Unlike conventional natural gas accumulations,unconventional ones have obvious particularity in reservoir forming conditions,enrichment mechanism,distribution modes,prediction method,and exploration technology.Analyzi...Unlike conventional natural gas accumulations,unconventional ones have obvious particularity in reservoir forming conditions,enrichment mechanism,distribution modes,prediction method,and exploration technology.Analyzing the reservoir forming process and main controlling factors of unconventional natural gas accumulations under the guide of the hydrocarbon accumulation system theory is of great significance for unconventional natural gas reservoir evaluation and prediction.Based on the reservoir forming mechanism and distribution mode,the unconventional natural gas accumulation systems are divided into six types,including shale gas,coalbed methane,tight carbonate gas,tight sandstone gas,water-soluble gas,and gas hydrate.According to the concept of“elementefunctionestructure”in the hydrocarbon accumulation system theory and the relationship of“gas source rockemigration systemeaccumulations distribution”,the unconventional gas accumulation system is divided into six“sourceelocation”types.The characteristics of the other five types of unconventional gas accumulation systems except gas hydrate are analyzed.The following results were obtained.(1)Shale gas,coalbed methane and tight carbonate gas belong to an intra-source type unconventional gas accumulation system,characterized by intense gas supply capacity,lack of either a transport system or secondary migration,integration of source,reservoir and caprock,in-situ accumulation,and so on.(2)Tight sandstone gas and water-soluble gas belong to a marginal unconventional gas accumulation system of source rock,characterized by diverse gas origin,near-source accumulation in adjacent layers of source rocks,internal migration within reservoirs,and so on.(3)Basin tectonic evolution,sedimentary environment and late tectonic events control the types of unconventional gas accumulation systems:The Paleozoic marine sediments in South China are conducive to the formation of shale gas and tight carbonate gas accumulation systems;The marineecontinental transitional facies deposits of Upper Paleozoic distributed in the South and North China are conducive to the development of coalbed methane,shale gas and tight sandstone gas accumulation systems;In the Middle and East China,MesozoiceCenozoic deep-water continental deposits are more conducive to the deep tight sandstone gas and shale gas accumulation systems,while shallow water continental basins are more conducive to the formation of coalbed methane,tight sandstone gas and shale gas accumulation systems.Water-soluble gas is widely found in the Cenozoic shallow-buried areas rich in organic matter or high-pressure reservoirs adjacent to gas source rocks.展开更多
Considering the existing problems of the petroleum system, this paper bringsforward the concept of natural gas accumulation system and presents the dividing principles. Thendetailed statistics on the accumulation fact...Considering the existing problems of the petroleum system, this paper bringsforward the concept of natural gas accumulation system and presents the dividing principles. Thendetailed statistics on the accumulation factors of the 32 typical natural gas accumulation systemsin China and studies on the laws controlling distribution of gas are collected. The research showsthat the petroleum accumulation system is the basic unit controlling petroleum generation, migrationand accumulation. Generating intensity, generating amount, accumulating efficiency and migrationdistance plays an important role in the distribution of natural gas. Through analysis on results ofresources evaluation, discovered reserves and residual reserves, potential areas in middle-scaledpetroliferous basins in China are forecasted in this paper. Ordos, Sichuan, Tarim and Qaidam basinsare found out to be the main basins developing and enriching gas accumulation systems.展开更多
Coal measures are significant hydrocarbon source rocks and reservoirs in petroliferous basins.Many large gas fields and coalbed methane fields globally are originated from coal-measure source rocks or accumulated in c...Coal measures are significant hydrocarbon source rocks and reservoirs in petroliferous basins.Many large gas fields and coalbed methane fields globally are originated from coal-measure source rocks or accumulated in coal rocks.Inspired by the discovery of shale oil and gas,and guided by“the overall exploration concept of considering coal rock as reservoir”,breakthroughs in the exploration and development of coal-rock gas have been achieved in deep coal seams with favorable preservation conditions,thereby opening up a new development frontier for the unconventional gas in coal-rock reservoirs.Based on the data from exploration and development practices,a systematic study on the accumulation mechanism of coal-rock gas has been conducted.The mechanisms of“three fields”controlling coal-rock gas accumulation are revealed.It is confirmed that the coal-rock gas is different from CBM in accumulation process.The whole petroleum systems in the Carboniferous–Permian transitional facies coal measures of the eastern margin of the Ordos Basin and in the Jurassic continental facies coal measures of the Junggar Basin are characterized,and the key research directions for further developing the whole petroleum system theory of coal measures are proposed.Coal rocks,compared to shale,possess intense hydrocarbon generation potential,strong adsorption capacity,dual-medium reservoir properties,and partial or weak oil and gas self-sealing capacity.Additionally,unlike other unconventional gas such as shale gas and tight gas,coal-rock gas exhibits more complex accumulation characteristics,and its accumulation requires a certain coal-rock play form lithological and structural traps.Coal-rock gas also has the characteristics of conventional fractured gas reservoirs.Compared with the basic theory and model of the whole petroleum system established based on detrital rock formations,coal measures have distinct characteristics and differences in coal-rock reservoirs and source-reservoir coupling.The whole petroleum system of coal measures is composed of various types of coal-measure hydrocarbon plays with coal(and dark shale)in coal measures as source rock and reservoir,and with adjacent tight layers as reservoirs or cap or transport layers.Under the action of source-reservoir coupling,coal-rock gas is accumulated in coal-rock reservoirs with good preservation conditions,tight oil/gas is accumulated in tight layers,conventional oil/gas is accumulated in traps far away from sources,and coalbed methane is accumulated in coal-rock reservoirs damaged by later geological processes.The proposed whole petroleum system of coal measures represents a novel type of whole petroleum system.展开更多
Based on the investigation of sedimentary filling characteristics and pool-forming factors of the Mesozoic in the Ordos Basin,the whole petroleum system in the Mesozoic is divided,the migration&accumulation charac...Based on the investigation of sedimentary filling characteristics and pool-forming factors of the Mesozoic in the Ordos Basin,the whole petroleum system in the Mesozoic is divided,the migration&accumulation characteristics and main controlling factors of conventional-unconventional hydrocarbons are analyzed,and the whole petroleum system model is established.First,the whole petroleum system developed in the Mesozoic takes the high-quality source rocks of the 7th member of the Triassic Yanchang Formation as the core and mainly consists of low-permeability and unconventional oil and gas reservoirs.It can be divided into four hydrocarbon accumulation domains,including intra-source retained hydrocarbon accumulation domain,near-source tight hydrocarbon accumulation domain,far-source conventional hydrocarbon accumulation domain and transitional hydrocarbon accumulation domain,which together form a continuous,symbiotic,and orderly accumulation entity wherein unconventional resources significantly outweigh conventional ones in proportion.Second,the spatial core area of sedimentary filling is the oil-rich core of the whole petroleum system.From the core to the periphery,the reservoir type evolves as shale oil→tight oil→conventional oil,the accumulation power is dominated by overpressure→buoyancy or overpressure and capillary force,the accumulation scale changes from extensive hundreds of millions of tons to a isolated hundreds of thousands-million of tons,and the gas-oil ratio and methane content decrease.Third,the sedimentary filling system provides the material basis and spatial framework for the whole petroleum system,the superimposed sand body,fault and unconformity constitute the dominant migration pathway of hydrocarbons in the far-source conventional hydrocarbon accumulation domain and the transitional hydrocarbon accumulation domain,the high-quality source rocks provide a solid resource basis for shale oil,and the micro-nano pore throat-fracture network constitute unconventional accumulation space.The hydrocarbon migration and accumulation process is mainly controlled by intense expulsion of hydrocarbon under overpressure in the pool-forming stage and the in-situ re-enrichment controlled by underpressure in post-pool-forming stage.The oil-gas enrichment and long-term preservation depends on the coordination among three factors(stable geological structure,multi-cycle sedimentation,and dual self-sealing).Fourth,the whole petroleum system model is defined as four domains,overpressure+underpressure drive,and dual self-sealing.展开更多
Strip-till(ST),including straw mulching in the inter-row and localized fertilization in the intra-row,is a conservation tillage system for improving soil quality and crop growth.However,the yield advantage of maize un...Strip-till(ST),including straw mulching in the inter-row and localized fertilization in the intra-row,is a conservation tillage system for improving soil quality and crop growth.However,the yield advantage of maize under ST compared to conventional tillage(CT)remains unstable,and the strategies to increase maize yield under ST are unclear.This study aims to understand the physiological mechanism underlining maize yield formation under ST by comparing two maize cultivars,DKM753 and DK517,with contrasting yield performance in ST versus CT systems.Compared to CT,ST resulted in a 4.5%yield increase for DKM753 but a 5.6%decrease for DK517.These yield differences were primarily attributed to variations in grain number per ear(GN).During the rapid growth stage(V14-R3),i.e.,two weeks before and after silking,DKM753 showed a 6.7%increase in maximum growth rate(V_(max))and a 6.3%increase in average growth rate(V)under ST,whereas DK517 exhibited decline of 8.5%in V_(max) and 12.3%in V.Significant positive correlations are observed between V_(max) and V with GN under ST(R^(2)=0.79 and R^(2)=0.90,respectively).Enhanced dry matter accumulation in DKM753 under ST was attributed to increased leaf expansion rates,contributing to a larger photosynthate source.The straw mulching and localized nitrogen fertilization increased root-zone nitrogen availability at silking in ST compared to CT.DKM753 had a greater root system which made better use of the soil N and lead to an increased leaf nitrogen accumulation by 14.9%under ST.It is concluded that maize yield under the strip-till system is determined by grain number per ear,which can be increased by increasing nitrogen accumulation,plant growth,and ear development around silking stage.A sound root system can efficiently utilize soil nitrogen resources under the strip-till system,increasing plant nitrogen accumulation and thereby promoting plant growth.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
A type of authigenic pyrites that fully fill or semi-fill the rock fractures of drillholes with gas hydrate anomalies are found in the Qilian Mountain permafrost; this type of pyrite is known as ＂fracture-filling＂ p...A type of authigenic pyrites that fully fill or semi-fill the rock fractures of drillholes with gas hydrate anomalies are found in the Qilian Mountain permafrost; this type of pyrite is known as ＂fracture-filling＂ pyrite. The occurrence of ＂fracture-filling＂ pyrite has a certain similarity with that of the hydrate found in this region, and the pyrite is generally concentrated in the lower part of the hydrate layer or the hydrate anomaly layer. The morphology, trace elements, rare earth elements, and sulfur isotope analyses of samples from drillhole DK-6 indicate that the ＂fracture-filling＂ pyrites are dominated by cubic ones mainly aligned in a step-like fashion along the surfaces of rock fractures and are associated with a circular structure, lower Co/Ni and Sr/Ba, lower ZREE, higher LREE, significant Eu negative anomalies, and 634ScDT positive bias. In terms of the pyrites＇ unique crys- tal morphology and geochemical characteristics and their relationship with the hydrate layers or abnormal layers, they are closely related with the accumulation system of the gas hydrate in the Qilian Mountain permafrost. As climate change is an important factor in affecting the stability of the gas hydrate, formation of fracture-filling pyrites is most likely closely related to the secondary change of the metastable gas hydrate under the regional climate warming. The distribution intensity of these py- rites indicates that when the gas hydrate stability zone （GHSZ） is narrowing, the hydrate decomposition at the bottom of the GHSZ is stronger than that at the top of the GHSZ, whereas the hydrate decomposition within the GHSZ is relatively weak. Thus, the zone between the shallowest and the deepest distribution of the fracture-filling pyrite recorded the largest possible original GHSZ.展开更多
The concept of the three-layer structure of continental basins is presented based on the characteristics of layered structure of basins. The reservoir could be classified into accumulation system assemblage, accumulat...The concept of the three-layer structure of continental basins is presented based on the characteristics of layered structure of basins. The reservoir could be classified into accumulation system assemblage, accumulation system, accumulation assemblage and reservoir. This paper discusses the characteristics of hydrocarbon accumulation system assemblages of the Zhanhua Depression, which include four kinds of genetic patterns： （1） buried-hill hydrocarbon accumulation system assemblage; （2） self-sourced accumulation system assemblage from the upper interval of member 4 to member 1 of Shahejie formation; （3） transition accumulation system assemblage from member 1 of the Shahejie formation to Dongying formation and （4） externally sourccd accumulation system assemblage in the late Tertiary. The hydrocarbon-source transport network layer consisted of faults and unconformities, which connected with the reservoir layer.展开更多
In this article, polyphosphate-accumulating organisms （PAOs） from a lab-scale continuous-flow two-sludge system was isolated and identified, the different phosphorus accumulation characteristics of the isolates unde...In this article, polyphosphate-accumulating organisms （PAOs） from a lab-scale continuous-flow two-sludge system was isolated and identified, the different phosphorus accumulation characteristics of the isolates under anoxic and aerobic conditions were investigated. Two kinds of PAOs were both found in the anoxic zones of the two-sludge system, one of them utilized only oxygen as electron aeceptor, and the other one utilized either nitrate or oxygen as electron aeceptor. Of the total eight isolates, five isolates were capable of utilizing both nitrate and oxygen as electron acceptors to uptake phosphorus to some extent. And three of the five isolates showed good phosphorus accumulative capacities both under anoxic or aerobic conditions, two identified as Alcaligenes and one identified as Pseudomonas. Streptococcus was observed weak anoxic phosphorus accumulation because of its weak denitrification capacity, but it showed good phosphorus accumulation capacity under aerobic conditions. One isolates identified as Enterobacteriaceae was proved to be a special species of PAOs, which could only uptake small amounts of phosphorus under anoxic conditions, although its denitrification capacity and aerobic phosphorus accumulation capacity were excellent.展开更多
Understanding hydrocarbon migration and accumulation mechanisms is one of the key scientif ic problems that should be solved for effective hydrocarbon exploration in the superimposed basins developed in northwest Chin...Understanding hydrocarbon migration and accumulation mechanisms is one of the key scientif ic problems that should be solved for effective hydrocarbon exploration in the superimposed basins developed in northwest China. The northwest striking No.1 slope break zone, which is a representative of superimposed basins in the Tarim Basin, can be divided into five parts due to the intersection of the northeast strike-slip faults. Controlled by the tectonic framework, the types and properties of reservoirs and the hydrocarbon compositions can also be divided into five parts from east to west. Anomalies of all the parameters were found on the fault intersection zone and weakened up-dip along the structural ridge away from it. Thus, it can be inferred that the intersection zone is the hydrocarbon charging position. This new conclusion differs greatly from the traditional viewpoint, which believes that the hydrocarbon migrates and accumulates along the whole plane of the No.1 slope break zone. The viewpoint is further supported by the evidence from the theory of main pathway systems, obvious improvement of the reservoir quality （2-3 orders of magnitude at the intersection zone） and the formation mechanisms of the fault intersection zone. Differential hydrocarbon migration and entrapment exists in and around the strike- slip faults. This is controlled by the internal structure of faults. It is concluded that the more complicated the fault structure is, the more significant the effects will be. If there is a deformation band, it will hinder the cross fault migration due to the common feature of two to four orders of magnitude reduction in permeability. Otherwise, hydrocarbons tend to accumulate in the up-dip structure under the control of buoyancy. Further research on the internal fault structure should be emphasized.展开更多
Time series bioaccumulation of rare earth elements （REEs） in field-grown wheat with and without a dressing of extraneous REE fertilizer at different growth stages and fractionation of REEs during their transport in ...Time series bioaccumulation of rare earth elements （REEs） in field-grown wheat with and without a dressing of extraneous REE fertilizer at different growth stages and fractionation of REEs during their transport in a soil-wheat system were determined. Time-dependent accumulation of extraneous REEs was found in different parts of wheat. An upward transport of extraneous REEs from roots to shoots under a soil dressing and a downward transport from leaves to roots with a foliar dressing were also observed. Moreover, fractionation of REEs occurred in the soil-wheat system. Compared to the host soil a positive Eu anomaly in the stems and grains as well as heavy REE enrichment in the grains were found. The ability of the different wheat organs to fractionate Eu from the REE series was ranked in the order of sterns 〉 grains 〉 leaves 〉 roots.展开更多
The concept and division method for petroleum accumulation system,based on layer structure,are presented according to characteristics of layer structure and reservoirs. The petroleum accumulation system of Jiyang depr...The concept and division method for petroleum accumulation system,based on layer structure,are presented according to characteristics of layer structure and reservoirs. The petroleum accumulation system of Jiyang depression can be divided into four levels,namely petroleum accumulation system combination,petroleum accumulation system,oil-gas reservoir combination and reservoir. The petro-leum accumulation system combination includes three types of genetic pattern: other-source bur-ied-ridge accumulation system combination in pre-Paleogene,medium-deep layer self-source accu-mulation system combination in Paleogene,and shallow layer other-source accumulation system combination in Neogene. This paper also describes the reservoir types and their distribution charac-teristics of different petroleum accumulation system combinations and their interior units.展开更多
One purpose of this research is to present accumulation of cadmium （Cd） and copper （Cu） by female Oxya chinensis （Orthopera： Acridoidea） in a simulated soil-plant-insect ecosystem treated with Cd. Fourth-instar...One purpose of this research is to present accumulation of cadmium （Cd） and copper （Cu） by female Oxya chinensis （Orthopera： Acridoidea） in a simulated soil-plant-insect ecosystem treated with Cd. Fourth-instar nymphs of O. chinensis had been fed on wheat （Triticurn aestivum） seedlings contaminated with Cd and Cu for one month. In the ecosystem, the Cd concentration in wheat seedlings rose greatly with the increasing of Cd in the soil, but the Cu concentration in wheat seedlings was not found elevated. There was a highly significant difference（P〈0.05） in Cd concentrations of wheat seedlings and not any significant difference（P〉0.05） in Cu concentrations of wheat seedlings. The Cd and Cu concentration in different body part-head, thorax, abdomen, and hind femur, varied under different Cd concentrations in soil. There were significant differences （P〈0.05） in the four parts of Cd and Cu accumulations with all treatments. The order of Cd accumulation was thorax 〉abdomen 〉head 〉hind femur and the Cu was abdomen 〉thorax 〉 head〉hind femur. The results indicated that Cd and Cu were accumulated from the soil to grasshoppers through the plant; that is to say, Cd and Cu in environment could be transported to animal or human via food chain.展开更多
The Carboniferous volcanic reservoirs in Junggar Basin contain rich hydrocarbon resources,implying a great exploration potential,so that they have become a key replacement target for“three-dimensional exploration”.T...The Carboniferous volcanic reservoirs in Junggar Basin contain rich hydrocarbon resources,implying a great exploration potential,so that they have become a key replacement target for“three-dimensional exploration”.The study on the Carboniferous volcanic reservoirs and their hydrocarbon accumulation elements is significant for clarifying the orientation for exploration.In this paper,based on 37 reserves reports and 3200 reservoir test data,the Carboniferous volcanic reservoirs in Junggar Basin were discussed from the prospective of lithology and lithofacies,physical properties,reservoir types,main controls on hydrocarbon accumulation,and hydrocarbon accumulation patterns.It is found that the Carboniferous in the basin is mostly in the multi-island ocean-volcanic island arc structural-sedimentary environment,so it is geologically eligible for forming in-situ volcanic reservoirs.The volcanic rocks are:(1)mostly distributed along deep and large faults,with the lithology and lithofacies controlled by volcanic architectures;(2)dominantly lava,followed by volcaniclastic lava and volcaniclastic rock;(3)distributed in the periphery of hydrocarbon-generating sag and within the source rocks horizontally,and concentrated in the weathering crust at the top longitudinally,possibly leading to reworked weathering crust reservoir;and(4)liable to form inner reservoirs.The volcanic reservoirs can be concluded into four hydrocarbon accumulation patterns,i.e.,self-generating&self-storing in paleo-uplift and vertical migration,self-generating&self-storing in paleo-uplift and lateral migration,young-generating&old-storing in fault zone and vertical migration,and young-generating&old-storing in paleo-uplift and lateral migration.Future exploration will focus on the effective source rock development and hydrocarbon supply zones and the selfgenerating&self-storing and young-generating&old-storing patterns.The exploration prospects are determined to be the Ludong-Wucaiwan-Baijiahai slope belt and the southern slope belt of the Shaqi uplift(self-generating&self-storing pattern)in eastern Junggar,and the fault and nasal arch zone at the northwestern margin and the nasal arch zone(deep and large structure)in the Luxi area(younggenerating&old-storing pattern)in western Junggar.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
According to the complex differential accumulation history of deep marine oil and gas in superimposed basins,the Lower Paleozoic petroleum system in Tahe Oilfield of Tarim Basin is selected as a typical case,and the p...According to the complex differential accumulation history of deep marine oil and gas in superimposed basins,the Lower Paleozoic petroleum system in Tahe Oilfield of Tarim Basin is selected as a typical case,and the process of hydrocarbon generation and expulsion,migration and accumulation,adjustment and transformation of deep oil and gas is restored by means of reservoine-forming dynamics simulation.The thermal evolution history of the Lower Cambrian source rocks in Tahe Oilfield reflects the obvious differences in hydrocarbon generation and expulsion process and intensity in different tectonic zones,which is the main reason controlling the differences in deep oil and gas phases.The complex transport system composed of strike-slip fault and unconformity,etc.controlled early migration and accumulation and late adjustment of deep oil and gas,while the Middle Cambrian gypsum-salt rock in inner carbonate platform prevented vertical migration and accumulation of deep oil and gas,resulting in an obvious"fault-controlled"feature of deep oil and gas,in which the low potential area superimposed by the NE-strike-slip fault zone and deep oil and gas migration was conducive to accumulation,and it is mainly beaded along the strike-slip fault zone in the northeast direction.The dynamic simulation of reservoir formation reveals that the spatio-temporal configuration of"source-fault-fracture-gypsum-preservation"controls the differential accumulation of deep oil and gas in Tahe Oilfield.The Ordovician has experienced the accumulation history of multiple periods of charging,vertical migration and accumulation,and lateral adjustment and transformation,and deep oil and gas have always been in the dynamic equilibrium of migration,accumulation and escape.The statistics of residual oil and gas show that the deep stratum of Tahe Oilfield still has exploration and development potential in the Ordovician Yingshan Formation and Penglaiba Formation,and the Middle and Upper Cambrian ultra-deep stratum has a certain oil and gas resource prospect.This study provides a reference for the dynamic quantitative evaluation of deep oil and gas in the Tarim Basin,and also provides a reference for the study of reservoir formation and evolution in carbonate reservoir of paleo-craton basin.展开更多
Based on the situation and progress of marine oil/gas exploration in the Sichuan Basin,SW China,the whole petroleum system is divided for marine carbonate rocks of the basin according to the combinations of hydrocarbo...Based on the situation and progress of marine oil/gas exploration in the Sichuan Basin,SW China,the whole petroleum system is divided for marine carbonate rocks of the basin according to the combinations of hydrocarbon accumulation elements,especially the source rock.The hydrocarbon accumulation characteristics of each whole petroleum system are analyzed,the patterns of integrated conventional and unconventional hydrocarbon accumulation are summarized,and the favorable exploration targets are proposed.Under the control of multiple extensional-convergent tectonic cycles,the marine carbonate rocks of the Sichuan Basin contain three sets of regional source rocks and three sets of regional cap rocks,and can be divided into the Cambrian,Silurian and Permian whole petroleum systems.These whole petroleum systems present mainly independent hydrocarbon accumulation,containing natural gas of affinity individually.Locally,large fault zones run through multiple whole petroleum systems,forming a fault-controlled complex whole petroleum system.The hydrocarbon accumulation sequence of continental shelf facies shale gas accumulation,marginal platform facies-controlled gas reservoirs,and intra-platform fault-and facies-controlled gas reservoirs is common in the whole petroleum system,with a stereoscopic accumulation and orderly distribution pattern.High-quality source rock is fundamental to the formation of large gas fields,and natural gas in a whole petroleum system is generally enriched near and within the source rocks.The development and maintenance of large-scale reservoirs are essential for natural gas enrichment,multiple sources,oil and gas transformation,and dynamic adjustment are the characteristics of marine petroleum accumulation,and good preservation conditions are critical to natural gas accumulation.Large-scale marginal-platform reef-bank facies zones,deep shale gas,and large-scale lithological complexes related to source-connected faults are future marine hydrocarbon exploration targets in the Sichuan Basin.展开更多
Based on the oil and gas exploration practice in the Songliao Basin,combined with the latest exploration and development data such as seismic,well logging and geochemistry,the basic geological conditions,oil and gas t...Based on the oil and gas exploration practice in the Songliao Basin,combined with the latest exploration and development data such as seismic,well logging and geochemistry,the basic geological conditions,oil and gas types and distribution characteristics,reservoir-forming dynamics,source-reservoir relationship and hydrocarbon accumulation model of the whole petroleum system in shallow and medium strata in the northern part of Songliao Basin are systematically studied.The shallow-medium strata in northern Songliao Basin have the conditions for the formation of whole petroleum system,with sufficient oil and gas sources,diverse reservoir types and well-developed transport system,forming a whole petroleum system centered on the source rocks of the Cretaceous Qingshankou Formation.Different types of oil and gas resources in the whole petroleum system are correlated with each other in terms of depositional system,lithologic association and physical property changes,and they,to a certain extent,have created the spatial framework with orderly symbiosis of shallow-medium conventional oil reservoirs,tight oil reservoirs and shale oil reservoirs in northern Songliao Basin.Vertically,the resources are endowed as conventional oil above source,shale oil/tight oil within source,and tight oil below source.Horizontally,conventional oil,tight oil,interlayer-type shale oil,and pure shale-type shale oil are developed in an orderly way,from the margin of the basin to the center of the depression.Three hydrocarbon accumulation models are recognized for the whole petroleum system in northern Songliao Basin,namely,buoyancy-driven charging of conventional oil above source,retention of shale oil within source,and pressure differential-driven charging of tight oil below source.展开更多
Formation of coal seam and coal-rich zone is an integrated result of a series of factors in coal accumulation process. The coal accumulation system is an architectural aggregation of coal accumulation factors. It can ...Formation of coal seam and coal-rich zone is an integrated result of a series of factors in coal accumulation process. The coal accumulation system is an architectural aggregation of coal accumulation factors. It can be classified into 4 levels： the global coal accumulation super-system, the coal accumulation domain mega-system, the coal accumulation basin system, and the coal seam or coal seam set sub-system. The coal accumulation process is an open, dynamic, and grey system, and is meanwhile a system with such natures as aggregation, relevance, entirety, purpose-orientated, hierarchy, and environment adaptability. In this paper, we take coal accumulation process as a system to study origin of coal seam and coal-rich zone; and we will discuss a methodology of the systematic analysis of coal accumulation process. As an example, the Ordos coal basin was investigated to elucidate the application of the method of the coal accumulation system analysis.展开更多
A study of faults and their control of deep gas accumulations has been made on the basis of dividing fault systems in the Xujiaweizi area. The study indicates two sets of fault systems are developed vertically in the ...A study of faults and their control of deep gas accumulations has been made on the basis of dividing fault systems in the Xujiaweizi area. The study indicates two sets of fault systems are developed vertically in the Xujiaweizi area, including a lower fault system and an upper fault system. Formed in the period of the Huoshiling Formation to Yingcheng Formation, the lower fault system consists of five fault systems including Xuxi strike-slip extensional fault system, NE-trending extensional fault system, near-EW-trending regulating fault system, Xuzhong strike-slip fault system and Xudong strike-slip fault system. Formed in the period of Qingshankou Formation to Yaojia Formation, the upper fault system was affected mainly by the boundary conditions of the lower fault system, and thus plenty of muiti-directionally distributed dense fault zones were formed in the T2 reflection horizon. The Xuxi fault controlled the formation and distribution of Shahezi coal-measure source rocks, and Xuzhong and Xndong faults controlled the formation and distribution of volcanic reservoirs of Y1 Member and Y3 Member, respectively. In the forming period of the upper fault system, the Xuzhong fault was of successive strong activities and directly connected gas source rock reservoirs and volcanic reservoirs, so it is a strongly-charged direct gas source fault. The volcanic reservoir development zones of good physical properties that may be found near the Xuzhong fault are the favorable target zones for the next exploration of deep gas accumulations in Xujiaweizi area.展开更多
基金Project supported by the National Natural Science Foundation of China“Formation&Evolution and Enrichment Mechanism of Continental Shale Oil in Typical Basins in Central-West China”(No.42090020).
文摘Unlike conventional natural gas accumulations,unconventional ones have obvious particularity in reservoir forming conditions,enrichment mechanism,distribution modes,prediction method,and exploration technology.Analyzing the reservoir forming process and main controlling factors of unconventional natural gas accumulations under the guide of the hydrocarbon accumulation system theory is of great significance for unconventional natural gas reservoir evaluation and prediction.Based on the reservoir forming mechanism and distribution mode,the unconventional natural gas accumulation systems are divided into six types,including shale gas,coalbed methane,tight carbonate gas,tight sandstone gas,water-soluble gas,and gas hydrate.According to the concept of“elementefunctionestructure”in the hydrocarbon accumulation system theory and the relationship of“gas source rockemigration systemeaccumulations distribution”,the unconventional gas accumulation system is divided into six“sourceelocation”types.The characteristics of the other five types of unconventional gas accumulation systems except gas hydrate are analyzed.The following results were obtained.(1)Shale gas,coalbed methane and tight carbonate gas belong to an intra-source type unconventional gas accumulation system,characterized by intense gas supply capacity,lack of either a transport system or secondary migration,integration of source,reservoir and caprock,in-situ accumulation,and so on.(2)Tight sandstone gas and water-soluble gas belong to a marginal unconventional gas accumulation system of source rock,characterized by diverse gas origin,near-source accumulation in adjacent layers of source rocks,internal migration within reservoirs,and so on.(3)Basin tectonic evolution,sedimentary environment and late tectonic events control the types of unconventional gas accumulation systems:The Paleozoic marine sediments in South China are conducive to the formation of shale gas and tight carbonate gas accumulation systems;The marineecontinental transitional facies deposits of Upper Paleozoic distributed in the South and North China are conducive to the development of coalbed methane,shale gas and tight sandstone gas accumulation systems;In the Middle and East China,MesozoiceCenozoic deep-water continental deposits are more conducive to the deep tight sandstone gas and shale gas accumulation systems,while shallow water continental basins are more conducive to the formation of coalbed methane,tight sandstone gas and shale gas accumulation systems.Water-soluble gas is widely found in the Cenozoic shallow-buried areas rich in organic matter or high-pressure reservoirs adjacent to gas source rocks.
文摘Considering the existing problems of the petroleum system, this paper bringsforward the concept of natural gas accumulation system and presents the dividing principles. Thendetailed statistics on the accumulation factors of the 32 typical natural gas accumulation systemsin China and studies on the laws controlling distribution of gas are collected. The research showsthat the petroleum accumulation system is the basic unit controlling petroleum generation, migrationand accumulation. Generating intensity, generating amount, accumulating efficiency and migrationdistance plays an important role in the distribution of natural gas. Through analysis on results ofresources evaluation, discovered reserves and residual reserves, potential areas in middle-scaledpetroliferous basins in China are forecasted in this paper. Ordos, Sichuan, Tarim and Qaidam basinsare found out to be the main basins developing and enriching gas accumulation systems.
基金Supported by the PetroChina Basic Project(2024DJ23)CNPC Science Research and Technology Development Project(2021DJ0101)。
文摘Coal measures are significant hydrocarbon source rocks and reservoirs in petroliferous basins.Many large gas fields and coalbed methane fields globally are originated from coal-measure source rocks or accumulated in coal rocks.Inspired by the discovery of shale oil and gas,and guided by“the overall exploration concept of considering coal rock as reservoir”,breakthroughs in the exploration and development of coal-rock gas have been achieved in deep coal seams with favorable preservation conditions,thereby opening up a new development frontier for the unconventional gas in coal-rock reservoirs.Based on the data from exploration and development practices,a systematic study on the accumulation mechanism of coal-rock gas has been conducted.The mechanisms of“three fields”controlling coal-rock gas accumulation are revealed.It is confirmed that the coal-rock gas is different from CBM in accumulation process.The whole petroleum systems in the Carboniferous–Permian transitional facies coal measures of the eastern margin of the Ordos Basin and in the Jurassic continental facies coal measures of the Junggar Basin are characterized,and the key research directions for further developing the whole petroleum system theory of coal measures are proposed.Coal rocks,compared to shale,possess intense hydrocarbon generation potential,strong adsorption capacity,dual-medium reservoir properties,and partial or weak oil and gas self-sealing capacity.Additionally,unlike other unconventional gas such as shale gas and tight gas,coal-rock gas exhibits more complex accumulation characteristics,and its accumulation requires a certain coal-rock play form lithological and structural traps.Coal-rock gas also has the characteristics of conventional fractured gas reservoirs.Compared with the basic theory and model of the whole petroleum system established based on detrital rock formations,coal measures have distinct characteristics and differences in coal-rock reservoirs and source-reservoir coupling.The whole petroleum system of coal measures is composed of various types of coal-measure hydrocarbon plays with coal(and dark shale)in coal measures as source rock and reservoir,and with adjacent tight layers as reservoirs or cap or transport layers.Under the action of source-reservoir coupling,coal-rock gas is accumulated in coal-rock reservoirs with good preservation conditions,tight oil/gas is accumulated in tight layers,conventional oil/gas is accumulated in traps far away from sources,and coalbed methane is accumulated in coal-rock reservoirs damaged by later geological processes.The proposed whole petroleum system of coal measures represents a novel type of whole petroleum system.
基金Supported by CNPC Basic Technology Research and Development Project(2021DJ2203)National Science and Technology Major Project for New Oil and Gas Exploration and Development(2025ZD1400200).
文摘Based on the investigation of sedimentary filling characteristics and pool-forming factors of the Mesozoic in the Ordos Basin,the whole petroleum system in the Mesozoic is divided,the migration&accumulation characteristics and main controlling factors of conventional-unconventional hydrocarbons are analyzed,and the whole petroleum system model is established.First,the whole petroleum system developed in the Mesozoic takes the high-quality source rocks of the 7th member of the Triassic Yanchang Formation as the core and mainly consists of low-permeability and unconventional oil and gas reservoirs.It can be divided into four hydrocarbon accumulation domains,including intra-source retained hydrocarbon accumulation domain,near-source tight hydrocarbon accumulation domain,far-source conventional hydrocarbon accumulation domain and transitional hydrocarbon accumulation domain,which together form a continuous,symbiotic,and orderly accumulation entity wherein unconventional resources significantly outweigh conventional ones in proportion.Second,the spatial core area of sedimentary filling is the oil-rich core of the whole petroleum system.From the core to the periphery,the reservoir type evolves as shale oil→tight oil→conventional oil,the accumulation power is dominated by overpressure→buoyancy or overpressure and capillary force,the accumulation scale changes from extensive hundreds of millions of tons to a isolated hundreds of thousands-million of tons,and the gas-oil ratio and methane content decrease.Third,the sedimentary filling system provides the material basis and spatial framework for the whole petroleum system,the superimposed sand body,fault and unconformity constitute the dominant migration pathway of hydrocarbons in the far-source conventional hydrocarbon accumulation domain and the transitional hydrocarbon accumulation domain,the high-quality source rocks provide a solid resource basis for shale oil,and the micro-nano pore throat-fracture network constitute unconventional accumulation space.The hydrocarbon migration and accumulation process is mainly controlled by intense expulsion of hydrocarbon under overpressure in the pool-forming stage and the in-situ re-enrichment controlled by underpressure in post-pool-forming stage.The oil-gas enrichment and long-term preservation depends on the coordination among three factors(stable geological structure,multi-cycle sedimentation,and dual self-sealing).Fourth,the whole petroleum system model is defined as four domains,overpressure+underpressure drive,and dual self-sealing.
基金the National Key Research and Development Program of China(2022YFD1500705)National Natural Science Foundation of China(U19A2035)for financial support。
文摘Strip-till(ST),including straw mulching in the inter-row and localized fertilization in the intra-row,is a conservation tillage system for improving soil quality and crop growth.However,the yield advantage of maize under ST compared to conventional tillage(CT)remains unstable,and the strategies to increase maize yield under ST are unclear.This study aims to understand the physiological mechanism underlining maize yield formation under ST by comparing two maize cultivars,DKM753 and DK517,with contrasting yield performance in ST versus CT systems.Compared to CT,ST resulted in a 4.5%yield increase for DKM753 but a 5.6%decrease for DK517.These yield differences were primarily attributed to variations in grain number per ear(GN).During the rapid growth stage(V14-R3),i.e.,two weeks before and after silking,DKM753 showed a 6.7%increase in maximum growth rate(V_(max))and a 6.3%increase in average growth rate(V)under ST,whereas DK517 exhibited decline of 8.5%in V_(max) and 12.3%in V.Significant positive correlations are observed between V_(max) and V with GN under ST(R^(2)=0.79 and R^(2)=0.90,respectively).Enhanced dry matter accumulation in DKM753 under ST was attributed to increased leaf expansion rates,contributing to a larger photosynthate source.The straw mulching and localized nitrogen fertilization increased root-zone nitrogen availability at silking in ST compared to CT.DKM753 had a greater root system which made better use of the soil N and lead to an increased leaf nitrogen accumulation by 14.9%under ST.It is concluded that maize yield under the strip-till system is determined by grain number per ear,which can be increased by increasing nitrogen accumulation,plant growth,and ear development around silking stage.A sound root system can efficiently utilize soil nitrogen resources under the strip-till system,increasing plant nitrogen accumulation and thereby promoting plant growth.
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 National Natural Science Foundation of China(Grant Nos.41102021,41202099)National Special Research Fund(Grant No.GZHL20110308)
文摘A type of authigenic pyrites that fully fill or semi-fill the rock fractures of drillholes with gas hydrate anomalies are found in the Qilian Mountain permafrost; this type of pyrite is known as ＂fracture-filling＂ pyrite. The occurrence of ＂fracture-filling＂ pyrite has a certain similarity with that of the hydrate found in this region, and the pyrite is generally concentrated in the lower part of the hydrate layer or the hydrate anomaly layer. The morphology, trace elements, rare earth elements, and sulfur isotope analyses of samples from drillhole DK-6 indicate that the ＂fracture-filling＂ pyrites are dominated by cubic ones mainly aligned in a step-like fashion along the surfaces of rock fractures and are associated with a circular structure, lower Co/Ni and Sr/Ba, lower ZREE, higher LREE, significant Eu negative anomalies, and 634ScDT positive bias. In terms of the pyrites＇ unique crys- tal morphology and geochemical characteristics and their relationship with the hydrate layers or abnormal layers, they are closely related with the accumulation system of the gas hydrate in the Qilian Mountain permafrost. As climate change is an important factor in affecting the stability of the gas hydrate, formation of fracture-filling pyrites is most likely closely related to the secondary change of the metastable gas hydrate under the regional climate warming. The distribution intensity of these py- rites indicates that when the gas hydrate stability zone （GHSZ） is narrowing, the hydrate decomposition at the bottom of the GHSZ is stronger than that at the top of the GHSZ, whereas the hydrate decomposition within the GHSZ is relatively weak. Thus, the zone between the shallowest and the deepest distribution of the fracture-filling pyrite recorded the largest possible original GHSZ.
文摘The concept of the three-layer structure of continental basins is presented based on the characteristics of layered structure of basins. The reservoir could be classified into accumulation system assemblage, accumulation system, accumulation assemblage and reservoir. This paper discusses the characteristics of hydrocarbon accumulation system assemblages of the Zhanhua Depression, which include four kinds of genetic patterns： （1） buried-hill hydrocarbon accumulation system assemblage; （2） self-sourced accumulation system assemblage from the upper interval of member 4 to member 1 of Shahejie formation; （3） transition accumulation system assemblage from member 1 of the Shahejie formation to Dongying formation and （4） externally sourccd accumulation system assemblage in the late Tertiary. The hydrocarbon-source transport network layer consisted of faults and unconformities, which connected with the reservoir layer.
基金Project supported by the Science and Technology Project of Heilongjiang Province (No. GA01C201-03).
文摘In this article, polyphosphate-accumulating organisms （PAOs） from a lab-scale continuous-flow two-sludge system was isolated and identified, the different phosphorus accumulation characteristics of the isolates under anoxic and aerobic conditions were investigated. Two kinds of PAOs were both found in the anoxic zones of the two-sludge system, one of them utilized only oxygen as electron aeceptor, and the other one utilized either nitrate or oxygen as electron aeceptor. Of the total eight isolates, five isolates were capable of utilizing both nitrate and oxygen as electron acceptors to uptake phosphorus to some extent. And three of the five isolates showed good phosphorus accumulative capacities both under anoxic or aerobic conditions, two identified as Alcaligenes and one identified as Pseudomonas. Streptococcus was observed weak anoxic phosphorus accumulation because of its weak denitrification capacity, but it showed good phosphorus accumulation capacity under aerobic conditions. One isolates identified as Enterobacteriaceae was proved to be a special species of PAOs, which could only uptake small amounts of phosphorus under anoxic conditions, although its denitrification capacity and aerobic phosphorus accumulation capacity were excellent.
基金supported by the National 973 Basic Research Program (Grant No.2006CB202308)the Major National Science & Technology Program (2008ZX05008-004-012)
文摘Understanding hydrocarbon migration and accumulation mechanisms is one of the key scientif ic problems that should be solved for effective hydrocarbon exploration in the superimposed basins developed in northwest China. The northwest striking No.1 slope break zone, which is a representative of superimposed basins in the Tarim Basin, can be divided into five parts due to the intersection of the northeast strike-slip faults. Controlled by the tectonic framework, the types and properties of reservoirs and the hydrocarbon compositions can also be divided into five parts from east to west. Anomalies of all the parameters were found on the fault intersection zone and weakened up-dip along the structural ridge away from it. Thus, it can be inferred that the intersection zone is the hydrocarbon charging position. This new conclusion differs greatly from the traditional viewpoint, which believes that the hydrocarbon migrates and accumulates along the whole plane of the No.1 slope break zone. The viewpoint is further supported by the evidence from the theory of main pathway systems, obvious improvement of the reservoir quality （2-3 orders of magnitude at the intersection zone） and the formation mechanisms of the fault intersection zone. Differential hydrocarbon migration and entrapment exists in and around the strike- slip faults. This is controlled by the internal structure of faults. It is concluded that the more complicated the fault structure is, the more significant the effects will be. If there is a deformation band, it will hinder the cross fault migration due to the common feature of two to four orders of magnitude reduction in permeability. Otherwise, hydrocarbons tend to accumulate in the up-dip structure under the control of buoyancy. Further research on the internal fault structure should be emphasized.
基金Project supported by the National Natural Science Foundation of China (Nos. 40232022 and 40571146).
文摘Time series bioaccumulation of rare earth elements （REEs） in field-grown wheat with and without a dressing of extraneous REE fertilizer at different growth stages and fractionation of REEs during their transport in a soil-wheat system were determined. Time-dependent accumulation of extraneous REEs was found in different parts of wheat. An upward transport of extraneous REEs from roots to shoots under a soil dressing and a downward transport from leaves to roots with a foliar dressing were also observed. Moreover, fractionation of REEs occurred in the soil-wheat system. Compared to the host soil a positive Eu anomaly in the stems and grains as well as heavy REE enrichment in the grains were found. The ability of the different wheat organs to fractionate Eu from the REE series was ranked in the order of sterns 〉 grains 〉 leaves 〉 roots.
基金Supported by National Natural Science Foundation of China (Grant No.40772088)
文摘The concept and division method for petroleum accumulation system,based on layer structure,are presented according to characteristics of layer structure and reservoirs. The petroleum accumulation system of Jiyang depression can be divided into four levels,namely petroleum accumulation system combination,petroleum accumulation system,oil-gas reservoir combination and reservoir. The petro-leum accumulation system combination includes three types of genetic pattern: other-source bur-ied-ridge accumulation system combination in pre-Paleogene,medium-deep layer self-source accu-mulation system combination in Paleogene,and shallow layer other-source accumulation system combination in Neogene. This paper also describes the reservoir types and their distribution charac-teristics of different petroleum accumulation system combinations and their interior units.
文摘One purpose of this research is to present accumulation of cadmium （Cd） and copper （Cu） by female Oxya chinensis （Orthopera： Acridoidea） in a simulated soil-plant-insect ecosystem treated with Cd. Fourth-instar nymphs of O. chinensis had been fed on wheat （Triticurn aestivum） seedlings contaminated with Cd and Cu for one month. In the ecosystem, the Cd concentration in wheat seedlings rose greatly with the increasing of Cd in the soil, but the Cu concentration in wheat seedlings was not found elevated. There was a highly significant difference（P〈0.05） in Cd concentrations of wheat seedlings and not any significant difference（P〉0.05） in Cu concentrations of wheat seedlings. The Cd and Cu concentration in different body part-head, thorax, abdomen, and hind femur, varied under different Cd concentrations in soil. There were significant differences （P〈0.05） in the four parts of Cd and Cu accumulations with all treatments. The order of Cd accumulation was thorax 〉abdomen 〉head 〉hind femur and the Cu was abdomen 〉thorax 〉 head〉hind femur. The results indicated that Cd and Cu were accumulated from the soil to grasshoppers through the plant; that is to say, Cd and Cu in environment could be transported to animal or human via food chain.
基金supported by the National Science&Technology Major Project“Distribution Law&Resource Evaluation of Deep Oil&Gas in Petroleum-bearing Basins in China”(No.2017ZX05008-006)PetroChina Key Scientific&Technological Project(Nos.2021DJ07,2019E-2601,2019B-0301).
文摘The Carboniferous volcanic reservoirs in Junggar Basin contain rich hydrocarbon resources,implying a great exploration potential,so that they have become a key replacement target for“three-dimensional exploration”.The study on the Carboniferous volcanic reservoirs and their hydrocarbon accumulation elements is significant for clarifying the orientation for exploration.In this paper,based on 37 reserves reports and 3200 reservoir test data,the Carboniferous volcanic reservoirs in Junggar Basin were discussed from the prospective of lithology and lithofacies,physical properties,reservoir types,main controls on hydrocarbon accumulation,and hydrocarbon accumulation patterns.It is found that the Carboniferous in the basin is mostly in the multi-island ocean-volcanic island arc structural-sedimentary environment,so it is geologically eligible for forming in-situ volcanic reservoirs.The volcanic rocks are:(1)mostly distributed along deep and large faults,with the lithology and lithofacies controlled by volcanic architectures;(2)dominantly lava,followed by volcaniclastic lava and volcaniclastic rock;(3)distributed in the periphery of hydrocarbon-generating sag and within the source rocks horizontally,and concentrated in the weathering crust at the top longitudinally,possibly leading to reworked weathering crust reservoir;and(4)liable to form inner reservoirs.The volcanic reservoirs can be concluded into four hydrocarbon accumulation patterns,i.e.,self-generating&self-storing in paleo-uplift and vertical migration,self-generating&self-storing in paleo-uplift and lateral migration,young-generating&old-storing in fault zone and vertical migration,and young-generating&old-storing in paleo-uplift and lateral migration.Future exploration will focus on the effective source rock development and hydrocarbon supply zones and the selfgenerating&self-storing and young-generating&old-storing patterns.The exploration prospects are determined to be the Ludong-Wucaiwan-Baijiahai slope belt and the southern slope belt of the Shaqi uplift(self-generating&self-storing pattern)in eastern Junggar,and the fault and nasal arch zone at the northwestern margin and the nasal arch zone(deep and large structure)in the Luxi area(younggenerating&old-storing pattern)in western Junggar.
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 Sichuan Province Regional Innovation Cooperation Project(21QYCX0048)Sinopec Science and Technology Department Project(P21048-3)。
文摘According to the complex differential accumulation history of deep marine oil and gas in superimposed basins,the Lower Paleozoic petroleum system in Tahe Oilfield of Tarim Basin is selected as a typical case,and the process of hydrocarbon generation and expulsion,migration and accumulation,adjustment and transformation of deep oil and gas is restored by means of reservoine-forming dynamics simulation.The thermal evolution history of the Lower Cambrian source rocks in Tahe Oilfield reflects the obvious differences in hydrocarbon generation and expulsion process and intensity in different tectonic zones,which is the main reason controlling the differences in deep oil and gas phases.The complex transport system composed of strike-slip fault and unconformity,etc.controlled early migration and accumulation and late adjustment of deep oil and gas,while the Middle Cambrian gypsum-salt rock in inner carbonate platform prevented vertical migration and accumulation of deep oil and gas,resulting in an obvious"fault-controlled"feature of deep oil and gas,in which the low potential area superimposed by the NE-strike-slip fault zone and deep oil and gas migration was conducive to accumulation,and it is mainly beaded along the strike-slip fault zone in the northeast direction.The dynamic simulation of reservoir formation reveals that the spatio-temporal configuration of"source-fault-fracture-gypsum-preservation"controls the differential accumulation of deep oil and gas in Tahe Oilfield.The Ordovician has experienced the accumulation history of multiple periods of charging,vertical migration and accumulation,and lateral adjustment and transformation,and deep oil and gas have always been in the dynamic equilibrium of migration,accumulation and escape.The statistics of residual oil and gas show that the deep stratum of Tahe Oilfield still has exploration and development potential in the Ordovician Yingshan Formation and Penglaiba Formation,and the Middle and Upper Cambrian ultra-deep stratum has a certain oil and gas resource prospect.This study provides a reference for the dynamic quantitative evaluation of deep oil and gas in the Tarim Basin,and also provides a reference for the study of reservoir formation and evolution in carbonate reservoir of paleo-craton basin.
基金Supported by the National Natural Science Foundation of China(42090022)。
文摘Based on the situation and progress of marine oil/gas exploration in the Sichuan Basin,SW China,the whole petroleum system is divided for marine carbonate rocks of the basin according to the combinations of hydrocarbon accumulation elements,especially the source rock.The hydrocarbon accumulation characteristics of each whole petroleum system are analyzed,the patterns of integrated conventional and unconventional hydrocarbon accumulation are summarized,and the favorable exploration targets are proposed.Under the control of multiple extensional-convergent tectonic cycles,the marine carbonate rocks of the Sichuan Basin contain three sets of regional source rocks and three sets of regional cap rocks,and can be divided into the Cambrian,Silurian and Permian whole petroleum systems.These whole petroleum systems present mainly independent hydrocarbon accumulation,containing natural gas of affinity individually.Locally,large fault zones run through multiple whole petroleum systems,forming a fault-controlled complex whole petroleum system.The hydrocarbon accumulation sequence of continental shelf facies shale gas accumulation,marginal platform facies-controlled gas reservoirs,and intra-platform fault-and facies-controlled gas reservoirs is common in the whole petroleum system,with a stereoscopic accumulation and orderly distribution pattern.High-quality source rock is fundamental to the formation of large gas fields,and natural gas in a whole petroleum system is generally enriched near and within the source rocks.The development and maintenance of large-scale reservoirs are essential for natural gas enrichment,multiple sources,oil and gas transformation,and dynamic adjustment are the characteristics of marine petroleum accumulation,and good preservation conditions are critical to natural gas accumulation.Large-scale marginal-platform reef-bank facies zones,deep shale gas,and large-scale lithological complexes related to source-connected faults are future marine hydrocarbon exploration targets in the Sichuan Basin.
基金Supported by the PetroChina Major Science and Technology Project (2016E0201,2021ZZ10,2021DJ0101)。
文摘Based on the oil and gas exploration practice in the Songliao Basin,combined with the latest exploration and development data such as seismic,well logging and geochemistry,the basic geological conditions,oil and gas types and distribution characteristics,reservoir-forming dynamics,source-reservoir relationship and hydrocarbon accumulation model of the whole petroleum system in shallow and medium strata in the northern part of Songliao Basin are systematically studied.The shallow-medium strata in northern Songliao Basin have the conditions for the formation of whole petroleum system,with sufficient oil and gas sources,diverse reservoir types and well-developed transport system,forming a whole petroleum system centered on the source rocks of the Cretaceous Qingshankou Formation.Different types of oil and gas resources in the whole petroleum system are correlated with each other in terms of depositional system,lithologic association and physical property changes,and they,to a certain extent,have created the spatial framework with orderly symbiosis of shallow-medium conventional oil reservoirs,tight oil reservoirs and shale oil reservoirs in northern Songliao Basin.Vertically,the resources are endowed as conventional oil above source,shale oil/tight oil within source,and tight oil below source.Horizontally,conventional oil,tight oil,interlayer-type shale oil,and pure shale-type shale oil are developed in an orderly way,from the margin of the basin to the center of the depression.Three hydrocarbon accumulation models are recognized for the whole petroleum system in northern Songliao Basin,namely,buoyancy-driven charging of conventional oil above source,retention of shale oil within source,and pressure differential-driven charging of tight oil below source.
文摘Formation of coal seam and coal-rich zone is an integrated result of a series of factors in coal accumulation process. The coal accumulation system is an architectural aggregation of coal accumulation factors. It can be classified into 4 levels： the global coal accumulation super-system, the coal accumulation domain mega-system, the coal accumulation basin system, and the coal seam or coal seam set sub-system. The coal accumulation process is an open, dynamic, and grey system, and is meanwhile a system with such natures as aggregation, relevance, entirety, purpose-orientated, hierarchy, and environment adaptability. In this paper, we take coal accumulation process as a system to study origin of coal seam and coal-rich zone; and we will discuss a methodology of the systematic analysis of coal accumulation process. As an example, the Ordos coal basin was investigated to elucidate the application of the method of the coal accumulation system analysis.
基金supported by the National Natural Foundation Project Polygonal Fault Genetic Mechanism and its Reservoir Controlling Mechanism in Rift Basin (number: 41072163) financial aid
文摘A study of faults and their control of deep gas accumulations has been made on the basis of dividing fault systems in the Xujiaweizi area. The study indicates two sets of fault systems are developed vertically in the Xujiaweizi area, including a lower fault system and an upper fault system. Formed in the period of the Huoshiling Formation to Yingcheng Formation, the lower fault system consists of five fault systems including Xuxi strike-slip extensional fault system, NE-trending extensional fault system, near-EW-trending regulating fault system, Xuzhong strike-slip fault system and Xudong strike-slip fault system. Formed in the period of Qingshankou Formation to Yaojia Formation, the upper fault system was affected mainly by the boundary conditions of the lower fault system, and thus plenty of muiti-directionally distributed dense fault zones were formed in the T2 reflection horizon. The Xuxi fault controlled the formation and distribution of Shahezi coal-measure source rocks, and Xuzhong and Xndong faults controlled the formation and distribution of volcanic reservoirs of Y1 Member and Y3 Member, respectively. In the forming period of the upper fault system, the Xuzhong fault was of successive strong activities and directly connected gas source rock reservoirs and volcanic reservoirs, so it is a strongly-charged direct gas source fault. The volcanic reservoir development zones of good physical properties that may be found near the Xuzhong fault are the favorable target zones for the next exploration of deep gas accumulations in Xujiaweizi area.
