine depression basin in the Triassic,and an intra-continental cratonic basin circled by a rift system in the Cenozoic.The basin scope has been decreasing till the present.The large,widespread prototype basin controlled the exploration area far beyond the present-day sedimentary basin boundary,with multiple target plays vertically.The Ordos Basin has the characteristics of a whole petroleum(or deposition)system.The Middle Proterozoic wide-rift system as a typical basin under the overlying Phanerozoic basin and the Cambrian-Ordovician passive margin basin and intra-cratonic depression in the deep-sited basin will be the important successions for oil and gas exploration in the coming years.
文摘An integrated geologic study was performed in the Baiyun–Liwan deep water areas,Pearl River Mouth Basin,based on the achievements obtained during the past five exploration stages.The following understandings were obtained.(1)The Baiyun Sag has superior source rock conditions and has experienced three tectonic evaluation stages like rifting,rifting-depression and depression.The Wenchang–Enping Fms deposited during the rifting stage have large hydrocarbon generation potentials.During the rifting-depression and depression stages,the deposition in the study area was controlled by the Oligocene and Miocene shelf slope break zones.The Oligocene Zhuhai Fm shallow marine delta-longshore depositional system and the Miocene Zhujiang–Hanjiang Fms deep fan depositional system were formed,and they are the most favorable reservoir-caprock assemblages in the study area.(2)The Hydrocarbon accumulation pattern in the deep waters is different from that in the northern shallow waters.Shelf slope break zone,composite conduction system consisting of structural ridge,fault,sandbody,unconformity and fluid diapir as well as late tectonic movement are the three major factors controlling hydrocarbon migration and accumulation in the study area.(3)The Liwan 3-1 gas field is a typical example.The superior trapping conditions,high-quality reservoirs of delta distributary channel controlled by shelf slope break zone,vertical conduction system consisting of fault and diapir,as well as the overlying massive marine mudstone caprock provide favorable geologic conditions for the formation of large gas fields.Four areas were identified as the targets of gas exploration in the near future:the deep water fan system in the central sag,the structural-stratigraphic traps in the uplifted areas on both sides of the main sag of Baiyun,a series of large structural traps on the fault terrace to the southwest of the main sag,and the ultra-deep frontiers in sags such as Liwan to the south of the main sag.
基金China International Seabed Area R & D Program under contract No.DYXM-115-01-1
文摘In 2001, the International Seabed Authority （ISBA） initiated the consideration relating to the Regulations for Prospecting and Exploration for Hydrothermal Polymetallic Sulphides and Cobalt-rich Ferromanganese Crusts in the Area at its 7th session. Since then, the consideration of the Regulations has been mainly focused on the size of areas to be allocated for exploration and exploitation of the crusts. This paper, based on the investigation data and the analysis of the distribution characteristics of the crusts, suggests a model for determining the size of areas for exploration and exploitation of the crusts, taking into account various factors such as production scale, crust thickness and grade, mineable area proportion, recovery efficiency, exploration venture, and so on. Through the modeling, the paper suggests that the exploration area （the area covered by each application for approval of a plan of work for exploration of cobalt-rich crusts） shall be 4 856 km2 and the exploitation area （the mine site area） shall be 1 214 km2, for 20 years of 1 million wet tonnes annual production.
基金supported by the National Natural Science Foundation of China (Grants Nos. 41902242)the Geological Survey Projects Foundation of the Institute of Hydrogeology and Environmental Geology (Grants Nos. DD20190303, DD20221773)。
文摘The geothermal resources in Fujian Province are mainly hydrothermal resources of medium-low temperature.To better understand the whole process and conditions of heat control in the middle and deep crust,this study focuses on the analysis of heat accumulation model in Hongtang Area of Xiamen,and the main conditions of the model such as faults and sags are explored and interpreted in detail by using gravity and wide-field electromagnetic methods.4 main faults(F33,F2,F12 and HT-F1)and 10 secondary faults(HT-F2,HT-F3,HT-F4,HT-F5,HT-F6,HT-F7,HT-F8,HT-F9,HT-F10 and HT-F11)were inferred,and the distribution range of sags was delineated.The convective geothermal system is composed of four components:Heat source,geothermal reservoir,heat-conductive fault and heat retaining cover,which form a quaternary heat accumulation model.According to the model,the intersection of the main faults F12,HTF1 and F33 can be delineated as the primary target area of geothermal exploration,while the intersection of the secondary faults(F12 and HT-F6;F12 and HT-F2;HT-F9,HT-F10 and F12;F12 and HT-F11;F33 and HT-F3;HT-F8 and HT-F3;HT-F2,HT-F10 and HT-F1)can be delineated as the secondary target area.Borehole DR01,which is located in the primary target area,shows that the water temperature increases from fast to slow in the depth range of 0–500 m,and stays at 36℃below 500 m.The reliability of the heat accumulation model and the target area was tested via geothermal boreholes,which is of great significance to the exploitation and utilization of geothermal resources in Hongtang Area of Xiamen.
基金CNPC Major Science and Technology Projects(2023ZZ07-01,2023ZZ07-02,2023ZZ07-05).
文摘The global trends in deepwater oil and gas exploration,characteristics of deepwater oil and gas discovery,and layout of deepwater oil and gas exploration business by seven major international oil companies are systematically analyzed using commercial databases(e.g.S&P Global and Rystad)and public information of oil companies.The deepwater area is currently the most important domain for global oil and gas exploration and discovery,with the most discoveries and reserves in passive continental margin basins.The deepwater discoveries have the greatest contribution to the total newly discovered oil and gas reserves in the sea areas,with an increasing number of lithological reservoirs discovered,and oil and gas discoveries mainly distributed in the Mesozoic–Cenozoic.The seven major international oil companies are widely active in various aspects of deepwater oil and gas exploration and development,and play a leading role.Based on years of theoretical understanding of global oil and gas geology and resource evaluation,it is proposed that favorable deepwater exploration areas in the future will mainly focus on three major areas:the Atlantic coast,the Indian Ocean periphery,and the Arctic Ocean periphery.Six suggestions are put forward for expanding overseas deepwater oil and gas exploration business:first,expand the sources for obtaining multi-user seismic data and improve the scientific selection of deepwater exploration areas;second,increase efforts to obtain deepwater exploration projects in key areas;third,adopt various methods to access into/exit from resource licenses flexibly;fourth,acquire licenses with large equity and operate in“dual-exploration”model;fifth,strengthen cooperation with leading international oil companies in deepwater technology;and sixth,improve business operation capabilities and gradually transform from“non-operators”to“operators”.
基金Petro China Scientific Research and Technology Development Project(2021DJ3101,2022-FW-041)。
文摘The global exploration investment, new oil and gas discoveries, exploration business adjustment strategies of oil companies in 2021, and future favorable exploration domains are systematically analyzed using commercial databases such as IHS and public information of oil companies. It has been found that the world oil and gas exploration situation in 2021 has continued the downturn since the outbreak of COVID-19. The investment and drilling workload decreased slightly, but the success rate of exploration wells, especially deepwater exploration wells, increased significantly, and the newly discovered reserves increased slightly compared with last year. Deep waters of the passive continental margin basins are still the leading sites for discovering conventional large and medium-sized oil and gas fields. The conventional oil and gas exploration in deep formations of onshore petroliferous basins has been keeping a good state, with tight/shale oil and gas discoveries made in Saudi Arabia, Russia, and other countries. While strengthening the exploration and development of local resources, national, international, and independent oil companies have been focusing on major overseas frontiers using their advantages, including risk exploration in deep waters and natural gas. Future favorable exploration directions in the three major frontiers, the global deep waters, deep onshore formations, and unconventional resources, have been clarified. Four suggestions are put forward for the global exploration business of Chinese oil companies: first, a farm in global deepwater frontier basins in advance through bidding at a low cost and adopt the “dual exploration model” after making large-scale discoveries;second, enter new blocks of emerging hot basins in the world through farm-in and other ways, to find large oil and gas fields quickly;third, cooperate with national oil companies of the resource host countries in the form of joint research and actively participate exploration of deep onshore formations of petroliferous basins;fourth, track tight/shale oil and gas cooperation opportunities in a few countries such as Saudi Arabia and Russia, and take advantage of mature domestic theories and technologies to farm in at an appropriate time.
基金Project supported by the National Major Science and Technology Project“Shale Gas Play Evaluation and Exploration Technologies”(No.:2017ZX05036).
文摘The Carboniferous shale in the Guizhong Depression of central Guangxi presents good exploration potential of shale gas,but its exploration effectiveness is restricted by the unclear distribution,quality and potential of high-quality shale.In this paper,the Lower Carboniferous Luzhai shale was taken as the research object in order to guide the exploration of Carboniferous shale gas in the Guizhong Depression.Based on the field outcrops,well drilling,well logging and test data of the Guizhong Depression and its surrounding areas,the shale formation was studied systematically based on the characteristics of distribution,organic geochemistry and reservoir,and the preservation conditions.Then,the development characteristics of black shale were confirmed and the distribution laws of high-quality shale were summarized.Finally,shale gas exploration was analyzed and the favorable exploration areas were defined.And the following research results were obtained.First,the Luzhai shale in the Guizhong Depression is mainly carbonaceous shale and siliceous shale of deepwater continental shelf facies.Second,the high-quality Luzhai shale is 20-60 m thick and it is characterized by high total organic carbon,good type of organic matters,moderate maturity of organic matter,high content of brittle minerals,good reservoir property and developed pores of organic matters.Third,regional caprocks and roofs&floors are well developed in the Liucheng Slope and the Yishan Sag.They are weakly deformed,suffer from less uplift and denudation,and are far away from the strong strikeeslip reverse fault,so they have good preservation conditions.Fourth,shallow wells which were drilled in the surface structures of the Guizhong Depression in the early stage present abundant gas shows,and most of them produce gas flow,which reveals a promising prospect of shale gas exploration in this area.In conclusion,the wide and gentle synclines with large burial depth in the Liucheng Slope and the Yishan Sag are the favorable areas for shale gas exploration in the Guizhong Depression.
基金Special and Significant Project of National Science and Technology“Evaluation on hydrocarbon-rich sags in deep water regions of northern South China Sea”(No.:2011ZX05025-002).
文摘To accelerate the petroleum exploration in deep sea of China,since the period of“the 11th Five-Year Plan”,the sedimentary process,source rock formation and hydrocarbon generation and expulsion process in deep-water area of the Qiongdongnan Basin in the western South China Sea have been studied systematically using the data like large-area 3D seismic survey,logging,drill core(cuttings)and geochemical analysis,providing three innovative understandings,i.e.excellent hydrocarbon source conditions,good accumulation conditions,and grouping and zonal distribution of large exploration targets.From the study,the following conclusions are drawn.First,the deep-water area located in the southern and central parts of the Qiongdongnan Basin was formed under the control of such tectonic events as IndosinianeEurasian Plate collision,Himalayan uplifting and South China Sea expansion,and experienced Paleogene lift and Neogene depression stages.Second,accompanied by lacustrine deposition,faulting activity was violent in Eocene;whereas in Early Oligocene,rift continued to develop under a sedimentary environment of marineeterrestrial transitional facies and littoral-neritic facies.Third,oil generation predominated Eocene lacustrine mudstone and gas generation predominated Lower Oligocene marineeterrestrial transitional facies coal-measure strata compose two sets of major source rocks.Fourth,analysis in respect of thermal evolution level,hydrocarbon generation volume and hydrocarbon generation intensity shows that Ledong,Lingshui,Baodao and Changchang sags belong to potential hydrocarbon-rich kitchens,among which Ledong and Lingshui sags have been proved to have great hydrocarbon generation potential by drilling.Fifth,researches of deep-water sedimentology and hydrocarbon accumulation dynamics reveal that Paleogene and Neogene plays are developed vertically,and favorable hydrocarbon accumulation zones like the Central Canyon lithologic trap zone(group),Changchang circum-sag trap zone(group)and southern Baodao fault terrace zone are developed horizontally in the area.Sixth,with its excellent petroleum accumulation conditions and great exploration potential,the Central Canyon lithologic trap zone should be taken as the preferred drilling target,which has been verified correct by the discovery of the Central Canyon Gas Field d the largest gas field in the northern South China Sea.
基金supported by a project of Special Research on Land and Research Public Welfare Industry(201511029)founded by Ministry of Land and Resources of the People’s Republic of China
文摘The gold concentration areas in the northwestern Jiaodong Peninsula constituted an important gold metallogenetic region in Eastern China during the Mesozoic. The deep geological bodies＇ texture characteristic is important for exploring the resources thoroughly and understanding the metallogenic process. The detailed textures were revealed using high-resolution seismic profiles through the three major ore-controlling structures-Sanshandao fault zone, Jiaojia fault zone and Zhaoping fault zone. This study aims to establish a deep structural framework of this area. Based on their formation mechanism, the fault structures developed in the area can be divided into regional and local fault structures. The structural styles are characterised by superimposing their compressional, strike-slip and extensional multi-stage activities. The crust is cut by vertical structures corresponding to a left-lateral strike-slip fault system on the surface. Nearby these structures are the arc-shape structures formed by multi-stage magma intrusions into the upper crust. Bounded by the Tancheng–Lujiang and Muping–Jimo fault zones, the current Jiaodong block, developed a series of NE-trending strike-slip fault systems, was probably formed by the assemblage of several obliquely aligned blocks. The intensive magmatism and hydrothermal activity between the blocks induced large-scale mineralisation. It provides a new angle of view for understanding the cratonic destruction and large ore-concentration formed during the Mesozoic.
基金jointly supported by the National Natural Science Foundation of China (42106052)Shandong Provincial Natural Science Foundation (ZR2020QD070)the project of China Geological Survey (DD20190221)。
文摘Large amounts of gas hydrate are distributed in the northern slope of the South China Sea,which is a potential threat of methane leakage.Aerobic methane oxidation by methanotrophs,significant methane biotransformation that occurs in sediment surface and water column,can effectively reduce atmospheric emission of hydrate-decomposed methane.To identify active aerobic methanotrophs and their methane oxidation potential in sediments from the Shenhu Area in the South China Sea,multi-day enrichment incubations were conducted in this study.The results show that the methane oxidation rates in the studied sediments were 2.03‒2.36μmol/gdw/d,which were higher than those obtained by sediment incubations from other areas in marine ecosystems.Thus the authors suspect that the methane oxidation potential of methanotrophs was relatively higher in sediments from the Shenhu Area.After the incubations family Methylococcaea(type I methanotrophs)mainly consisted of genus Methylobacter and Methylococcaea_Other were predominant with an increased proportion of 70.3%,whereas Methylocaldum decreased simultaneously in the incubated sediments.Collectively,this study may help to gain a better understanding of the methane biotransformation in the Shenhu Area.
文摘Natural gas resources in China are abundant. The undiscovered recoverable natural gas resources in China are estimated to be 19.27 ×10^12 m^3. Natural gas is mainly distributed in the middle and west China and offshore areas of China. The Tarim Basin, Sichuan Basin, Ordos Basin, East China Sea Basin, Tsaidam Basin, Yinggehai Basin, and Qiongdongnan Basin are the main gas-bearing basins. The natural gas resources are not distributed evenly and are under-explored in China. The deeper horizons in east China, foreland basins and craton paleo-uplifts in the middle and west China, and the offshore basins are the main exploration areas in the future.
文摘The Caledonian Palaeohigh is an important gas exploration domain of Sinian and Lower Paleozoic in western Central Sichuan Basin where gas discoveries have been made successively in recent years.In order to sort out the relationship between the tectonic evolution of this Palaeohigh and hydrocarbon accumulation there,we carried out a new round of research based on previous study results.The evolution history of this Palaeohigh can be divided into seven episodes:the Late Sinian overall tilting and the youth form development of this Palaeohigh,the Cambrian-Ordovician syndepositional uplifting,the Silurian joint uplifting,the Devonian-Carboniferous uplifting and erosion,the Permian overall subsidence and deposition of regional caprock,the Triassic-Jurassic migration of structural high of the eastern segment of this Palaeohigh,and Cretaceous-Neogene strong deformation of the western segment of this Palaeohigh.The hydrocarbon accumulation in the Sinian-Lower Paleozoic experienced three evolution stages,namely the formation of ancient oil reservoirs in the Silurian-Triassic period,the development of the paleo-gas reservoirs in the Jurassic-Oligocene period,and differential evolution of gas reservoirs since the Miocene era.The Sinian-Lower Paleozoic paleo-reservoirs mainly occur in the Leshan-Ziyang-Gaoshiti-Longnǚsi zone and in the area to its north.The tectonic movement of the western segment of the Palaeohigh was strong,while its eastern segment was relatively stable since the later Himalayan epoch,which is favorable for gas accumulation and preservation.It is believed that the Gaoshiti-Moxi-Longnǚsi structural belt and its northern flank are not only favorable for the development of structural gas reservoirs in the Lower Paleozoic but also for gas reservoirs of karstic-lithologic type on the top of the Cambrian and Ordovician.The later type will be the major exploration target of this area in the future.
基金National Major S&T Project“Formation Conditions,Accumulation Regularity and Target Evaluation of Large Gas Fields”(Grant No.2011ZX05007).
文摘Oil-cracked gas,as the main type of high-over mature marine natural gas in China,is mainly derived from occluded hydrocarbon.So it is significant to carry out quantitative study on occluded hydrocarbon.In this paper,the occluded hydrocarbon volume of the main basins in China was calculated depending on their types,abundances and evolution stages by means of the forward method(experimental simulation)and the inversion method(geologic profile dissection).And then,occluded hydrocarbon evolution models were established for five types of source rocks(sapropelic,sapropelic prone hybrid,humic prone hybrid,humic and coal).It is shown that the hydrocarbon expulsion efficiency of sapropelic and sapropelic prone hybrid excellent source rocks is lower than 30%at the low-maturity stage,30%e60%at the principal oil generation stage,and 50%e80%at the high-maturity stage,which are all about 10%higher than that of humic prone hybrid and humic source rocks at the corresponding stages.The resource distribution and cracked gas expulsion of occluded hydrocarbon since the high-maturity stage of marine source rocks in the Sichuan Basin were preliminarily calculated on the basis of the evolution models.The cracked gas expulsion is 230.4×10^(12) m^(3) at the high evolution stage of occluded hydrocarbon of the Lower Cambrian Qiongzhusi Fm in this basin,and 12.3×10^(12) m^(3) from the source rocks of Sinian Doushantuo Fm,indicating good potential for natural gas resources.It is indicated that the favorable areas of occluded hydrocarbon cracked gas in the Qiongzhusi Fm source rocks in the Sichuan Basin include GaoshitieMoxi,Ziyang and Weiyuan,covering a favorable area of 4.3×10^(4) km^(2).
基金Project supported by the National Major S&T Project(Grant No.2011ZX05004&2011ZX05003-004)the National Natural Science Fund Project(Grant No.41472103).
文摘Various types of paleo-uplifts with different characteristics are developed in the Tarim Basin.Previously,there were multiple opinions on the pale-uplifts origins and structural evolution,so the oil and gas exploration ideas and deployment in the Tarim Basin were not developed smoothly.In this paper,regional seismic interpretation and structural analysis were carried out on the deep marine carbonate rocks in this basin based on the new seismic and drilling data.Then combined with the structural denudation results,the paleo-structural frameworks were reconstructed.And finally,the formation stage and main controlling factors of paleo-uplifts were discussed.It is shown that the Middle Ordovician is the key period when regional extension was converted to compression in this basin,so stratigraphic,sedimentary and structural differences occurred.Before the deposition of Yijianfang Fm in late Middle Ordovician,three carbonate paleo-uplifts(i.e.,the Northern,Central and SW Tarim paleo-uplifts)begun to appear,and they were all broad-folded paleo-uplifts of nearly E-W striking and were formed at the same stage.The distribution and development of the Phanerozoic uplifts in this basin are restricted by the Northern and Southern Tarim basement paleuplifts of nearly E-W striking which were developed during the Precambrian.It is indicated that all the three paleo-uplifts are compressional paleo-uplifts originated from the convergence of the southern plate margin based on the basement paleo-uplifts and they are all characterized by similar structural characteristics and inherited formation and evolution.The current differences of paleo-uplifts are controlled by multi-stage intense structural reformation since the Silurian.It is concluded that the oil and gas exploration potential is immense in the carbonate reservoirs of well-preserved deep paleo-structural zones in a larger area.
基金supported by the National Natural Science Foundation of China“Water-soluble gas accumulation and its quantitative research method based on rare gas tracking”(No.41872162)the National Natural Science Foundation of China“Enrichment mechanism and resource potential of helium in superimposed basins in central-western China”(No.42141022).
文摘Owing to the characteristics of chemical inertness,low molecular weight,low boiling point,strong permeability and high heat conductivity,helium is extensively used in the fields of aerospace,low-temperature superconductivity,medicine and high tech,and it is a kind of irreplaceable strategic rare resource.So far,however,less research has been conducted on the enrichment of helium in natural gas reservoirs.To solve this problem,this paper discusses the classification standard of helium-rich gas reservoirs.Based on this,the origin,source and enrichment process of helium in typical helium-rich gas reservoirs are studied,highlighting the contribution of main helium sources to helium-rich gas reservoirs.In addition,helium enrichment models of helium-rich gas reservoir in petroliferous basins are established.And the following research results are obtained.First,6 helium enrichment models of two categories(crust-source helium enrichment and crust-mantle mixing helium enrichment)are established for different petroliferous basins in China.Second,helium-rich gas reservoirs are characterized by using the multiple helium supply and diverse helium enrichment model.And no matter what enrichment model it is,the contribution of the main helium source to gas reservoirs is indispensable.Third,the helium in the gas reservoirs of central and western basins is mainly crust-source helium,and its enrichment models include ancient formation water moving upward along the fault to dilute helium,helium enrichment in the process of natural gas migration along ancient reservoirs,and helium enrichment of shale gas.Fourth,the helium in the helium-rich gas reservoirs of eastern basins is of crust-mantle mixing origin and its enrichment models are mainly hydrocarbon gas based,carbon dioxide based and nitrogen based.In conclusion,the establishment of the helium enrichment models of helium-rich gas reservoirs in petroliferous basins provides reference and guidance for studying helium enrichment laws and main controlling factors and is of great significance to the evaluation of favorable helium exploration areas.
基金National Basic Research Program of China(973 Program)“Fundamental research on petroleum resources generation and distribution in deep basins in the South China Sea”(No.2009CB219400)National Science and Technology Major Project“Key technologies of deep sea petroleum exploration”(No.2008ZX05025,2011ZX05025).
文摘Taking a hydrocarbon zone or a basin group as a unit,this paper analyzed the vertical hydrocarbon generation regularity of onshore and offshore oil and gasfields in China,based on the theory of co-control of source and heat.The results demonstrated that the hydrocarbon generation modes of oil and gasfields in China are orderly.First,the hydrocarbon zones in southeastern China offshore area,including the East and South China Sea basins,are dominated by single hydrocarbon generation mode,which displays as either single oil generation in the near shore or single gas generation in the offshore controlled by both source and heat.Second,the eastern hydrocarbon zones,including the Bohai Bay,Songliao and Jianghan basins and the North and South Yellow Sea basins,are dominated by a two-layer hydrocarbon generation mode,which performs as“upper oil and lower gas”.Third,the central hydrocarbon zones,including the Ordos,Sichuan and Chuxiong basins,are also dominated by the“upper oil and lower gas”two-layer hydrocarbon generation mode.In the Ordos Basin,gas is mainly generated in the Triassic,and oil is predominantly generated in the Paleozoic.In the Sichuan Basin,oil was discovered in the Jurassic,and gas was mostly discovered in the Sinian and Triassic.Fourth,the western hydrocarbon zones are dominated by a“sandwich”multi-layer mode,such as the Junggar,Tarim,Qaidam basins.In summary,the theory of co-control of source and heat will be widely applied to oil and gas exploration all over China.Oil targets should be focused on the near shore areas in the southeastern China sea,the upper strata in the eastern and middle hydrocarbon zones,and the Ordovician,Permian and Paleogene strata in the western hydrocarbon zone,while gas targets should be focused on the off-shore areas in the southeastern China sea,the Cambrian,Carboniferous,Jurassic,and Quaternary strata in the western hydrocarbon zone.A pattern of exploring gasfields under or outside oilfields and oilfields under or outside gasfields is presented.Therefore,there is still a great prospect for oil and gas exploration in China.
