The year of 2024 marks the 50th anniversary of the publication of Petroleum Exploration and Development.For half a century,Petroleum Exploration and Development has been committed to disseminating petroleum technology...The year of 2024 marks the 50th anniversary of the publication of Petroleum Exploration and Development.For half a century,Petroleum Exploration and Development has been committed to disseminating petroleum technology,witnessing and recording the glorious journey of China's petroleum industry from being weak to becoming strong.The journal has also become a bright banner in China's petroleum technology industry.展开更多
After years of strenuous efforts and with the approval of the State Administration of Press,Publication,Radio,Film and Television of the People's Republic of China,the Petroleum Exploration and Development(English...After years of strenuous efforts and with the approval of the State Administration of Press,Publication,Radio,Film and Television of the People's Republic of China,the Petroleum Exploration and Development(English Version)is officially published in hard copy.The publication of the English version comes at the right time when China is witnessing further deepening in its reform and opening up and all-round development in its science and technology.We are confident that the journal will further advance the progress and development of petroleum science and technology,promote exchanges and cooperation in petroleum science and technology,and make contributions to the development of the petroleum industry.展开更多
The Neogene Shawan Formation in the Chepaizi Uplift of the Junggar Basin(NW China)has obtained high oil flow,demonstrating a good potential for oil and gas exploration.The multi-source hydrocarbon generation backgroun...The Neogene Shawan Formation in the Chepaizi Uplift of the Junggar Basin(NW China)has obtained high oil flow,demonstrating a good potential for oil and gas exploration.The multi-source hydrocarbon generation background and strong tectonic activity have led to the simultaneous production of heavy oil and light oil from multi-layer in the area,which makes it very difficult to identify oil origins,presently,the hot debate on the oil origins needs to be clarified.In this paper,due to the selective consumption of different types of compounds in crude oils by severe and intense biodegradation,the commonly used oilsource correlation tools are ineffective or may produce misleading results,this study adopted a biomarker recovery method based on the principle of mass conservation that uses the sum of the mass of the residual biomarkers and their corresponding biodegradation products to obtain the mass of the original biomarkers,improving the reliability of oil origins determination.Based on the nature and occurrence of crude oils,the investigated oils are subdivided into three types,Group A,Group B and Group C.Group A,light oils occurred mainly in lower structure Neogene Shawan Formation in the western Chepaizi Uplift,while Group B,heavy oils occurred mainly in higher structure Neogene Shawan Formation in the western Chepaizi Uplift.The two types of crude oils may come from the mixed source of Jurassic Badaowan Formation source rocks(J_(1)b)and Paleogene Anjihaihe Formation source rocks(E_(2-3)a)in the Sikeshu Sag,and Jurassic Badaowan Formation source rocks(J_(1)b)are the main source of crude oils.Group C,heavy oils occurred mainly in Neogene Shawan Formation in the eastern Chepaizi Uplift,showing good correlation with the Permian(P_(1)f and P_(2)w)source rocks in the Shawan Sag.At the same time,by combining stable carbon isotope and parameters related to triaromatic steroids,the accuracy of the oilsource correlation results by biomarker recovery method was further verified.展开更多
The ultra-deep(deeper than 8000 m)petroleum in the platform-basin zones of the Tarim Basin has been found mainly in the Lower Paleozoic reservoirs located to the east of the strike-slip fault F5 in the north depressio...The ultra-deep(deeper than 8000 m)petroleum in the platform-basin zones of the Tarim Basin has been found mainly in the Lower Paleozoic reservoirs located to the east of the strike-slip fault F5 in the north depression.However,the source and exploration potential of the ultra-deep petroleum in the Cambrian on the west of F5 are still unclear.Through the analysis of lithofacies and biomarkers,it is revealed that there are at least three kinds of isochronous source rocks(SRs)in the Cambrian Newfoundland Series in Tarim Basin,which were deposited in three sedimentary environments,i.e.sulfide slope,deep-water shelf and restricted bay.In 2024,Well XT-1 in the western part of northern Tarim Basin has yielded a high production of condensate from the Cambrian.In the produced oil,entire aryl-isoprenoid alkane biomarkers were detected,but triaromatic dinosterane was absent.This finding is well consistent with the geochemical characteristics of the Newfoundland sulfidized slope SRs represented by those in wells LT-1 and QT-1,suggesting that the Newfoundland SRs are the main source of the Cambrian petroleum discovered in Well XT-1.Cambrian crude oil of Well XT-1 also presents the predominance of C29 steranes and is rich in long-chain tricyclic terpanes(up to C39),which can be the indicators for effectively distinguishing lithofacies such as siliceous mudstone and carbonate rock.Combined with the analysis of hydrocarbon accumulation in respect of conduction systems including thrust fault and strike-slip fault,it is found that the area to the west of F5 is possible to receive effective supply of hydrocarbons from the Cambrian Newfoundland SRs in Manxi hydrocarbon-generation center.This finding suggests that the area to the west of F5 will be a new target of exploration in the Cambrian ultra-deep structural-lithologic reservoirs in the Tarim Basin,in addition to the Cambrian ultra-deep platform-margin facies-controlled reservoirs in the eastern part of the basin.展开更多
As petroleum exploration advances and as most of the oil-gas reservoirs in shallow layers have been explored, petroleum exploration starts to move toward deep basins, which has become an inevitable choice. In this pap...As petroleum exploration advances and as most of the oil-gas reservoirs in shallow layers have been explored, petroleum exploration starts to move toward deep basins, which has become an inevitable choice. In this paper, the petroleum geology features and research progress on oil-gas reservoirs in deep petroliferous basins across the world are characterized by using the latest results of worldwide deep petroleum exploration. Research has demonstrated that the deep petroleum shows ten major geological features. （1） While oil-gas reservoirs have been discovered in many different types of deep petroliferous basins, most have been discovered in low heat flux deep basins. （2） Many types of petroliferous traps are developed in deep basins, and tight oil-gas reservoirs in deep basin traps are arousing increasing attention. （3） Deep petroleum normally has more natural gas than liquid oil, and the natural gas ratio increases with the burial depth. （4） The residual organic matter in deep source rocks reduces but the hydrocarbon expulsion rate and efficiency increase with the burial depth. （5） There are many types of rocks in deep hydrocarbon reservoirs, and most are clastic rocks and carbonates. （6） The age of deep hydrocarbon reservoirs is widely different, but those recently discovered are pre- dominantly Paleogene and Upper Paleozoic. （7） The porosity and permeability of deep hydrocarbon reservoirs differ widely, but they vary in a regular way with lithology and burial depth. （8） The temperatures of deep oil-gas reservoirs are widely different, but they typically vary with the burial depth and basin geothermal gradient. （9） The pressures of deep oil-gas reservoirs differ significantly, but they typically vary with burial depth, genesis, and evolu- tion period. （10） Deep oil-gas reservoirs may exist with or without a cap, and those without a cap are typically of unconventional genesis. Over the past decade, six major steps have been made in the understanding of deep hydrocarbon reservoir formation. （1） Deep petroleum in petroliferous basins has multiple sources and many dif- ferent genetic mechanisms. （2） There are high-porosity, high-permeability reservoirs in deep basins, the formation of which is associated with tectonic events and subsurface fluid movement. （3） Capillary pressure differences inside and outside the target reservoir are the principal driving force of hydrocarbon enrichment in deep basins. （4） There are three dynamic boundaries for deep oil-gas reservoirs; a buoyancy-controlled threshold, hydrocarbon accumulation limits, and the upper limit of hydrocarbon generation. （5） The formation and distribution of deep hydrocarbon res- ervoirs are controlled by free, limited, and bound fluid dynamic fields. And （6） tight conventional, tight deep, tight superimposed, and related reconstructed hydrocarbon reservoirs formed in deep-limited fluid dynamic fields have great resource potential and vast scope for exploration. Compared with middle-shallow strata, the petroleum geology and accumulation in deep basins are more complex, which overlap the feature of basin evolution in different stages. We recommend that further study should pay more attention to four aspects： （1） identification of deep petroleum sources and evaluation of their relative contributions; （2） preservation conditions and genetic mechanisms of deep high-quality reservoirs with high permeability and high porosity; （3） facies feature and transformation of deep petroleum and their potential distribution; and （4） economic feasibility evaluation of deep tight petroleum exploration and development.展开更多
Coal measures are significant hydrocarbon source rocks and reservoirs in petroliferous basins.Many large gas fields and coalbed methane fields globally are originated from coal-measure source rocks or accumulated in c...Coal measures are significant hydrocarbon source rocks and reservoirs in petroliferous basins.Many large gas fields and coalbed methane fields globally are originated from coal-measure source rocks or accumulated in coal rocks.Inspired by the discovery of shale oil and gas,and guided by“the overall exploration concept of considering coal rock as reservoir”,breakthroughs in the exploration and development of coal-rock gas have been achieved in deep coal seams with favorable preservation conditions,thereby opening up a new development frontier for the unconventional gas in coal-rock reservoirs.Based on the data from exploration and development practices,a systematic study on the accumulation mechanism of coal-rock gas has been conducted.The mechanisms of“three fields”controlling coal-rock gas accumulation are revealed.It is confirmed that the coal-rock gas is different from CBM in accumulation process.The whole petroleum systems in the Carboniferous–Permian transitional facies coal measures of the eastern margin of the Ordos Basin and in the Jurassic continental facies coal measures of the Junggar Basin are characterized,and the key research directions for further developing the whole petroleum system theory of coal measures are proposed.Coal rocks,compared to shale,possess intense hydrocarbon generation potential,strong adsorption capacity,dual-medium reservoir properties,and partial or weak oil and gas self-sealing capacity.Additionally,unlike other unconventional gas such as shale gas and tight gas,coal-rock gas exhibits more complex accumulation characteristics,and its accumulation requires a certain coal-rock play form lithological and structural traps.Coal-rock gas also has the characteristics of conventional fractured gas reservoirs.Compared with the basic theory and model of the whole petroleum system established based on detrital rock formations,coal measures have distinct characteristics and differences in coal-rock reservoirs and source-reservoir coupling.The whole petroleum system of coal measures is composed of various types of coal-measure hydrocarbon plays with coal(and dark shale)in coal measures as source rock and reservoir,and with adjacent tight layers as reservoirs or cap or transport layers.Under the action of source-reservoir coupling,coal-rock gas is accumulated in coal-rock reservoirs with good preservation conditions,tight oil/gas is accumulated in tight layers,conventional oil/gas is accumulated in traps far away from sources,and coalbed methane is accumulated in coal-rock reservoirs damaged by later geological processes.The proposed whole petroleum system of coal measures represents a novel type of whole petroleum system.展开更多
The shale gas resources in China have great potential and the geological resources of shale gas is over 100×10^(12)m^(3),which includes about 20×10^(12)m^(3) of recoverable resources.Organic-rich shales can ...The shale gas resources in China have great potential and the geological resources of shale gas is over 100×10^(12)m^(3),which includes about 20×10^(12)m^(3) of recoverable resources.Organic-rich shales can be divided into three types according to their sedimentary environments,namely marine,marine-continental transitional,and continental shales,which are distributed in 13 stratigraphic systems from the Mesoproterozoic to the Cenozoic.The Sichuan Basin and its surrounding areas have the highest geological resources of shale gas,and the commercial development of shale gas has been achieved in the Upper Ordovician Wufeng Formation-Lower Silurian Longmaxi Formation in these areas,with a shale gas production of up to 20×10^(9)m^(3) in 2020.China has seen rapid shale gas exploration and development over the last five years,successively achieving breakthroughs and important findings in many areas and strata.The details are as follows.(1)Large-scale development of middle-shallow shale gas(burial depth:less than 3500 m)has been realized,with the productivity having rapidly increased;(2)breakthroughs have been constantly made in the development of deep shale gas(burial depth:3500-4500 m),and the ultradeep shale gas(burial depth:greater than 4500 m)is under testing;(3)breakthroughs have been made in the development of normal-pressure shale gas,and the assessment of the shale gas in complex tectonic areas is being accelerated;(4)shale gas has been frequently discovered in new areas and new strata,exhibiting a great prospect.Based on the exploration and development practice,three aspects of consensus have been gradually reached on the research progress in the geological theories of shale gas achieved in China.(1)in terms of deep-water fine-grained sediments,organic-rich shales are the base for the formation of shale gas;(2)in terms of high-quality reservoirs,the development of micro-nano organic matter-hosted pores serves as the core of shale gas accumulation;(3)in terms of preservation conditions,weak structural transformation,a moderate degree of thermal evolution,and a high pressure coefficient are the key to shale gas enrichment.As a type of important low-carbon fossil energy,shale gas will play an increasingly important role in achieving the strategic goals of peak carbon dioxide emissions and carbon neutrality.Based on the in-depth study of shale gas geological conditions and current exploration progress,three important directions for shale gas exploration in China in the next five years are put forward.展开更多
Based on seismic,drilling,and source rock analysis data,the petroleum geological characteristics and future exploration direction of the oil-rich sags in the Central and West African Rift System(CWARS)are discussed.Th...Based on seismic,drilling,and source rock analysis data,the petroleum geological characteristics and future exploration direction of the oil-rich sags in the Central and West African Rift System(CWARS)are discussed.The study shows that the Central African Rift System mainly develops high-quality lacustrine source rocks in the Lower Cretaceous,and the West African Rift System mainly develops high-quality terrigenous organic matter-rich marine source rocks in the Upper Cretaceous,and the two types of source rocks provide a material basis for the enrichment of oil and gas in the CWARS.Multiple sets of reservoir rocks including fractured basement and three sets of regional cap rocks in the Lower Cretaceous,the Upper Cretaceous,and the Paleogene are developed in the CWARS.Since the Late Mesozoic,due to the geodynamic factors including the dextral strike-slip movement of the Central African Shear Zone,the basins in different directions of the CWARS differ in terms of rifting stages,intervals of regional cap rocks,trap types and accumulation models.The NE-SW trending basins have mainly preserved one stage of rifting in the Early Cretaceous,with regional cap rocks developed in the Lower Cretaceous strata,forming traps of reverse anticlines,flower-shaped structures and basement buried hill,and two types of hydrocarbon accumulation models of"source and reservoir in the same formation,and accumulation inside source rocks"and"up-source and down-reservoir,and accumulation below source rocks".The NW–SE basins are characterized by multiple rifting stages superimposition,with the development of regional cap rocks in the Upper Cretaceous and Paleogene,forming traps of draping anticlines,faulted anticlines,antithetic fault blocks and the accumulation model of"down-source and up-reservoir,and accumulation above source rocks".The combination of reservoir and cap rocks inside source rocks of basins with multiple superimposed rifting stages,as well as the lithologic reservoirs and the shale oil inside source rocks of strong inversion basins are important fields for future exploration in basins of the CWARS.展开更多
By examining field outcrops, drilling cores and seismic data, it is concluded that the Middle and Late Permian “Emeishan basalts” in Western Sichuan Basin were developed in two large eruption cycles, and the two set...By examining field outcrops, drilling cores and seismic data, it is concluded that the Middle and Late Permian “Emeishan basalts” in Western Sichuan Basin were developed in two large eruption cycles, and the two sets of igneous rocks are in unconformable contact. The lower cycle is dominated by overflow volcanic rocks;while the upper cycle made up of pyroclastic flow volcanic breccia and pyroclastic lava is typical explosive facies accumulation. With high-quality micro-dissolution pores and ultra-fine dissolution pores, the upper cycle is a set of high-quality porous reservoir. Based on strong heterogeneity and great differences of pyroclastic flow subfacies from surrounding rocks in lithology and physical properties, the volcanic facies and volcanic edifices in Western Sichuan were effectively predicted and characterized by using seismic attribute analysis method and instantaneous amplitude and instantaneous frequency coherence analysis. The pyroclastic flow volcanic rocks are widely distributed in the Jianyang area. Centering around wells YT1, TF2 and TF8, the volcanic rocks in Jianyang area had 3edifice groups and an area of about 500 km^(2), which is the most favorable area for oil and gas exploration in volcanic rocks.展开更多
In the past five years,shale gas exploration and development has grown in a leaping-forward way in China.Following USA and Canada,China is now the third country where industrial shale gas production is realized,with t...In the past five years,shale gas exploration and development has grown in a leaping-forward way in China.Following USA and Canada,China is now the third country where industrial shale gas production is realized,with the cumulative production exceeding 60×10^(8) m^(3) until the end of 2015.In this paper,the main achievements of shale gas exploration and development in China in recent years were reviewed and the future development prospect was analyzed.It is pointed out that shale gas exploration and development in China is,on the whole,still at its early stage.Especially,marine shale gas in the Sichuan Basin has dominated the recent exploration and development.For the realization of shale gas scale development in China,one key point lies in the breakthrough and industrial production of transitional facies and continental facies shale gas.Lowemoderate yield of shale gas wells is the normal in China,so it is crucial to develop key exploration and development technologies.Especially,strictly controlling single well investment and significantly reducing cost are the important means to increase shale gas exploration and development benefits.And finally,suggestions were proposed in five aspects.First,continuously strengthen theoretical and technical re-searches,actively carry out appraisal on shale gas“sweet spots”,and gradually accumulate development basis.Second,stress on primary evaluation of exploration and development,highlight the effective implementation of shale gas resources,and control the rhythm of appraisal drilling and productivity construction.Third,highlight fine description and evaluation of shale gas reservoirs and increase the overall devel-opment level.Fourth,intensify the research on exploration and development technologies in order to stand out simple and practical technologies with low costs.And fifth,summarize the experiences in fast growth of shale gas exploration and development,highlight the demonstration and evaluation of key indicators,and try to achieve more breakthroughs and replacement in new areas,new domains and new strata.展开更多
Fifty-one large gas fields had been proved in China until 2013.Specifically,exploration characteristics of those discovered since 2000 are as follows:(1)Large gas fields are only found in basins with sedimentary area ...Fifty-one large gas fields had been proved in China until 2013.Specifically,exploration characteristics of those discovered since 2000 are as follows:(1)Large gas fields are only found in basins with sedimentary area larger than 10×10^(4) km^(2);(2)Large gas fields have been proved in 9 basins,with total proved reserves of 27085.88×10^(8) m^(3) before 2005,much less than that after 2005,which reached 81683.77×10^(8) m^(3) by the end of 2013;(3)The reserve abundance of large gas fields varies a lot.The Kela2 gas field has the largest reserve abundance of 59.05×10^(8) m^(3)/km^(2),which is 86 times that of the smallest reserve abundance,i.e.0.684×10^(8) m^(3)/km^(2) of the Jingbian gas field;and(4)The reservoirs of large gas fields between 3000 m and 4500 m share a large proportion of proved reserves,accounting for 46.11%of the total.Development characteristics of the large gas fields in China are as follows:(1)The yield of large gas fields is essential to the natural gas industry of China.In 2013,the total yield was 922.72×10^(8) m^(3),accounting for 76.3%of the nation’s total natural gas yield;(2)The yield is dominated by coal-derived gas,which reached 710.13×10^(8) m^(3) in 2013,accounting for 77.0%of the total yield of large gas fields in China;and(3)The yield of key large gas fields(Sulige,Jingbian,Daniudi,Puguang,and Kela2)is fundamental in making China a major gas producer.展开更多
Under the guidance of the whole petroleum system theory,using seismic,drilling and laboratory analysis data,and combined with the practical achievements of oil and gas exploration,the distribution patterns of differen...Under the guidance of the whole petroleum system theory,using seismic,drilling and laboratory analysis data,and combined with the practical achievements of oil and gas exploration,the distribution patterns of different types of natural gas in the deep-water area of the Qiongdongnan Basin of China were systematically reviewed,the orderly symbiosis mechanisms and hydrocarbon accumulation processes of diverse gas reservoirs were analyzed,and a composite whole petroleum system model for the deep-water strongly active basins in the northern South China Sea was constructed.In the deep-water area of the Qiongdongnan Basin,there are three sets of source rocks,namely the Eocene,the Oligocene,and the upper Miocene-Quaternary,and three whole petroleum systems can be accordingly classified.The source rocks have the characteristics of multilayers,multiple types,and multiple hydrocarbon generation centers.The Eocene lacustrine source rocks,Oligocene marine and continental dual-origin source rocks,and upper Miocene-Quaternary marine source rocks form multiple hydrocarbon generation centers,which are orderly distributed from east to west.The reservoirs are characterized by multiple geological ages,multiple rock types,and multiple hydrodynamic influences,and exist as a reservoir composite superposition pattern with basement buried hill-lower traction flow sandbody-upper gravity flow sandbody vertically in the deep-water area.Fluid activities within the basin are controlled by free dynamic fields,confined dynamic fields,and bound dynamic fields.The natural gas in the whole petroleum system presents an orderly distribution of shale gas(speculated)-tight gas-conventional gas-ultra-shallow gas-hydrate from bottom to top.The research results have verified the adaptability of the whole petroleum system theory in the deep-water area of the Qiongdongnan Basin,providing a theoretical support for the exploration of complex oil and gas resources in the deep-water area,and are expected to effectively guide the distribution prediction and exploration of different types of petroleum resources in deep-water areas.展开更多
Exploration budgets for primary battery metals-nickel,lithium and cobalt-tempered in 2024 at$1.697 billion,reflecting a marginal 0.4%decline and a virtually flat annual total,compared to$1.704 billion in 2023.Below is...Exploration budgets for primary battery metals-nickel,lithium and cobalt-tempered in 2024 at$1.697 billion,reflecting a marginal 0.4%decline and a virtually flat annual total,compared to$1.704 billion in 2023.Below is an introduction to the 2024 global exploration trends and prospects for lithium,cobalt,and nickel battery metals.展开更多
Currently,unconventional reservoirs are characterized by low single well-controlled reserves,high initial production but fast production decline.This paper sorts out the problems of energy dispersion and limited lengt...Currently,unconventional reservoirs are characterized by low single well-controlled reserves,high initial production but fast production decline.This paper sorts out the problems of energy dispersion and limited length and height of main hydraulic fractures induced in staged multi-cluster fracturing,and proposes an innovative concept of“energy-focused fracturing development”.The technical connotation,theoretical model,and core techniques of energy-focused fracturing development are systematically examined,and the implementation path of this technology is determined.The energy-focused fracturing development technology incorporates the techniques such as geology-engineering integrated design,perforation optimization design,fracturing process design,and drainage engineering control.It transforms the numerous,short and dense hydraulic fractures to limited,long and sparse fractures.It focuses on fracturing energy,and aims to improve the fracture length,height and lateral width,and the proppant long-distance transportation capacity,thus enhancing the single well-controlled reserves and development effect.The energy-focused fracturing development technology has been successfully applied in the carbonate reservoirs in buried hill,shallow coalbed methane reservoirs,and coal-rock gas reservoirs in China,demonstrating the technology's promising application.It is concluded that the energy-focused fracturing development technology can significantly increase the single well production and estimated ultimate recovery(EUR),and will be helpful for efficiently developing low-permeability,unconventional and low-grade resources in China.展开更多
Research on the distribution and development of black shales in the Lianggaoshan Formation has been deficient,which has hindered exploration for lacustrine shale oil in the Sichuan Basin.Our study characterized the we...Research on the distribution and development of black shales in the Lianggaoshan Formation has been deficient,which has hindered exploration for lacustrine shale oil in the Sichuan Basin.Our study characterized the well logging data,core samples,outcrops,and geochemistry of black shales in the Lianggaoshan Formation in the Sichuan Basin.Our analysis focused on the lake basin evolution and the migration characteristics,paleoenvironmental features,formation mechanisms,and developmental model of the black shales.The results indicated that black shales in the Lianggaoshan Formation exhibited significant lateral migration,with an overall thickening trend from east to west.Within the 1st Member of the formation,black shale occurred as a single thick layer in the eastern region that gradually thinned toward the central region.Multiple sets of shale developed within the 2nd and 3rd members,and these had lower thicknesses than the 1st Member and migrated toward central Sichuan.Paleoproductivity and terrigenous input were the main factors controlling the deposition of black shales.A semi-humid climate influenced the deposition of black shales,bringing abundant freshwater,terrigenous debris,and nutrients into the basin.Decomposition of organic matter consumed oxygen in sediment and bottom water,causing localized oxygen deficiency in the strata.展开更多
The coal-bearing source rocks in the Jurassic Shuixigou Group have received widespread attention as the primary source rocks in the Turpan-Hami Basin of China,but the hydrocarbon generation potential and process of th...The coal-bearing source rocks in the Jurassic Shuixigou Group have received widespread attention as the primary source rocks in the Turpan-Hami Basin of China,but the hydrocarbon generation potential and process of the mudstone in the Shuixigou Group,especially the mudstone at the top of the Sangonghe Formation,are unclear.Taking the source rocks of the Xishanyao Formation and the Sangonghe Formation as objectives,this study conducted rock pyrolysis and gold tube simulation experiment to investigate their hydrocarbon generation characteristics and differences.Our results indicate that the source rocks of the Xishanyao Formation include mudstone,carbonaceous mudstone and coal,and the quality of the source rocks is highly heterogeneous;the source rocks of the Sangonghe Formation are mainly composed of mudstone,and it is a good gas source rock.Simulation experiments found that the activation energy required for the generation of gaseous hydrocarbons by the mudstone of the Sangonghe Formation is lower than that by the mudstone of the Xishanyao Formation.The hydrocarbon generation process can be divided into three stages for both formations,but the gas generation potential of the Xishanyao Formation mudstone is higher than that of the Sangonghe Formation mudstone.A large amount of hydrocarbon was generated by the mudstone of the Xishanyao Formation when entering late thermal evolution,of which methane is dominant,mainly from the demethylation reaction of mature kerogen.On the other hand,a large amount of hydrocarbon was generated by the mudstone of the Sangonghe Formation in the early stage of thermal evolution,of which light hydrocarbon and wet gas are dominant,mainly from the early cracking stage of kerogen.This difference may be attributed to the structure of kerogen.The mudstone of the Xishanyao Formation is conducive to the formation of highly mature dry gas reservoirs,while the mudstone of the Sangonghe Formation is conducive to the formation of low maturity condensate gas and volatile oil reservoirs.The research result provides a scientific basis for the comparison of oil and gas sources and the evaluation of oil and gas resources in the Turpan-Hami Basin.展开更多
The reservoired petroleum fluids in the deep Ordovician carbonates in the Tazhong area,Tarim Basin,exhibit diverse and intricate geochemical properties and petroleum phases.However,the study on the causal mechanisms f...The reservoired petroleum fluids in the deep Ordovician carbonates in the Tazhong area,Tarim Basin,exhibit diverse and intricate geochemical properties and petroleum phases.However,the study on the causal mechanisms for the genesis of co-existed complex petroleum phases and their distribution remains relatively limited.The quantitative assessment of changes in molecular compounds in petroleum pools influenced by secondary alteration to different degrees also needs further investigation.In this study,eight samples including condensate,volatile,and black oil from the Tazhong area were analyzed via GC×GC-TOFMS.The results reveal that condensate oil exhibits complete normal alkane distribution,with abundant diamantanes and organic sulfur compounds(OSCs),and features high density(>0.83 g/cm^(3)),elevated wax content(>20%),and remarkable gas washing loss.The condensate gas is characterized by highly mature oil-cracking gas with a heavy carbon isotope.Geological analysis indicates that the current Ordovician reservoir temperatures generally remain below 140℃,which is insufficient to induce in-situ oil cracking.Additionally,black oil pools are formed adjacent to the condensate gas pools,suggesting that the latter is not a result of in-situ oil cracking,but rather represents a secondary condensate gas pool formed through gas invasion of a pre-existed oil pool.Based on the loss of n-alkanes and variations in adamantanes(As)and diamantanes(Ds)content across different oil samples,the degree of gas invasion was assessed.We divided gas invasion intensity into strong(Q≥80%,As≥5000μg/g,Ds≥400μg/g),weak(20%≤Q<80%,3000μg/g≤As<5000μg/g,200μg/g≤Ds<400μg/g)and negligible(0≤Q<20%,As<3000μg/g,Ds<200μg/g).The multistage oil/gas charging events,specifically the sequence of“early oil and late gas”in the Ordovician from the Tazhong area,predominantly drives the phase evolution of reservoired petroleum.Furthermore,differential gas invasion alteration exacerbates the intricacy of petroleum phase distribution.Notably,gas washing processes significantly influence the disparate enrichment of diamondoids homologues in crude oil.Specifically,lower carbon number diamondoids are more abundant in condensate oil,while higher ones exhibit relatively increased abundance in black oil,potentially serving as a valuable quantitative assessment parameter.The findings in this study will provide guiding significance for the analysis and quantitative assessment of deep petroleum phase diversity.Additionally,this research will provide novel insights for comprehensively evaluating basins worldwide with complex petroleum phases distribution.展开更多
The 128.6-m-thick,shale-dominated Klimoli,Wulalike and Lashizhong formations exposed at the Hatuke Creek Section in the Zhuozishan area of Inner Monglia,North China,have been investigated for conodonts.Detailed strati...The 128.6-m-thick,shale-dominated Klimoli,Wulalike and Lashizhong formations exposed at the Hatuke Creek Section in the Zhuozishan area of Inner Monglia,North China,have been investigated for conodonts.Detailed stratigraphical collections of conodonts preserved on bedding planes from graptolitic shales,supplemented by additional discrete conodonts acid-leached from limestones,enable a refinement of the conodont biostratigraphic scheme at this section.Four successive conodont biozones,ranging in age from mid Darriwilian to late Sandbian(Stage slices Dw2–Sa2),are identified:the Dzikodus tablepointensis Biozone,the Eoplacognathus suecicus Biozone,the Pygodus serra Biozone,and the Pygodus anserinus Biozone,in ascending order.New sub-biozones,based on morphotypes of the biozonal index species,are proposed for the Pygodus serra and Pygodus anserinus biozones,providing alternatives when the traditional sub-biozones are unrecognizable.The biozonation is clearly correlated with the coeval Baltoscandian,South American and South China reference standard successions.The diverse preservation states of conodont bedding plane assemblages suggest that the alteration of conodonts in graptolitic shales represents a diagenetic process,challenging the prevailing hypothesis of pre-diagenetic dissolution.This study highlights the crucial role of previously overlooked conodont bedding plane assemblages in correlating Ordovician slope/basin facies shales,which holds great potential for marine shale gas exploration.展开更多
The exploration and development theory and technology of marine shale gas with shallow burial depth of 3500 m in South China has become mature after more than 10 years of practice.In order to continuously promote the ...The exploration and development theory and technology of marine shale gas with shallow burial depth of 3500 m in South China has become mature after more than 10 years of practice.In order to continuously promote the exploration and development of shale gas in China,based on the research results of many scholars,combined with production practice,the main characteristics of marine shale gas in China and the main theory and technology of exploration and development are further summarized.The results show that:(1)The basic characteristics of marine shale gas in southern China are marine deep-water shelf deposition,and organic-rich shale is distributed continuously in a large area;The organic matter is stored in situ after high thermal maturity gas generation,and the gas content of shale is affected by late tectonic activity;The reservoir space is dominated by nano-scale pores,and the reservoir is super-tight and ultra-low permeability,which has no natural productivity without well stimulation;Bedding and natural fracture affect the productivity of shale gas wells;The mechanical properties of shale rock determine the effect of horizontal wells.In the early stage of well production,the production rate is high and the decline is fast,while in the middle and late stage,the rate is low but the production cycle is long.(2)Based on the above characteristics,the theory of“sweet spot”and“sweet interval”of shale gas and the theory of effective development of artificial gas reservoir are established,that is,the sedimentary and tectonic interaction forms the“sweet area”or“sweet spot”of marine shale gas.Gas productivity is determined by geological and engineering factors,so the“sweet spot”must be found to develop.By constructing artificial gas reservoir through“making an artificial high permeability area,and reconstructing a seepage field”,the effective development of ultra-tight and low permeability shale gas reservoirs can be realized.It is the most effective technique for shale gas development to accurately create“transparent geological body”of reservoirs based on geologyengineering integrated evaluation technology and establish artificial gas reservoir through multi-stage fracturing technology.(3)The overpressure area in the southern Sichuan Basin is the“sweet area”for shale gas development.The“sweet interval”of the lower Silurian Longmaxi Formation with a thickness of 3e5 m and high brittle-rich organic matter is the optimal“golden target”for horizontal wells.(4)The development leapfrog from the first generation to the second generation has been realized by the key technology of multi-stage fracturing of horizontal wells.The EUR per well of Upper Ordovician Wufeng Formation and Longmaxi Formation in southern Sichuan has increased from 0.5108 m3 in the initial stage to 1.0108 e1.2108 m3 at present with a buried depth of shallower than 3500 m.(5)The effective area favorable for shale gas development in southern Sichuan is 2.0104 km2,and it is estimated that the proven geological reserves of shale gas can reach 101012 m3.It is preliminarily predicted that the shale gas production in China will exceed 300108 m3 in 2025 and reach 400108 m3 in 2035.展开更多
By integrating core observations,logging data and seismic interpretation,this study takes the massive Cretaceous carbonates in the M block of the Santos Basin,Brazil,as an example to establish the sequence filling pat...By integrating core observations,logging data and seismic interpretation,this study takes the massive Cretaceous carbonates in the M block of the Santos Basin,Brazil,as an example to establish the sequence filling pattern of fault-bounded isolated platforms in rift lake basins,reveal the control mechanisms of shoal-body development and reservoir formation,and reconstruct the evolutionary history of lithofacies paleogeography.The following results are obtained.(1)Three tertiary sequences(SQ1-SQ3)are identified in the Lower Cretaceous Itapema-Barra Velha of the M block.During the depositional period of SQ1,the rift basement faults controlled the stratigraphic distribution pattern of thick on both sides and thin in the middle.The strata overlapped to uplift in the early stage.During the depositional period of SQ2-SQ3,the synsedimentary faults controlled the paleogeomorphic reworking process with subsidence in the northwest and uplifting in the northeast,accompanied with the relative fall of lake level.(2)The Lower Cretaceous in the M block was deposited in a littoral-shallow lake,with the lithofacies paleogeographic pattern transiting from the inner clastic shoals and outer shelly shoals in SQ1 to the alternation of mounds and shoals in SQ2-SQ3.(3)Under the joint control of relative lake-level fluctuation,synsedimentary faults and volcanic activity,the shelly shoals in SQ1 tend to accumulated vertically in the raised area,and the mound-shoal complex in SQ2-SQ3 tends to migrate laterally towards the slope-break belt due to the reduction of accommodation space.(4)The evolution pattern of high-energy mounds and shoals,which were vertically accumulated in the early stage and laterally migrated in the later stage,controlled the transformation of high-quality reservoirs from“centralized”to“ring shaped”distribution.The research findings clarify the sedimentary patterns of mounds and shoals and the distribution of favorable reservoirs in the fault-controlled lacustrine isolated platform,providing support for the deepwater hydrocarbon exploration in the subsalt carbonate rocks in the Santos Basin.展开更多
文摘The year of 2024 marks the 50th anniversary of the publication of Petroleum Exploration and Development.For half a century,Petroleum Exploration and Development has been committed to disseminating petroleum technology,witnessing and recording the glorious journey of China's petroleum industry from being weak to becoming strong.The journal has also become a bright banner in China's petroleum technology industry.
文摘After years of strenuous efforts and with the approval of the State Administration of Press,Publication,Radio,Film and Television of the People's Republic of China,the Petroleum Exploration and Development(English Version)is officially published in hard copy.The publication of the English version comes at the right time when China is witnessing further deepening in its reform and opening up and all-round development in its science and technology.We are confident that the journal will further advance the progress and development of petroleum science and technology,promote exchanges and cooperation in petroleum science and technology,and make contributions to the development of the petroleum industry.
基金co-funded by the National Natural Science Foundation of China(42372160,42072172)。
文摘The Neogene Shawan Formation in the Chepaizi Uplift of the Junggar Basin(NW China)has obtained high oil flow,demonstrating a good potential for oil and gas exploration.The multi-source hydrocarbon generation background and strong tectonic activity have led to the simultaneous production of heavy oil and light oil from multi-layer in the area,which makes it very difficult to identify oil origins,presently,the hot debate on the oil origins needs to be clarified.In this paper,due to the selective consumption of different types of compounds in crude oils by severe and intense biodegradation,the commonly used oilsource correlation tools are ineffective or may produce misleading results,this study adopted a biomarker recovery method based on the principle of mass conservation that uses the sum of the mass of the residual biomarkers and their corresponding biodegradation products to obtain the mass of the original biomarkers,improving the reliability of oil origins determination.Based on the nature and occurrence of crude oils,the investigated oils are subdivided into three types,Group A,Group B and Group C.Group A,light oils occurred mainly in lower structure Neogene Shawan Formation in the western Chepaizi Uplift,while Group B,heavy oils occurred mainly in higher structure Neogene Shawan Formation in the western Chepaizi Uplift.The two types of crude oils may come from the mixed source of Jurassic Badaowan Formation source rocks(J_(1)b)and Paleogene Anjihaihe Formation source rocks(E_(2-3)a)in the Sikeshu Sag,and Jurassic Badaowan Formation source rocks(J_(1)b)are the main source of crude oils.Group C,heavy oils occurred mainly in Neogene Shawan Formation in the eastern Chepaizi Uplift,showing good correlation with the Permian(P_(1)f and P_(2)w)source rocks in the Shawan Sag.At the same time,by combining stable carbon isotope and parameters related to triaromatic steroids,the accuracy of the oilsource correlation results by biomarker recovery method was further verified.
基金Supported by the CNPC Science and Technology Project(2024ZZ0203)。
文摘The ultra-deep(deeper than 8000 m)petroleum in the platform-basin zones of the Tarim Basin has been found mainly in the Lower Paleozoic reservoirs located to the east of the strike-slip fault F5 in the north depression.However,the source and exploration potential of the ultra-deep petroleum in the Cambrian on the west of F5 are still unclear.Through the analysis of lithofacies and biomarkers,it is revealed that there are at least three kinds of isochronous source rocks(SRs)in the Cambrian Newfoundland Series in Tarim Basin,which were deposited in three sedimentary environments,i.e.sulfide slope,deep-water shelf and restricted bay.In 2024,Well XT-1 in the western part of northern Tarim Basin has yielded a high production of condensate from the Cambrian.In the produced oil,entire aryl-isoprenoid alkane biomarkers were detected,but triaromatic dinosterane was absent.This finding is well consistent with the geochemical characteristics of the Newfoundland sulfidized slope SRs represented by those in wells LT-1 and QT-1,suggesting that the Newfoundland SRs are the main source of the Cambrian petroleum discovered in Well XT-1.Cambrian crude oil of Well XT-1 also presents the predominance of C29 steranes and is rich in long-chain tricyclic terpanes(up to C39),which can be the indicators for effectively distinguishing lithofacies such as siliceous mudstone and carbonate rock.Combined with the analysis of hydrocarbon accumulation in respect of conduction systems including thrust fault and strike-slip fault,it is found that the area to the west of F5 is possible to receive effective supply of hydrocarbons from the Cambrian Newfoundland SRs in Manxi hydrocarbon-generation center.This finding suggests that the area to the west of F5 will be a new target of exploration in the Cambrian ultra-deep structural-lithologic reservoirs in the Tarim Basin,in addition to the Cambrian ultra-deep platform-margin facies-controlled reservoirs in the eastern part of the basin.
基金the National Basic Research Program of China (973 Program, 2011CB201100)‘‘Complex hydrocarbon accumulation mechanism and enrichmentregularities of deep superimposed basins in Western China’’ National Natural Science Foundation of China (U1262205) under the guidance of related department heads and experts
文摘As petroleum exploration advances and as most of the oil-gas reservoirs in shallow layers have been explored, petroleum exploration starts to move toward deep basins, which has become an inevitable choice. In this paper, the petroleum geology features and research progress on oil-gas reservoirs in deep petroliferous basins across the world are characterized by using the latest results of worldwide deep petroleum exploration. Research has demonstrated that the deep petroleum shows ten major geological features. （1） While oil-gas reservoirs have been discovered in many different types of deep petroliferous basins, most have been discovered in low heat flux deep basins. （2） Many types of petroliferous traps are developed in deep basins, and tight oil-gas reservoirs in deep basin traps are arousing increasing attention. （3） Deep petroleum normally has more natural gas than liquid oil, and the natural gas ratio increases with the burial depth. （4） The residual organic matter in deep source rocks reduces but the hydrocarbon expulsion rate and efficiency increase with the burial depth. （5） There are many types of rocks in deep hydrocarbon reservoirs, and most are clastic rocks and carbonates. （6） The age of deep hydrocarbon reservoirs is widely different, but those recently discovered are pre- dominantly Paleogene and Upper Paleozoic. （7） The porosity and permeability of deep hydrocarbon reservoirs differ widely, but they vary in a regular way with lithology and burial depth. （8） The temperatures of deep oil-gas reservoirs are widely different, but they typically vary with the burial depth and basin geothermal gradient. （9） The pressures of deep oil-gas reservoirs differ significantly, but they typically vary with burial depth, genesis, and evolu- tion period. （10） Deep oil-gas reservoirs may exist with or without a cap, and those without a cap are typically of unconventional genesis. Over the past decade, six major steps have been made in the understanding of deep hydrocarbon reservoir formation. （1） Deep petroleum in petroliferous basins has multiple sources and many dif- ferent genetic mechanisms. （2） There are high-porosity, high-permeability reservoirs in deep basins, the formation of which is associated with tectonic events and subsurface fluid movement. （3） Capillary pressure differences inside and outside the target reservoir are the principal driving force of hydrocarbon enrichment in deep basins. （4） There are three dynamic boundaries for deep oil-gas reservoirs; a buoyancy-controlled threshold, hydrocarbon accumulation limits, and the upper limit of hydrocarbon generation. （5） The formation and distribution of deep hydrocarbon res- ervoirs are controlled by free, limited, and bound fluid dynamic fields. And （6） tight conventional, tight deep, tight superimposed, and related reconstructed hydrocarbon reservoirs formed in deep-limited fluid dynamic fields have great resource potential and vast scope for exploration. Compared with middle-shallow strata, the petroleum geology and accumulation in deep basins are more complex, which overlap the feature of basin evolution in different stages. We recommend that further study should pay more attention to four aspects： （1） identification of deep petroleum sources and evaluation of their relative contributions; （2） preservation conditions and genetic mechanisms of deep high-quality reservoirs with high permeability and high porosity; （3） facies feature and transformation of deep petroleum and their potential distribution; and （4） economic feasibility evaluation of deep tight petroleum exploration and development.
基金Supported by the PetroChina Basic Project(2024DJ23)CNPC Science Research and Technology Development Project(2021DJ0101)。
文摘Coal measures are significant hydrocarbon source rocks and reservoirs in petroliferous basins.Many large gas fields and coalbed methane fields globally are originated from coal-measure source rocks or accumulated in coal rocks.Inspired by the discovery of shale oil and gas,and guided by“the overall exploration concept of considering coal rock as reservoir”,breakthroughs in the exploration and development of coal-rock gas have been achieved in deep coal seams with favorable preservation conditions,thereby opening up a new development frontier for the unconventional gas in coal-rock reservoirs.Based on the data from exploration and development practices,a systematic study on the accumulation mechanism of coal-rock gas has been conducted.The mechanisms of“three fields”controlling coal-rock gas accumulation are revealed.It is confirmed that the coal-rock gas is different from CBM in accumulation process.The whole petroleum systems in the Carboniferous–Permian transitional facies coal measures of the eastern margin of the Ordos Basin and in the Jurassic continental facies coal measures of the Junggar Basin are characterized,and the key research directions for further developing the whole petroleum system theory of coal measures are proposed.Coal rocks,compared to shale,possess intense hydrocarbon generation potential,strong adsorption capacity,dual-medium reservoir properties,and partial or weak oil and gas self-sealing capacity.Additionally,unlike other unconventional gas such as shale gas and tight gas,coal-rock gas exhibits more complex accumulation characteristics,and its accumulation requires a certain coal-rock play form lithological and structural traps.Coal-rock gas also has the characteristics of conventional fractured gas reservoirs.Compared with the basic theory and model of the whole petroleum system established based on detrital rock formations,coal measures have distinct characteristics and differences in coal-rock reservoirs and source-reservoir coupling.The whole petroleum system of coal measures is composed of various types of coal-measure hydrocarbon plays with coal(and dark shale)in coal measures as source rock and reservoir,and with adjacent tight layers as reservoirs or cap or transport layers.Under the action of source-reservoir coupling,coal-rock gas is accumulated in coal-rock reservoirs with good preservation conditions,tight oil/gas is accumulated in tight layers,conventional oil/gas is accumulated in traps far away from sources,and coalbed methane is accumulated in coal-rock reservoirs damaged by later geological processes.The proposed whole petroleum system of coal measures represents a novel type of whole petroleum system.
基金supported by a project of shale gas in Southern China(DD20190561)initiated by the China Geological Surveythe project for High-level Innovative Talents in Science and Technology,Ministry of Natural Resources(12110600000018003918)。
文摘The shale gas resources in China have great potential and the geological resources of shale gas is over 100×10^(12)m^(3),which includes about 20×10^(12)m^(3) of recoverable resources.Organic-rich shales can be divided into three types according to their sedimentary environments,namely marine,marine-continental transitional,and continental shales,which are distributed in 13 stratigraphic systems from the Mesoproterozoic to the Cenozoic.The Sichuan Basin and its surrounding areas have the highest geological resources of shale gas,and the commercial development of shale gas has been achieved in the Upper Ordovician Wufeng Formation-Lower Silurian Longmaxi Formation in these areas,with a shale gas production of up to 20×10^(9)m^(3) in 2020.China has seen rapid shale gas exploration and development over the last five years,successively achieving breakthroughs and important findings in many areas and strata.The details are as follows.(1)Large-scale development of middle-shallow shale gas(burial depth:less than 3500 m)has been realized,with the productivity having rapidly increased;(2)breakthroughs have been constantly made in the development of deep shale gas(burial depth:3500-4500 m),and the ultradeep shale gas(burial depth:greater than 4500 m)is under testing;(3)breakthroughs have been made in the development of normal-pressure shale gas,and the assessment of the shale gas in complex tectonic areas is being accelerated;(4)shale gas has been frequently discovered in new areas and new strata,exhibiting a great prospect.Based on the exploration and development practice,three aspects of consensus have been gradually reached on the research progress in the geological theories of shale gas achieved in China.(1)in terms of deep-water fine-grained sediments,organic-rich shales are the base for the formation of shale gas;(2)in terms of high-quality reservoirs,the development of micro-nano organic matter-hosted pores serves as the core of shale gas accumulation;(3)in terms of preservation conditions,weak structural transformation,a moderate degree of thermal evolution,and a high pressure coefficient are the key to shale gas enrichment.As a type of important low-carbon fossil energy,shale gas will play an increasingly important role in achieving the strategic goals of peak carbon dioxide emissions and carbon neutrality.Based on the in-depth study of shale gas geological conditions and current exploration progress,three important directions for shale gas exploration in China in the next five years are put forward.
基金Supported by the National Natural Science Foundation Project(92255302)National Science and Technology Major Project(2016ZX05029005)Scientific Research and Technological Development Project of PetroChina(2021DJ31).
文摘Based on seismic,drilling,and source rock analysis data,the petroleum geological characteristics and future exploration direction of the oil-rich sags in the Central and West African Rift System(CWARS)are discussed.The study shows that the Central African Rift System mainly develops high-quality lacustrine source rocks in the Lower Cretaceous,and the West African Rift System mainly develops high-quality terrigenous organic matter-rich marine source rocks in the Upper Cretaceous,and the two types of source rocks provide a material basis for the enrichment of oil and gas in the CWARS.Multiple sets of reservoir rocks including fractured basement and three sets of regional cap rocks in the Lower Cretaceous,the Upper Cretaceous,and the Paleogene are developed in the CWARS.Since the Late Mesozoic,due to the geodynamic factors including the dextral strike-slip movement of the Central African Shear Zone,the basins in different directions of the CWARS differ in terms of rifting stages,intervals of regional cap rocks,trap types and accumulation models.The NE-SW trending basins have mainly preserved one stage of rifting in the Early Cretaceous,with regional cap rocks developed in the Lower Cretaceous strata,forming traps of reverse anticlines,flower-shaped structures and basement buried hill,and two types of hydrocarbon accumulation models of"source and reservoir in the same formation,and accumulation inside source rocks"and"up-source and down-reservoir,and accumulation below source rocks".The NW–SE basins are characterized by multiple rifting stages superimposition,with the development of regional cap rocks in the Upper Cretaceous and Paleogene,forming traps of draping anticlines,faulted anticlines,antithetic fault blocks and the accumulation model of"down-source and up-reservoir,and accumulation above source rocks".The combination of reservoir and cap rocks inside source rocks of basins with multiple superimposed rifting stages,as well as the lithologic reservoirs and the shale oil inside source rocks of strong inversion basins are important fields for future exploration in basins of the CWARS.
基金Supported by the Scientific and Technological Major Project of the Southwest Oil and Gas Field Company (2019ZD01-03)。
文摘By examining field outcrops, drilling cores and seismic data, it is concluded that the Middle and Late Permian “Emeishan basalts” in Western Sichuan Basin were developed in two large eruption cycles, and the two sets of igneous rocks are in unconformable contact. The lower cycle is dominated by overflow volcanic rocks;while the upper cycle made up of pyroclastic flow volcanic breccia and pyroclastic lava is typical explosive facies accumulation. With high-quality micro-dissolution pores and ultra-fine dissolution pores, the upper cycle is a set of high-quality porous reservoir. Based on strong heterogeneity and great differences of pyroclastic flow subfacies from surrounding rocks in lithology and physical properties, the volcanic facies and volcanic edifices in Western Sichuan were effectively predicted and characterized by using seismic attribute analysis method and instantaneous amplitude and instantaneous frequency coherence analysis. The pyroclastic flow volcanic rocks are widely distributed in the Jianyang area. Centering around wells YT1, TF2 and TF8, the volcanic rocks in Jianyang area had 3edifice groups and an area of about 500 km^(2), which is the most favorable area for oil and gas exploration in volcanic rocks.
基金Major Special Items of National Oil and Gas(No.:2011ZX05018-001)National Key Basic Research&Development Plan(Plan 973)project(No.:2013CB228001).
文摘In the past five years,shale gas exploration and development has grown in a leaping-forward way in China.Following USA and Canada,China is now the third country where industrial shale gas production is realized,with the cumulative production exceeding 60×10^(8) m^(3) until the end of 2015.In this paper,the main achievements of shale gas exploration and development in China in recent years were reviewed and the future development prospect was analyzed.It is pointed out that shale gas exploration and development in China is,on the whole,still at its early stage.Especially,marine shale gas in the Sichuan Basin has dominated the recent exploration and development.For the realization of shale gas scale development in China,one key point lies in the breakthrough and industrial production of transitional facies and continental facies shale gas.Lowemoderate yield of shale gas wells is the normal in China,so it is crucial to develop key exploration and development technologies.Especially,strictly controlling single well investment and significantly reducing cost are the important means to increase shale gas exploration and development benefits.And finally,suggestions were proposed in five aspects.First,continuously strengthen theoretical and technical re-searches,actively carry out appraisal on shale gas“sweet spots”,and gradually accumulate development basis.Second,stress on primary evaluation of exploration and development,highlight the effective implementation of shale gas resources,and control the rhythm of appraisal drilling and productivity construction.Third,highlight fine description and evaluation of shale gas reservoirs and increase the overall devel-opment level.Fourth,intensify the research on exploration and development technologies in order to stand out simple and practical technologies with low costs.And fifth,summarize the experiences in fast growth of shale gas exploration and development,highlight the demonstration and evaluation of key indicators,and try to achieve more breakthroughs and replacement in new areas,new domains and new strata.
文摘Fifty-one large gas fields had been proved in China until 2013.Specifically,exploration characteristics of those discovered since 2000 are as follows:(1)Large gas fields are only found in basins with sedimentary area larger than 10×10^(4) km^(2);(2)Large gas fields have been proved in 9 basins,with total proved reserves of 27085.88×10^(8) m^(3) before 2005,much less than that after 2005,which reached 81683.77×10^(8) m^(3) by the end of 2013;(3)The reserve abundance of large gas fields varies a lot.The Kela2 gas field has the largest reserve abundance of 59.05×10^(8) m^(3)/km^(2),which is 86 times that of the smallest reserve abundance,i.e.0.684×10^(8) m^(3)/km^(2) of the Jingbian gas field;and(4)The reservoirs of large gas fields between 3000 m and 4500 m share a large proportion of proved reserves,accounting for 46.11%of the total.Development characteristics of the large gas fields in China are as follows:(1)The yield of large gas fields is essential to the natural gas industry of China.In 2013,the total yield was 922.72×10^(8) m^(3),accounting for 76.3%of the nation’s total natural gas yield;(2)The yield is dominated by coal-derived gas,which reached 710.13×10^(8) m^(3) in 2013,accounting for 77.0%of the total yield of large gas fields in China;and(3)The yield of key large gas fields(Sulige,Jingbian,Daniudi,Puguang,and Kela2)is fundamental in making China a major gas producer.
基金Supported by China National Key R&D Program Project of the 15th Five-Year Plan(2025ZD1402703).
文摘Under the guidance of the whole petroleum system theory,using seismic,drilling and laboratory analysis data,and combined with the practical achievements of oil and gas exploration,the distribution patterns of different types of natural gas in the deep-water area of the Qiongdongnan Basin of China were systematically reviewed,the orderly symbiosis mechanisms and hydrocarbon accumulation processes of diverse gas reservoirs were analyzed,and a composite whole petroleum system model for the deep-water strongly active basins in the northern South China Sea was constructed.In the deep-water area of the Qiongdongnan Basin,there are three sets of source rocks,namely the Eocene,the Oligocene,and the upper Miocene-Quaternary,and three whole petroleum systems can be accordingly classified.The source rocks have the characteristics of multilayers,multiple types,and multiple hydrocarbon generation centers.The Eocene lacustrine source rocks,Oligocene marine and continental dual-origin source rocks,and upper Miocene-Quaternary marine source rocks form multiple hydrocarbon generation centers,which are orderly distributed from east to west.The reservoirs are characterized by multiple geological ages,multiple rock types,and multiple hydrodynamic influences,and exist as a reservoir composite superposition pattern with basement buried hill-lower traction flow sandbody-upper gravity flow sandbody vertically in the deep-water area.Fluid activities within the basin are controlled by free dynamic fields,confined dynamic fields,and bound dynamic fields.The natural gas in the whole petroleum system presents an orderly distribution of shale gas(speculated)-tight gas-conventional gas-ultra-shallow gas-hydrate from bottom to top.The research results have verified the adaptability of the whole petroleum system theory in the deep-water area of the Qiongdongnan Basin,providing a theoretical support for the exploration of complex oil and gas resources in the deep-water area,and are expected to effectively guide the distribution prediction and exploration of different types of petroleum resources in deep-water areas.
文摘Exploration budgets for primary battery metals-nickel,lithium and cobalt-tempered in 2024 at$1.697 billion,reflecting a marginal 0.4%decline and a virtually flat annual total,compared to$1.704 billion in 2023.Below is an introduction to the 2024 global exploration trends and prospects for lithium,cobalt,and nickel battery metals.
基金Supported by the PetroChina Scentific and Technological Projects(2023ZZ082023ZZ28)。
文摘Currently,unconventional reservoirs are characterized by low single well-controlled reserves,high initial production but fast production decline.This paper sorts out the problems of energy dispersion and limited length and height of main hydraulic fractures induced in staged multi-cluster fracturing,and proposes an innovative concept of“energy-focused fracturing development”.The technical connotation,theoretical model,and core techniques of energy-focused fracturing development are systematically examined,and the implementation path of this technology is determined.The energy-focused fracturing development technology incorporates the techniques such as geology-engineering integrated design,perforation optimization design,fracturing process design,and drainage engineering control.It transforms the numerous,short and dense hydraulic fractures to limited,long and sparse fractures.It focuses on fracturing energy,and aims to improve the fracture length,height and lateral width,and the proppant long-distance transportation capacity,thus enhancing the single well-controlled reserves and development effect.The energy-focused fracturing development technology has been successfully applied in the carbonate reservoirs in buried hill,shallow coalbed methane reservoirs,and coal-rock gas reservoirs in China,demonstrating the technology's promising application.It is concluded that the energy-focused fracturing development technology can significantly increase the single well production and estimated ultimate recovery(EUR),and will be helpful for efficiently developing low-permeability,unconventional and low-grade resources in China.
基金funded by Science and Technology Cooperation Project of the CNPC-SWPU Innovation Alliance(2020CX050103).
文摘Research on the distribution and development of black shales in the Lianggaoshan Formation has been deficient,which has hindered exploration for lacustrine shale oil in the Sichuan Basin.Our study characterized the well logging data,core samples,outcrops,and geochemistry of black shales in the Lianggaoshan Formation in the Sichuan Basin.Our analysis focused on the lake basin evolution and the migration characteristics,paleoenvironmental features,formation mechanisms,and developmental model of the black shales.The results indicated that black shales in the Lianggaoshan Formation exhibited significant lateral migration,with an overall thickening trend from east to west.Within the 1st Member of the formation,black shale occurred as a single thick layer in the eastern region that gradually thinned toward the central region.Multiple sets of shale developed within the 2nd and 3rd members,and these had lower thicknesses than the 1st Member and migrated toward central Sichuan.Paleoproductivity and terrigenous input were the main factors controlling the deposition of black shales.A semi-humid climate influenced the deposition of black shales,bringing abundant freshwater,terrigenous debris,and nutrients into the basin.Decomposition of organic matter consumed oxygen in sediment and bottom water,causing localized oxygen deficiency in the strata.
基金supported by the China Petroleum Science and Technology Major Project(No.2023ZZ18-03).
文摘The coal-bearing source rocks in the Jurassic Shuixigou Group have received widespread attention as the primary source rocks in the Turpan-Hami Basin of China,but the hydrocarbon generation potential and process of the mudstone in the Shuixigou Group,especially the mudstone at the top of the Sangonghe Formation,are unclear.Taking the source rocks of the Xishanyao Formation and the Sangonghe Formation as objectives,this study conducted rock pyrolysis and gold tube simulation experiment to investigate their hydrocarbon generation characteristics and differences.Our results indicate that the source rocks of the Xishanyao Formation include mudstone,carbonaceous mudstone and coal,and the quality of the source rocks is highly heterogeneous;the source rocks of the Sangonghe Formation are mainly composed of mudstone,and it is a good gas source rock.Simulation experiments found that the activation energy required for the generation of gaseous hydrocarbons by the mudstone of the Sangonghe Formation is lower than that by the mudstone of the Xishanyao Formation.The hydrocarbon generation process can be divided into three stages for both formations,but the gas generation potential of the Xishanyao Formation mudstone is higher than that of the Sangonghe Formation mudstone.A large amount of hydrocarbon was generated by the mudstone of the Xishanyao Formation when entering late thermal evolution,of which methane is dominant,mainly from the demethylation reaction of mature kerogen.On the other hand,a large amount of hydrocarbon was generated by the mudstone of the Sangonghe Formation in the early stage of thermal evolution,of which light hydrocarbon and wet gas are dominant,mainly from the early cracking stage of kerogen.This difference may be attributed to the structure of kerogen.The mudstone of the Xishanyao Formation is conducive to the formation of highly mature dry gas reservoirs,while the mudstone of the Sangonghe Formation is conducive to the formation of low maturity condensate gas and volatile oil reservoirs.The research result provides a scientific basis for the comparison of oil and gas sources and the evaluation of oil and gas resources in the Turpan-Hami Basin.
基金jointly supported by the National Natural Science Foundation of China(Grant Nos.42002178 and 42472203)“CUG Scholar”Scientific Research Funds at China University of Geosciences(Grant No.2022193)China National Petroleum Corporation(CNPC)Scientific Research and Technology Development Projects(Grant Nos.2019B-04 and 2021DJ05)。
文摘The reservoired petroleum fluids in the deep Ordovician carbonates in the Tazhong area,Tarim Basin,exhibit diverse and intricate geochemical properties and petroleum phases.However,the study on the causal mechanisms for the genesis of co-existed complex petroleum phases and their distribution remains relatively limited.The quantitative assessment of changes in molecular compounds in petroleum pools influenced by secondary alteration to different degrees also needs further investigation.In this study,eight samples including condensate,volatile,and black oil from the Tazhong area were analyzed via GC×GC-TOFMS.The results reveal that condensate oil exhibits complete normal alkane distribution,with abundant diamantanes and organic sulfur compounds(OSCs),and features high density(>0.83 g/cm^(3)),elevated wax content(>20%),and remarkable gas washing loss.The condensate gas is characterized by highly mature oil-cracking gas with a heavy carbon isotope.Geological analysis indicates that the current Ordovician reservoir temperatures generally remain below 140℃,which is insufficient to induce in-situ oil cracking.Additionally,black oil pools are formed adjacent to the condensate gas pools,suggesting that the latter is not a result of in-situ oil cracking,but rather represents a secondary condensate gas pool formed through gas invasion of a pre-existed oil pool.Based on the loss of n-alkanes and variations in adamantanes(As)and diamantanes(Ds)content across different oil samples,the degree of gas invasion was assessed.We divided gas invasion intensity into strong(Q≥80%,As≥5000μg/g,Ds≥400μg/g),weak(20%≤Q<80%,3000μg/g≤As<5000μg/g,200μg/g≤Ds<400μg/g)and negligible(0≤Q<20%,As<3000μg/g,Ds<200μg/g).The multistage oil/gas charging events,specifically the sequence of“early oil and late gas”in the Ordovician from the Tazhong area,predominantly drives the phase evolution of reservoired petroleum.Furthermore,differential gas invasion alteration exacerbates the intricacy of petroleum phase distribution.Notably,gas washing processes significantly influence the disparate enrichment of diamondoids homologues in crude oil.Specifically,lower carbon number diamondoids are more abundant in condensate oil,while higher ones exhibit relatively increased abundance in black oil,potentially serving as a valuable quantitative assessment parameter.The findings in this study will provide guiding significance for the analysis and quantitative assessment of deep petroleum phase diversity.Additionally,this research will provide novel insights for comprehensively evaluating basins worldwide with complex petroleum phases distribution.
基金supported by the National Natural Science Foundation of China (Nos. 42572017, 42172037)the State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, CAS (Nos. 213107, 173122)the International Geoscience Programme (IGCP) project 735 “Rocks and the Rise of Ordovician Life: Filling knowledge gaps in the Early Palaeozoic biodiversification”
文摘The 128.6-m-thick,shale-dominated Klimoli,Wulalike and Lashizhong formations exposed at the Hatuke Creek Section in the Zhuozishan area of Inner Monglia,North China,have been investigated for conodonts.Detailed stratigraphical collections of conodonts preserved on bedding planes from graptolitic shales,supplemented by additional discrete conodonts acid-leached from limestones,enable a refinement of the conodont biostratigraphic scheme at this section.Four successive conodont biozones,ranging in age from mid Darriwilian to late Sandbian(Stage slices Dw2–Sa2),are identified:the Dzikodus tablepointensis Biozone,the Eoplacognathus suecicus Biozone,the Pygodus serra Biozone,and the Pygodus anserinus Biozone,in ascending order.New sub-biozones,based on morphotypes of the biozonal index species,are proposed for the Pygodus serra and Pygodus anserinus biozones,providing alternatives when the traditional sub-biozones are unrecognizable.The biozonation is clearly correlated with the coeval Baltoscandian,South American and South China reference standard successions.The diverse preservation states of conodont bedding plane assemblages suggest that the alteration of conodonts in graptolitic shales represents a diagenetic process,challenging the prevailing hypothesis of pre-diagenetic dissolution.This study highlights the crucial role of previously overlooked conodont bedding plane assemblages in correlating Ordovician slope/basin facies shales,which holds great potential for marine shale gas exploration.
基金Project supported by the Prospective Basic Research Project of CNPC“Exploration and development technologies for marine shale gas”(No.2021DJ19).
文摘The exploration and development theory and technology of marine shale gas with shallow burial depth of 3500 m in South China has become mature after more than 10 years of practice.In order to continuously promote the exploration and development of shale gas in China,based on the research results of many scholars,combined with production practice,the main characteristics of marine shale gas in China and the main theory and technology of exploration and development are further summarized.The results show that:(1)The basic characteristics of marine shale gas in southern China are marine deep-water shelf deposition,and organic-rich shale is distributed continuously in a large area;The organic matter is stored in situ after high thermal maturity gas generation,and the gas content of shale is affected by late tectonic activity;The reservoir space is dominated by nano-scale pores,and the reservoir is super-tight and ultra-low permeability,which has no natural productivity without well stimulation;Bedding and natural fracture affect the productivity of shale gas wells;The mechanical properties of shale rock determine the effect of horizontal wells.In the early stage of well production,the production rate is high and the decline is fast,while in the middle and late stage,the rate is low but the production cycle is long.(2)Based on the above characteristics,the theory of“sweet spot”and“sweet interval”of shale gas and the theory of effective development of artificial gas reservoir are established,that is,the sedimentary and tectonic interaction forms the“sweet area”or“sweet spot”of marine shale gas.Gas productivity is determined by geological and engineering factors,so the“sweet spot”must be found to develop.By constructing artificial gas reservoir through“making an artificial high permeability area,and reconstructing a seepage field”,the effective development of ultra-tight and low permeability shale gas reservoirs can be realized.It is the most effective technique for shale gas development to accurately create“transparent geological body”of reservoirs based on geologyengineering integrated evaluation technology and establish artificial gas reservoir through multi-stage fracturing technology.(3)The overpressure area in the southern Sichuan Basin is the“sweet area”for shale gas development.The“sweet interval”of the lower Silurian Longmaxi Formation with a thickness of 3e5 m and high brittle-rich organic matter is the optimal“golden target”for horizontal wells.(4)The development leapfrog from the first generation to the second generation has been realized by the key technology of multi-stage fracturing of horizontal wells.The EUR per well of Upper Ordovician Wufeng Formation and Longmaxi Formation in southern Sichuan has increased from 0.5108 m3 in the initial stage to 1.0108 e1.2108 m3 at present with a buried depth of shallower than 3500 m.(5)The effective area favorable for shale gas development in southern Sichuan is 2.0104 km2,and it is estimated that the proven geological reserves of shale gas can reach 101012 m3.It is preliminarily predicted that the shale gas production in China will exceed 300108 m3 in 2025 and reach 400108 m3 in 2035.
基金Supported by the China National Science and Technology Major Project(2025ZD1403000)CNPC Major Science and Technology Project(2023ZZ19).
文摘By integrating core observations,logging data and seismic interpretation,this study takes the massive Cretaceous carbonates in the M block of the Santos Basin,Brazil,as an example to establish the sequence filling pattern of fault-bounded isolated platforms in rift lake basins,reveal the control mechanisms of shoal-body development and reservoir formation,and reconstruct the evolutionary history of lithofacies paleogeography.The following results are obtained.(1)Three tertiary sequences(SQ1-SQ3)are identified in the Lower Cretaceous Itapema-Barra Velha of the M block.During the depositional period of SQ1,the rift basement faults controlled the stratigraphic distribution pattern of thick on both sides and thin in the middle.The strata overlapped to uplift in the early stage.During the depositional period of SQ2-SQ3,the synsedimentary faults controlled the paleogeomorphic reworking process with subsidence in the northwest and uplifting in the northeast,accompanied with the relative fall of lake level.(2)The Lower Cretaceous in the M block was deposited in a littoral-shallow lake,with the lithofacies paleogeographic pattern transiting from the inner clastic shoals and outer shelly shoals in SQ1 to the alternation of mounds and shoals in SQ2-SQ3.(3)Under the joint control of relative lake-level fluctuation,synsedimentary faults and volcanic activity,the shelly shoals in SQ1 tend to accumulated vertically in the raised area,and the mound-shoal complex in SQ2-SQ3 tends to migrate laterally towards the slope-break belt due to the reduction of accommodation space.(4)The evolution pattern of high-energy mounds and shoals,which were vertically accumulated in the early stage and laterally migrated in the later stage,controlled the transformation of high-quality reservoirs from“centralized”to“ring shaped”distribution.The research findings clarify the sedimentary patterns of mounds and shoals and the distribution of favorable reservoirs in the fault-controlled lacustrine isolated platform,providing support for the deepwater hydrocarbon exploration in the subsalt carbonate rocks in the Santos Basin.
