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
Gas chromatography-mass spectrometry(GC-MS)was used to analyze the pentacyclic triterpenoid distributions,specifically hopane and oleanane fingerprints,in 24 crude oil samples from the Niger Delta depobelts,with the a...Gas chromatography-mass spectrometry(GC-MS)was used to analyze the pentacyclic triterpenoid distributions,specifically hopane and oleanane fingerprints,in 24 crude oil samples from the Niger Delta depobelts,with the aim of defining the petroleum system,filling history,and the age of source rock producing these oils.The results indicate that the Niger Delta oils belong to a single fluvio-deltaic petroleum system,reflecting similar source organic facies and depositional environments.Geochemical parameters,including C29/C30hopane ratios,oleanane index,Ts/Tm,(Ts/(Ts+Tm)),moretane/C30hopane ratios,and C3222S/(22S+22R)ratios,suggest oxic conditions during source rock deposition and thermal maturity of the oils.The presence of terrigenous organic matter and complex filling history are also evident and influenced by multiple phases of sedimentation,and petroleum generation.A comparative plot of geologic time(Paleogene-Neogene age)and oleanane percentage composition show that the crude oils are constrained to the chronostratigraphic ages of their respective depobelts,demonstrating the potential of oleanane-derived parameters for relative dating of hydrocarbon sources,complementing traditional index fossil methods.展开更多
Natural gas hydrate(NGH),as a widely recognized clean energy,has shown a significant resource potential.However,due to the lack of a unified evaluation methodology and the difficult determination of key parameters,the...Natural gas hydrate(NGH),as a widely recognized clean energy,has shown a significant resource potential.However,due to the lack of a unified evaluation methodology and the difficult determination of key parameters,the evaluation results of global NGH resource are greatly different.This paper establishes a quantitative relationship between NGH resource potential and conventional oil and gas resource and a NGH resource evaluation model based on the whole petroleum system(WPS)and through the analysis of dynamic field controlling hydrocarbon accumulation.The global NGH initially in-place and recoverable resources are inverted through the Monte Carlo simulation,and verified by using the volume analogy method based on drilling results and the trend analysis method of previous evaluation results.The proposed evaluation model considers two genetic mechanisms of natural gas(biological degradation and thermal degradation),surface volume conversion factor difference between conventional natural gas and NGH,and the impacts of differences in favorable distribution area and thickness and in other aspects on the results of NGH resource evaluation.The study shows that the global NGH initially in-place and recoverable resources are 99×10^(12) m^(3) and 30×10^(12) m3,with averages of 214×10^(12) m^(3) and 68×10^(12) m^(3),respectively,less than 5% of the total conventional oil and gas resources,and they can be used as a supplement for the future energy of the world.The proposed NGH resource evaluation model creates a new option of evaluation method and technology,and generates reliable data of NGH resource according to the reliability comprehensive analysis and test,providing a parameter basis for subsequent NGH exploration and development.展开更多
Based on a large amount of basic research and experimental analysis data from Shengli Oilfield,Bohai Bay Basin,guided by the theory of whole petroleum system,the distribution of sedimentary systems,the distribution an...Based on a large amount of basic research and experimental analysis data from Shengli Oilfield,Bohai Bay Basin,guided by the theory of whole petroleum system,the distribution of sedimentary systems,the distribution and hydrocarbon generation and expulsion process of source rocks,the variation of reservoir properties,and the control of fracture systems on hydrocarbon accumulation in the Paleogene of the Jiyang Depression,Boahai Bay Basin,were systematically analyzed,and the geological characteristics of the whole petroleum system in the rift basin were identified.Taking the Dongying Sag as an example,combined with the distribution of discovered conventional,tight,and shale oil/gas,a hydrocarbon accumulation model of the fault-controlled whole petroleum system in rift basin was proposed,and the distribution patterns of conventional and unconventional oil and gas reservoirs in large geological bodies horizontally and vertically were clarified.The research results show that paleoclimate and tectonic cycles control the orderly distribution of the Paleogene sedimentary system in the Jiyang Depression,the multi-stage source rocks provide sufficient material basis for in-situ shale oil/gas accumulation and other hydrocarbon migration and accumulation,the changes in reservoir properties control the dynamic threshold of hydrocarbon accumulation,and the combination of faults and fractures at different stages controls hydrocarbon migration and accumulation,and in-situ retention and accumulation of shale oil/gas,making the whole petroleum system in the rift basin associated,segmented and abrupt.The above elements are configured to form a composite whole petroleum system controlled by faults in the Paleogene of the Jiyang Depression.Moreover,under the control of hydrocarbon accumulation dynamics,a whole petroleum system can be divided into conventional subsystem and unconventional subsystem,with shale oil,tight oil and conventional oil in an orderly distribution in horizontal and vertical directions.This systematic understanding is referential for analyzing the whole petroleum system in continental rift basins in eastern China.展开更多
Based on the investigation of sedimentary filling characteristics and pool-forming factors of the Mesozoic in the Ordos Basin,the whole petroleum system in the Mesozoic is divided,the migration&accumulation charac...Based on the investigation of sedimentary filling characteristics and pool-forming factors of the Mesozoic in the Ordos Basin,the whole petroleum system in the Mesozoic is divided,the migration&accumulation characteristics and main controlling factors of conventional-unconventional hydrocarbons are analyzed,and the whole petroleum system model is established.First,the whole petroleum system developed in the Mesozoic takes the high-quality source rocks of the 7th member of the Triassic Yanchang Formation as the core and mainly consists of low-permeability and unconventional oil and gas reservoirs.It can be divided into four hydrocarbon accumulation domains,including intra-source retained hydrocarbon accumulation domain,near-source tight hydrocarbon accumulation domain,far-source conventional hydrocarbon accumulation domain and transitional hydrocarbon accumulation domain,which together form a continuous,symbiotic,and orderly accumulation entity wherein unconventional resources significantly outweigh conventional ones in proportion.Second,the spatial core area of sedimentary filling is the oil-rich core of the whole petroleum system.From the core to the periphery,the reservoir type evolves as shale oil→tight oil→conventional oil,the accumulation power is dominated by overpressure→buoyancy or overpressure and capillary force,the accumulation scale changes from extensive hundreds of millions of tons to a isolated hundreds of thousands-million of tons,and the gas-oil ratio and methane content decrease.Third,the sedimentary filling system provides the material basis and spatial framework for the whole petroleum system,the superimposed sand body,fault and unconformity constitute the dominant migration pathway of hydrocarbons in the far-source conventional hydrocarbon accumulation domain and the transitional hydrocarbon accumulation domain,the high-quality source rocks provide a solid resource basis for shale oil,and the micro-nano pore throat-fracture network constitute unconventional accumulation space.The hydrocarbon migration and accumulation process is mainly controlled by intense expulsion of hydrocarbon under overpressure in the pool-forming stage and the in-situ re-enrichment controlled by underpressure in post-pool-forming stage.The oil-gas enrichment and long-term preservation depends on the coordination among three factors(stable geological structure,multi-cycle sedimentation,and dual self-sealing).Fourth,the whole petroleum system model is defined as four domains,overpressure+underpressure drive,and dual self-sealing.展开更多
Guided by the fundamental principles of the whole petroleum system,the control of tectonism,sedimentation,and diagenesis on hydrocarbon accumulation in a rifted basin is studied using the data of petroleum geology and...Guided by the fundamental principles of the whole petroleum system,the control of tectonism,sedimentation,and diagenesis on hydrocarbon accumulation in a rifted basin is studied using the data of petroleum geology and exploration of the second member of the Paleogene Kongdian Formation(Kong-2 Member)in the Cangdong Sag,Bohai Bay Basin,China.It is clarified that the circle structure and circle effects are the marked features of a continental fault petroliferous basin,and they govern the orderly distribution of conventional and unconventional hydrocarbons in the whole petroleum systems of the rifted basin.Tectonic circle zones control sedimentary circle zones,while sedimentary circle zones and diagenetic circle zones control the spatial distribution of favorable reservoirs,thereby determining the orderly distribution of hydrocarbon accumulations in various circles.A model for the integrated,systematic accumulation of conventional and unconventional hydrocarbons under a multi-circle structure of the whole petroleum system of continental rifted basin has been developed.It reveals that each sag of the rifted basin is an independent whole petroleum system and circle system,which encompasses multiple orderly circles of conventional and unconventional hydrocarbons controlled by the same source kitchen.From the outer circle to the middle circle and then to the inner circle,there is an orderly transition from structural and stratigraphic reservoirs,to lithological and structural-lithological reservoirs,and finally to tight oil/gas and shale oil/gas enrichment zones.The significant feature of the whole petroleum system is the orderly control of hydrocarbons by multi-circle stratigraphic coupling,with the integrated,orderly distribution of conventional and unconventional reserves being the inevitable result of the multi-layered interaction within the whole petroleum system.This concept of multi-circle stratigraphic coupling for the orderly,integrated accumulation of conventional and unconventional hydrocarbons has guided significant breakthroughs in the overall,three-dimensional exploration and shale oil exploration in the Cangdong Sag.展开更多
There are various types of natural gas resources in coal measures,making them major targets for natural gas exploration and development in China.In view of the particularity of the whole petroleum system of coal measu...There are various types of natural gas resources in coal measures,making them major targets for natural gas exploration and development in China.In view of the particularity of the whole petroleum system of coal measures and the reservoir-forming evolution of natural gas in coal,this study reveals the formation,enrichment characteristics and distribution laws of coal-rock gas by systematically reviewing the main types and geological characteristics of natural gas in the whole petroleum system of coal measures.First,natural gas in the whole petroleum system of coal measures is divided into two types,conventional gas and unconventional gas,according to its occurrence characteristics and accumulation mechanism,and into six types,distal detrital rock gas,special rock gas,distal/proximal tight sandstone gas,inner-source tight sandstone gas,shale gas,and coal-rock gas,according to its source and reservoir lithology.The natural gas present in coal-rock reservoirs is collectively referred to as coal-rock gas.Existing data indicate significant differences in the geological characteristics of coal-rock gas exploration and development between shallow and deep layers in the same area,with the transition depth boundary generally 1500-2000 m.Based on the current understanding of coal-rock gas and respecting the historical usage conventions of coalbed methane terminology,coal-rock gas can be divided into deep coal-rock gas and shallow coalbed methane according to burial depth.Second,according to the research concept of“full-process reservoir formation”in the theory of the whole petroleum system of coal measures,based on the formation and evolution of typical coal-rock gas reservoirs,coal-rock gas is further divided into four types:primary coal-rock gas,regenerated coal-rock gas,residual coal-rock gas,and bio coal-rock gas.The first two belong to deep coal-rock gas,while the latter two belong to shallow coal-rock gas.Third,research on the coal-rock gas reservoir formation and evolution shows that shallow coal-rock gas is mainly residual coal-rock gas or bio coal-rock gas formed after geological transformation of primary coal-rock gas,with the reservoir characteristics such as low reservoir pressure,low gas saturation,adsorbed gas in dominance,and gas production by drainage and depressurization,while deep coal-rock gas is mainly primary coal-rock gas and regenerated coal-rock gas,with the reservoir characteristics such as high reservoir pressure,high gas saturation,abundant free gas,and no or little water.In particular,the primary coal-rock gas is wide in distribution,large in resource quantity,and good in reservoir quality,making it the most favorable type of coal-rock gas for exploration and development.展开更多
This paper expounds the basic principles and structures of the whole petroleum system to reveal the pattern of conventional oil/gas-tight oil/gas-shale oil/gas sequential accumulation and the hydrocarbon accumulation ...This paper expounds the basic principles and structures of the whole petroleum system to reveal the pattern of conventional oil/gas-tight oil/gas-shale oil/gas sequential accumulation and the hydrocarbon accumulation models and mechanisms of the whole petroleum system.It delineates the geological model,flow model,and production mechanism of shale and tight reservoirs,and proposes future research orientations.The main structure of the whole petroleum system includes three fluid dynamic fields,three types of oil and gas reservoirs/resources,and two types of reservoir-forming processes.Conventional oil/gas,tight oil/gas,and shale oil/gas are orderly in generation time and spatial distribution,and sequentially rational in genetic mechanism,showing the pattern of sequential accumulation.The whole petroleum system involves two categories of hydrocarbon accumulation models:hydrocarbon accumulation in the detrital basin and hydrocarbon accumulation in the carbonate basin/formation.The accumulation of unconventional oil/gas is self-containment,which is microscopically driven by the intermolecular force(van der Waals force).The unconventional oil/gas production has proved that the geological model,flow model,and production mechanism of shale and tight reservoirs represent a new and complex field that needs further study.Shale oil/gas must be the most important resource replacement for oil and gas resources of China.Future research efforts include:(1)the characteristics of the whole petroleum system in carbonate basins and the source-reservoir coupling patterns in the evolution of composite basins;(2)flow mechanisms in migration,accumulation,and production of shale oil/gas and tight oil/gas;(3)geological characteristics and enrichment of deep and ultra-deep shale oil/gas,tight oil/gas and coalbed methane;(4)resource evaluation and new generation of basin simulation technology of the whole petroleum system;(5)research on earth system-earth organic rock and fossil fuel system-whole petroleum system.展开更多
The classical source-to-trap petroleum system concept only considers the migration and accumulation of conventional oil and gas in traps driven dominantly by buoyance in a basin,although revised and improved,even some...The classical source-to-trap petroleum system concept only considers the migration and accumulation of conventional oil and gas in traps driven dominantly by buoyance in a basin,although revised and improved,even some new concepts as composite petroleum system,total petroleum system,total composite petroleum system,were proposed,but they do not account for the vast unconventional oil and gas reservoirs within the system,which is not formed and distributed in traps dominantly by buoyancedriven.Therefore,the petroleum system concept is no longer adequate in dealing with all the oil and gas accumulations in a basin where significant amount of the unconventional oil and gas resources are present in addition to the conventional oil and gas accumulations.This paper looked into and analyzed the distribution characteristics of conventional and unconventional oil/gas reservoirs and their differences and correlations in petroliferous basins in China and North America,and then proposed whole petroleum system(WPS)concept,the WPS is defined as a natural system that encompasses all the conventional and unconventional oil and gas,reservoirs and resources originated from organic matter in source rocks,the geological elements and processes involving the formation,evolution,and distribution of these oil and gas,reservoirs and resources.It is found in the WPS that there are three kinds of hydrocarbons dynamic fields,three kinds of original hydrocarbons,three kinds of reservoir rocks,and the coupling of these three essential elements lead to the basic ordered distribution model of shale oil/gas reservoirs contacting or interbeded with tight oil/gas reservoirs and separated conventional oil/gas reservoirs from source rocks upward,which is expressed as“S\T-C”.Abnormal conditions lead to other three special ordered distribution models:The first is that with shale oil/gas reservoirs separated from tight oil/gas reservoirs.The second is that with two direction ordered distributions from source upward and downward.The third is with lateral distribution from source outside.展开更多
Recent decades have witnessed an increasing number of studies investigating petroleum systems with the application of rhenium-osmium(Re-Os) isotopic geochemistry. Here, we review the use of the 187 Re-187 Os geochrono...Recent decades have witnessed an increasing number of studies investigating petroleum systems with the application of rhenium-osmium(Re-Os) isotopic geochemistry. Here, we review the use of the 187 Re-187 Os geochronometer with respect to the geochemical behaviour of rhenium and osmium in hydrocarbon-related geological processes. The Re-Os budget in hydrocarbon source rock predominantly originates from natural water columns during its deposition. Open seawater tends to have a homogeneous Os isotopic composition because its residence time in seawater is longer than the time taken for ocean mixing. On the contrary, restricted water bodies(e.g., lakes) may have heterogeneous Os isotopic compositions due to the greater amount of terrigenous input. Hydrogenous Re and Os atoms are sequestered from the water body into sedimentary organic matter and transferred into crude oil through thermal maturation of organic matter. Thermal maturation likely does not significantly alter the Re-Os isotopic systematics of the source rock as a Re-Os isochron age of 442±21 Ma(2σ) is yielded in this study for over matured source rocks within the Silurian Longmaxi Formation from the Sichuan Basin. Re-Os atoms are mainly hosted by the highly polar/aggregating/aromatic asphaltenes in hydrocarbons, possibly chelating with organic complexes or occurring as metalloporphyrins. Resin and aromatic hydrocarbons also contribute to the Re-Os budget, but are 2 to 3 orders of magnitude lower than that of asphaltenes, whereas saturates do not contain appreciable Re-Os contents. The distribution of Re-Os atoms in hydrocarbons is heterogeneous because the duplicate analysis of pure single bitumen samples yields similar ^(187)Os/^(188)Os ratios whereas variable ^(187)Re/^(188)Os ratios. The Re-Os system in crude oils can be reset during transport away from the source rocks, with Os-rich organic fractions more readily expelled than Re-rich fractions. Contact with metal-rich fluids(e.g., hydrothermal fluid) or compositional changes related to asphaltene contents(e.g., deasphalting, biodegradation, thermal cracking and thermochemical sulphate reduction) are also likely to alter the Re-Os systematics in hydrocarbons. These geochemical features enable the ^(187)Re-^(187)Os isotopic system to have robust applicability for petroleum system investigations, which may use the Re-Os radiometric tool for:(1) stratigraphic correlation of source rocks,(2) dating geological events altering the asphaltene content in hydrocarbon such as hydrocarbon generation, thermochemical sulphate reduction, etc., and,(3) fingerprinting hydrocarbons. Regardless of the robustness of the ^(187)Re-^(187)Os geochronometer for petroleum system investigations, there are several pending questions such as partitioning between solid organic species or between organic matter and sulphide, chelating sites in hydrocarbons and Os isotopic equilibration between hydrocarbon subfractions. To improve the understanding of the Re-Os behaviour in petroleum systems, we underscore multi-proxies-based geochemistry(e.g., inorganic-organic geochemistry) and experimental studies(e.g., hydrous pyrolysis).展开更多
Based on the analysis of the hydrocarbon geochemical characteristics in the Kuqa petroleum system of the Tarim Basin, this study discusses the causes and controlling factors of the phase diversities and their differen...Based on the analysis of the hydrocarbon geochemical characteristics in the Kuqa petroleum system of the Tarim Basin, this study discusses the causes and controlling factors of the phase diversities and their differences in geochemical features. According to the characteristics and differences in oil and gas phase, the petroleum system can be divided into five categories： oil reservoir, wet gas reservoir, condensate gas-rich reservoir, condensate gas-poor reservoir and dry gas reservoir. The causes for the diversities in oil and gas phases include diversities of the sources of parent material, maturity of natural gas and the process of hydrocarbon accumulation of different hydrocarbon phases. On the whole, the Jurassic and Triassic terrestrial source rocks are the main sources for the hydrocarbon in the Kuqa Depression. The small differences in parent material may cause diversities in oil and gas amount, but the impact is small. The differences in oil and gas phase are mainly affected by maturity and the accumulation process, which closely relates with each other. Oil and gas at different thermal evolution stage can be captured in different accumulation process.展开更多
The northern South China Sea margin has experienced a rifting stage and a post-rifting stage during the Cenozoic. In the rifting stage, the margin received lacustrine and shallow marine facies sediments. In the post-r...The northern South China Sea margin has experienced a rifting stage and a post-rifting stage during the Cenozoic. In the rifting stage, the margin received lacustrine and shallow marine facies sediments. In the post-rifting thermal subsidence, the margin accumulated shallow marine facies and hemipelagic deposRs, and the deepwater basins formed. Petroleum systems of deepwater setting have been imaged from seismic data and drill wells. Two kinds of source rocks including Paleogene lacustrine black shale and Oligocene-Early Miocene mudstone were developed in the deepwater basin of the South China Sea. The deepwater reservoirs are characterized by the deep sea channel fill, mass flow complexes and drowned reef carbonate platform. Profitable capping rocks on the top are mudstones with huge thickness in the post-rifting stage. Meanwhile, the faults developed during the rifting stage provide a migration path favourable for the formation of reservoirs. The analysis of seismic and drilling data suggests that the joint structural and stratigraphic traps could form giant hydrocarbon fields and hydrocarbon reservoirs including syn-rifting graben subaqueous delta, deepwater submarine fan sandstone and reef carbonate reservoirs.展开更多
The present paper mainly studies the petroleum system of the Sufyan Depression in the Muglad Basin of central Africa and analyzes its control of hydrocarbon accumulation. On the basis of comprehensive analysis of effe...The present paper mainly studies the petroleum system of the Sufyan Depression in the Muglad Basin of central Africa and analyzes its control of hydrocarbon accumulation. On the basis of comprehensive analysis of effective source rock, reservoir bed types and source-reservoir-seal assemblages, petroleum system theory has been used to classify the petroleum system of the Sufyan Depression. Vertically, the Sufyan Depression consists of two subsystems. One is an Abu Gabra subsystem as a self generating, accumulating and sealing assemblage. The other subsystem is composed of an Abu Gabra source rock, Bentiu channel sandstone reservoir and Darfur group shale seal, which is a prolific assemblage in this area. Laterally, the Sufyan Depression is divided into eastern and western parts with separate hydrocarbon generation centers more than 10 000 m deep. The potential of the petroleum system is tremendous. Recently, there has been a great breakthrough in exploration. The Sufyan C-1 well drilled in the central structural belt obtained high-yielding oil flow exceeding 100 tons per day and controlled geologic reserves of tens of millions of tons. The total resource potential of the Sufyan Depression is considerable. The central structural belt is most favorable as an exploration and development prospect.展开更多
Based on the analysis of Upper Paleozoic source rocks, source-reservoir-caprock assemblage, and gas accumulation characteristics in the Ordos Basin, the gas accumulation geological model of total petroleum system is d...Based on the analysis of Upper Paleozoic source rocks, source-reservoir-caprock assemblage, and gas accumulation characteristics in the Ordos Basin, the gas accumulation geological model of total petroleum system is determined. Then, taking the Carboniferous Benxi Formation and the Permian Taiyuan Formation and Shanxi Formation as examples, the main controlling factors of gas accumulation and enrichment are discussed, and the gas enrichment models of total petroleum system are established. The results show that the source rocks, faults and tight reservoirs and their mutual coupling relations control the distribution and enrichment of gas. Specifically, the distribution and hydrocarbon generation capacity of source rocks control the enrichment degree and distribution range of retained shale gas and tight gas in the source. The coupling between the hydrocarbon generation capacity of source rocks and the physical properties of tight reservoirs controls the distribution and sweet spot development of near-source tight gas in the basin center. The far-source tight gas in the basin margin is mainly controlled by the distribution of faults, and the distribution of inner-source, near-source and far-source gas is adjusted and reformed by faults. Generally, the Upper Paleozoic gas in the Ordos Basin is recognized in four enrichment models: inner-source coalbed gas and shale gas, inner-source tight sandstone gas, near-source tight gas, and far-source fault-transported gas. In the Ordos Basin, inner-source tight gas and near-source tight gas are the current focuses of exploration, and inner-source coalbed gas and shale gas and far-source gas will be important potential targets in the future.展开更多
Through an integrated study of Mesozoic and Palaeozoic petroleum geology insouthern China and a summing-up of the results of exploration, the authors tentatively put forward aset of methods of studying petroleum syste...Through an integrated study of Mesozoic and Palaeozoic petroleum geology insouthern China and a summing-up of the results of exploration, the authors tentatively put forward aset of methods of studying petroleum systems in modified residual basins or superposed basins. Itscore idea is to put emphasis on the study of the dynamic evolution of petroleum systems. Thetempo-spatial evolution, hydrocarbon-generating processes and hydrocarbon-generating intensities andamounts of resources in different geological stages of chief source rocks are mainly deducedbackward by 3-D basin modelling. The regularities of formation and destruction of oil and gasaccumulations are summarized by analyzing the fossil and existing oil and gas accumulations, thedirection of migration is studied by palaeo-structural analysis, and the dynamic evolution ofPalaeozoic and Mesozoic petroleum systems in southern China is studied according to stages of majortectonic movements. The authors suggest that the realistic exploration targets of Palaeozoic andMesozoic petroleum systems in southern China are secondary and hydrocarbon-regeneration petroleumsystems, while the existing primary petroleum systems are rare. They propose that the favourableareas for exploration of Palaeozoic and Mesozoic petroleum systems in southern China are the frontarea of the Daba Mountains and the steep anticlinal zone on the western side of the Shizhusynclinorium in northeastern Sichuan, the Funin-Yancheng-Hai'an-Xinghua-Baoying area in the northernJiangsu basin, the Qianjiang-Xiantao-Paizhou-Chacan 1 well area in the southern part of the Chenhuarea of the Jianghan basin, the South Poyang basin in Jiangxi and the North subbasin of the Chuxiongbasin. This view has been supported by the discovery of the Zhujiadun gas field in the Yanchengsubbasin of the northern Jiangsu basin and the Kaixiantaixi oil-bearing structure in the southernpart of the Chenhu area of the Jianghan basin.展开更多
Petroleum system theory has been used to study characteristics of the Fula depression in the Central African fault zone.In this system,deep lacustrine facies mudstone in the Abu Gabra For-mation of the Lower Cretaceou...Petroleum system theory has been used to study characteristics of the Fula depression in the Central African fault zone.In this system,deep lacustrine facies mudstone in the Abu Gabra For-mation of the Lower Cretaceous is a very good source rock,thick deltaic facies sandstone of the Abu Gabra Formation and fluvial facies sandstone of the Bentiu Formation are good reservoir beds,and the mudstone in the Upper Cretaceous Darfur Group is the regional cap rock.The oil search mode and fault block trap seal-off conditions are considered here for passive rift basins.Particularly with respect to oil source rock distribution,successive development of reverse fault block and faulted anticlinal traps on low relief structures could have accumulated hydrocarbons because of lateral sealing by down-thrown mudstone along the up-dipping reservoir beds.At present,discoveries in this system are all large-duty oil fields.In 2009,proved reserves exceeded 2×108 t,and about 3×106 t annual throughput of crude oil was obtained.Risk exploration of the Fula depression is of short cycle and high benefit,which will be of great help for exploration in the Muglad basin.展开更多
The Triassic in the Longmengshan foreland basin is rich in oil and gas resources. Its reservoirs feature low-porosity, low-permeability, small pore throat, high water saturation, and strong heterogeneity. The existenc...The Triassic in the Longmengshan foreland basin is rich in oil and gas resources. Its reservoirs feature low-porosity, low-permeability, small pore throat, high water saturation, and strong heterogeneity. The existence of abnormally high pressure and various reservoir-cap combinations developed at different times provide favorable conditions for trapping oil and gas. Taking the theory of petroleum systems as a guide, and beginning with research on tectonics, sedimentary history, distribution and evolution of source rocks, reservoir evolution, hydraulic force distribution, and hydrocarbon migration, analysis and study of static factors like source rocks, reservoirs and cap rocks, and dynamic factors such as hydrocarbon generation, migration, and accumulation revealed the characteristics of the Upper Triassic petroleum system in western Sichuan province. The deepbasin gas in the central hydrocarbon kitchen of the Upper Triassic, structural-lithological combination traps on the surrounding slopes, and the structural traps of the Indo-Chinese-Yangshan paleohighs, are potential plays. The relatively well- developed fault zones in the southern segment of the Longmengshan foothill belt are favorable Jurassic gas plays. Pengshan-Xinjin, Qiongxi, and Dayi are recent exploration targets for Jurassic oil/gas reservoirs.展开更多
The Junggar basin is located in the northern part of Xinjiang of China. It is part of the Kazakstan plate, surrounded by the Paleozoic folded mountains: the Halaart, Zayier and Chepaizi Mountains in the northwest, the...The Junggar basin is located in the northern part of Xinjiang of China. It is part of the Kazakstan plate, surrounded by the Paleozoic folded mountains: the Halaart, Zayier and Chepaizi Mountains in the northwest, the Qingelidi and Karamaili Mountains in the northeast, and the Tianshan Mountains in the south. In different evolution stages, the basin's types are different, and the stratigraphy and deposition are also different. From the Carboniferous to Tertiary the basin has in turn gone through rift basin, collision foreland basin, intraplate depression basin and regenerated foreland basin. Based on an analysis of thermal evolution history and buried history of the source rocks, three major periods of oil generation are found in the basin. According to the characteristics of source rock distribution, evolution, oil-source correlation, structure and multi-phase and mixed pools, the Junggar basin could be divided into 4 composite petroleum systems. Due to the variation in sedimentary facies, difference in structural patterns and development histories, the petroleum pool-forming conditions in different areas and horizons are greatly different, so are the petroleum pool types, the accumulation mechanisms in different areas and horizons.展开更多
Based on the situation and progress of marine oil/gas exploration in the Sichuan Basin,SW China,the whole petroleum system is divided for marine carbonate rocks of the basin according to the combinations of hydrocarbo...Based on the situation and progress of marine oil/gas exploration in the Sichuan Basin,SW China,the whole petroleum system is divided for marine carbonate rocks of the basin according to the combinations of hydrocarbon accumulation elements,especially the source rock.The hydrocarbon accumulation characteristics of each whole petroleum system are analyzed,the patterns of integrated conventional and unconventional hydrocarbon accumulation are summarized,and the favorable exploration targets are proposed.Under the control of multiple extensional-convergent tectonic cycles,the marine carbonate rocks of the Sichuan Basin contain three sets of regional source rocks and three sets of regional cap rocks,and can be divided into the Cambrian,Silurian and Permian whole petroleum systems.These whole petroleum systems present mainly independent hydrocarbon accumulation,containing natural gas of affinity individually.Locally,large fault zones run through multiple whole petroleum systems,forming a fault-controlled complex whole petroleum system.The hydrocarbon accumulation sequence of continental shelf facies shale gas accumulation,marginal platform facies-controlled gas reservoirs,and intra-platform fault-and facies-controlled gas reservoirs is common in the whole petroleum system,with a stereoscopic accumulation and orderly distribution pattern.High-quality source rock is fundamental to the formation of large gas fields,and natural gas in a whole petroleum system is generally enriched near and within the source rocks.The development and maintenance of large-scale reservoirs are essential for natural gas enrichment,multiple sources,oil and gas transformation,and dynamic adjustment are the characteristics of marine petroleum accumulation,and good preservation conditions are critical to natural gas accumulation.Large-scale marginal-platform reef-bank facies zones,deep shale gas,and large-scale lithological complexes related to source-connected faults are future marine hydrocarbon exploration targets in the Sichuan Basin.展开更多
North Africa, which is one of the main oil and gas producing regions in the world, is best known for its subsalt Paleozoic-Triassic reservoirs and Paleozoic source rocks. Hydrocarbon abundance varies greatly from one ...North Africa, which is one of the main oil and gas producing regions in the world, is best known for its subsalt Paleozoic-Triassic reservoirs and Paleozoic source rocks. Hydrocarbon abundance varies greatly from one structural domain to another areally and from one stratigraphic interval to another vertically. Analyses of the essential elements and geological processes of the Paleozoic petroleum system indicate that the distribution of the Lower Silurian shale source rocks, the development of a thick Mesozoic overburden, the presence of the Upper Triassic-Lower Jurassic evaporite seal are the most important factors goveming the distribution of the Paleozoic-sourced hydrocarbons in North Africa. The Mesozoic sequence plays a critical role for hydrocarbons to accumulate by enabling the maturation of the Paleozoic source rocks during the Mesozoic-Paleogene times and preserving the accumulated hydrocarbons. Basins and surrounding uplifts, particularly the latter, with a thick Mesozoic sequence and a regional evaporite seal generally have abundant hydrocarbons. Basins where only a thin Mesozoic overburden was developed tend to have a very poor to moderate hydrocarbon prospectivity.展开更多
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.
文摘Gas chromatography-mass spectrometry(GC-MS)was used to analyze the pentacyclic triterpenoid distributions,specifically hopane and oleanane fingerprints,in 24 crude oil samples from the Niger Delta depobelts,with the aim of defining the petroleum system,filling history,and the age of source rock producing these oils.The results indicate that the Niger Delta oils belong to a single fluvio-deltaic petroleum system,reflecting similar source organic facies and depositional environments.Geochemical parameters,including C29/C30hopane ratios,oleanane index,Ts/Tm,(Ts/(Ts+Tm)),moretane/C30hopane ratios,and C3222S/(22S+22R)ratios,suggest oxic conditions during source rock deposition and thermal maturity of the oils.The presence of terrigenous organic matter and complex filling history are also evident and influenced by multiple phases of sedimentation,and petroleum generation.A comparative plot of geologic time(Paleogene-Neogene age)and oleanane percentage composition show that the crude oils are constrained to the chronostratigraphic ages of their respective depobelts,demonstrating the potential of oleanane-derived parameters for relative dating of hydrocarbon sources,complementing traditional index fossil methods.
基金Supported by the Major Consultation Project of the Chinese Academy of Sciences(2019-ZW11-Z-035)Technology Development Project of PetroChina Research Institute of Petroleum Exploration&Development(2021DJ0101)。
文摘Natural gas hydrate(NGH),as a widely recognized clean energy,has shown a significant resource potential.However,due to the lack of a unified evaluation methodology and the difficult determination of key parameters,the evaluation results of global NGH resource are greatly different.This paper establishes a quantitative relationship between NGH resource potential and conventional oil and gas resource and a NGH resource evaluation model based on the whole petroleum system(WPS)and through the analysis of dynamic field controlling hydrocarbon accumulation.The global NGH initially in-place and recoverable resources are inverted through the Monte Carlo simulation,and verified by using the volume analogy method based on drilling results and the trend analysis method of previous evaluation results.The proposed evaluation model considers two genetic mechanisms of natural gas(biological degradation and thermal degradation),surface volume conversion factor difference between conventional natural gas and NGH,and the impacts of differences in favorable distribution area and thickness and in other aspects on the results of NGH resource evaluation.The study shows that the global NGH initially in-place and recoverable resources are 99×10^(12) m^(3) and 30×10^(12) m3,with averages of 214×10^(12) m^(3) and 68×10^(12) m^(3),respectively,less than 5% of the total conventional oil and gas resources,and they can be used as a supplement for the future energy of the world.The proposed NGH resource evaluation model creates a new option of evaluation method and technology,and generates reliable data of NGH resource according to the reliability comprehensive analysis and test,providing a parameter basis for subsequent NGH exploration and development.
基金Supported by the National Science and Technology Major Project(2024ZD1400101)Project of Sinopec(P23234)。
文摘Based on a large amount of basic research and experimental analysis data from Shengli Oilfield,Bohai Bay Basin,guided by the theory of whole petroleum system,the distribution of sedimentary systems,the distribution and hydrocarbon generation and expulsion process of source rocks,the variation of reservoir properties,and the control of fracture systems on hydrocarbon accumulation in the Paleogene of the Jiyang Depression,Boahai Bay Basin,were systematically analyzed,and the geological characteristics of the whole petroleum system in the rift basin were identified.Taking the Dongying Sag as an example,combined with the distribution of discovered conventional,tight,and shale oil/gas,a hydrocarbon accumulation model of the fault-controlled whole petroleum system in rift basin was proposed,and the distribution patterns of conventional and unconventional oil and gas reservoirs in large geological bodies horizontally and vertically were clarified.The research results show that paleoclimate and tectonic cycles control the orderly distribution of the Paleogene sedimentary system in the Jiyang Depression,the multi-stage source rocks provide sufficient material basis for in-situ shale oil/gas accumulation and other hydrocarbon migration and accumulation,the changes in reservoir properties control the dynamic threshold of hydrocarbon accumulation,and the combination of faults and fractures at different stages controls hydrocarbon migration and accumulation,and in-situ retention and accumulation of shale oil/gas,making the whole petroleum system in the rift basin associated,segmented and abrupt.The above elements are configured to form a composite whole petroleum system controlled by faults in the Paleogene of the Jiyang Depression.Moreover,under the control of hydrocarbon accumulation dynamics,a whole petroleum system can be divided into conventional subsystem and unconventional subsystem,with shale oil,tight oil and conventional oil in an orderly distribution in horizontal and vertical directions.This systematic understanding is referential for analyzing the whole petroleum system in continental rift basins in eastern China.
基金Supported by CNPC Basic Technology Research and Development Project(2021DJ2203)National Science and Technology Major Project for New Oil and Gas Exploration and Development(2025ZD1400200).
文摘Based on the investigation of sedimentary filling characteristics and pool-forming factors of the Mesozoic in the Ordos Basin,the whole petroleum system in the Mesozoic is divided,the migration&accumulation characteristics and main controlling factors of conventional-unconventional hydrocarbons are analyzed,and the whole petroleum system model is established.First,the whole petroleum system developed in the Mesozoic takes the high-quality source rocks of the 7th member of the Triassic Yanchang Formation as the core and mainly consists of low-permeability and unconventional oil and gas reservoirs.It can be divided into four hydrocarbon accumulation domains,including intra-source retained hydrocarbon accumulation domain,near-source tight hydrocarbon accumulation domain,far-source conventional hydrocarbon accumulation domain and transitional hydrocarbon accumulation domain,which together form a continuous,symbiotic,and orderly accumulation entity wherein unconventional resources significantly outweigh conventional ones in proportion.Second,the spatial core area of sedimentary filling is the oil-rich core of the whole petroleum system.From the core to the periphery,the reservoir type evolves as shale oil→tight oil→conventional oil,the accumulation power is dominated by overpressure→buoyancy or overpressure and capillary force,the accumulation scale changes from extensive hundreds of millions of tons to a isolated hundreds of thousands-million of tons,and the gas-oil ratio and methane content decrease.Third,the sedimentary filling system provides the material basis and spatial framework for the whole petroleum system,the superimposed sand body,fault and unconformity constitute the dominant migration pathway of hydrocarbons in the far-source conventional hydrocarbon accumulation domain and the transitional hydrocarbon accumulation domain,the high-quality source rocks provide a solid resource basis for shale oil,and the micro-nano pore throat-fracture network constitute unconventional accumulation space.The hydrocarbon migration and accumulation process is mainly controlled by intense expulsion of hydrocarbon under overpressure in the pool-forming stage and the in-situ re-enrichment controlled by underpressure in post-pool-forming stage.The oil-gas enrichment and long-term preservation depends on the coordination among three factors(stable geological structure,multi-cycle sedimentation,and dual self-sealing).Fourth,the whole petroleum system model is defined as four domains,overpressure+underpressure drive,and dual self-sealing.
基金Supported by the National Science and Technology Major Project of China(2024ZD1400101)China National Key Research and Development Project(2022YFF0801204)Major Science and Technology Project of CNPC(2023ZZ15YJ01,2021DJ0702)。
文摘Guided by the fundamental principles of the whole petroleum system,the control of tectonism,sedimentation,and diagenesis on hydrocarbon accumulation in a rifted basin is studied using the data of petroleum geology and exploration of the second member of the Paleogene Kongdian Formation(Kong-2 Member)in the Cangdong Sag,Bohai Bay Basin,China.It is clarified that the circle structure and circle effects are the marked features of a continental fault petroliferous basin,and they govern the orderly distribution of conventional and unconventional hydrocarbons in the whole petroleum systems of the rifted basin.Tectonic circle zones control sedimentary circle zones,while sedimentary circle zones and diagenetic circle zones control the spatial distribution of favorable reservoirs,thereby determining the orderly distribution of hydrocarbon accumulations in various circles.A model for the integrated,systematic accumulation of conventional and unconventional hydrocarbons under a multi-circle structure of the whole petroleum system of continental rifted basin has been developed.It reveals that each sag of the rifted basin is an independent whole petroleum system and circle system,which encompasses multiple orderly circles of conventional and unconventional hydrocarbons controlled by the same source kitchen.From the outer circle to the middle circle and then to the inner circle,there is an orderly transition from structural and stratigraphic reservoirs,to lithological and structural-lithological reservoirs,and finally to tight oil/gas and shale oil/gas enrichment zones.The significant feature of the whole petroleum system is the orderly control of hydrocarbons by multi-circle stratigraphic coupling,with the integrated,orderly distribution of conventional and unconventional reserves being the inevitable result of the multi-layered interaction within the whole petroleum system.This concept of multi-circle stratigraphic coupling for the orderly,integrated accumulation of conventional and unconventional hydrocarbons has guided significant breakthroughs in the overall,three-dimensional exploration and shale oil exploration in the Cangdong Sag.
基金Supported by the National Science and Technology Major Project for New Oil and Gas Exploration and Development(2025ZD1404200)Forward-looking and Fundamental Project of PetroChina Company Limited(2024DJ23)Scientific Research and Technology Development Project of PetroChina Research Institute of Petroleum Exploration&Development(2024vzz).
文摘There are various types of natural gas resources in coal measures,making them major targets for natural gas exploration and development in China.In view of the particularity of the whole petroleum system of coal measures and the reservoir-forming evolution of natural gas in coal,this study reveals the formation,enrichment characteristics and distribution laws of coal-rock gas by systematically reviewing the main types and geological characteristics of natural gas in the whole petroleum system of coal measures.First,natural gas in the whole petroleum system of coal measures is divided into two types,conventional gas and unconventional gas,according to its occurrence characteristics and accumulation mechanism,and into six types,distal detrital rock gas,special rock gas,distal/proximal tight sandstone gas,inner-source tight sandstone gas,shale gas,and coal-rock gas,according to its source and reservoir lithology.The natural gas present in coal-rock reservoirs is collectively referred to as coal-rock gas.Existing data indicate significant differences in the geological characteristics of coal-rock gas exploration and development between shallow and deep layers in the same area,with the transition depth boundary generally 1500-2000 m.Based on the current understanding of coal-rock gas and respecting the historical usage conventions of coalbed methane terminology,coal-rock gas can be divided into deep coal-rock gas and shallow coalbed methane according to burial depth.Second,according to the research concept of“full-process reservoir formation”in the theory of the whole petroleum system of coal measures,based on the formation and evolution of typical coal-rock gas reservoirs,coal-rock gas is further divided into four types:primary coal-rock gas,regenerated coal-rock gas,residual coal-rock gas,and bio coal-rock gas.The first two belong to deep coal-rock gas,while the latter two belong to shallow coal-rock gas.Third,research on the coal-rock gas reservoir formation and evolution shows that shallow coal-rock gas is mainly residual coal-rock gas or bio coal-rock gas formed after geological transformation of primary coal-rock gas,with the reservoir characteristics such as low reservoir pressure,low gas saturation,adsorbed gas in dominance,and gas production by drainage and depressurization,while deep coal-rock gas is mainly primary coal-rock gas and regenerated coal-rock gas,with the reservoir characteristics such as high reservoir pressure,high gas saturation,abundant free gas,and no or little water.In particular,the primary coal-rock gas is wide in distribution,large in resource quantity,and good in reservoir quality,making it the most favorable type of coal-rock gas for exploration and development.
基金Supported by the National Natural Science Foundation of China(U22B6002)PetroChina Science Research and Technology Development Project(2021DJ0101)。
文摘This paper expounds the basic principles and structures of the whole petroleum system to reveal the pattern of conventional oil/gas-tight oil/gas-shale oil/gas sequential accumulation and the hydrocarbon accumulation models and mechanisms of the whole petroleum system.It delineates the geological model,flow model,and production mechanism of shale and tight reservoirs,and proposes future research orientations.The main structure of the whole petroleum system includes three fluid dynamic fields,three types of oil and gas reservoirs/resources,and two types of reservoir-forming processes.Conventional oil/gas,tight oil/gas,and shale oil/gas are orderly in generation time and spatial distribution,and sequentially rational in genetic mechanism,showing the pattern of sequential accumulation.The whole petroleum system involves two categories of hydrocarbon accumulation models:hydrocarbon accumulation in the detrital basin and hydrocarbon accumulation in the carbonate basin/formation.The accumulation of unconventional oil/gas is self-containment,which is microscopically driven by the intermolecular force(van der Waals force).The unconventional oil/gas production has proved that the geological model,flow model,and production mechanism of shale and tight reservoirs represent a new and complex field that needs further study.Shale oil/gas must be the most important resource replacement for oil and gas resources of China.Future research efforts include:(1)the characteristics of the whole petroleum system in carbonate basins and the source-reservoir coupling patterns in the evolution of composite basins;(2)flow mechanisms in migration,accumulation,and production of shale oil/gas and tight oil/gas;(3)geological characteristics and enrichment of deep and ultra-deep shale oil/gas,tight oil/gas and coalbed methane;(4)resource evaluation and new generation of basin simulation technology of the whole petroleum system;(5)research on earth system-earth organic rock and fossil fuel system-whole petroleum system.
基金This work was supported by the major science and technology projects of CNPC during the“14th five-year plan”(Grant number 2021DJ0101)。
文摘The classical source-to-trap petroleum system concept only considers the migration and accumulation of conventional oil and gas in traps driven dominantly by buoyance in a basin,although revised and improved,even some new concepts as composite petroleum system,total petroleum system,total composite petroleum system,were proposed,but they do not account for the vast unconventional oil and gas reservoirs within the system,which is not formed and distributed in traps dominantly by buoyancedriven.Therefore,the petroleum system concept is no longer adequate in dealing with all the oil and gas accumulations in a basin where significant amount of the unconventional oil and gas resources are present in addition to the conventional oil and gas accumulations.This paper looked into and analyzed the distribution characteristics of conventional and unconventional oil/gas reservoirs and their differences and correlations in petroliferous basins in China and North America,and then proposed whole petroleum system(WPS)concept,the WPS is defined as a natural system that encompasses all the conventional and unconventional oil and gas,reservoirs and resources originated from organic matter in source rocks,the geological elements and processes involving the formation,evolution,and distribution of these oil and gas,reservoirs and resources.It is found in the WPS that there are three kinds of hydrocarbons dynamic fields,three kinds of original hydrocarbons,three kinds of reservoir rocks,and the coupling of these three essential elements lead to the basic ordered distribution model of shale oil/gas reservoirs contacting or interbeded with tight oil/gas reservoirs and separated conventional oil/gas reservoirs from source rocks upward,which is expressed as“S\T-C”.Abnormal conditions lead to other three special ordered distribution models:The first is that with shale oil/gas reservoirs separated from tight oil/gas reservoirs.The second is that with two direction ordered distributions from source upward and downward.The third is with lateral distribution from source outside.
基金This study was supported by the Research Start-up Project for Introduced Talent of Yunnan University(No.20190043)the CNPC Key Laboratory of Carbonate Reservoirs Innovation Fund(No.RIPED-2020-JS-51020)。
文摘Recent decades have witnessed an increasing number of studies investigating petroleum systems with the application of rhenium-osmium(Re-Os) isotopic geochemistry. Here, we review the use of the 187 Re-187 Os geochronometer with respect to the geochemical behaviour of rhenium and osmium in hydrocarbon-related geological processes. The Re-Os budget in hydrocarbon source rock predominantly originates from natural water columns during its deposition. Open seawater tends to have a homogeneous Os isotopic composition because its residence time in seawater is longer than the time taken for ocean mixing. On the contrary, restricted water bodies(e.g., lakes) may have heterogeneous Os isotopic compositions due to the greater amount of terrigenous input. Hydrogenous Re and Os atoms are sequestered from the water body into sedimentary organic matter and transferred into crude oil through thermal maturation of organic matter. Thermal maturation likely does not significantly alter the Re-Os isotopic systematics of the source rock as a Re-Os isochron age of 442±21 Ma(2σ) is yielded in this study for over matured source rocks within the Silurian Longmaxi Formation from the Sichuan Basin. Re-Os atoms are mainly hosted by the highly polar/aggregating/aromatic asphaltenes in hydrocarbons, possibly chelating with organic complexes or occurring as metalloporphyrins. Resin and aromatic hydrocarbons also contribute to the Re-Os budget, but are 2 to 3 orders of magnitude lower than that of asphaltenes, whereas saturates do not contain appreciable Re-Os contents. The distribution of Re-Os atoms in hydrocarbons is heterogeneous because the duplicate analysis of pure single bitumen samples yields similar ^(187)Os/^(188)Os ratios whereas variable ^(187)Re/^(188)Os ratios. The Re-Os system in crude oils can be reset during transport away from the source rocks, with Os-rich organic fractions more readily expelled than Re-rich fractions. Contact with metal-rich fluids(e.g., hydrothermal fluid) or compositional changes related to asphaltene contents(e.g., deasphalting, biodegradation, thermal cracking and thermochemical sulphate reduction) are also likely to alter the Re-Os systematics in hydrocarbons. These geochemical features enable the ^(187)Re-^(187)Os isotopic system to have robust applicability for petroleum system investigations, which may use the Re-Os radiometric tool for:(1) stratigraphic correlation of source rocks,(2) dating geological events altering the asphaltene content in hydrocarbon such as hydrocarbon generation, thermochemical sulphate reduction, etc., and,(3) fingerprinting hydrocarbons. Regardless of the robustness of the ^(187)Re-^(187)Os geochronometer for petroleum system investigations, there are several pending questions such as partitioning between solid organic species or between organic matter and sulphide, chelating sites in hydrocarbons and Os isotopic equilibration between hydrocarbon subfractions. To improve the understanding of the Re-Os behaviour in petroleum systems, we underscore multi-proxies-based geochemistry(e.g., inorganic-organic geochemistry) and experimental studies(e.g., hydrous pyrolysis).
基金supported by the Tarim Oil Field Research InstituteNational Natural Science Foundation (sanctified number:40602016)National Key Basic Research and Development Projects (Itemnumber:113404GJ0003)
文摘Based on the analysis of the hydrocarbon geochemical characteristics in the Kuqa petroleum system of the Tarim Basin, this study discusses the causes and controlling factors of the phase diversities and their differences in geochemical features. According to the characteristics and differences in oil and gas phase, the petroleum system can be divided into five categories： oil reservoir, wet gas reservoir, condensate gas-rich reservoir, condensate gas-poor reservoir and dry gas reservoir. The causes for the diversities in oil and gas phases include diversities of the sources of parent material, maturity of natural gas and the process of hydrocarbon accumulation of different hydrocarbon phases. On the whole, the Jurassic and Triassic terrestrial source rocks are the main sources for the hydrocarbon in the Kuqa Depression. The small differences in parent material may cause diversities in oil and gas amount, but the impact is small. The differences in oil and gas phase are mainly affected by maturity and the accumulation process, which closely relates with each other. Oil and gas at different thermal evolution stage can be captured in different accumulation process.
基金supported by the National Basic Research Pro-gram of China (No. 2007CB411703)the CAS Knowledge In-novation Program (No. KZCX2-YW-203)+1 种基金the National MLR Petroleum Resource Strategic Target Survey and Evaluation Programthe Taishan Scholarship Program of Shandong Province
文摘The northern South China Sea margin has experienced a rifting stage and a post-rifting stage during the Cenozoic. In the rifting stage, the margin received lacustrine and shallow marine facies sediments. In the post-rifting thermal subsidence, the margin accumulated shallow marine facies and hemipelagic deposRs, and the deepwater basins formed. Petroleum systems of deepwater setting have been imaged from seismic data and drill wells. Two kinds of source rocks including Paleogene lacustrine black shale and Oligocene-Early Miocene mudstone were developed in the deepwater basin of the South China Sea. The deepwater reservoirs are characterized by the deep sea channel fill, mass flow complexes and drowned reef carbonate platform. Profitable capping rocks on the top are mudstones with huge thickness in the post-rifting stage. Meanwhile, the faults developed during the rifting stage provide a migration path favourable for the formation of reservoirs. The analysis of seismic and drilling data suggests that the joint structural and stratigraphic traps could form giant hydrocarbon fields and hydrocarbon reservoirs including syn-rifting graben subaqueous delta, deepwater submarine fan sandstone and reef carbonate reservoirs.
基金supported by the CNPC Science and Technology Study Financing Project (EDR/CN-01-102)
文摘The present paper mainly studies the petroleum system of the Sufyan Depression in the Muglad Basin of central Africa and analyzes its control of hydrocarbon accumulation. On the basis of comprehensive analysis of effective source rock, reservoir bed types and source-reservoir-seal assemblages, petroleum system theory has been used to classify the petroleum system of the Sufyan Depression. Vertically, the Sufyan Depression consists of two subsystems. One is an Abu Gabra subsystem as a self generating, accumulating and sealing assemblage. The other subsystem is composed of an Abu Gabra source rock, Bentiu channel sandstone reservoir and Darfur group shale seal, which is a prolific assemblage in this area. Laterally, the Sufyan Depression is divided into eastern and western parts with separate hydrocarbon generation centers more than 10 000 m deep. The potential of the petroleum system is tremendous. Recently, there has been a great breakthrough in exploration. The Sufyan C-1 well drilled in the central structural belt obtained high-yielding oil flow exceeding 100 tons per day and controlled geologic reserves of tens of millions of tons. The total resource potential of the Sufyan Depression is considerable. The central structural belt is most favorable as an exploration and development prospect.
基金Supported by the National Natural Science Foundation of China (41872128)the CNPC Major Science and Technology Project (2021DJ0101)。
文摘Based on the analysis of Upper Paleozoic source rocks, source-reservoir-caprock assemblage, and gas accumulation characteristics in the Ordos Basin, the gas accumulation geological model of total petroleum system is determined. Then, taking the Carboniferous Benxi Formation and the Permian Taiyuan Formation and Shanxi Formation as examples, the main controlling factors of gas accumulation and enrichment are discussed, and the gas enrichment models of total petroleum system are established. The results show that the source rocks, faults and tight reservoirs and their mutual coupling relations control the distribution and enrichment of gas. Specifically, the distribution and hydrocarbon generation capacity of source rocks control the enrichment degree and distribution range of retained shale gas and tight gas in the source. The coupling between the hydrocarbon generation capacity of source rocks and the physical properties of tight reservoirs controls the distribution and sweet spot development of near-source tight gas in the basin center. The far-source tight gas in the basin margin is mainly controlled by the distribution of faults, and the distribution of inner-source, near-source and far-source gas is adjusted and reformed by faults. Generally, the Upper Paleozoic gas in the Ordos Basin is recognized in four enrichment models: inner-source coalbed gas and shale gas, inner-source tight sandstone gas, near-source tight gas, and far-source fault-transported gas. In the Ordos Basin, inner-source tight gas and near-source tight gas are the current focuses of exploration, and inner-source coalbed gas and shale gas and far-source gas will be important potential targets in the future.
文摘Through an integrated study of Mesozoic and Palaeozoic petroleum geology insouthern China and a summing-up of the results of exploration, the authors tentatively put forward aset of methods of studying petroleum systems in modified residual basins or superposed basins. Itscore idea is to put emphasis on the study of the dynamic evolution of petroleum systems. Thetempo-spatial evolution, hydrocarbon-generating processes and hydrocarbon-generating intensities andamounts of resources in different geological stages of chief source rocks are mainly deducedbackward by 3-D basin modelling. The regularities of formation and destruction of oil and gasaccumulations are summarized by analyzing the fossil and existing oil and gas accumulations, thedirection of migration is studied by palaeo-structural analysis, and the dynamic evolution ofPalaeozoic and Mesozoic petroleum systems in southern China is studied according to stages of majortectonic movements. The authors suggest that the realistic exploration targets of Palaeozoic andMesozoic petroleum systems in southern China are secondary and hydrocarbon-regeneration petroleumsystems, while the existing primary petroleum systems are rare. They propose that the favourableareas for exploration of Palaeozoic and Mesozoic petroleum systems in southern China are the frontarea of the Daba Mountains and the steep anticlinal zone on the western side of the Shizhusynclinorium in northeastern Sichuan, the Funin-Yancheng-Hai'an-Xinghua-Baoying area in the northernJiangsu basin, the Qianjiang-Xiantao-Paizhou-Chacan 1 well area in the southern part of the Chenhuarea of the Jianghan basin, the South Poyang basin in Jiangxi and the North subbasin of the Chuxiongbasin. This view has been supported by the discovery of the Zhujiadun gas field in the Yanchengsubbasin of the northern Jiangsu basin and the Kaixiantaixi oil-bearing structure in the southernpart of the Chenhu area of the Jianghan basin.
基金supported by the CNPC Science and Technology Study Financing Project (No. EDR/CN-01-102)
文摘Petroleum system theory has been used to study characteristics of the Fula depression in the Central African fault zone.In this system,deep lacustrine facies mudstone in the Abu Gabra For-mation of the Lower Cretaceous is a very good source rock,thick deltaic facies sandstone of the Abu Gabra Formation and fluvial facies sandstone of the Bentiu Formation are good reservoir beds,and the mudstone in the Upper Cretaceous Darfur Group is the regional cap rock.The oil search mode and fault block trap seal-off conditions are considered here for passive rift basins.Particularly with respect to oil source rock distribution,successive development of reverse fault block and faulted anticlinal traps on low relief structures could have accumulated hydrocarbons because of lateral sealing by down-thrown mudstone along the up-dipping reservoir beds.At present,discoveries in this system are all large-duty oil fields.In 2009,proved reserves exceeded 2×108 t,and about 3×106 t annual throughput of crude oil was obtained.Risk exploration of the Fula depression is of short cycle and high benefit,which will be of great help for exploration in the Muglad basin.
文摘The Triassic in the Longmengshan foreland basin is rich in oil and gas resources. Its reservoirs feature low-porosity, low-permeability, small pore throat, high water saturation, and strong heterogeneity. The existence of abnormally high pressure and various reservoir-cap combinations developed at different times provide favorable conditions for trapping oil and gas. Taking the theory of petroleum systems as a guide, and beginning with research on tectonics, sedimentary history, distribution and evolution of source rocks, reservoir evolution, hydraulic force distribution, and hydrocarbon migration, analysis and study of static factors like source rocks, reservoirs and cap rocks, and dynamic factors such as hydrocarbon generation, migration, and accumulation revealed the characteristics of the Upper Triassic petroleum system in western Sichuan province. The deepbasin gas in the central hydrocarbon kitchen of the Upper Triassic, structural-lithological combination traps on the surrounding slopes, and the structural traps of the Indo-Chinese-Yangshan paleohighs, are potential plays. The relatively well- developed fault zones in the southern segment of the Longmengshan foothill belt are favorable Jurassic gas plays. Pengshan-Xinjin, Qiongxi, and Dayi are recent exploration targets for Jurassic oil/gas reservoirs.
文摘The Junggar basin is located in the northern part of Xinjiang of China. It is part of the Kazakstan plate, surrounded by the Paleozoic folded mountains: the Halaart, Zayier and Chepaizi Mountains in the northwest, the Qingelidi and Karamaili Mountains in the northeast, and the Tianshan Mountains in the south. In different evolution stages, the basin's types are different, and the stratigraphy and deposition are also different. From the Carboniferous to Tertiary the basin has in turn gone through rift basin, collision foreland basin, intraplate depression basin and regenerated foreland basin. Based on an analysis of thermal evolution history and buried history of the source rocks, three major periods of oil generation are found in the basin. According to the characteristics of source rock distribution, evolution, oil-source correlation, structure and multi-phase and mixed pools, the Junggar basin could be divided into 4 composite petroleum systems. Due to the variation in sedimentary facies, difference in structural patterns and development histories, the petroleum pool-forming conditions in different areas and horizons are greatly different, so are the petroleum pool types, the accumulation mechanisms in different areas and horizons.
基金Supported by the National Natural Science Foundation of China(42090022)。
文摘Based on the situation and progress of marine oil/gas exploration in the Sichuan Basin,SW China,the whole petroleum system is divided for marine carbonate rocks of the basin according to the combinations of hydrocarbon accumulation elements,especially the source rock.The hydrocarbon accumulation characteristics of each whole petroleum system are analyzed,the patterns of integrated conventional and unconventional hydrocarbon accumulation are summarized,and the favorable exploration targets are proposed.Under the control of multiple extensional-convergent tectonic cycles,the marine carbonate rocks of the Sichuan Basin contain three sets of regional source rocks and three sets of regional cap rocks,and can be divided into the Cambrian,Silurian and Permian whole petroleum systems.These whole petroleum systems present mainly independent hydrocarbon accumulation,containing natural gas of affinity individually.Locally,large fault zones run through multiple whole petroleum systems,forming a fault-controlled complex whole petroleum system.The hydrocarbon accumulation sequence of continental shelf facies shale gas accumulation,marginal platform facies-controlled gas reservoirs,and intra-platform fault-and facies-controlled gas reservoirs is common in the whole petroleum system,with a stereoscopic accumulation and orderly distribution pattern.High-quality source rock is fundamental to the formation of large gas fields,and natural gas in a whole petroleum system is generally enriched near and within the source rocks.The development and maintenance of large-scale reservoirs are essential for natural gas enrichment,multiple sources,oil and gas transformation,and dynamic adjustment are the characteristics of marine petroleum accumulation,and good preservation conditions are critical to natural gas accumulation.Large-scale marginal-platform reef-bank facies zones,deep shale gas,and large-scale lithological complexes related to source-connected faults are future marine hydrocarbon exploration targets in the Sichuan Basin.
文摘North Africa, which is one of the main oil and gas producing regions in the world, is best known for its subsalt Paleozoic-Triassic reservoirs and Paleozoic source rocks. Hydrocarbon abundance varies greatly from one structural domain to another areally and from one stratigraphic interval to another vertically. Analyses of the essential elements and geological processes of the Paleozoic petroleum system indicate that the distribution of the Lower Silurian shale source rocks, the development of a thick Mesozoic overburden, the presence of the Upper Triassic-Lower Jurassic evaporite seal are the most important factors goveming the distribution of the Paleozoic-sourced hydrocarbons in North Africa. The Mesozoic sequence plays a critical role for hydrocarbons to accumulate by enabling the maturation of the Paleozoic source rocks during the Mesozoic-Paleogene times and preserving the accumulated hydrocarbons. Basins and surrounding uplifts, particularly the latter, with a thick Mesozoic sequence and a regional evaporite seal generally have abundant hydrocarbons. Basins where only a thin Mesozoic overburden was developed tend to have a very poor to moderate hydrocarbon prospectivity.
