The effectsof annealing process on the hardness, microstructure, Si diffusion, and the sagging resistance of cold-rolled 4343/3003/4343 Al alloy clad sheets and their 3003 Al alloy core sheets were experimentally inve...The effectsof annealing process on the hardness, microstructure, Si diffusion, and the sagging resistance of cold-rolled 4343/3003/4343 Al alloy clad sheets and their 3003 Al alloy core sheets were experimentally investigated through hardness tests, EBSD observations, EDS analysis, and sagging test.The results showedthat with the increase of annealing temperature, the hardness of both clad sheet and core sheet decreased, while thesaggingresistancesof both clad and core sheets achieved maximum values after annealing at 380℃ for 1h. After annealing at 380℃, the clad layer contained fine and equiaxedrecrystallized grains; the core layer was composed of fully recrystallized coarse grains elongated along the rolling direction. The Si diffusion from the clad layer to the core zone was limited. After annealing at a higher temperature of 440℃ or 550℃, thesaggingresistance of clad sheets worsened precipitously. The grains in the clad layer grew up, obscuring the interface between the clad and core layer; the recrystallized grains in the core layer became finer. Significant amount of Si penetrated into the core layer through the accelerated diffusion. Compared with the microstructure refinement, Si diffusion is the main factor influencing thesaggingresistance.展开更多
Studied in this paper is free vibration of a long span pipeline with nonlinearities taken into account. The pipeline sags under gravity and takes the shape of a plane curve. Vibration in the plane and out of the plane...Studied in this paper is free vibration of a long span pipeline with nonlinearities taken into account. The pipeline sags under gravity and takes the shape of a plane curve. Vibration in the plane and out of the plane is regarded as small motions about the large static deflection. Manifestations of nonlinearities such as amplitude-dependent frequencies and internal resonance are investigated.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
Based on the comprehensive analysis of data from petrology and mineralogy,well logging,seismic surveys,paleontology,and geochemistry,a detailed research was conducted on paleoenvironmental and paleoclimatic conditions...Based on the comprehensive analysis of data from petrology and mineralogy,well logging,seismic surveys,paleontology,and geochemistry,a detailed research was conducted on paleoenvironmental and paleoclimatic conditions,and modeling of the source rocks in the second member of the Eocene Wenchang Formation(Wen 2 Member)in the Northern Shunde Subsag at the southwestern margin of the Pearl River Mouth Basin.The Wen 2 Member hosts excellent,thick lacustrine source rocks with strong longitudinal heterogeneity and an average total organic carbon(TOC)content of over 4.9%.The Wen 2 Member can be divided into three units(I,II,III)from bottom to top.Unit I features excellent source rocks with Type I organic matters(average TOC of 5.9%)primarily sourced from lake organisms;Unit II hosts source rocks dominated by Type II2 organic matters(average TOC of 2.2%),which are originated from mixed sources dominated by terrestrial input.Unit III contains good to excellent source rocks dominated by Type II1 organic matters(average TOC of 4.9%),which are mainly contributed by lake organisms and partially by terrestrial input.Under the background of rapid subsidence and limited source supply during intense rifting period in the Eocene,excellent source rocks were developed in Wen 2 Member in the Northern Shunde Subsag under the coordinated control of warm and humid climate,volcanic activity,and deep-water reducing conditions.During the deposition of Unit I,the warm and humid climate and volcanic activity promoted the proliferation of lake algaes,primarily Granodiscus,resulting in high initial productivity,and deep-water reducing conditions enabled satisfactory preservation of organic matters.These factors jointly controlled the development and occurrence of excellent source rocks.During the deposition of Unit II,a transition from warm to cool and semi-arid paleoclimatic conditions led to a decrease in lake algaes and initial productivity.Additionally,enhanced terrestrial input and shallow-water,weakly oxidizing water conditions caused a significant dilution and decomposition of organic matters,degrading the quality of source rocks.During the deposition of Unit III,when the paleoclimatic conditions are cool and humid,Pediastrum and Botryococcus began to thrive,leading to an increase in productivity.Meanwhile,the reducing environment of semi-deep water facilitated the preservation of excellent source rocks,albeit slightly inferior to those in Unit I.The study results clarify the differential origins and development models of various source rocks in the Shunde Sag,offering valuable guidance for evaluating source rocks and selecting petroleum exploration targets in similar marginal sags.展开更多
For shale oil reservoirs in the Jimsar Sag of Junggar Basin,the fracturing treatments are challenged by poor prediction accuracy and difficulty in parameter optimization.This paper presents a fracturing parameter inte...For shale oil reservoirs in the Jimsar Sag of Junggar Basin,the fracturing treatments are challenged by poor prediction accuracy and difficulty in parameter optimization.This paper presents a fracturing parameter intelligent optimization technique for shale oil reservoirs and verifies it by field application.A self-governing database capable of automatic capture,storage,calls and analysis is established.With this database,22 geological and engineering variables are selected for correlation analysis.A separated fracturing effect prediction model is proposed,with the fracturing learning curve decomposed into two parts:(1)overall trend,which is predicted by the algorithm combining the convolutional neural network with the characteristics of local connection and parameter sharing and the gated recurrent unit that can solve the gradient disappearance;and(2)local fluctuation,which is predicted by integrating the adaptive boosting algorithm to dynamically adjust the random forest weight.A policy gradient-genetic-particle swarm algorithm is designed,which can adaptively adjust the inertia weights and learning factors in the iterative process,significantly improving the optimization ability of the optimization strategy.The fracturing effect prediction and optimization strategy are combined to realize the intelligent optimization of fracturing parameters.The field application verifies that the proposed technique significantly improves the fracturing effects of oil wells,and it has good practicability.展开更多
Alkaline lacustrine shale is highly heterogeneous,and the complex relationship between the organicinorganic porosity network and hydrocarbon occurrence restricts the effectiveness of shale oil exploration and developm...Alkaline lacustrine shale is highly heterogeneous,and the complex relationship between the organicinorganic porosity network and hydrocarbon occurrence restricts the effectiveness of shale oil exploration and development.Herein,we investigated the Fengcheng Formation(P_(1)f)in Mahu Sag.This study integrated geochemistry,Soxhlet extraction,scanning electron microscopy,gas adsorption,and nuclear magnetic resonance T_(1)-T_(2)spectroscopy to elucidate the microscopic oil occurrence mechanisms in shales.Results indicate the presence of felsic shale,dolomitic shale,lime shale,and mixed shale within the P_(1)f.Matrix pores and microfractures associated with inorganic minerals are the predominant pore types in P_(1)f.Adsorbed oil primarily resides on the surfaces of organic matter and clay minerals,while free oil predominantly occupies inorganic pores and microfractures with larger pore sizes.Variations exist in the quantity and distribution of shale oil accumulation across different scales,where free oil and adsorbed oil are governed by dominant pores with diameters exceeding 10 nm and ineffective pores with diameters below 10 nm,respectively.Shale oil occurrence characteristics are influenced by organic matter,pore structure,and mineral composition.Felsic shale exhibits a high abundance of dominant pores,possesses the highest oil content,predominantly harbors free oil within these dominant pores,and demonstrates good mobility.Fluid occurrence in dolomitic shale and lime shale is intricate,with low oil content and a free oil to adsorbed oil ratio of 1:1.Mixed shale exhibits elevated clay mineral content and a scarcity of dominant pores.Moreover,ineffective pores contain increased bound water,resulting in medium oil content and limited mobility predominantly due to adsorption.Presently,shale oil mainly occurs in the dominant pores with a diameter larger than 10 nm in a free state.During the exploration and development of alkaline lacustrine shale oil resources,emphasis should be placed on identifying sweet spots within the felsic shale characterized by dominant pores.展开更多
Addressing the critical challenges of viscosity loss and barite sag in synthetic-based drilling fluids(SBDFs)under high-temperature,high-pressure(HTHP)conditions,this study innovatively developed a hyperbranched amide...Addressing the critical challenges of viscosity loss and barite sag in synthetic-based drilling fluids(SBDFs)under high-temperature,high-pressure(HTHP)conditions,this study innovatively developed a hyperbranched amide polymer(SS-1)through a unique stepwise polycondensation strategy.By integrating dynamic ionic crosslinking for temperature-responsive rheology and rigid aromatic moieties ensuring thermal stability beyond 260℃,SS-1 achieves a molecular-level breakthrough.Performance evaluations demonstrate that adding merely 2.0 wt% SS-1 significantly enhances key properties of 210℃-aged SBDFs:plastic viscosity rises to 45 mPa⋅s,electrical stability(emulsion voltage)reaches 1426 V,and the sag factor declines to 0.509,outperforming conventional sulfonated polyacrylamide(S-PAM,0.531)by 4.3%.Mechanistic investigations reveal a trifunctional synergistic anti-sag mechanism involving electrostatic adsorption onto barite surfaces,hyperbranched steric hindrance,and colloid-stabilizing network formation.SS-1 exhibits exceptional HTHP stabilization efficacy,substantially surpassing S-PAM,thereby providing an innovative molecular design strategy and scalable solution for next-generation high-performance drilling fluid stabilizers.展开更多
The Shanan sag in the central-western Bohai Bay Basin hosts high-quality Paleogene source rocks within the Shahejie Formation’s third member(E_(2)s_(3)).Despite hydrocarbon indications in Cenozoic strata,no commercia...The Shanan sag in the central-western Bohai Bay Basin hosts high-quality Paleogene source rocks within the Shahejie Formation’s third member(E_(2)s_(3)).Despite hydrocarbon indications in Cenozoic strata,no commercial accumulations have been discovered.An integrated approach combining geochemical analysis,fluid inclusion thermometry,apatite fission-track(AFT)thermochronology,and basin modeling was employed to unravel the paleo-geothermal regime and hydrocarbon generation history of E_(2)s_(3) source rocks.AFT data from the Shahejie Formation’s second member(E_(2)s_(2))reveal a tectonothermal event at 25 Ma that accelerated E_(2)s_(3) maturation.Outside three sub-sag depocenters,current E_(2)s_(2) reservoir temperatures remain below the 25 Ma paleo-geothermal maxima despite subsequent Neogene burial.Hydrocarbon-bearing brine inclusions in E_(2)s_(2) reservoirs exhibit peak homogenization temperatures(Th)at 25 Ma,with minimal high-temperature signals,indicating that E_(2)s_(3) hydrocarbon generation peaked during the Paleogene thermal event,with limited late-stage accumulation.The regional effects of the Dongying Movement necessitate thick Neogene sedimentation to compensate for the 25 Ma paleo-geothermal anomaly.Our findings emphasize targeting Neogene depocenters in petroleum exploration to mitigate the inhibitory effects of high paleo-heat flow on late hydrocarbon generation,thereby enhancing current accumulation potential.展开更多
The study on sand body connectivity and distribution patterns is of great significance for well emplacement and injection-production pattern analysis in the A oilfield of the Weixi?nan Sag currently at a pre-developme...The study on sand body connectivity and distribution patterns is of great significance for well emplacement and injection-production pattern analysis in the A oilfield of the Weixi?nan Sag currently at a pre-development stage.Based on the current drilling data,seismic data,and fault development characteristics,this study investigates the connectivity,geometric morphology,planar distribution,and vertical evolution of composite sand bodies(multi-stage superimposed channel sand bodies)within the fault block using seismic forward and inversion modeling.The El3I oil layer group in the third member of the Liushagang Formation is developed in the fan delta-front sub-facies,which mainly consists of subaqueous distributary channels.The thickness of single-stage subaqueous distributary channel sand bodies ranges from 2 to 6 m,and the width of composite channel sand bodies varies from 50 to 100 m.Under the long-term transgression background,the subaqueous distributary channels in the El3I oil layer group are relatively narrow,forming superimposed and continuous composite channel sand bodies through lateral migration and vertical stacking.The long-term base-level cycles control the width of subaqueous distributary channels,while the mid-term base-level cycles control the thickness of these channels.The subaqueous distributary channels developed during the late stage of mid-term base-level fall are thicker than those formed during the early stage.Accordingly,quantitative relationships between channel thickness and width are established for the early and late stages of mid-term base-level fall,to finely depict the evolution patterns of channel sand body geometry and stacking styles across different stages.These findings provide important guidance for accurately predicting the planar distribution and channel width of composite subaqueous distributary channels at different stages of the mid-term baselevel cycles.展开更多
The microscopic occurrence characteristics primarily constrain the enrichment and mobility of shale oil.This study collected the lacustrine shales from the Palaeogene Funing Formation in the Gaoyou Sag, Subei Basin. C...The microscopic occurrence characteristics primarily constrain the enrichment and mobility of shale oil.This study collected the lacustrine shales from the Palaeogene Funing Formation in the Gaoyou Sag, Subei Basin. Conventional and multistage Rock-Eval, scanning electron microscopy, and nuclear magnetic resonance(NMR) T1-T2were performed to analyze the contents and occurrence characteristics of shale oil. Low-temperature nitrogen adsorption-desorption(LTNA/D) experiments were conducted on the shales before and after extraction. The relationships between shale oil occurrence with organic matter and pore structures were then discussed. Predominantly, the shale oil in the Funing Formation is found within fractures, with secondary occurrences in interparticle pores linked to brittle minerals and sizeable intraparticle pores associated with clay minerals. The selected shales can be categorized into two types based on the nitrogen isotherms. Type A shales are characterized by high contents of felsic and calcareous minerals but low clay minerals, with larger TOC and shale oil values. Conversely, Type B shales are marked by abundant clay minerals but diminished TOC and shale oil contents. The lower BET specific surface area(SSA), larger average pore diameter, and simpler pore surfaces and pore structures lead to the Type A shales being more conducive to shale oil enrichment and mobility. Shale oil content is predominantly governed by the abundance of organic matter, while an overabundance of organic matter typically equates to a reduced ratio of free oil and diminished fluidity. The BET SSA, volumes of pores less than 25 and 100 nm at extracted state all correlate negatively with total and adsorbed oil contents but display no correlation with free oil, while they have positive relationships with capillary-bound water.Consequently, pore water is mainly saturated in micropores(<25 nm) and minipores(25-100 nm), as well as adsorbed oil, while free oil, i.e., bound and movable oil, primarily exists in mesopores(100-1000 nm) and macropores(>1000 nm). These findings may enhance the understanding of the microscopic occurrence characteristics of shale oil and will contribute to guide resource estimation and shale oil sweet spot exploitation in the Gaoyou Sag, Subei Basin.展开更多
The Late Permian to Early Triassic marked a pivotal phase in paleoenvironmental and tectonic shifts.The Kaijiang-Liangping intracratonic sag,a tectonic geomorphology formed by Emei taphrogenesis in the Sichuan Basin,i...The Late Permian to Early Triassic marked a pivotal phase in paleoenvironmental and tectonic shifts.The Kaijiang-Liangping intracratonic sag,a tectonic geomorphology formed by Emei taphrogenesis in the Sichuan Basin,is situated within a clear water carbonate platform.Under these conditions,the black shales of the Dalong Formation in the sag have ultrahigh organic matter content.However,the mechanism by which these conditions control the accumulation of such organic matter remains unclear.Petrological and geochemical analyses of well DY-1H revealed four distinct units within the Dalong Formation:A,B,C,and D,with average total organic carbon contents of 3.00%,9.59%,4.57%,and 0.27%,respectively.The kerogen maceral,carbon isotope,and pyrolysis results show that the organic matter mainly comprises Type Ⅱ_(2) kerogen.Benthic plants growing in clear water may be the primary source of this kerogen.Shallow water,suboxic conditions,strong volcanism,and high productivity characterize Unit A.Unit B features restricted ocean circulation,anoxic conditions,weak upwelling,moderate volcanism,and high productivity.Unit C is characterized by anoxic conditions,strong upwelling,weak volcanism,and moderate productivity.Oxic conditions and low productivity define Unit D.These findings challenge traditional models that struggle to explain the accumulation of ultrahigh organic matter in Unit A under suboxic conditions,Unit C under moderate productivity,and Unit B with abnormally high organic matter content.The flourishing of benthic plants,a considerable source of Type Ⅱ_(2) kerogen that resists decomposition and favors preservation,is the dominant factor controlling the ultrahigh organic matter accumulation of black shales in Units A,B,and C under clear water conditions.Oxidized bottom waters and decreased benthic plant growth were crucial to the sharp decline in organic matter.展开更多
The Jurassic tight sandstone oil and gas exploration and development in the eastern Yangxia Sag is a new field.To elucidate the origin,accumulation process and potential of tight oil and gas,the authors have conducted...The Jurassic tight sandstone oil and gas exploration and development in the eastern Yangxia Sag is a new field.To elucidate the origin,accumulation process and potential of tight oil and gas,the authors have conducted comprehensive analyses employing methodologies encompassing source rocks,oil geochemistry,and fluid inclusions.The results show that the abundance of organic matter of Jurassic source rocks is high,and the type of organic matter is ofⅡ-Ⅲand in mature evolution stage.The main source rocks of oil and gas are Huangshanjie Formation and Jurassic coal-bearing source rocks.Ahe Formation developed two stages of hydrocarbon charging,and the period is later than the reservoir densification time.Yangxia Formation oil charged before the reservoir densified,and the late gas charged after the reservoir densified.Hydrocarbon generation intensity of Jurassic source rocks has reached the basic conditions for the formation of tight gas reservoirs.Controlled by the difference of source rocks distribution and accumulation process,tight sandstone oil and gas accumulation conditions are better in the depression direction than in the southeast margin area.This study is of practical importance for expanding the exploration field and selecting favorable areas in the eastern Yangxia sag.展开更多
The Beibu Gulf Basin is an important oil-and gas-bearing basin offshore the China Sea,but the geological reserves of oil and gas are not very high,and there are significant differences between different sags.Previous ...The Beibu Gulf Basin is an important oil-and gas-bearing basin offshore the China Sea,but the geological reserves of oil and gas are not very high,and there are significant differences between different sags.Previous studies have shown that the formation and accumulation of oil and gas are closely related to deep structures,especially the crustal thickness or the relative undulation characteristics between the Moho and basement,but there is a lack of specific evaluation and quantitative standards.In this paper,we first invert the depth of the Moho in the Beibu Gulf Basin using satellite gravity anomalies and calculate the crustal thickness value based on this.Then,we count and analyze the crustal thickness value as well as the stretching factor that characterizes the crustal extension and thinning degree,and find that the NWW-trending contour closure of the 28 km Moho depth or 26 km crustal thickness corresponds significantly to the Weixinan-Fushan sag belt,which has already been proven to have considerable oil and gas discoveries,with a typical feature of crustal thinning to 22 km and the stretching factor reaching 1.1.Finally,we propose a comprehensive evaluation scheme based on the entropy weight method to normalize and evaluate the statistical features of the crust,and take a comprehensive score of Si>0.5 as an evaluation indicator for an oil-gas-rich sag.Based on this research,we believe that the Haizhong sag has considerable exploratory potential,followed by the Maichen sag,while the Leidong and Haitoubei sags have relatively smaller exploratory potential.The research results will help strategic decision-making of the oil and gas exploration in the Beibu Gulf Basin and provide new perspectives for studying the relationship between deep structures and the differential distribution of oil-gas-rich sags.展开更多
Research based on oil accumulation models is essential for exploring the hydrocarbon accumulation theory further.Studies on tight oil accumulation models focused on fan delta depositional systems,and in particular,sys...Research based on oil accumulation models is essential for exploring the hydrocarbon accumulation theory further.Studies on tight oil accumulation models focused on fan delta depositional systems,and in particular,systems involving source-reservoir separated type are scarce.To explore the accumulation model of tight oil in conglomerate,this study focused on the Permian-Triassic tight conglomerate oil in Mahu sag,Junggar Basin,using well drilling,well logging,seismic profiling,oil testing,and laboratory data,and analyzed the formation conditions,formation types,and distribution patterns of conglomerate reservoirs.The results show that,the conglomerate reservoirs are predominantly lithologic reservoirs and partly fault-lithologic reservoirs;there is no water evident at the edge or bottom around the reservoirs.The tight conglomerate layer in the delta plain subfacies of each fan exhibits high clay content and intense diagenesis,and the argillaceous rocks in the pro-fan delta subfacies and shallow lacustrine facies form the sealing and floor conditions.The sandy conglomerate of fan delta front subfacies is the main reservoir body.Additionally,strikeslip faulting in the Indosinian-Himalayan period formed an efficient faulting system for trans-stratal migration with Hercynian-Indosinian inverse faulting.Oil migration is driven by the overpressure caused by hydrocarbon generation from alkali lacustrine source rocks.The distribution of reservoirs is primarily controlled by the large fan bodies,namely the Zhongguai,Baijiantan,Karamay,Huangyangquan,Xiazijie,Xiayan,and Dabasong fans.Each fan body forms a group of reservoirs or oilfields,resulting in a widely distributed pattern,according to which reservoir and sealing constitute one whole body—i.e.,patterns of“one sand and one reservoir,one fan and one field.”This results in a quasi-continuous accumulation model,which includes strong oil charging,efficient faulting transportation,trans-stratal migration,and lithologic trapped accumulation.The proposed model is an important supplement to the existing model of quasi-continuous oil and gas accumulation.Overall,this study enriches unconventional oil and gas accumulation theories.展开更多
Understanding the occurrence state of shale oil is crucial for the effective development of shale oil resources.Although the second member of the Kongdian Formation(Ek2)is a key interval for lacustrine shale oil produ...Understanding the occurrence state of shale oil is crucial for the effective development of shale oil resources.Although the second member of the Kongdian Formation(Ek2)is a key interval for lacustrine shale oil production in the Cangdong Sag,Bohai Bay Basin,the occurrence state and controlling factors of shale oil in this formation remain poorly understood.This study established a multi-step programmed pyrolysis,combined with a light hydrocarbon recovery scheme,to quantitatively characterize the shale oil in different occurrence states.An integrated approach utilizing Rock-Eval pyrolysis,pyrolysis-gas chromatography,and crude oil gas chromatography was employed.Factors influencing the shale oil occurrence state were analyzed from petrology and organic geochemistry perspectives.The study revealed significant variations of shale oil occurrence states within the Ek2,attributed to differences in sedimentary organic matter,mineral compositions,sedimentary structures,and thermal maturity.Felsic laminae are the primary reservoir space for oil in laminated shales,and the frequent interbedding of felsic and organic-rich laminae facilitates the retention of free oil.The contents of free and adsorbed oil are primarily influenced by organic matter content and shale storage capacity,both of which exhibit distinct occurrence patterns.Based on the shale reservoir quality classification using the pyrolysis values of S1-1+S1-2 and(S1-1+S1-2)×100/TOC,the Ek2 shale demonstrates significant exploitation potential,with the first-level reservoirs comprising 66%,second-level reservoirs 11%,and third-level reservoirs 23%.These findings provide new insights into the geological accumulation and production of shale oil.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
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
Improving salt tolerance and mitigating senescence in the presence of high salinity are crucial for sustaining agricultural productivity.Previous research has demonstrated that hydrogen peroxide(H_(2)O_(2)),specifical...Improving salt tolerance and mitigating senescence in the presence of high salinity are crucial for sustaining agricultural productivity.Previous research has demonstrated that hydrogen peroxide(H_(2)O_(2)),specifically H_(2)O_(2)derived from roots and mediated by the respiratory burst oxidase homolog(NADPH),plays a significant role in regulating ion and plant hormone homeostasis in glycophytic plants,such as Arabidopsis.However,the extent to which root-derived H_(2)O_(2)fulfils similar functions in halophytic plants remains uncertain.Therefore,our study aimed to explore the potential contribution of root-sourced H_(2)O_(2)in delaying leaf senescence induced by high salinity,utilizing seashore paspalum as a model halophytic plant.The application of the NADPH-oxidase inhibitor DPI,coupled with a series of leaf senescence analyses,we revealed that root-derived H_(2)O_(2)significantly retards salt-induced leaf senescence.Furthermore,through the application of hormone analysis,lipidomics,ionomics,Non-invasive Micro-test Technology(NMT),and transcriptomics,we established that NADPH-dependent H_(2)O_(2)induced by salt stress in the roots was indispensable for maintaining the balance of the aging hormone,jasmonic acid(JA),and sodium ion homeostasis within this halophytic plant.Finally,by utilizing AtrbohD Arabidopsis mutants and virus-induced gene silencing(VIGs)in Paspalum vaginatum,we demonstrated the pivotal role played by root-sourced H_(2)O_(2)in upholding JA homeostasis and regulating JA-triggered leaf senescence in P.vaginatum.This study offers novel insights into the mechanisms that govern plant leaf senescence and its response to salinity-induced stress.展开更多
基金Project(U1360104)supported by the National Natural Science Foundation and Bao Steel of ChinaProject(A type,12QH1401200)supported by the Shanghai Rising-Star Program,China
文摘The effectsof annealing process on the hardness, microstructure, Si diffusion, and the sagging resistance of cold-rolled 4343/3003/4343 Al alloy clad sheets and their 3003 Al alloy core sheets were experimentally investigated through hardness tests, EBSD observations, EDS analysis, and sagging test.The results showedthat with the increase of annealing temperature, the hardness of both clad sheet and core sheet decreased, while thesaggingresistancesof both clad and core sheets achieved maximum values after annealing at 380℃ for 1h. After annealing at 380℃, the clad layer contained fine and equiaxedrecrystallized grains; the core layer was composed of fully recrystallized coarse grains elongated along the rolling direction. The Si diffusion from the clad layer to the core zone was limited. After annealing at a higher temperature of 440℃ or 550℃, thesaggingresistance of clad sheets worsened precipitously. The grains in the clad layer grew up, obscuring the interface between the clad and core layer; the recrystallized grains in the core layer became finer. Significant amount of Si penetrated into the core layer through the accelerated diffusion. Compared with the microstructure refinement, Si diffusion is the main factor influencing thesaggingresistance.
文摘Studied in this paper is free vibration of a long span pipeline with nonlinearities taken into account. The pipeline sags under gravity and takes the shape of a plane curve. Vibration in the plane and out of the plane is regarded as small motions about the large static deflection. Manifestations of nonlinearities such as amplitude-dependent frequencies and internal resonance are investigated.
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Supported by the Research Project of China National Offshore Oil Corporation(SCKY-2023-HN-3)。
文摘Based on the comprehensive analysis of data from petrology and mineralogy,well logging,seismic surveys,paleontology,and geochemistry,a detailed research was conducted on paleoenvironmental and paleoclimatic conditions,and modeling of the source rocks in the second member of the Eocene Wenchang Formation(Wen 2 Member)in the Northern Shunde Subsag at the southwestern margin of the Pearl River Mouth Basin.The Wen 2 Member hosts excellent,thick lacustrine source rocks with strong longitudinal heterogeneity and an average total organic carbon(TOC)content of over 4.9%.The Wen 2 Member can be divided into three units(I,II,III)from bottom to top.Unit I features excellent source rocks with Type I organic matters(average TOC of 5.9%)primarily sourced from lake organisms;Unit II hosts source rocks dominated by Type II2 organic matters(average TOC of 2.2%),which are originated from mixed sources dominated by terrestrial input.Unit III contains good to excellent source rocks dominated by Type II1 organic matters(average TOC of 4.9%),which are mainly contributed by lake organisms and partially by terrestrial input.Under the background of rapid subsidence and limited source supply during intense rifting period in the Eocene,excellent source rocks were developed in Wen 2 Member in the Northern Shunde Subsag under the coordinated control of warm and humid climate,volcanic activity,and deep-water reducing conditions.During the deposition of Unit I,the warm and humid climate and volcanic activity promoted the proliferation of lake algaes,primarily Granodiscus,resulting in high initial productivity,and deep-water reducing conditions enabled satisfactory preservation of organic matters.These factors jointly controlled the development and occurrence of excellent source rocks.During the deposition of Unit II,a transition from warm to cool and semi-arid paleoclimatic conditions led to a decrease in lake algaes and initial productivity.Additionally,enhanced terrestrial input and shallow-water,weakly oxidizing water conditions caused a significant dilution and decomposition of organic matters,degrading the quality of source rocks.During the deposition of Unit III,when the paleoclimatic conditions are cool and humid,Pediastrum and Botryococcus began to thrive,leading to an increase in productivity.Meanwhile,the reducing environment of semi-deep water facilitated the preservation of excellent source rocks,albeit slightly inferior to those in Unit I.The study results clarify the differential origins and development models of various source rocks in the Shunde Sag,offering valuable guidance for evaluating source rocks and selecting petroleum exploration targets in similar marginal sags.
基金Supported by the National Science and Technology Major Project(2017ZX05009-005-003)National Natural Science Grant Fund for Surface Project(52174045)+1 种基金Chinese Academy of Engineering Strategic Consulting Project(2018-XZ-09)China National Petroleum Corporation(CNPC)-China University of Petroleum(Beijing)Special Project for Strategic Cooperation in Science and Technology(ZLZX2020-01)。
文摘For shale oil reservoirs in the Jimsar Sag of Junggar Basin,the fracturing treatments are challenged by poor prediction accuracy and difficulty in parameter optimization.This paper presents a fracturing parameter intelligent optimization technique for shale oil reservoirs and verifies it by field application.A self-governing database capable of automatic capture,storage,calls and analysis is established.With this database,22 geological and engineering variables are selected for correlation analysis.A separated fracturing effect prediction model is proposed,with the fracturing learning curve decomposed into two parts:(1)overall trend,which is predicted by the algorithm combining the convolutional neural network with the characteristics of local connection and parameter sharing and the gated recurrent unit that can solve the gradient disappearance;and(2)local fluctuation,which is predicted by integrating the adaptive boosting algorithm to dynamically adjust the random forest weight.A policy gradient-genetic-particle swarm algorithm is designed,which can adaptively adjust the inertia weights and learning factors in the iterative process,significantly improving the optimization ability of the optimization strategy.The fracturing effect prediction and optimization strategy are combined to realize the intelligent optimization of fracturing parameters.The field application verifies that the proposed technique significantly improves the fracturing effects of oil wells,and it has good practicability.
基金financially supported by the State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Efficient Development(33550000-22-ZC0613-0006)National Natural Science Foundation of China(42202133)+2 种基金CNPC Innovation Fund(2022DQ02-0106)Strategic Cooperation Technology Projects of the CNPC and CUPB(ZLZX2020-01-05)Key Laboratory of Tectonics and Petroleum Resources(China University of Geosciences),Ministry of Education,China(TPR-2023-05)。
文摘Alkaline lacustrine shale is highly heterogeneous,and the complex relationship between the organicinorganic porosity network and hydrocarbon occurrence restricts the effectiveness of shale oil exploration and development.Herein,we investigated the Fengcheng Formation(P_(1)f)in Mahu Sag.This study integrated geochemistry,Soxhlet extraction,scanning electron microscopy,gas adsorption,and nuclear magnetic resonance T_(1)-T_(2)spectroscopy to elucidate the microscopic oil occurrence mechanisms in shales.Results indicate the presence of felsic shale,dolomitic shale,lime shale,and mixed shale within the P_(1)f.Matrix pores and microfractures associated with inorganic minerals are the predominant pore types in P_(1)f.Adsorbed oil primarily resides on the surfaces of organic matter and clay minerals,while free oil predominantly occupies inorganic pores and microfractures with larger pore sizes.Variations exist in the quantity and distribution of shale oil accumulation across different scales,where free oil and adsorbed oil are governed by dominant pores with diameters exceeding 10 nm and ineffective pores with diameters below 10 nm,respectively.Shale oil occurrence characteristics are influenced by organic matter,pore structure,and mineral composition.Felsic shale exhibits a high abundance of dominant pores,possesses the highest oil content,predominantly harbors free oil within these dominant pores,and demonstrates good mobility.Fluid occurrence in dolomitic shale and lime shale is intricate,with low oil content and a free oil to adsorbed oil ratio of 1:1.Mixed shale exhibits elevated clay mineral content and a scarcity of dominant pores.Moreover,ineffective pores contain increased bound water,resulting in medium oil content and limited mobility predominantly due to adsorption.Presently,shale oil mainly occurs in the dominant pores with a diameter larger than 10 nm in a free state.During the exploration and development of alkaline lacustrine shale oil resources,emphasis should be placed on identifying sweet spots within the felsic shale characterized by dominant pores.
基金the National Natural Science Foundation(41802169)Key Laboratory of Polar Geology and Marine Mineral Resources Foudation(HNPY-202506)for supporting this study.
文摘The Shanan sag in the central-western Bohai Bay Basin hosts high-quality Paleogene source rocks within the Shahejie Formation’s third member(E_(2)s_(3)).Despite hydrocarbon indications in Cenozoic strata,no commercial accumulations have been discovered.An integrated approach combining geochemical analysis,fluid inclusion thermometry,apatite fission-track(AFT)thermochronology,and basin modeling was employed to unravel the paleo-geothermal regime and hydrocarbon generation history of E_(2)s_(3) source rocks.AFT data from the Shahejie Formation’s second member(E_(2)s_(2))reveal a tectonothermal event at 25 Ma that accelerated E_(2)s_(3) maturation.Outside three sub-sag depocenters,current E_(2)s_(2) reservoir temperatures remain below the 25 Ma paleo-geothermal maxima despite subsequent Neogene burial.Hydrocarbon-bearing brine inclusions in E_(2)s_(2) reservoirs exhibit peak homogenization temperatures(Th)at 25 Ma,with minimal high-temperature signals,indicating that E_(2)s_(3) hydrocarbon generation peaked during the Paleogene thermal event,with limited late-stage accumulation.The regional effects of the Dongying Movement necessitate thick Neogene sedimentation to compensate for the 25 Ma paleo-geothermal anomaly.Our findings emphasize targeting Neogene depocenters in petroleum exploration to mitigate the inhibitory effects of high paleo-heat flow on late hydrocarbon generation,thereby enhancing current accumulation potential.
文摘The study on sand body connectivity and distribution patterns is of great significance for well emplacement and injection-production pattern analysis in the A oilfield of the Weixi?nan Sag currently at a pre-development stage.Based on the current drilling data,seismic data,and fault development characteristics,this study investigates the connectivity,geometric morphology,planar distribution,and vertical evolution of composite sand bodies(multi-stage superimposed channel sand bodies)within the fault block using seismic forward and inversion modeling.The El3I oil layer group in the third member of the Liushagang Formation is developed in the fan delta-front sub-facies,which mainly consists of subaqueous distributary channels.The thickness of single-stage subaqueous distributary channel sand bodies ranges from 2 to 6 m,and the width of composite channel sand bodies varies from 50 to 100 m.Under the long-term transgression background,the subaqueous distributary channels in the El3I oil layer group are relatively narrow,forming superimposed and continuous composite channel sand bodies through lateral migration and vertical stacking.The long-term base-level cycles control the width of subaqueous distributary channels,while the mid-term base-level cycles control the thickness of these channels.The subaqueous distributary channels developed during the late stage of mid-term base-level fall are thicker than those formed during the early stage.Accordingly,quantitative relationships between channel thickness and width are established for the early and late stages of mid-term base-level fall,to finely depict the evolution patterns of channel sand body geometry and stacking styles across different stages.These findings provide important guidance for accurately predicting the planar distribution and channel width of composite subaqueous distributary channels at different stages of the mid-term baselevel cycles.
基金supported by the National Natural Science Foundation of China(42302160)the Sanya City Science and Technology Innovation Project(2022KJCX51)the Support Plan for Outstanding Youth Innovation Team in Shandong Higher Education Institutions(2022KJ060).
文摘The microscopic occurrence characteristics primarily constrain the enrichment and mobility of shale oil.This study collected the lacustrine shales from the Palaeogene Funing Formation in the Gaoyou Sag, Subei Basin. Conventional and multistage Rock-Eval, scanning electron microscopy, and nuclear magnetic resonance(NMR) T1-T2were performed to analyze the contents and occurrence characteristics of shale oil. Low-temperature nitrogen adsorption-desorption(LTNA/D) experiments were conducted on the shales before and after extraction. The relationships between shale oil occurrence with organic matter and pore structures were then discussed. Predominantly, the shale oil in the Funing Formation is found within fractures, with secondary occurrences in interparticle pores linked to brittle minerals and sizeable intraparticle pores associated with clay minerals. The selected shales can be categorized into two types based on the nitrogen isotherms. Type A shales are characterized by high contents of felsic and calcareous minerals but low clay minerals, with larger TOC and shale oil values. Conversely, Type B shales are marked by abundant clay minerals but diminished TOC and shale oil contents. The lower BET specific surface area(SSA), larger average pore diameter, and simpler pore surfaces and pore structures lead to the Type A shales being more conducive to shale oil enrichment and mobility. Shale oil content is predominantly governed by the abundance of organic matter, while an overabundance of organic matter typically equates to a reduced ratio of free oil and diminished fluidity. The BET SSA, volumes of pores less than 25 and 100 nm at extracted state all correlate negatively with total and adsorbed oil contents but display no correlation with free oil, while they have positive relationships with capillary-bound water.Consequently, pore water is mainly saturated in micropores(<25 nm) and minipores(25-100 nm), as well as adsorbed oil, while free oil, i.e., bound and movable oil, primarily exists in mesopores(100-1000 nm) and macropores(>1000 nm). These findings may enhance the understanding of the microscopic occurrence characteristics of shale oil and will contribute to guide resource estimation and shale oil sweet spot exploitation in the Gaoyou Sag, Subei Basin.
基金supported by the National Natural Science Foundation of China(Grant Nos.U2344209,U42230310,U42207293)Natural Science Foundation of Sichuan Province,China(Grant No.2023NSFSC0262).
文摘The Late Permian to Early Triassic marked a pivotal phase in paleoenvironmental and tectonic shifts.The Kaijiang-Liangping intracratonic sag,a tectonic geomorphology formed by Emei taphrogenesis in the Sichuan Basin,is situated within a clear water carbonate platform.Under these conditions,the black shales of the Dalong Formation in the sag have ultrahigh organic matter content.However,the mechanism by which these conditions control the accumulation of such organic matter remains unclear.Petrological and geochemical analyses of well DY-1H revealed four distinct units within the Dalong Formation:A,B,C,and D,with average total organic carbon contents of 3.00%,9.59%,4.57%,and 0.27%,respectively.The kerogen maceral,carbon isotope,and pyrolysis results show that the organic matter mainly comprises Type Ⅱ_(2) kerogen.Benthic plants growing in clear water may be the primary source of this kerogen.Shallow water,suboxic conditions,strong volcanism,and high productivity characterize Unit A.Unit B features restricted ocean circulation,anoxic conditions,weak upwelling,moderate volcanism,and high productivity.Unit C is characterized by anoxic conditions,strong upwelling,weak volcanism,and moderate productivity.Oxic conditions and low productivity define Unit D.These findings challenge traditional models that struggle to explain the accumulation of ultrahigh organic matter in Unit A under suboxic conditions,Unit C under moderate productivity,and Unit B with abnormally high organic matter content.The flourishing of benthic plants,a considerable source of Type Ⅱ_(2) kerogen that resists decomposition and favors preservation,is the dominant factor controlling the ultrahigh organic matter accumulation of black shales in Units A,B,and C under clear water conditions.Oxidized bottom waters and decreased benthic plant growth were crucial to the sharp decline in organic matter.
基金supported by Joint Fund Project of National Natural Science Foundation(No.U22B6002)CNPC Scientific Research and Technology Development Project(No.2023ZZ14YJ02).
文摘The Jurassic tight sandstone oil and gas exploration and development in the eastern Yangxia Sag is a new field.To elucidate the origin,accumulation process and potential of tight oil and gas,the authors have conducted comprehensive analyses employing methodologies encompassing source rocks,oil geochemistry,and fluid inclusions.The results show that the abundance of organic matter of Jurassic source rocks is high,and the type of organic matter is ofⅡ-Ⅲand in mature evolution stage.The main source rocks of oil and gas are Huangshanjie Formation and Jurassic coal-bearing source rocks.Ahe Formation developed two stages of hydrocarbon charging,and the period is later than the reservoir densification time.Yangxia Formation oil charged before the reservoir densified,and the late gas charged after the reservoir densified.Hydrocarbon generation intensity of Jurassic source rocks has reached the basic conditions for the formation of tight gas reservoirs.Controlled by the difference of source rocks distribution and accumulation process,tight sandstone oil and gas accumulation conditions are better in the depression direction than in the southeast margin area.This study is of practical importance for expanding the exploration field and selecting favorable areas in the eastern Yangxia sag.
基金The Scientific and Technological Project of China National Offshore Oil Corporation(CNOOC)Research Institute Co.,Ltd.under contract No.CCL2021RCPS0167KQNthe Open Fund Project for the year 2022 of National Engineering Research Center of Offshore Oil and Gas Exploration under contract No.CCL2022RCPS0794RQN.
文摘The Beibu Gulf Basin is an important oil-and gas-bearing basin offshore the China Sea,but the geological reserves of oil and gas are not very high,and there are significant differences between different sags.Previous studies have shown that the formation and accumulation of oil and gas are closely related to deep structures,especially the crustal thickness or the relative undulation characteristics between the Moho and basement,but there is a lack of specific evaluation and quantitative standards.In this paper,we first invert the depth of the Moho in the Beibu Gulf Basin using satellite gravity anomalies and calculate the crustal thickness value based on this.Then,we count and analyze the crustal thickness value as well as the stretching factor that characterizes the crustal extension and thinning degree,and find that the NWW-trending contour closure of the 28 km Moho depth or 26 km crustal thickness corresponds significantly to the Weixinan-Fushan sag belt,which has already been proven to have considerable oil and gas discoveries,with a typical feature of crustal thinning to 22 km and the stretching factor reaching 1.1.Finally,we propose a comprehensive evaluation scheme based on the entropy weight method to normalize and evaluate the statistical features of the crust,and take a comprehensive score of Si>0.5 as an evaluation indicator for an oil-gas-rich sag.Based on this research,we believe that the Haizhong sag has considerable exploratory potential,followed by the Maichen sag,while the Leidong and Haitoubei sags have relatively smaller exploratory potential.The research results will help strategic decision-making of the oil and gas exploration in the Beibu Gulf Basin and provide new perspectives for studying the relationship between deep structures and the differential distribution of oil-gas-rich sags.
基金the National Science and Technology Major Project of China for their support。
文摘Research based on oil accumulation models is essential for exploring the hydrocarbon accumulation theory further.Studies on tight oil accumulation models focused on fan delta depositional systems,and in particular,systems involving source-reservoir separated type are scarce.To explore the accumulation model of tight oil in conglomerate,this study focused on the Permian-Triassic tight conglomerate oil in Mahu sag,Junggar Basin,using well drilling,well logging,seismic profiling,oil testing,and laboratory data,and analyzed the formation conditions,formation types,and distribution patterns of conglomerate reservoirs.The results show that,the conglomerate reservoirs are predominantly lithologic reservoirs and partly fault-lithologic reservoirs;there is no water evident at the edge or bottom around the reservoirs.The tight conglomerate layer in the delta plain subfacies of each fan exhibits high clay content and intense diagenesis,and the argillaceous rocks in the pro-fan delta subfacies and shallow lacustrine facies form the sealing and floor conditions.The sandy conglomerate of fan delta front subfacies is the main reservoir body.Additionally,strikeslip faulting in the Indosinian-Himalayan period formed an efficient faulting system for trans-stratal migration with Hercynian-Indosinian inverse faulting.Oil migration is driven by the overpressure caused by hydrocarbon generation from alkali lacustrine source rocks.The distribution of reservoirs is primarily controlled by the large fan bodies,namely the Zhongguai,Baijiantan,Karamay,Huangyangquan,Xiazijie,Xiayan,and Dabasong fans.Each fan body forms a group of reservoirs or oilfields,resulting in a widely distributed pattern,according to which reservoir and sealing constitute one whole body—i.e.,patterns of“one sand and one reservoir,one fan and one field.”This results in a quasi-continuous accumulation model,which includes strong oil charging,efficient faulting transportation,trans-stratal migration,and lithologic trapped accumulation.The proposed model is an important supplement to the existing model of quasi-continuous oil and gas accumulation.Overall,this study enriches unconventional oil and gas accumulation theories.
基金supported by the National Natural Science Foundation of China(No.41830431)the Shandong Provincial Key Research and Development Program(No.2020ZLYS08).
文摘Understanding the occurrence state of shale oil is crucial for the effective development of shale oil resources.Although the second member of the Kongdian Formation(Ek2)is a key interval for lacustrine shale oil production in the Cangdong Sag,Bohai Bay Basin,the occurrence state and controlling factors of shale oil in this formation remain poorly understood.This study established a multi-step programmed pyrolysis,combined with a light hydrocarbon recovery scheme,to quantitatively characterize the shale oil in different occurrence states.An integrated approach utilizing Rock-Eval pyrolysis,pyrolysis-gas chromatography,and crude oil gas chromatography was employed.Factors influencing the shale oil occurrence state were analyzed from petrology and organic geochemistry perspectives.The study revealed significant variations of shale oil occurrence states within the Ek2,attributed to differences in sedimentary organic matter,mineral compositions,sedimentary structures,and thermal maturity.Felsic laminae are the primary reservoir space for oil in laminated shales,and the frequent interbedding of felsic and organic-rich laminae facilitates the retention of free oil.The contents of free and adsorbed oil are primarily influenced by organic matter content and shale storage capacity,both of which exhibit distinct occurrence patterns.Based on the shale reservoir quality classification using the pyrolysis values of S1-1+S1-2 and(S1-1+S1-2)×100/TOC,the Ek2 shale demonstrates significant exploitation potential,with the first-level reservoirs comprising 66%,second-level reservoirs 11%,and third-level reservoirs 23%.These findings provide new insights into the geological accumulation and production of shale oil.
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 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 Project funded by the Natural Science Foundation of Hainan Province(Grant No.322QN248)the National Natural Science Foundation of China(Grant Nos.32401488,32060409,32371782 and 32460358)+3 种基金the Innovational Fund for Scientific and Technological Personnel of Hainan Province(Grant No.KJRC 2023C21)the Hainan High-level Talents Project(Grant No.321RC475)Collaborative Innovation Center Project of Nanfan and High-Efficiency Tropical Agriculture in Hainan University(XTCX2022NYB08)Collaborative Innovation Center Project of Ecological Civilization in Hainan University(XTCX2022STC10).
文摘Improving salt tolerance and mitigating senescence in the presence of high salinity are crucial for sustaining agricultural productivity.Previous research has demonstrated that hydrogen peroxide(H_(2)O_(2)),specifically H_(2)O_(2)derived from roots and mediated by the respiratory burst oxidase homolog(NADPH),plays a significant role in regulating ion and plant hormone homeostasis in glycophytic plants,such as Arabidopsis.However,the extent to which root-derived H_(2)O_(2)fulfils similar functions in halophytic plants remains uncertain.Therefore,our study aimed to explore the potential contribution of root-sourced H_(2)O_(2)in delaying leaf senescence induced by high salinity,utilizing seashore paspalum as a model halophytic plant.The application of the NADPH-oxidase inhibitor DPI,coupled with a series of leaf senescence analyses,we revealed that root-derived H_(2)O_(2)significantly retards salt-induced leaf senescence.Furthermore,through the application of hormone analysis,lipidomics,ionomics,Non-invasive Micro-test Technology(NMT),and transcriptomics,we established that NADPH-dependent H_(2)O_(2)induced by salt stress in the roots was indispensable for maintaining the balance of the aging hormone,jasmonic acid(JA),and sodium ion homeostasis within this halophytic plant.Finally,by utilizing AtrbohD Arabidopsis mutants and virus-induced gene silencing(VIGs)in Paspalum vaginatum,we demonstrated the pivotal role played by root-sourced H_(2)O_(2)in upholding JA homeostasis and regulating JA-triggered leaf senescence in P.vaginatum.This study offers novel insights into the mechanisms that govern plant leaf senescence and its response to salinity-induced stress.
