【正】For the last 4-5 years,we,the editors of the Journal of Palaeogeo graphy(in Chinese)and the Journal of Palaeogeography(in English),and the teachers from College of Geosciences,China University of Petroleum(Beiji...【正】For the last 4-5 years,we,the editors of the Journal of Palaeogeo graphy(in Chinese)and the Journal of Palaeogeography(in English),and the teachers from College of Geosciences,China University of Petroleum(Beijing)altogether,taking spare time after our routine editing and teaching work,participated in the designation,organization,writing,editing and revision processes of the Sedimentology of China(Second Edition).We put great efforts into this great work which represents the latest research results of various domains of sedimentology in China.We specially published this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
In October 2023,China University of Petroleum will celebrate its 70th anniversary,as a scientific and technological support force in the field of petrochemical industry in China,China University of Petroleum has made ...In October 2023,China University of Petroleum will celebrate its 70th anniversary,as a scientific and technological support force in the field of petrochemical industry in China,China University of Petroleum has made significant contributions to the development of energy and chemical industry,cultivated a large number of outstanding talents,and promoted the development of energy and chemical engineering.With the proposal of peaking carbon dioxide emissions and achieving carbon neutrality,China University of Petroleum actively transformed and made a series of breakthroughs in the fields of low-carbon chemical industry,new energy,and new materials,continuing to support the national energy strategy in the new era.To celebrate China University of Petroleum’s 70^(th)anniversary,this special issue features a collection of scientific research and innovation achievements by the research team and alumni of China University of Petroleum,covering multidisciplinary topics including nanotechnology,catalysis,energy,chemical engineering,environment,devices,biology,etc.This special issue is aiming to show the research advances of China University of Petroleum in the field of nano science.China University of Petroleum was established in Beijing in 1953,when the national economy was desperate for petroleum resources and the development of the petroleum industry was urgently needed professionals.展开更多
Based on the experimental results of casting thin section,low temperature nitrogen adsorption,high pressure mercury injection,nuclear magnetic resonance T2 spectrum,contact angle and oil-water interfacial tension,the ...Based on the experimental results of casting thin section,low temperature nitrogen adsorption,high pressure mercury injection,nuclear magnetic resonance T2 spectrum,contact angle and oil-water interfacial tension,the relationship between pore throat structure and crude oil mobility characteristics of full particle sequence reservoirs in the Lower Permian Fengcheng Formation of Mahu Sag,Junggar Basin,are revealed.(1)With the decrease of reservoir particle size,the volume of pores connected by large throats and the volume of large pores show a decreasing trend,and the distribution and peak ranges of throat and pore radius shift to smaller size in an orderly manner.The upper limits of throat radius,porosity and permeability of unconventional reservoirs in Fengcheng Formation are approximately 0.7μm,8%and 0.1×10^(−3)μm^(2),respectively.(2)As the reservoir particle size decreases,the distribution and peak ranges of pores hosting retained oil and movable oil are shifted to a smaller size in an orderly manner.With the increase of driving pressure,the amount of retained and movable oil of the larger particle reservoir samples shows a more obvious trend of decreasing and increasing,respectively.(3)With the increase of throat radius,the driving pressure of reservoir with different particle levels presents three stages,namely rapid decrease,slow decrease and stabilization.The oil driving pressures of various reservoirs and the differences of them decrease with the increase of temperature and obviously decrease with the increase of throat radius.According to the above experimental analysis,it is concluded that the deep shale oil of Fengcheng Formation in Mahu Sag has great potential for production under geological conditions.展开更多
Characterized by complex lithology and strong heterogeneity, volcanic reservoirs in China developed three reservoir space types： primary pores, secondary pores and fractures. The formation of reservoir space went thr...Characterized by complex lithology and strong heterogeneity, volcanic reservoirs in China developed three reservoir space types： primary pores, secondary pores and fractures. The formation of reservoir space went through the cooling and solidification stage （including blast fragmentation, crystallization differentiation and solidification） and the epidiagenesis stage （including metasomatism, filling, weathering and leaching, formation fluid dissolution and tectonism）. Primary pores were formed at the solidification stage, which laid the foundation for the development and transformation of effective reservoirs. Secondary pores were formed at the epidiagenesis stage, with key factors as weathering and leaching, formation fluid dissolution and tectonism. In China, Mesozoic-Cenozoic volcanic rocks developed in the Songliao Basin and Bohai Bay Basin in the east and Late Paleozoic volcanic rocks developed in the Junggar Basin, Santanghu Basin and Ta- rim Basin in the west. There are primary volcanic reser- voirs and secondary volcanic reservoirs in these volcanic rocks, which have good accumulation conditions and great exploration potential.展开更多
Taking the second member of the Xujiahe Formation of the Upper Triassic in the Xinchang structural belt as an example,based on data such as logging,production,seismic interpretation and test,a systematic analysis was ...Taking the second member of the Xujiahe Formation of the Upper Triassic in the Xinchang structural belt as an example,based on data such as logging,production,seismic interpretation and test,a systematic analysis was conducted on the structural characteristics and evolution,reservoir diagenesis and densification processes,and types and stages of faults/fractures,and revealing the multi-stage and multi-factor dynamic coupled enrichment mechanisms of tight gas reservoirs.(1)In the early Yanshan period,the paleo-structural traps were formed with low-medium maturity hydrocarbons accumulating in structural highs driven by buoyancy since reservoirs were not fully densified in this stage,demonstrating paleo-structure control on traps and early hydrocarbon accumulation.(2)In the middle-late Yanshan period,the source rocks became mature to generate and expel a large quantity of hydrocarbons.Grain size and type of sandstone controlled the time of reservoir densification,which restricted the scale of hydrocarbon charging,allowing for only a small-scale migration through sand bodies near the fault/fracture or less-densified matrix reservoirs.(3)During the Himalayan period,the source rocks reached overmaturity,and the residual oil cracking gas was efficiently transported along the late-stage faults/fractures.Wells with high production capacity were mainly located in Type I and II fault/fracture zones comprising the late-stage north-south trending fourth-order faults and the late-stage fractures.The productivity of the wells was controlled by the transformation of the late-stage faults/fractures.(4)The Xinchang structural belt underwent three stages of tectonic evolution,two stages of reservoir formation,and three stages of fault/fractures development.Hydrocarbons mainly accumulated in the paleo-structure highs.After reservoir densification and late fault/fracture adjustment,a complex gas-water distribution pattern was formed.Thus,it is summarized as the model of“near-source and low-abundance hydrocarbon charging in the early stage,and differential enrichment of natural gas under the joint control of fault-fold-fracture complex,high-quality reservoirs and structural highs in the late stage”.Faults/fractures with well-coupled fault-fold-fracture-pore are favorable exploration targets with high exploration effectiveness.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
The isolated fracture-vug systems controlled by small-scale strike-slip faults within ultra-deep carbonate rocks of the Tarim Basin exhibit significant exploration potential.The study employs a novel training set inco...The isolated fracture-vug systems controlled by small-scale strike-slip faults within ultra-deep carbonate rocks of the Tarim Basin exhibit significant exploration potential.The study employs a novel training set incorporating innovative fault labels to train a U-Net-structured CNN model,enabling effective identification of small-scale strike-slip faults through seismic data interpretation.Based on the CNN faults,we analyze the distribution patterns of small-scale strike-slip faults.The small-scale strike-slip faults can be categorized into NNW-trending and NE-trending groups with strike lengths ranging 200–5000 m.The development intensity of small-scale strike-slip faults in the Lower Yingshan Member notably exceeds that in the Upper Member.The Lower and Upper Yingshan members are two distinct mechanical layers with contrasting brittleness characteristics,separated by a low-brittleness layer.The superior brittleness of the Lower Yingshan Member enhances the development intensity of small-scale strike-slip faults compared to the upper member,while the low-brittleness layer exerts restrictive effects on vertical fault propagation.Fracture-vug systems formed by interactions of two or more small-scale strike-slip faults demonstrate larger sizes than those controlled by individual faults.All fracture-vug system sizes show positive correlations with the vertical extents of associated small-scale strike-slip faults,particularly intersection and approaching fracture-vug systems exhibit accelerated size increases proportional to the vertical extents.展开更多
It is known from macrocomparisons and microresearches of bioherm reservoirs in main sedimentary basins of the South China Sea through deep-water petroleum explorations and by means of 2D/3D seismic data and a whole-co...It is known from macrocomparisons and microresearches of bioherm reservoirs in main sedimentary basins of the South China Sea through deep-water petroleum explorations and by means of 2D/3D seismic data and a whole-coring core from the Xisha Islands that there are great dif- ferences between deep-sea oil and gas fields in the world and those in the South China Sea, as reservoir systems of the former are mainly clastic rocks, whereas the latter have organic reefs that act as reser- voirs of their largest oil and gas fields, which are represented by large Liuhua 11-1 reef oilfield in the north and super-large L reef gas field in the south of the South China Sea. Therefore, it is of great significance to study deep-water hioherm reservoirs in the South China Sea. Comparisons of organic reefs in the four large islands of the South China Sea give evidences that such reefs in main sedimentary basins came into being during Cenozoic, especially in Neogene, and mainly occur as tower （point） reef, massive reef, platform-edge reef, and patch reef in shape, which show different reservoir physical properties and seismic reflection configurations and make up carbonate rock-bioherm formations in the island reef and sedimentary basin areas. Generally, the south and north parts differ from the east and the west of the South China Sea in geologic conditions, as their corresponding continental shelf/island shelf areas are relatively wide/ narrow, large stream current systems are well developed/not so well developed, and terrigenous sediments are relatively sufficient/insufficient. The southeast and south parts of the South China Sea had organic reefs built up earlier than the north and the reef building mainly took place in Neogene; these Neogene organic reefs all be- long to plant algal reef rocks. Liuhua oilfield in the Pearl River Mouth basin is found to mainly have red algal bindstone, Malampaya reef in the northern Palawan basin is rich in both red algal bind- stone and green algal reef segmented rock, and especially Miocene red algal framestone and green algal segmented rock are discovered in the Xisha Islands. These algal reefs created different sedimentary mi- crofacies as well as various rock structures and types, and through recent researches on the mechanism of dolomitization, freshwater dolomite was discovered and grouped under products from dolomitization in mixed water that was regression reefal dolomite of good reservoir properties.展开更多
Determining the orientation of in-situ stresses is crucial for various geoscience and engineering appli-cations.Conventional methods for estimating these stress orientations often depend on focal mechanism solutions(F...Determining the orientation of in-situ stresses is crucial for various geoscience and engineering appli-cations.Conventional methods for estimating these stress orientations often depend on focal mechanism solutions(FMSs)derived from earthquake data and formation micro-imager(FMI)data from well logs.However,these techniques can be costly,depth-inaccurate,and may lack spatial coverage.To address this issue,we introduce the use of three-dimensional(3D)seismic data(active sources)as a lateral constraint to approximate the 3D stress orientation field.Recognizing that both stress and fracture patterns are closely related to seismic velocity anisotropy,we derive the orientation of azimuthal anisotropy from multi-azimuth 3D seismic data to compensate for the lack of spatial stress orientation information.We apply our proposed workflow to a case study in the Weiyuan area of the Sichuan Basin,China,a region targeted for shale gas production.By integrating diverse datasets,including 3D seismic,earthquakes,and well logs,we develop a comprehensive 3D model of in-situ stress(orientations and magnitudes).Our results demonstrate that the estimated anisotropy orientations from 3D seismic data are consistent with the direction of maximum horizontal principal stress(SHmax)obtained from FMIs.We analyzed 12 earthquakes(magnitude>3)recorded between 2016 and 2020 for their FMSs and compressional axis(P-axis)orientations.The derived SHmax direction from our 3D stress model is 110°ES(East-South),which shows excellent agreement with the FMSs(within 3.96°).This close alignment validates the reliability and precision of our integrated method for predicting 3D SHmax orientations.展开更多
Various orders of sequences were recognized in the Tarim Basin from unconformities. Three mega-sequence groups, six mega-sequences, sixteen super-sequences and forty-two sequences were determined from the Sinian to th...Various orders of sequences were recognized in the Tarim Basin from unconformities. Three mega-sequence groups, six mega-sequences, sixteen super-sequences and forty-two sequences were determined from the Sinian to the Quaternary. The mega-sequences and super-sequences were in accordance with the locally tectonic events occurring in both the north and the south margins of the Tarim plate. The global sea level changes only worked to control formations in the tectonically stable periods or in the low order sequences. The sequences had close relationship to the source rocks, reservoirs and cap rocks, and the tectonic events determined the migration, accumulation, and preservation of the hydrocarbon. The three mega-sequence group cycles, including the early cycle-the Sinian-middle Devonian, the middle cycle-the upper Devonian-Triassic, and the late cycle-the Jurassic-Quaternary, corresponded to three reservoir formation cycles. So, it can be concluded that the local tectonic events controlled both the sequences and the distribution of oil and gas in the Tarim 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 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
It is of great significance to accurately and rapidly identify shale lithofacies in relation to the evaluation and prediction of sweet spots for shale oil and gas reservoirs.To address the problem of low resolution in...It is of great significance to accurately and rapidly identify shale lithofacies in relation to the evaluation and prediction of sweet spots for shale oil and gas reservoirs.To address the problem of low resolution in logging curves,this study establishes a grayscale-phase model based on high-resolution grayscale curves using clustering analysis algorithms for shale lithofacies identification,working with the Shahejie For-mation,Bohai Bay Basin,China.The grayscale phase is defined as the sum of absolute grayscale and relative amplitude as well as their features.The absolute grayscale is the absolute magnitude of the gray values and is utilized for evaluating the material composition(mineral composition+total organic carbon)of shale,while the relative amplitude is the difference between adjacent gray values and is used to identify the shale structure type.The research results show that the grayscale phase model can identify shale lithofacies well,and the accuracy and applicability of this model were verified by the fitting relationship between absolute grayscale and shale mineral composition,as well as corresponding re-lationships between relative amplitudes and laminae development in shales.Four lithofacies are iden-tified in the target layer of the study area:massive mixed shale,laminated mixed shale,massive calcareous shale and laminated calcareous shale.This method can not only effectively characterize the material composition of shale,but also numerically characterize the development degree of shale laminae,and solve the problem that difficult to identify millimeter-scale laminae based on logging curves,which can provide technical support for shale lithofacies identification,sweet spot evaluation and prediction of complex continental lacustrine basins.展开更多
It is significant to distinguish the dynamic systems of petroleum accumulation （DSPA） for the understanding of petroleum accumulation and distribution. According to the formation pressure framework, genetic types of...It is significant to distinguish the dynamic systems of petroleum accumulation （DSPA） for the understanding of petroleum accumulation and distribution. According to the formation pressure framework, genetic types of petroleum and characteristics of conduit systems, three dynamic systems of petroleum accumulation were identified in the vertical profile in the Nanpu depression, Bohai Bay basin. The deeper DSPA （including formations Es3 to Es2） is a sealed system with high-overpressure and high-mature self-sourced oil. Most of the crude oil in the system accumulated in the periods of late Oligocene （23.5 Ma） and late Pliocene （2.4 Ma）. The middle DSPA （including formations Es~ to Edl） is an overpressured half-sealed system with mature or lower-mature self-sourced oil. The accumulation of oil in the system also occurred in the late Oligocene （23.5 Ma） and late Pliocene （2.4 Ma）. The shallower DSPA （including formations Ed2 to Q） is a hydrostatic system with lower-mature aliensourced oil from the middle system. Oil within this system accumulated only in the late Pliocene period. The oil in the shallower system migrated vertically along the faults from the formerly accumulated oil in the middle system by lateral migration along the sandbodies, whereas petroleum accumulation in the deeper system was mainly derived from the system itself by lateral migration along the sandbodies and rarely migrated out of the system. In this case, it seems that the deeper system is a more potential exploration prospect in addition to the other two proved favorable systems.展开更多
Secondary petroleum migration in the eastern Pearl River Mouth basin was modeled using the three-dimensional PATHWAYSTM model, which assumes that the positions of petroleum migration pathways are controlled by the mor...Secondary petroleum migration in the eastern Pearl River Mouth basin was modeled using the three-dimensional PATHWAYSTM model, which assumes that the positions of petroleum migration pathways are controlled by the morphology of the sealing surfaces. The modeling results have accurately predicted the petroleum occurrences. Most commercial petroleum accumulations are along the predicted preferential petroleum migration pathways （PPMP）, and most large fields （petroleum reserves greater than 1×10^8t） have more than one preferential petroleum migration pathways to convey petroleum to the traps. The lateral migration distance for oil in the LHII-1 field, the largest ollfield so far discovered in the Pearl River Mouth basin, was more than 80 km. The case study suggests that in lacustrine fault basins, petroleum can migrate over a long distance to form large oilfields without driving force from groundwater flow. The focusing of petroleum originating from a large area of the generative kitchens into restricted channels seems to be essential not only for long-range petroleum migration in hydrostatic conditions, but also for the formation of large oil or gas fields. The strong porosity and permeability heterogeneities of the carrier beds and the relatively high prediction accuracy by a model that does not take into consideration of the effect of heterogeneity suggest that the positions of petroleum migration pathways in heterogeneous carrier beds with relatively large dipping angles are determined primarily by the morphology of the sealing surfaces at regional scales.展开更多
This paper investigates the origin and migration characteristics of petroleum in the northeastern part of the Baiyun Depression,Pearl River Mouth Basin(PRMB).The discovered petroleum in the study area is mainly locate...This paper investigates the origin and migration characteristics of petroleum in the northeastern part of the Baiyun Depression,Pearl River Mouth Basin(PRMB).The discovered petroleum in the study area is mainly located in the Lower Zhujiang Member(N_(1)z^(2))and mainly originated from the Enping Formation source rocks in the eastern sag.Active faults(vertical migration)and N_(1)z^(2)sandstones(lateral migration)acted as the petroleum migration systems.The fault activities in the Dongsha event controlled the episodic petroleum migration.Fractures in the fault zones provided effective conduits,and overpressure was the driving force.The vertical migration could not cross the fault zones laterally.The petroleum injection areas in the carrier beds were the contact zones of petroleum-migration faults and carrier beds.The lateral migration was steady-state migration,and buoyancy was the driving force.The migration pathways in the carrier beds were controlled by the structural morphology.Secondary petroleum migration in the study area could be divided into two parts:vertical migration along the fractures in the fault zones and lateral migration through preferential petroleum migration pathways(PPMPs)in the carrier beds.The petroleum migration behaviors,including migrating direction,driving force,and migration pattern,in the faults and sandstone carrier beds were quite different.This study provides a typical example for comprehending secondary migration processes and has great importance for determining future exploration targets in the deep-water area of the PRMB.展开更多
The organic geochemistry and petrology of source rocks determine the hydrocarbon generation potential of the Banqiao Sag. In this study, organic geochemistry and petrology were used to determine the abundance of organ...The organic geochemistry and petrology of source rocks determine the hydrocarbon generation potential of the Banqiao Sag. In this study, organic geochemistry and petrology were used to determine the abundance of organic matter(OM), OM type, OM maturity, and sedimentary environments of the source rocks, collected from Cenozoic Shahejie Formation, Banqiao Sag, Bohai Bay Basin, China. Vitrinite and liptinite are the main maceral composition of the source rocks, and range from 18% to 81% and from 2% to82% on a mineral matter free(MMF) basis, respectively. The values of vitrinite reflectance(Ro)(0.36%-1.20%) and the Tmaxvalues(397-486.C) show that the thermal maturity range from low mature to peak-maturity. The abundance of OM varies between 0.22% and 4.37%, suggesting that the source rocks of the Shahejie(Es) Formation are mainly fair to good source rocks. The Rock-Eval pyrolysis results show that the source rocks have good petroleum generation potential. The amount of free hydrocarbons(S_1)and hydrocarbons generated from pyrolysis(S_(2)) range within 0.01-3.70 mg/g, and 0.04-29.17 mg/g. The hydrogen index(HI) varies between 18.18 and 741.13 mg HC/g TOC, with most of the samples appearing to be mainly Type II kerogen, and thereby exhibiting the ability to generate both oil and gas. The ratios of Pr/Ph, the cross plot of Pr/nC_(17)-Ph/nC_(18), the cross plot of C_(29)/C_(27)-Pr/Ph, and ternary of dibenzothiophene, dibenzofuran, and fluorene, indicate that the Shahejie Formation deposited in suboxic and weak reducing environments. The main biological source is from advanced plants. The maceral composition and rock pyrolysis data indicate the kerogen type is a humic type or mixed sapropelic-humic type. The source rocks of the Shahejie(Es) Formation occur in the oil window, and the abundant organic richness,humic kerogen demonstrate that these rocks are effective oil and gas source rocks. The mudstone rocks in the Shahejie Formation are the main source of oil and gas and represent the main exploration target for the Banqiao Sag. This study enhances the great prospect of oil and gas production in the Banqiao Sag.展开更多
Relaxation of control over the upstream business of the petroleum industry in China is discussed. The authors suggest that a basic institutional preparation should be made before relaxing control over the upstream bus...Relaxation of control over the upstream business of the petroleum industry in China is discussed. The authors suggest that a basic institutional preparation should be made before relaxing control over the upstream business, and that the institutional preparation includes at least four parts： 1） setting up the admission standards, 2） perfecting the management system of mining rights, 3） reforming the royalty and taxation system for oil and gas resources, and 4） improving the supervision and management system. Stressing the institutional preparation before relaxation of control does not mean that China could not relax control over the upstream business until the management systems are perfected, but the authors suggest that China could establish a necessary system for relaxation of control and to improve it with future practice.展开更多
Halite and gypsum minerals in saline shale make the retention mechanism and chemical fractionation of residual oil unique. The Dongpu Depression in North China is a typically saline lacustrine basin with developing ha...Halite and gypsum minerals in saline shale make the retention mechanism and chemical fractionation of residual oil unique. The Dongpu Depression in North China is a typically saline lacustrine basin with developing halite and gypsum. The effect of gypsum minerals on residual oil content and chemical fractionation remains unclear. In this study, shale samples with different gypsum contents were used in organic geochemical experiments, showing that the high total organic matter (TOC) content and type II kerogen leads to a high residual oil content, as shown by high values of volatile hydrocarbon (S1) and extractable organic matter (EOM). XRD and FE-SEM result indicate that the existence of gypsum in saline shale contributes to an enhanced pore space and a higher residual oil content in comparison to non-gypsum shale. Additionally, the increase in the gypsum mineral content leads to an increase in the saturated hydrocarbon percentage and a decrease in polar components percentage (resins and asphaltene). Furthermore, thermal simulation experiments on low-mature saline shale show that the percentage of saturated hydrocarbons in the residual oil is high and remains stable and that the storage space is mainly mesoporous (> 20 nm) in the oil expulsion stage. However, the saturated hydrocarbons percentage decreases rapidly, and oil exists in mesopores (> 20 nm and < 5 nm) in the gas expulsion stage. In general, gypsum is conducive to the development of pore space, the adsorption of hydrocarbons and the occurrence of saturated hydrocarbon, leading to large quantities of residual oil. The data in this paper should prove to be reliable for shale oil exploration in saline lacustrine basins.展开更多
文摘【正】For the last 4-5 years,we,the editors of the Journal of Palaeogeo graphy(in Chinese)and the Journal of Palaeogeography(in English),and the teachers from College of Geosciences,China University of Petroleum(Beijing)altogether,taking spare time after our routine editing and teaching work,participated in the designation,organization,writing,editing and revision processes of the Sedimentology of China(Second Edition).We put great efforts into this great work which represents the latest research results of various domains of sedimentology in China.We specially published this
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.
文摘In October 2023,China University of Petroleum will celebrate its 70th anniversary,as a scientific and technological support force in the field of petrochemical industry in China,China University of Petroleum has made significant contributions to the development of energy and chemical industry,cultivated a large number of outstanding talents,and promoted the development of energy and chemical engineering.With the proposal of peaking carbon dioxide emissions and achieving carbon neutrality,China University of Petroleum actively transformed and made a series of breakthroughs in the fields of low-carbon chemical industry,new energy,and new materials,continuing to support the national energy strategy in the new era.To celebrate China University of Petroleum’s 70^(th)anniversary,this special issue features a collection of scientific research and innovation achievements by the research team and alumni of China University of Petroleum,covering multidisciplinary topics including nanotechnology,catalysis,energy,chemical engineering,environment,devices,biology,etc.This special issue is aiming to show the research advances of China University of Petroleum in the field of nano science.China University of Petroleum was established in Beijing in 1953,when the national economy was desperate for petroleum resources and the development of the petroleum industry was urgently needed professionals.
基金Supported by Leading Talent Program of Autonomous Region(2022TSYCLJ0070)PetroChina Prospective and Basic Technological Project(2021DJ0108)Natural Science Foundation for Outstanding Young People in Shandong Province(ZR2022YQ30).
文摘Based on the experimental results of casting thin section,low temperature nitrogen adsorption,high pressure mercury injection,nuclear magnetic resonance T2 spectrum,contact angle and oil-water interfacial tension,the relationship between pore throat structure and crude oil mobility characteristics of full particle sequence reservoirs in the Lower Permian Fengcheng Formation of Mahu Sag,Junggar Basin,are revealed.(1)With the decrease of reservoir particle size,the volume of pores connected by large throats and the volume of large pores show a decreasing trend,and the distribution and peak ranges of throat and pore radius shift to smaller size in an orderly manner.The upper limits of throat radius,porosity and permeability of unconventional reservoirs in Fengcheng Formation are approximately 0.7μm,8%and 0.1×10^(−3)μm^(2),respectively.(2)As the reservoir particle size decreases,the distribution and peak ranges of pores hosting retained oil and movable oil are shifted to a smaller size in an orderly manner.With the increase of driving pressure,the amount of retained and movable oil of the larger particle reservoir samples shows a more obvious trend of decreasing and increasing,respectively.(3)With the increase of throat radius,the driving pressure of reservoir with different particle levels presents three stages,namely rapid decrease,slow decrease and stabilization.The oil driving pressures of various reservoirs and the differences of them decrease with the increase of temperature and obviously decrease with the increase of throat radius.According to the above experimental analysis,it is concluded that the deep shale oil of Fengcheng Formation in Mahu Sag has great potential for production under geological conditions.
基金sponsored by the National Key Basic Research Program of China (973 Program, 2014CB239000, 2009CB219304)National Science and Technology Major Project (2011ZX05001)
文摘Characterized by complex lithology and strong heterogeneity, volcanic reservoirs in China developed three reservoir space types： primary pores, secondary pores and fractures. The formation of reservoir space went through the cooling and solidification stage （including blast fragmentation, crystallization differentiation and solidification） and the epidiagenesis stage （including metasomatism, filling, weathering and leaching, formation fluid dissolution and tectonism）. Primary pores were formed at the solidification stage, which laid the foundation for the development and transformation of effective reservoirs. Secondary pores were formed at the epidiagenesis stage, with key factors as weathering and leaching, formation fluid dissolution and tectonism. In China, Mesozoic-Cenozoic volcanic rocks developed in the Songliao Basin and Bohai Bay Basin in the east and Late Paleozoic volcanic rocks developed in the Junggar Basin, Santanghu Basin and Ta- rim Basin in the west. There are primary volcanic reser- voirs and secondary volcanic reservoirs in these volcanic rocks, which have good accumulation conditions and great exploration potential.
基金Supported by the National Natural Science Foundation of China(42302141).
文摘Taking the second member of the Xujiahe Formation of the Upper Triassic in the Xinchang structural belt as an example,based on data such as logging,production,seismic interpretation and test,a systematic analysis was conducted on the structural characteristics and evolution,reservoir diagenesis and densification processes,and types and stages of faults/fractures,and revealing the multi-stage and multi-factor dynamic coupled enrichment mechanisms of tight gas reservoirs.(1)In the early Yanshan period,the paleo-structural traps were formed with low-medium maturity hydrocarbons accumulating in structural highs driven by buoyancy since reservoirs were not fully densified in this stage,demonstrating paleo-structure control on traps and early hydrocarbon accumulation.(2)In the middle-late Yanshan period,the source rocks became mature to generate and expel a large quantity of hydrocarbons.Grain size and type of sandstone controlled the time of reservoir densification,which restricted the scale of hydrocarbon charging,allowing for only a small-scale migration through sand bodies near the fault/fracture or less-densified matrix reservoirs.(3)During the Himalayan period,the source rocks reached overmaturity,and the residual oil cracking gas was efficiently transported along the late-stage faults/fractures.Wells with high production capacity were mainly located in Type I and II fault/fracture zones comprising the late-stage north-south trending fourth-order faults and the late-stage fractures.The productivity of the wells was controlled by the transformation of the late-stage faults/fractures.(4)The Xinchang structural belt underwent three stages of tectonic evolution,two stages of reservoir formation,and three stages of fault/fractures development.Hydrocarbons mainly accumulated in the paleo-structure highs.After reservoir densification and late fault/fracture adjustment,a complex gas-water distribution pattern was formed.Thus,it is summarized as the model of“near-source and low-abundance hydrocarbon charging in the early stage,and differential enrichment of natural gas under the joint control of fault-fold-fracture complex,high-quality reservoirs and structural highs in the late stage”.Faults/fractures with well-coupled fault-fold-fracture-pore are favorable exploration targets with high exploration effectiveness.
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.
基金supported by the National Natural Science Foundation of China(No.U21B2062).
文摘The isolated fracture-vug systems controlled by small-scale strike-slip faults within ultra-deep carbonate rocks of the Tarim Basin exhibit significant exploration potential.The study employs a novel training set incorporating innovative fault labels to train a U-Net-structured CNN model,enabling effective identification of small-scale strike-slip faults through seismic data interpretation.Based on the CNN faults,we analyze the distribution patterns of small-scale strike-slip faults.The small-scale strike-slip faults can be categorized into NNW-trending and NE-trending groups with strike lengths ranging 200–5000 m.The development intensity of small-scale strike-slip faults in the Lower Yingshan Member notably exceeds that in the Upper Member.The Lower and Upper Yingshan members are two distinct mechanical layers with contrasting brittleness characteristics,separated by a low-brittleness layer.The superior brittleness of the Lower Yingshan Member enhances the development intensity of small-scale strike-slip faults compared to the upper member,while the low-brittleness layer exerts restrictive effects on vertical fault propagation.Fracture-vug systems formed by interactions of two or more small-scale strike-slip faults demonstrate larger sizes than those controlled by individual faults.All fracture-vug system sizes show positive correlations with the vertical extents of associated small-scale strike-slip faults,particularly intersection and approaching fracture-vug systems exhibit accelerated size increases proportional to the vertical extents.
基金supported by the National Natural Science Foundation of China (Nos.49206061 and 41106064)the Major National Oil and Gas Special Programs (Nos.2008ZX05025-03 and 2011ZX05025-002)the 973 Program of China (No.2012CB956004)
文摘It is known from macrocomparisons and microresearches of bioherm reservoirs in main sedimentary basins of the South China Sea through deep-water petroleum explorations and by means of 2D/3D seismic data and a whole-coring core from the Xisha Islands that there are great dif- ferences between deep-sea oil and gas fields in the world and those in the South China Sea, as reservoir systems of the former are mainly clastic rocks, whereas the latter have organic reefs that act as reser- voirs of their largest oil and gas fields, which are represented by large Liuhua 11-1 reef oilfield in the north and super-large L reef gas field in the south of the South China Sea. Therefore, it is of great significance to study deep-water hioherm reservoirs in the South China Sea. Comparisons of organic reefs in the four large islands of the South China Sea give evidences that such reefs in main sedimentary basins came into being during Cenozoic, especially in Neogene, and mainly occur as tower （point） reef, massive reef, platform-edge reef, and patch reef in shape, which show different reservoir physical properties and seismic reflection configurations and make up carbonate rock-bioherm formations in the island reef and sedimentary basin areas. Generally, the south and north parts differ from the east and the west of the South China Sea in geologic conditions, as their corresponding continental shelf/island shelf areas are relatively wide/ narrow, large stream current systems are well developed/not so well developed, and terrigenous sediments are relatively sufficient/insufficient. The southeast and south parts of the South China Sea had organic reefs built up earlier than the north and the reef building mainly took place in Neogene; these Neogene organic reefs all be- long to plant algal reef rocks. Liuhua oilfield in the Pearl River Mouth basin is found to mainly have red algal bindstone, Malampaya reef in the northern Palawan basin is rich in both red algal bind- stone and green algal reef segmented rock, and especially Miocene red algal framestone and green algal segmented rock are discovered in the Xisha Islands. These algal reefs created different sedimentary mi- crofacies as well as various rock structures and types, and through recent researches on the mechanism of dolomitization, freshwater dolomite was discovered and grouped under products from dolomitization in mixed water that was regression reefal dolomite of good reservoir properties.
基金supported by the National Key R&D Program of China(Grant No.2020YFA0710604)NSFC(Grant No.42374064).
文摘Determining the orientation of in-situ stresses is crucial for various geoscience and engineering appli-cations.Conventional methods for estimating these stress orientations often depend on focal mechanism solutions(FMSs)derived from earthquake data and formation micro-imager(FMI)data from well logs.However,these techniques can be costly,depth-inaccurate,and may lack spatial coverage.To address this issue,we introduce the use of three-dimensional(3D)seismic data(active sources)as a lateral constraint to approximate the 3D stress orientation field.Recognizing that both stress and fracture patterns are closely related to seismic velocity anisotropy,we derive the orientation of azimuthal anisotropy from multi-azimuth 3D seismic data to compensate for the lack of spatial stress orientation information.We apply our proposed workflow to a case study in the Weiyuan area of the Sichuan Basin,China,a region targeted for shale gas production.By integrating diverse datasets,including 3D seismic,earthquakes,and well logs,we develop a comprehensive 3D model of in-situ stress(orientations and magnitudes).Our results demonstrate that the estimated anisotropy orientations from 3D seismic data are consistent with the direction of maximum horizontal principal stress(SHmax)obtained from FMIs.We analyzed 12 earthquakes(magnitude>3)recorded between 2016 and 2020 for their FMSs and compressional axis(P-axis)orientations.The derived SHmax direction from our 3D stress model is 110°ES(East-South),which shows excellent agreement with the FMSs(within 3.96°).This close alignment validates the reliability and precision of our integrated method for predicting 3D SHmax orientations.
文摘Various orders of sequences were recognized in the Tarim Basin from unconformities. Three mega-sequence groups, six mega-sequences, sixteen super-sequences and forty-two sequences were determined from the Sinian to the Quaternary. The mega-sequences and super-sequences were in accordance with the locally tectonic events occurring in both the north and the south margins of the Tarim plate. The global sea level changes only worked to control formations in the tectonically stable periods or in the low order sequences. The sequences had close relationship to the source rocks, reservoirs and cap rocks, and the tectonic events determined the migration, accumulation, and preservation of the hydrocarbon. The three mega-sequence group cycles, including the early cycle-the Sinian-middle Devonian, the middle cycle-the upper Devonian-Triassic, and the late cycle-the Jurassic-Quaternary, corresponded to three reservoir formation cycles. So, it can be concluded that the local tectonic events controlled both the sequences and the distribution of oil and gas in the Tarim 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.
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 National Natural Science Foundation of China(42122017,41821002)the Independent Innovation Research Program of China University of Petroleum(East China)(21CX06001A).
文摘It is of great significance to accurately and rapidly identify shale lithofacies in relation to the evaluation and prediction of sweet spots for shale oil and gas reservoirs.To address the problem of low resolution in logging curves,this study establishes a grayscale-phase model based on high-resolution grayscale curves using clustering analysis algorithms for shale lithofacies identification,working with the Shahejie For-mation,Bohai Bay Basin,China.The grayscale phase is defined as the sum of absolute grayscale and relative amplitude as well as their features.The absolute grayscale is the absolute magnitude of the gray values and is utilized for evaluating the material composition(mineral composition+total organic carbon)of shale,while the relative amplitude is the difference between adjacent gray values and is used to identify the shale structure type.The research results show that the grayscale phase model can identify shale lithofacies well,and the accuracy and applicability of this model were verified by the fitting relationship between absolute grayscale and shale mineral composition,as well as corresponding re-lationships between relative amplitudes and laminae development in shales.Four lithofacies are iden-tified in the target layer of the study area:massive mixed shale,laminated mixed shale,massive calcareous shale and laminated calcareous shale.This method can not only effectively characterize the material composition of shale,but also numerically characterize the development degree of shale laminae,and solve the problem that difficult to identify millimeter-scale laminae based on logging curves,which can provide technical support for shale lithofacies identification,sweet spot evaluation and prediction of complex continental lacustrine basins.
基金supported by the National Basic Research Program of China(Grant No. 2007CB209503)
文摘It is significant to distinguish the dynamic systems of petroleum accumulation （DSPA） for the understanding of petroleum accumulation and distribution. According to the formation pressure framework, genetic types of petroleum and characteristics of conduit systems, three dynamic systems of petroleum accumulation were identified in the vertical profile in the Nanpu depression, Bohai Bay basin. The deeper DSPA （including formations Es3 to Es2） is a sealed system with high-overpressure and high-mature self-sourced oil. Most of the crude oil in the system accumulated in the periods of late Oligocene （23.5 Ma） and late Pliocene （2.4 Ma）. The middle DSPA （including formations Es~ to Edl） is an overpressured half-sealed system with mature or lower-mature self-sourced oil. The accumulation of oil in the system also occurred in the late Oligocene （23.5 Ma） and late Pliocene （2.4 Ma）. The shallower DSPA （including formations Ed2 to Q） is a hydrostatic system with lower-mature aliensourced oil from the middle system. Oil within this system accumulated only in the late Pliocene period. The oil in the shallower system migrated vertically along the faults from the formerly accumulated oil in the middle system by lateral migration along the sandbodies, whereas petroleum accumulation in the deeper system was mainly derived from the system itself by lateral migration along the sandbodies and rarely migrated out of the system. In this case, it seems that the deeper system is a more potential exploration prospect in addition to the other two proved favorable systems.
基金supported by the National Natural Science Foundation of China (No. 40772089)
文摘Secondary petroleum migration in the eastern Pearl River Mouth basin was modeled using the three-dimensional PATHWAYSTM model, which assumes that the positions of petroleum migration pathways are controlled by the morphology of the sealing surfaces. The modeling results have accurately predicted the petroleum occurrences. Most commercial petroleum accumulations are along the predicted preferential petroleum migration pathways （PPMP）, and most large fields （petroleum reserves greater than 1×10^8t） have more than one preferential petroleum migration pathways to convey petroleum to the traps. The lateral migration distance for oil in the LHII-1 field, the largest ollfield so far discovered in the Pearl River Mouth basin, was more than 80 km. The case study suggests that in lacustrine fault basins, petroleum can migrate over a long distance to form large oilfields without driving force from groundwater flow. The focusing of petroleum originating from a large area of the generative kitchens into restricted channels seems to be essential not only for long-range petroleum migration in hydrostatic conditions, but also for the formation of large oil or gas fields. The strong porosity and permeability heterogeneities of the carrier beds and the relatively high prediction accuracy by a model that does not take into consideration of the effect of heterogeneity suggest that the positions of petroleum migration pathways in heterogeneous carrier beds with relatively large dipping angles are determined primarily by the morphology of the sealing surfaces at regional scales.
基金supported by the National Science and Technology Major Projects of China(Grant No:2016ZX05026-007)。
文摘This paper investigates the origin and migration characteristics of petroleum in the northeastern part of the Baiyun Depression,Pearl River Mouth Basin(PRMB).The discovered petroleum in the study area is mainly located in the Lower Zhujiang Member(N_(1)z^(2))and mainly originated from the Enping Formation source rocks in the eastern sag.Active faults(vertical migration)and N_(1)z^(2)sandstones(lateral migration)acted as the petroleum migration systems.The fault activities in the Dongsha event controlled the episodic petroleum migration.Fractures in the fault zones provided effective conduits,and overpressure was the driving force.The vertical migration could not cross the fault zones laterally.The petroleum injection areas in the carrier beds were the contact zones of petroleum-migration faults and carrier beds.The lateral migration was steady-state migration,and buoyancy was the driving force.The migration pathways in the carrier beds were controlled by the structural morphology.Secondary petroleum migration in the study area could be divided into two parts:vertical migration along the fractures in the fault zones and lateral migration through preferential petroleum migration pathways(PPMPs)in the carrier beds.The petroleum migration behaviors,including migrating direction,driving force,and migration pattern,in the faults and sandstone carrier beds were quite different.This study provides a typical example for comprehending secondary migration processes and has great importance for determining future exploration targets in the deep-water area of the PRMB.
基金financially supported by the National Key Research and Development Program of China (Grant No. 2017YFC0603106)。
文摘The organic geochemistry and petrology of source rocks determine the hydrocarbon generation potential of the Banqiao Sag. In this study, organic geochemistry and petrology were used to determine the abundance of organic matter(OM), OM type, OM maturity, and sedimentary environments of the source rocks, collected from Cenozoic Shahejie Formation, Banqiao Sag, Bohai Bay Basin, China. Vitrinite and liptinite are the main maceral composition of the source rocks, and range from 18% to 81% and from 2% to82% on a mineral matter free(MMF) basis, respectively. The values of vitrinite reflectance(Ro)(0.36%-1.20%) and the Tmaxvalues(397-486.C) show that the thermal maturity range from low mature to peak-maturity. The abundance of OM varies between 0.22% and 4.37%, suggesting that the source rocks of the Shahejie(Es) Formation are mainly fair to good source rocks. The Rock-Eval pyrolysis results show that the source rocks have good petroleum generation potential. The amount of free hydrocarbons(S_1)and hydrocarbons generated from pyrolysis(S_(2)) range within 0.01-3.70 mg/g, and 0.04-29.17 mg/g. The hydrogen index(HI) varies between 18.18 and 741.13 mg HC/g TOC, with most of the samples appearing to be mainly Type II kerogen, and thereby exhibiting the ability to generate both oil and gas. The ratios of Pr/Ph, the cross plot of Pr/nC_(17)-Ph/nC_(18), the cross plot of C_(29)/C_(27)-Pr/Ph, and ternary of dibenzothiophene, dibenzofuran, and fluorene, indicate that the Shahejie Formation deposited in suboxic and weak reducing environments. The main biological source is from advanced plants. The maceral composition and rock pyrolysis data indicate the kerogen type is a humic type or mixed sapropelic-humic type. The source rocks of the Shahejie(Es) Formation occur in the oil window, and the abundant organic richness,humic kerogen demonstrate that these rocks are effective oil and gas source rocks. The mudstone rocks in the Shahejie Formation are the main source of oil and gas and represent the main exploration target for the Banqiao Sag. This study enhances the great prospect of oil and gas production in the Banqiao Sag.
文摘Relaxation of control over the upstream business of the petroleum industry in China is discussed. The authors suggest that a basic institutional preparation should be made before relaxing control over the upstream business, and that the institutional preparation includes at least four parts： 1） setting up the admission standards, 2） perfecting the management system of mining rights, 3） reforming the royalty and taxation system for oil and gas resources, and 4） improving the supervision and management system. Stressing the institutional preparation before relaxation of control does not mean that China could not relax control over the upstream business until the management systems are perfected, but the authors suggest that China could establish a necessary system for relaxation of control and to improve it with future practice.
基金funded by the National Natural Science Foundation of China (NSFC) (41872128)the Science Foundation of China University of Petroleum, Beijing (No. 2462020YXZZ021).
文摘Halite and gypsum minerals in saline shale make the retention mechanism and chemical fractionation of residual oil unique. The Dongpu Depression in North China is a typically saline lacustrine basin with developing halite and gypsum. The effect of gypsum minerals on residual oil content and chemical fractionation remains unclear. In this study, shale samples with different gypsum contents were used in organic geochemical experiments, showing that the high total organic matter (TOC) content and type II kerogen leads to a high residual oil content, as shown by high values of volatile hydrocarbon (S1) and extractable organic matter (EOM). XRD and FE-SEM result indicate that the existence of gypsum in saline shale contributes to an enhanced pore space and a higher residual oil content in comparison to non-gypsum shale. Additionally, the increase in the gypsum mineral content leads to an increase in the saturated hydrocarbon percentage and a decrease in polar components percentage (resins and asphaltene). Furthermore, thermal simulation experiments on low-mature saline shale show that the percentage of saturated hydrocarbons in the residual oil is high and remains stable and that the storage space is mainly mesoporous (> 20 nm) in the oil expulsion stage. However, the saturated hydrocarbons percentage decreases rapidly, and oil exists in mesopores (> 20 nm and < 5 nm) in the gas expulsion stage. In general, gypsum is conducive to the development of pore space, the adsorption of hydrocarbons and the occurrence of saturated hydrocarbon, leading to large quantities of residual oil. The data in this paper should prove to be reliable for shale oil exploration in saline lacustrine basins.
