Extensive research has been conducted on remaining oil in the Daqing Oilfield during high water cuts’late stage,but few studies have offered multi-level analyses from both macro and micro perspectives for remaining o...Extensive research has been conducted on remaining oil in the Daqing Oilfield during high water cuts’late stage,but few studies have offered multi-level analyses from both macro and micro perspectives for remaining oil under varying formation conditions and displacement methods.This article focuses on the remaining oil in the S,P,and G reservoirs of Daqing Oilfield by employing the frozen section analysis method on the cores from the S,P,and G oil layers.The research identifies patterns among them,revealing that the Micro Remaining Oil types in these cores primarily include pore surface thin film,corner,throat,cluster,intergranular adsorption,and particle adsorption.Among these,intergranular adsorption contains the highest amount of remaining oil(the highest proportion reaches 60%)and serves as the main target for development potential.The overall distribution pattern of the Micro Remaining Oil in the S,P,and G oil layers shows that as flooding intensity increases,the amount of free-state remaining oil gradually decreases,while bound-state remaining oil gradually increases.The study also examines eight typical coring wells for macroscopic remaining oil,finding four main types in the reservoir:interlayer difference,interlayer loss,interlayer interference,and injection-production imperfect types.Among these,the injection-production imperfect type has the highest remaining oil content and is the primary target for development potential.Analyzing the reservoir utilization status and oil flooding efficiency reveals that as water flooding intensifies,the oil displacement efficiency of the oil layer gradually decreases,while the efficiency of oil layer displacement improves.Strongly flooded cores exhibit less free-state remaining oil than weakly flooded cores,making displacement more challenging.This study aims to provide a foundation and support for the development of remaining oil in the S,P,and G oil layers.展开更多
This study discussed the division of matrix- and fracture-type shale oils in the Jiyang Depression, and proposed the concept of fracture development coefficient. The fracture development coefficient is defined as the ...This study discussed the division of matrix- and fracture-type shale oils in the Jiyang Depression, and proposed the concept of fracture development coefficient. The fracture development coefficient is defined as the ratio of fault throw to the distance between a shale oil well and the nearest fault. Based on CO_2 content, state of water, oil production and logging response of shale oil formations, the classification of shale oils was established, i.e., a fracture-type shale oil well has a fracture development coefficient greater than 0.2, while a matrix-type one has a fracture development coefficient less than 0.2. Furthermore, the key control factors of matrix- and fracture-type shale oil enrichment were analyzed using typical anatomical and statistical methods. For matrix-type shale oil enrichment, these factors are lithofacies, total organic carbon（TOC）, shale porosity and abnormal pressure; for fracture-type shale oil enrichment, they are lithofacies, extent of fracture development, and abnormal pressure. This study also first described the differences between matrix- and fracture-type shale oils. The results provide reference for the exploration of terrestrial faulted basins in eastern China.展开更多
Rational determination and reduction of local energy loss of oil flow at pipe junctions are of important significance to improve hydraulic pipeline＇s work efficiency, especially for complex hydraulic pipeline connect...Rational determination and reduction of local energy loss of oil flow at pipe junctions are of important significance to improve hydraulic pipeline＇s work efficiency, especially for complex hydraulic pipeline connected by isodiametric T-type ducts with sharp comers to get combined and divided flow. From this point of view, the formulae of resistance loss for combined flow and divided flow through isodiametric T-type duct with sharp comers as well as the correlations of resistance loss coefficients in the branches of the duct are derived using energy method. On this basis, resistance characteristics of hydraulic oil in the duct are obtained by numerical simulation of different flow modes, which are commonly applied in hydraulic pipelines, using computational fluid dynamics （CFD） method, and the reasons for the resistance loss are analyzed based on the pressure change mechanism in the flow field. A part of simulation results was validated with the reference data. The research shows that for combined flows the resistance loss of symmetrical is lower than that of unsymmetrical to obtain low speed in common branch, but to gain high speed is quite the contrary, for divided flows, the symmetrical is always a reasonable choice to reduce resistance loss. These conclusions can be applied to optimize the design of hydraulic pipeline.展开更多
Crude oil samples taken from the southern part of western Qaidam Basin were analyzed with GC/MS in order to understand the geochemical characteristics of crude oils.The results reveal that most crude oils are characte...Crude oil samples taken from the southern part of western Qaidam Basin were analyzed with GC/MS in order to understand the geochemical characteristics of crude oils.The results reveal that most crude oils are characterized by high abundance of gammacerane and C35 homohopane,which are the representative characteristics of saline lacustrine crude oils.Based on the variation of the ratios of gammacerane/C30 hopane(G/H) and C35 homoho-pane/C34 homohopane(C35/C34H),two crude oil groups,A and B,are identified.Group-A crude oils mainly occurr in the north of the study area,with higher ratios of G/H(>0.8) and C35/C34H(>1.2),whereas group-B crude oils,selected from the south of the study area,show lower ratios of G/H(<0.8) and C35/C34H(<1.0).In addition,group-A crude oils are distinguished into three subgroups in accordance with their different ratios of G/H and C35/C34H and different distribution characteristics of n-alkanes,isoprenoids and steranes.These may be helpful for understanding the distribution characteristics of crude oils in the southern part of western Qaidam Basin and providing clues to the forthcoming exploration of crude oils and gas.展开更多
The current study tested the gas component and carbon isotopic composition of gas samples from 6 oilgas fields at the northern margin of Qaidam Basin, and established a chart to quantitatively identify the mixing rati...The current study tested the gas component and carbon isotopic composition of gas samples from 6 oilgas fields at the northern margin of Qaidam Basin, and established a chart to quantitatively identify the mixing ratio of source-mixed gas. Besides, this research quantitatively investigated the natural gas generated by different types of organic matter. The results show that different ratios of source-mixed gas exist in the 6 oil-gas fields at the northern margin of Qaidam Basin. Among them, Mabei has the highest mixing ratio of coal-type gas, followed by Nanbaxian, Mahai, Lenghu-4, Lenghu-3 and Lenghu-5, with the ratios of coal-type gas 91%, 87%, 83%, 66%, 55% and 36%, respectively. Lenghu-3 and Lenghu-4 oil-gas fields were mainly filled by coal-type gas earlier. For Lenghu-3, the gas was mainly generated from low matured source rocks in lower Jurassic Series of Lengxi sub-sag. For Lenghu-4, the gas was mainly generated from humus-mature source rocks in lower Jurassic Series of the northern slope of Kunteyi sub-sag. Gas in Lenghu-5 was mainly later filled oil-type gas, which was generated from high matured sapropelics in lower Jurassic Series of Kunteyi sub-sag. Earlier filled coal-type gas was the main part of Mahai, Nanbaxian and Mabei oil-gas fields. Gas source of Mahai was mainly generated from high mature humics in lower Jurassic Series of Yibei sub-sag; for Nanbaxian, the gas was mainly generated from high matured humics in middle-lower Jurassic Series of Saishiteng sub-sag; for Mabei, the gas was mainly generated from humus-mature source rocks in middle Jurassic Series of Yuqia sub-sag.展开更多
Eight different types of Bologna type cooked sausages apart from the control were produced in order to reduce the fat content (15%, 30%, 45%), replace the animal fat by olive oil (3%, 6.5% and 10%) as well as concomit...Eight different types of Bologna type cooked sausages apart from the control were produced in order to reduce the fat content (15%, 30%, 45%), replace the animal fat by olive oil (3%, 6.5% and 10%) as well as concomitant reduction and replacement of animal fat (30% of fat reduction with 2% of olive oil as an animal fat replacer). Quality attributes such as texture, water binding and color were monitored. Texture and water binding of fat reduced and fat replaced samples were quite similar to the control while color was strongly affected by the fat reduction and replacement. Fat reduction led to a redder cooked sausage and the addition of olive oil to a more yellow product. Chemical analysis revealed no major changes among samples apart from protein and fat content and fatty acid profile. Noteworthy, cooked sausage with more than 6.5% of olive oil achieved the World Health Organization’s recommendation on the nutritional fat index ((polyunsaturated + monounsaturated)/saturated fatty acid ≥ 2) which is very relevant to the development of healthier formulations. Cooked sausages with 45% of fat reduction and 30% fat reduced with 2% of olive oil were considered as the best by the panelists, which in addition had a balanced nutritional content by a lower caloric content. We concluded that fat reduction (up to 45%) and replacement (up to 10%) are possible with acceptable sensory quality and improved nutritional composition. When replacing animal fats by plant oils, the color of the product, which has a strong influence on the sensory acceptability of Bologna type cooked sausages, is affected. Therefore it must be controlled for a proper product development of meat products containing vegetable oils.展开更多
The diversity of sandstone diagenesis mechanisms caused by the complex geological conditions of oil/gas basins in China could hardly be reasonably explained by the traditional concept of burial diagenesis. Three genes...The diversity of sandstone diagenesis mechanisms caused by the complex geological conditions of oil/gas basins in China could hardly be reasonably explained by the traditional concept of burial diagenesis. Three genesis types of thermal diagenesis, tectonic diagenesis and fluid diagenesis are presented on the basis of the dynamic environment of the oil/gas basins and.the controlling factors and mechanisms of sandstone diagenesis. Thermal diagenesis of sandstone reservoirs is related not only to the effect of formation temperature on diagenesis, but also to the significant changes in diagenesis caused by geothermal gradients. The concept of thermal compaction is presented. Thermal compaction becomes weaker with increasing depth and becomes stronger at a higher geothermal gradient. At the same formation temperature, the sandstone porosity in the region with a lower geothermal gradient is e^0.077＋0.0042T times higher than that in the region with a higher geothermal gradient. Both sudden and gradual changes are observed in diagenetic evolution caused by structural deformation. Average sandstone compaction increased by 0.1051% for every 1.0MPa increase of lateral tectonic compressional stress, while late tectonic napping helped to preserve a higher porosity of underlying sandstone reservoir. Fluid diagenesis is a general phenomenon. The compaction caused by fluid properties is significant. The coarser the grain size, the stronger the fluid effect on compaction. The greater the burial depth, the weaker the fluid effect on compaction for the specific reservoir lithology and the greater the difference in the fluid effects on compaction between different grain sizes.展开更多
The relationship between NaCl concentration and the phase change behavior of microemulsion of anionic surfactant was characterized by the salinity scan experiments.The wettability of WinsorⅠtype surfactant solution(W...The relationship between NaCl concentration and the phase change behavior of microemulsion of anionic surfactant was characterized by the salinity scan experiments.The wettability of WinsorⅠtype surfactant solution(WⅠsolution)and the effect of NaCL concentration on phase change behavior of WⅠsolution and imbibition in oil-wet porous media were investigated by microfluidic experiments in this study.The WⅠsolution and WinsorⅠtype microemulsion are similar in wetting phase with stronger wettability than other phases.Two main mechanisms of WⅠsolution enhancing imbibitions recovery in oil wet porous media are the wetting phase drive and residual oil solubilization.Under the salinity condition of WinsorⅠtype microemulsion,the NaCl concentration has strong impact on the imbibition mechanism of WⅠsolution,the higher the NaCl concentration,the complex the imbibition process and the higher the imbibition efficiency will be.The NaCl concentration has strong impact on the solubilization ability to oil of the WⅠsolution,the higher the NaCl concentration,the stronger the solubility of the WⅠsolution to residual oil will be.展开更多
Significant scientific and economic benefits may be derived from investigating the best choice of catalyst in the alkyd resin synthesis. The effect of catalyst type and concentration on the production of alkyd resin u...Significant scientific and economic benefits may be derived from investigating the best choice of catalyst in the alkyd resin synthesis. The effect of catalyst type and concentration on the production of alkyd resin using castor seed oil (CSO) was evaluated. Lithium hydroxide, lead (II) oxide, calcium carbonate, sodium hydroxide and calcium oxide were investigated. The fatty acid profile of the raw CSO was determined using GC-MS while structural elucidation of the CSO based alkyd resins was determined using FTIR spectrometry. The CSO modified alkyd resin produced has acid values of 5.0, 5.61, 7.0 8.24 and 11 for lithium hydroxide, lead (II) oxide, calcium carbonate, sodium hydroxide and calcium oxide respectively. The extent of reaction was 95%, 95%, 91%, 89% and 88% for lithium hydroxide, lead (II) oxide, calcium carbonate, sodium hydroxide and calcium oxide respectively at the reaction time of 150 minutes. The alcoholysis reaction completion time was fastest in LiOH followed by PbO, CaCO<sub>3</sub>, NaOH and CaO catalyst. Physico-chemical parameters of the oil and performance evaluation of the alkyd films suggest that they are sustainable materials for surface coating. LiOH shows excellent robustness to expanded process parameters.展开更多
This study aims to clarify the factors influencing oil recovery of surfactant-polymer(SP)flooding and to establish a quantitative calculation model of oil recovery during different displacement stages from water flood...This study aims to clarify the factors influencing oil recovery of surfactant-polymer(SP)flooding and to establish a quantitative calculation model of oil recovery during different displacement stages from water flooding to SP flooding.The conglomerate reservoir of the Badaowan Formation in the seventh block of the Karamay Oilfield is selected as the research object to reveal the start-up mechanism of residual oil and determine the controlling factors of oil recovery through SP flooding experiments of natural cores and microetching models.The experimental results are used to identify four types of residual oil after water flooding in this conglomerate reservoir with a complex pore structure:oil droplets retained in pore throats by capillary forces,oil cluster trapped at the junction of pores and throats,oil film on the rock surface,isolated oil in dead-ends of flow channel.For the four types of residual oil identified,the SP solution can enhance oil recovery by enlarging the sweep volume and improving the oil displacement efficiency.First,the viscosity-increasing effect of the polymer can effectively reduce the permeability of the displacement liquid phase,change the oil-water mobility ratio,and increase the water absorption.Furthermore,the stronger the shear drag force of the SP solution,the more the crude oil in a porous medium is displaced.Second,the surfactant can change the rock wettability and reduce the absorption capacity of residual oil by lowering interfacial tension.At the same time,the emulsification further increases the viscosity of the SP solution,and the residual oil is recovered effectively under the combined effect of the above two factors.For the four start-up mechanisms of residual oil identified after water flooding,enlarging the sweep volume and improving the oil displacement efficiency are interdependent,but their contribution to enhanced oil recovery are different.The SP flooding system primarily enlarges the sweep volume by increasing viscosity of solution to start two kinds of residual oil such as oil droplet retained in pore throats and isolated oil in dead-ends of flow channel,and primarily improves the oil displacement efficiency by lowing interfacial tension of oil phase to start two kinds of residual oil such as oil cluster trapped at the junction of pores and oil film on the rock surface.On this basis,the experimental results of the oil displacement from seven natural cores show that the pore structure of the reservoir is the main factor influencing water flooding recovery,while the physical properties and original oil saturation have relatively little influence.The main factor influencing SP flooding recovery is the physical and chemical properties of the solution itself,which primarily control the interfacial tension and solution viscosity in the reservoir.The residual oil saturation after water flooding is the material basis of SP flooding,and it is the second-most dominant factor controlling oil recovery.Combined with the analysis results of the influencing factors and reservoir parameters,the water flooding recovery index and SP flooding recovery index are defined to further establish quantitative calculation models of oil recovery under different displacement modes.The average relative errors of the two models are 4.4%and 2.5%,respectively;thus,they can accurately predict the oil recovery of different displacement stages and the ultimate reservoir oil recovery.展开更多
The Bohai Bay Basin is a typical oil-prone basin, in which natural gas geological reserves have a small proportion. In this basin, the gas source rock is largely medium-deep lake mudstone with oil-prone type Ⅱ2-Ⅱ1 k...The Bohai Bay Basin is a typical oil-prone basin, in which natural gas geological reserves have a small proportion. In this basin, the gas source rock is largely medium-deep lake mudstone with oil-prone type Ⅱ2-Ⅱ1 kerogens, and natural gas preservation conditions are poor due to active late tectonic movements. The formation conditions of large natural gas fields in the Bohai Bay Basin have been elusive. Based on the exploration results of Bohai Bay Basin and comparison with large gas fields in China and abroad, the formation conditions of conventional large-scale natural gas reservoirs in the Bohai Bay Basin were examined from accumulation dynamics, structure and sedimentation. The results show that the formation conditions of conventional large natural gas reservoirs in Bohai Bay Basin mainly include one core element and two key elements. The core factor is the strong sealing of Paleogene "quilt-like" overpressure mudstone. The two key factors include the rapid maturation and high-intensity gas generation of source rock in the late stage and large scale reservoir. On this basis, large-scale nature gas accumulation models in the Bohai Bay Basin have been worked out, including regional overpressure mudstone enriching model, local overpressure mudstone depleting model, sand-rich sedimentary subsag depleting model and late strongly-developed fault depleting model. It is found that Bozhong sag, northern Liaozhong sag and Banqiao sag have favorable conditions for the formation of large-scale natural gas reservoirs, and are worth exploring. The study results have important guidance for exploration of large scale natural gas reservoirs in the Bohai Bay Basin.展开更多
Recently,exploration breakthroughs have been made in the Lower Cretaceous sandstone reservoirs in the Doseo Basin,but the identification of reservoir fluid property is difficult due to variable reservoir lithology,com...Recently,exploration breakthroughs have been made in the Lower Cretaceous sandstone reservoirs in the Doseo Basin,but the identification of reservoir fluid property is difficult due to variable reservoir lithology,complex oil-water contact within and faint responses of the oil zone,which causes the lower accuracy of reservoir fluid property identification with conventional mudlogging and wirelogging techniques.Applying the geochemical logging,fluorescent logging,mud logging and cutting logging technology,in combination with formation test data,this paper distinguishes the crude oil types,analyzes the logging response characteristics of oil zone after water washing,and establishes the interpretation charts and parameter standards for reservoir fluid properties.The crude oil can be divided into two types,namely viscous-heavy and thin-light,based on total hydrocarbon content and component concentration tested by mud logging,features of pyrolysis gas chromatogram and fluorescence spectroscopy.The general characteristics of oil layers experienced water washing include the decrease of total hydrocarbon content and component concentration from mud logging,the decrease of S1 and PS values from geochemical logging,the decrease of hydrocarbon abundance and absence of some light components in pyrolysis gas chromatogram,and the decrease of fluorescence area and intensity from fluorescence logging.According to crude oil types,the cross plots of S1 versus peak-baseline ratio,and the cross plots of rock wettability versus fluorescence area ratio are drawn and used to interpret reservoir fluid property.Meanwhile,the standards of reservoir fluid parameter are established combining with the parameters of PS and the parameters in above charts,and comprehensive multiparameter correlation in both vertical and horizontal ways is also performed to interpret reservoir fluid property.The application in the Doseo Basin achieved great success,improving interpretation ability of fluid property in the reservoir with complex oil-water contact,and also provided technical reference for the efficient exploration and development of similar reservoirs.展开更多
Based on the geological and geochemical analysis of potential source rocks in different formations and the classification of crude oil types,combined with the hydrocarbon generation thermal simulation experiments,the ...Based on the geological and geochemical analysis of potential source rocks in different formations and the classification of crude oil types,combined with the hydrocarbon generation thermal simulation experiments,the source,genesis,and distribution of different types of oils in the Mahu large oil province of the Junggar Basin are investigated.Four sets of potential source rocks are developed in the Mahu Sag.Specifically,the source rocks of the Permian Fengcheng Formation have the highest hydrocarbon generation potential and contain mainly TypesⅡandⅠorganic matters,with a high oil generation capacity.In contrast,the source rocks in other formations exhibit lower hydrocarbon generation potential and contain mainly TypeⅢorganic matter,with dominant gas generation.Oils in the Mahu Sag can be classified as three types:A,B and C,which display ascending,mountainous and descending C_(20)-C_(21)-C_(23)tricyclic terpenes abundance patterns in sequence,and gradually increasing relative content of tricyclic terpenes and sterane isomerization parameters,indicating an increasing oil maturity.Different types of oils are distributed spatially in an obviously orderly manner:Type A oil is close to the edge of the sag,Type C oil is concentrated in the center of the sag,and Type B oil lies in the slope area between Type A and Type C.The results of oil-source correlation and thermal simulation experiments show that the three types of oils come from the source rocks of the Fengcheng Formation at different thermal evolution stages.This new understanding of the differential genesis of oils in the Mahu Sag reasonably explains the source,distribution,and genetic mechanism of the three types of oils.The study results are of important guidance for the comprehensive and three-dimensional oil exploration,the identification of oil distribution in the total petroleum system,and the prediction of favorable exploration areas in the Mahu Sag.展开更多
The region around the Karamay-Baikouquan （Ke-Bai） overthrust belt is the richest in hydrocarbon accumulation in the Junggar Basin. Previous research has indicated that oil in the region came from the Fengcheng Forma...The region around the Karamay-Baikouquan （Ke-Bai） overthrust belt is the richest in hydrocarbon accumulation in the Junggar Basin. Previous research has indicated that oil in the region came from the Fengcheng Formation in the Mahu Depression to the northeast of the region, but the oil distribution around the Mahu Depression is remarkably uneven. Large amounts of oil have been found in the Ke-Bai overthrust belt to the west of the depression and only some small oilfields have been discovered in the eastern margin of the depression. This uneven distribution revealed that the oil source of the Ke- Bai region might not be from the Mahu Depression. The oil type distribution and the oil migration pattern revealed in this paper showed that there may be another oil source under the Karamay overthrust. Based on geochemical data, the oil was classified into two types from the sterane and terpane characteristics. Type A oil was mainly distributed in the Huwan area and blocks V and VIII of the Karamay Oilfield in the southern part of the region, while type B oil was mainly distributed in the Baikouquan Oilfield in the northern part of the region. In addition, oil migration pathways and direction were determined by the values of diasterane / regular sterane and C30 moretane / C30 hopane ratios. It is shown that the oil of Huwan area on the hanging wall of the overthrust was mainly charged along the overthrust fault surfaces and then migrated to the west, whereas the oil in blocks V and VIII on the foot wall of the overthrust came from the Mahu Depression in the east. As a result, there may be at least two hydrocarbon source kitchens in the study area. The hydrocarbons in the blocks V and VIII on the footwall of the overthrust belt and in the Baikouquan Oilfield mainly came from the Fengcheng Formation in the Mahu Depression, and the hydrocarbons in the Huwan area on the hanging wall of the overthrust belt may come from another hydrocarbon source kitchen below the overthrust. This recognition indicates that there is substantial exploration potential in the deep Carboniferous strata on the hanging wall of the overthrust belt.展开更多
Novel tetracyclic terpanes X and Y namely C24-des-A-oleanane and C27 tetracyclic terpane were detected in crude oils and source rock extracts in Zhu 1 depression in Pearl River Mouth Basin by GC-MS analysis technology...Novel tetracyclic terpanes X and Y namely C24-des-A-oleanane and C27 tetracyclic terpane were detected in crude oils and source rock extracts in Zhu 1 depression in Pearl River Mouth Basin by GC-MS analysis technology. These compounds are similar to oleanane in the structure, and their relative abundance in m/z 191 partial mass cbromatogram has a good correlation with oleanane. Here compounds X and Y are considered to be derived from the des-A degradation of oleanoid precursor. The ratio of X/（X-I-C24） and Y/（Y-I-C24） increase with the increasing inputs of terrigenous organic matter in crude oils. Wenchang Formation middle-deep lacustrine source rocks with planktonic algae organic matter inputs and oil generating from it contain low abundance of compounds X and Y, while Enping Formation coal measures source rocks with terrigenous higher plants organic matter inputs and oil generating from it usually have higher compounds X and Y. In general when two terrigenous compounds C19 tricyclic terpane and bicadinane-T are high in crude oils, there are also a corresponding high abundant compounds X and Y. Relative abundance of compounds X and Y is closely related to the source of organic matter and it can indicate the input of terrigenous organic matter.展开更多
Based on the production curves,changes in hydrocarbon composition and quantities over time,and production systems from key trial production wells in lacustrine shale oil areas in China,fine fraction cutting experiment...Based on the production curves,changes in hydrocarbon composition and quantities over time,and production systems from key trial production wells in lacustrine shale oil areas in China,fine fraction cutting experiments and molecular dynamics numerical simulations were conducted to investigate the effects of changes in shale oil composition on macroscopic fluidity.The concept of“component flow”for shale oil was proposed,and the formation mechanism and conditions of component flow were discussed.The research reveals findings in four aspects.First,a miscible state of light,medium and heavy hydrocarbons form within micropores/nanopores of underground shale according to similarity and intermiscibility principles,which make components with poor fluidity suspended as molecular aggregates in light and medium hydrocarbon solvents,such as heavy hydrocarbons,thereby decreasing shale oil viscosity and enhancing fluidity and outflows.Second,small-molecule aromatic hydrocarbons act as carriers for component flow,and the higher the content of gaseous and light hydrocarbons,the more conducive it is to inhibit the formation of larger aggregates of heavy components such as resin and asphalt,thus increasing their plastic deformation ability and bringing about better component flow efficiency.Third,higher formation temperatures reduce the viscosity of heavy hydrocarbon components,such as wax,thereby improving their fluidity.Fourth,preservation conditions,formation energy,and production system play important roles in controlling the content of light hydrocarbon components,outflow rate,and forming stable“component flow”,which are crucial factors for the optimal compatibility and maximum flow rate of multi-component hydrocarbons in shale oil.The component flow of underground shale oil is significant for improving single-well production and the cumulative ultimate recovery of shale oil.展开更多
The Linnan subsag is the main oil producer of the Linpan oil zone. Based on the oil group composition,gas chromatography data and biomarker analysis,it was indicated that crude oils from different oilfields varied gre...The Linnan subsag is the main oil producer of the Linpan oil zone. Based on the oil group composition,gas chromatography data and biomarker analysis,it was indicated that crude oils from different oilfields varied greatly in group composition and showed obvious heterogeneities in the aspects of precursor type,crude oil maturity and hydrocarbon depositional environment. According to the characteristics of source rocks,three oil populations can be distinguished,i.e.,the southern,northern and transitional oil populations. Furthermore,on the basis of post-reservoir reworking processes,the medium conditions of hydrocarbon-generating environment and differences in maturity,six oil families and twelve sub-families were distinquished. An integrated study suggested that the fac-tors leading to such heterogeneities in crude oil composition mainly include different source rocks,multi-stage oil/gas charging,geo-chromatographic effects during oil/gas migration,reservoir heterogeneities and various post-reservoir secondary alterations.展开更多
The uplift is a positive structural unit of the crust. It is an important window for continental dynamics owing to its abundant structural phenomena, such as fault, fold, unconformity and denudation of strata. Meanwhi...The uplift is a positive structural unit of the crust. It is an important window for continental dynamics owing to its abundant structural phenomena, such as fault, fold, unconformity and denudation of strata. Meanwhile, it is the very place to store important minerals like oil, natural gas, coal and uranium. Giant and large-scale oil and gas fields in China, such as the Daqing Oilfield, Lunnan-Tahe Oilfield, Penglai 19-3 Oilfield, Puguang Gas Field and Jingbian Gas Field, are developed mainly on uplifts. Therefore, it is the main target both for oil and gas exploration and for geological study. The uplift can be either a basement uplift, or one developed only in the sedimentary cover. Extension, compression and wrench or their combined forces may give rise to uplifts. The development process of uplifting, such as formation, development, dwindling and destruction, can be taken as the uplifting cycle. The uplifts on the giant Precambrian cratons are large in scale with less extensive structural deformation. The uplifts on the medium- and small-sized cratons or neo-cratons are formed in various shapes with strong structural deformation and complicated geological structure. Owing to changes in the geodynamic environment, uplift experiences a multi-stage or multi-cycle development process. Its geological structure is characterized in superposition of multi-structural layers. Based on the basement properties, mechanical stratigraphy and development sequence, uplifts can be divided into three basic types-the succession, superposition and destruction ones. The succession type is subdivided into the maintaining type and the lasting type. The superposition type can be subdivided into the composite anticlinal type, the buried-hill draped type, the faulted uplift type and the migration type according to the different scales and superimposed styles of uplifts in different cycles. The destruction type is subdivided into the tilting type and the negative inverted type. The development history of uplifts and their controlling effects on sedimentation and fluids are quite different from one another, although the uplifts with different structural types store important minerals. Uplifts and their slopes are the main areas for oil and gas accumulation. They usually become the composite oil and gas accumulation zones （belts） with multiple productive formations and various types of oil and gas reservoirs.展开更多
文摘Extensive research has been conducted on remaining oil in the Daqing Oilfield during high water cuts’late stage,but few studies have offered multi-level analyses from both macro and micro perspectives for remaining oil under varying formation conditions and displacement methods.This article focuses on the remaining oil in the S,P,and G reservoirs of Daqing Oilfield by employing the frozen section analysis method on the cores from the S,P,and G oil layers.The research identifies patterns among them,revealing that the Micro Remaining Oil types in these cores primarily include pore surface thin film,corner,throat,cluster,intergranular adsorption,and particle adsorption.Among these,intergranular adsorption contains the highest amount of remaining oil(the highest proportion reaches 60%)and serves as the main target for development potential.The overall distribution pattern of the Micro Remaining Oil in the S,P,and G oil layers shows that as flooding intensity increases,the amount of free-state remaining oil gradually decreases,while bound-state remaining oil gradually increases.The study also examines eight typical coring wells for macroscopic remaining oil,finding four main types in the reservoir:interlayer difference,interlayer loss,interlayer interference,and injection-production imperfect types.Among these,the injection-production imperfect type has the highest remaining oil content and is the primary target for development potential.Analyzing the reservoir utilization status and oil flooding efficiency reveals that as water flooding intensifies,the oil displacement efficiency of the oil layer gradually decreases,while the efficiency of oil layer displacement improves.Strongly flooded cores exhibit less free-state remaining oil than weakly flooded cores,making displacement more challenging.This study aims to provide a foundation and support for the development of remaining oil in the S,P,and G oil layers.
基金supported by the National Basic Research Program of China(973 Program)(Grant No2014CB239104)
文摘This study discussed the division of matrix- and fracture-type shale oils in the Jiyang Depression, and proposed the concept of fracture development coefficient. The fracture development coefficient is defined as the ratio of fault throw to the distance between a shale oil well and the nearest fault. Based on CO_2 content, state of water, oil production and logging response of shale oil formations, the classification of shale oils was established, i.e., a fracture-type shale oil well has a fracture development coefficient greater than 0.2, while a matrix-type one has a fracture development coefficient less than 0.2. Furthermore, the key control factors of matrix- and fracture-type shale oil enrichment were analyzed using typical anatomical and statistical methods. For matrix-type shale oil enrichment, these factors are lithofacies, total organic carbon（TOC）, shale porosity and abnormal pressure; for fracture-type shale oil enrichment, they are lithofacies, extent of fracture development, and abnormal pressure. This study also first described the differences between matrix- and fracture-type shale oils. The results provide reference for the exploration of terrestrial faulted basins in eastern China.
基金supported by Hebei Provincial Natural Science Foundation of China (Grant No. 503292)
文摘Rational determination and reduction of local energy loss of oil flow at pipe junctions are of important significance to improve hydraulic pipeline＇s work efficiency, especially for complex hydraulic pipeline connected by isodiametric T-type ducts with sharp comers to get combined and divided flow. From this point of view, the formulae of resistance loss for combined flow and divided flow through isodiametric T-type duct with sharp comers as well as the correlations of resistance loss coefficients in the branches of the duct are derived using energy method. On this basis, resistance characteristics of hydraulic oil in the duct are obtained by numerical simulation of different flow modes, which are commonly applied in hydraulic pipelines, using computational fluid dynamics （CFD） method, and the reasons for the resistance loss are analyzed based on the pressure change mechanism in the flow field. A part of simulation results was validated with the reference data. The research shows that for combined flows the resistance loss of symmetrical is lower than that of unsymmetrical to obtain low speed in common branch, but to gain high speed is quite the contrary, for divided flows, the symmetrical is always a reasonable choice to reduce resistance loss. These conclusions can be applied to optimize the design of hydraulic pipeline.
文摘Crude oil samples taken from the southern part of western Qaidam Basin were analyzed with GC/MS in order to understand the geochemical characteristics of crude oils.The results reveal that most crude oils are characterized by high abundance of gammacerane and C35 homohopane,which are the representative characteristics of saline lacustrine crude oils.Based on the variation of the ratios of gammacerane/C30 hopane(G/H) and C35 homoho-pane/C34 homohopane(C35/C34H),two crude oil groups,A and B,are identified.Group-A crude oils mainly occurr in the north of the study area,with higher ratios of G/H(>0.8) and C35/C34H(>1.2),whereas group-B crude oils,selected from the south of the study area,show lower ratios of G/H(<0.8) and C35/C34H(<1.0).In addition,group-A crude oils are distinguished into three subgroups in accordance with their different ratios of G/H and C35/C34H and different distribution characteristics of n-alkanes,isoprenoids and steranes.These may be helpful for understanding the distribution characteristics of crude oils in the southern part of western Qaidam Basin and providing clues to the forthcoming exploration of crude oils and gas.
基金Financial support from the National Natural Science Foundation of China (No. 40730422)the Priority Academic Program Development of Jiangsu Higher Education Institutions of Chinadata provided by Jurassic Project Department in Research Institute of Petroleum Exploration and Development of China are gratefully acknowledged
文摘The current study tested the gas component and carbon isotopic composition of gas samples from 6 oilgas fields at the northern margin of Qaidam Basin, and established a chart to quantitatively identify the mixing ratio of source-mixed gas. Besides, this research quantitatively investigated the natural gas generated by different types of organic matter. The results show that different ratios of source-mixed gas exist in the 6 oil-gas fields at the northern margin of Qaidam Basin. Among them, Mabei has the highest mixing ratio of coal-type gas, followed by Nanbaxian, Mahai, Lenghu-4, Lenghu-3 and Lenghu-5, with the ratios of coal-type gas 91%, 87%, 83%, 66%, 55% and 36%, respectively. Lenghu-3 and Lenghu-4 oil-gas fields were mainly filled by coal-type gas earlier. For Lenghu-3, the gas was mainly generated from low matured source rocks in lower Jurassic Series of Lengxi sub-sag. For Lenghu-4, the gas was mainly generated from humus-mature source rocks in lower Jurassic Series of the northern slope of Kunteyi sub-sag. Gas in Lenghu-5 was mainly later filled oil-type gas, which was generated from high matured sapropelics in lower Jurassic Series of Kunteyi sub-sag. Earlier filled coal-type gas was the main part of Mahai, Nanbaxian and Mabei oil-gas fields. Gas source of Mahai was mainly generated from high mature humics in lower Jurassic Series of Yibei sub-sag; for Nanbaxian, the gas was mainly generated from high matured humics in middle-lower Jurassic Series of Saishiteng sub-sag; for Mabei, the gas was mainly generated from humus-mature source rocks in middle Jurassic Series of Yuqia sub-sag.
文摘Eight different types of Bologna type cooked sausages apart from the control were produced in order to reduce the fat content (15%, 30%, 45%), replace the animal fat by olive oil (3%, 6.5% and 10%) as well as concomitant reduction and replacement of animal fat (30% of fat reduction with 2% of olive oil as an animal fat replacer). Quality attributes such as texture, water binding and color were monitored. Texture and water binding of fat reduced and fat replaced samples were quite similar to the control while color was strongly affected by the fat reduction and replacement. Fat reduction led to a redder cooked sausage and the addition of olive oil to a more yellow product. Chemical analysis revealed no major changes among samples apart from protein and fat content and fatty acid profile. Noteworthy, cooked sausage with more than 6.5% of olive oil achieved the World Health Organization’s recommendation on the nutritional fat index ((polyunsaturated + monounsaturated)/saturated fatty acid ≥ 2) which is very relevant to the development of healthier formulations. Cooked sausages with 45% of fat reduction and 30% fat reduced with 2% of olive oil were considered as the best by the panelists, which in addition had a balanced nutritional content by a lower caloric content. We concluded that fat reduction (up to 45%) and replacement (up to 10%) are possible with acceptable sensory quality and improved nutritional composition. When replacing animal fats by plant oils, the color of the product, which has a strong influence on the sensory acceptability of Bologna type cooked sausages, is affected. Therefore it must be controlled for a proper product development of meat products containing vegetable oils.
文摘The diversity of sandstone diagenesis mechanisms caused by the complex geological conditions of oil/gas basins in China could hardly be reasonably explained by the traditional concept of burial diagenesis. Three genesis types of thermal diagenesis, tectonic diagenesis and fluid diagenesis are presented on the basis of the dynamic environment of the oil/gas basins and.the controlling factors and mechanisms of sandstone diagenesis. Thermal diagenesis of sandstone reservoirs is related not only to the effect of formation temperature on diagenesis, but also to the significant changes in diagenesis caused by geothermal gradients. The concept of thermal compaction is presented. Thermal compaction becomes weaker with increasing depth and becomes stronger at a higher geothermal gradient. At the same formation temperature, the sandstone porosity in the region with a lower geothermal gradient is e^0.077＋0.0042T times higher than that in the region with a higher geothermal gradient. Both sudden and gradual changes are observed in diagenetic evolution caused by structural deformation. Average sandstone compaction increased by 0.1051% for every 1.0MPa increase of lateral tectonic compressional stress, while late tectonic napping helped to preserve a higher porosity of underlying sandstone reservoir. Fluid diagenesis is a general phenomenon. The compaction caused by fluid properties is significant. The coarser the grain size, the stronger the fluid effect on compaction. The greater the burial depth, the weaker the fluid effect on compaction for the specific reservoir lithology and the greater the difference in the fluid effects on compaction between different grain sizes.
基金Supported by China National Science and Technology Major Project(2017ZX05009-005-003).
文摘The relationship between NaCl concentration and the phase change behavior of microemulsion of anionic surfactant was characterized by the salinity scan experiments.The wettability of WinsorⅠtype surfactant solution(WⅠsolution)and the effect of NaCL concentration on phase change behavior of WⅠsolution and imbibition in oil-wet porous media were investigated by microfluidic experiments in this study.The WⅠsolution and WinsorⅠtype microemulsion are similar in wetting phase with stronger wettability than other phases.Two main mechanisms of WⅠsolution enhancing imbibitions recovery in oil wet porous media are the wetting phase drive and residual oil solubilization.Under the salinity condition of WinsorⅠtype microemulsion,the NaCl concentration has strong impact on the imbibition mechanism of WⅠsolution,the higher the NaCl concentration,the complex the imbibition process and the higher the imbibition efficiency will be.The NaCl concentration has strong impact on the solubilization ability to oil of the WⅠsolution,the higher the NaCl concentration,the stronger the solubility of the WⅠsolution to residual oil will be.
文摘Significant scientific and economic benefits may be derived from investigating the best choice of catalyst in the alkyd resin synthesis. The effect of catalyst type and concentration on the production of alkyd resin using castor seed oil (CSO) was evaluated. Lithium hydroxide, lead (II) oxide, calcium carbonate, sodium hydroxide and calcium oxide were investigated. The fatty acid profile of the raw CSO was determined using GC-MS while structural elucidation of the CSO based alkyd resins was determined using FTIR spectrometry. The CSO modified alkyd resin produced has acid values of 5.0, 5.61, 7.0 8.24 and 11 for lithium hydroxide, lead (II) oxide, calcium carbonate, sodium hydroxide and calcium oxide respectively. The extent of reaction was 95%, 95%, 91%, 89% and 88% for lithium hydroxide, lead (II) oxide, calcium carbonate, sodium hydroxide and calcium oxide respectively at the reaction time of 150 minutes. The alcoholysis reaction completion time was fastest in LiOH followed by PbO, CaCO<sub>3</sub>, NaOH and CaO catalyst. Physico-chemical parameters of the oil and performance evaluation of the alkyd films suggest that they are sustainable materials for surface coating. LiOH shows excellent robustness to expanded process parameters.
基金supported by the National Natural Science Foundation of China(No.41902141)the Fundamental Research Fund for the Central Universities(No.E1E40403)the PetroChina Innovation Foundation(No.2018D-5007-0103)
文摘This study aims to clarify the factors influencing oil recovery of surfactant-polymer(SP)flooding and to establish a quantitative calculation model of oil recovery during different displacement stages from water flooding to SP flooding.The conglomerate reservoir of the Badaowan Formation in the seventh block of the Karamay Oilfield is selected as the research object to reveal the start-up mechanism of residual oil and determine the controlling factors of oil recovery through SP flooding experiments of natural cores and microetching models.The experimental results are used to identify four types of residual oil after water flooding in this conglomerate reservoir with a complex pore structure:oil droplets retained in pore throats by capillary forces,oil cluster trapped at the junction of pores and throats,oil film on the rock surface,isolated oil in dead-ends of flow channel.For the four types of residual oil identified,the SP solution can enhance oil recovery by enlarging the sweep volume and improving the oil displacement efficiency.First,the viscosity-increasing effect of the polymer can effectively reduce the permeability of the displacement liquid phase,change the oil-water mobility ratio,and increase the water absorption.Furthermore,the stronger the shear drag force of the SP solution,the more the crude oil in a porous medium is displaced.Second,the surfactant can change the rock wettability and reduce the absorption capacity of residual oil by lowering interfacial tension.At the same time,the emulsification further increases the viscosity of the SP solution,and the residual oil is recovered effectively under the combined effect of the above two factors.For the four start-up mechanisms of residual oil identified after water flooding,enlarging the sweep volume and improving the oil displacement efficiency are interdependent,but their contribution to enhanced oil recovery are different.The SP flooding system primarily enlarges the sweep volume by increasing viscosity of solution to start two kinds of residual oil such as oil droplet retained in pore throats and isolated oil in dead-ends of flow channel,and primarily improves the oil displacement efficiency by lowing interfacial tension of oil phase to start two kinds of residual oil such as oil cluster trapped at the junction of pores and oil film on the rock surface.On this basis,the experimental results of the oil displacement from seven natural cores show that the pore structure of the reservoir is the main factor influencing water flooding recovery,while the physical properties and original oil saturation have relatively little influence.The main factor influencing SP flooding recovery is the physical and chemical properties of the solution itself,which primarily control the interfacial tension and solution viscosity in the reservoir.The residual oil saturation after water flooding is the material basis of SP flooding,and it is the second-most dominant factor controlling oil recovery.Combined with the analysis results of the influencing factors and reservoir parameters,the water flooding recovery index and SP flooding recovery index are defined to further establish quantitative calculation models of oil recovery under different displacement modes.The average relative errors of the two models are 4.4%and 2.5%,respectively;thus,they can accurately predict the oil recovery of different displacement stages and the ultimate reservoir oil recovery.
基金Supported by the China National Science and Technology Major Project (2016ZX05024-003)
文摘The Bohai Bay Basin is a typical oil-prone basin, in which natural gas geological reserves have a small proportion. In this basin, the gas source rock is largely medium-deep lake mudstone with oil-prone type Ⅱ2-Ⅱ1 kerogens, and natural gas preservation conditions are poor due to active late tectonic movements. The formation conditions of large natural gas fields in the Bohai Bay Basin have been elusive. Based on the exploration results of Bohai Bay Basin and comparison with large gas fields in China and abroad, the formation conditions of conventional large-scale natural gas reservoirs in the Bohai Bay Basin were examined from accumulation dynamics, structure and sedimentation. The results show that the formation conditions of conventional large natural gas reservoirs in Bohai Bay Basin mainly include one core element and two key elements. The core factor is the strong sealing of Paleogene "quilt-like" overpressure mudstone. The two key factors include the rapid maturation and high-intensity gas generation of source rock in the late stage and large scale reservoir. On this basis, large-scale nature gas accumulation models in the Bohai Bay Basin have been worked out, including regional overpressure mudstone enriching model, local overpressure mudstone depleting model, sand-rich sedimentary subsag depleting model and late strongly-developed fault depleting model. It is found that Bozhong sag, northern Liaozhong sag and Banqiao sag have favorable conditions for the formation of large-scale natural gas reservoirs, and are worth exploring. The study results have important guidance for exploration of large scale natural gas reservoirs in the Bohai Bay Basin.
基金funded by a project entitled exploration field evaluation and target optimization of key basins in Chad and Niger(No.2019D-4308)initiated by the scientific research and technology development project of china national petroleum corporation.
文摘Recently,exploration breakthroughs have been made in the Lower Cretaceous sandstone reservoirs in the Doseo Basin,but the identification of reservoir fluid property is difficult due to variable reservoir lithology,complex oil-water contact within and faint responses of the oil zone,which causes the lower accuracy of reservoir fluid property identification with conventional mudlogging and wirelogging techniques.Applying the geochemical logging,fluorescent logging,mud logging and cutting logging technology,in combination with formation test data,this paper distinguishes the crude oil types,analyzes the logging response characteristics of oil zone after water washing,and establishes the interpretation charts and parameter standards for reservoir fluid properties.The crude oil can be divided into two types,namely viscous-heavy and thin-light,based on total hydrocarbon content and component concentration tested by mud logging,features of pyrolysis gas chromatogram and fluorescence spectroscopy.The general characteristics of oil layers experienced water washing include the decrease of total hydrocarbon content and component concentration from mud logging,the decrease of S1 and PS values from geochemical logging,the decrease of hydrocarbon abundance and absence of some light components in pyrolysis gas chromatogram,and the decrease of fluorescence area and intensity from fluorescence logging.According to crude oil types,the cross plots of S1 versus peak-baseline ratio,and the cross plots of rock wettability versus fluorescence area ratio are drawn and used to interpret reservoir fluid property.Meanwhile,the standards of reservoir fluid parameter are established combining with the parameters of PS and the parameters in above charts,and comprehensive multiparameter correlation in both vertical and horizontal ways is also performed to interpret reservoir fluid property.The application in the Doseo Basin achieved great success,improving interpretation ability of fluid property in the reservoir with complex oil-water contact,and also provided technical reference for the efficient exploration and development of similar reservoirs.
文摘Based on the geological and geochemical analysis of potential source rocks in different formations and the classification of crude oil types,combined with the hydrocarbon generation thermal simulation experiments,the source,genesis,and distribution of different types of oils in the Mahu large oil province of the Junggar Basin are investigated.Four sets of potential source rocks are developed in the Mahu Sag.Specifically,the source rocks of the Permian Fengcheng Formation have the highest hydrocarbon generation potential and contain mainly TypesⅡandⅠorganic matters,with a high oil generation capacity.In contrast,the source rocks in other formations exhibit lower hydrocarbon generation potential and contain mainly TypeⅢorganic matter,with dominant gas generation.Oils in the Mahu Sag can be classified as three types:A,B and C,which display ascending,mountainous and descending C_(20)-C_(21)-C_(23)tricyclic terpenes abundance patterns in sequence,and gradually increasing relative content of tricyclic terpenes and sterane isomerization parameters,indicating an increasing oil maturity.Different types of oils are distributed spatially in an obviously orderly manner:Type A oil is close to the edge of the sag,Type C oil is concentrated in the center of the sag,and Type B oil lies in the slope area between Type A and Type C.The results of oil-source correlation and thermal simulation experiments show that the three types of oils come from the source rocks of the Fengcheng Formation at different thermal evolution stages.This new understanding of the differential genesis of oils in the Mahu Sag reasonably explains the source,distribution,and genetic mechanism of the three types of oils.The study results are of important guidance for the comprehensive and three-dimensional oil exploration,the identification of oil distribution in the total petroleum system,and the prediction of favorable exploration areas in the Mahu Sag.
文摘The region around the Karamay-Baikouquan （Ke-Bai） overthrust belt is the richest in hydrocarbon accumulation in the Junggar Basin. Previous research has indicated that oil in the region came from the Fengcheng Formation in the Mahu Depression to the northeast of the region, but the oil distribution around the Mahu Depression is remarkably uneven. Large amounts of oil have been found in the Ke-Bai overthrust belt to the west of the depression and only some small oilfields have been discovered in the eastern margin of the depression. This uneven distribution revealed that the oil source of the Ke- Bai region might not be from the Mahu Depression. The oil type distribution and the oil migration pattern revealed in this paper showed that there may be another oil source under the Karamay overthrust. Based on geochemical data, the oil was classified into two types from the sterane and terpane characteristics. Type A oil was mainly distributed in the Huwan area and blocks V and VIII of the Karamay Oilfield in the southern part of the region, while type B oil was mainly distributed in the Baikouquan Oilfield in the northern part of the region. In addition, oil migration pathways and direction were determined by the values of diasterane / regular sterane and C30 moretane / C30 hopane ratios. It is shown that the oil of Huwan area on the hanging wall of the overthrust was mainly charged along the overthrust fault surfaces and then migrated to the west, whereas the oil in blocks V and VIII on the foot wall of the overthrust came from the Mahu Depression in the east. As a result, there may be at least two hydrocarbon source kitchens in the study area. The hydrocarbons in the blocks V and VIII on the footwall of the overthrust belt and in the Baikouquan Oilfield mainly came from the Fengcheng Formation in the Mahu Depression, and the hydrocarbons in the Huwan area on the hanging wall of the overthrust belt may come from another hydrocarbon source kitchen below the overthrust. This recognition indicates that there is substantial exploration potential in the deep Carboniferous strata on the hanging wall of the overthrust belt.
文摘Novel tetracyclic terpanes X and Y namely C24-des-A-oleanane and C27 tetracyclic terpane were detected in crude oils and source rock extracts in Zhu 1 depression in Pearl River Mouth Basin by GC-MS analysis technology. These compounds are similar to oleanane in the structure, and their relative abundance in m/z 191 partial mass cbromatogram has a good correlation with oleanane. Here compounds X and Y are considered to be derived from the des-A degradation of oleanoid precursor. The ratio of X/（X-I-C24） and Y/（Y-I-C24） increase with the increasing inputs of terrigenous organic matter in crude oils. Wenchang Formation middle-deep lacustrine source rocks with planktonic algae organic matter inputs and oil generating from it contain low abundance of compounds X and Y, while Enping Formation coal measures source rocks with terrigenous higher plants organic matter inputs and oil generating from it usually have higher compounds X and Y. In general when two terrigenous compounds C19 tricyclic terpane and bicadinane-T are high in crude oils, there are also a corresponding high abundant compounds X and Y. Relative abundance of compounds X and Y is closely related to the source of organic matter and it can indicate the input of terrigenous organic matter.
基金Supported by the National Natural Science Foundation of China(U22B6004)Scientific Research and Technological Development Project of RIPED(2022yjcq03)Technology Research Project of PetroChina Changqing Oilfield Company(KJZX2023-01)。
文摘Based on the production curves,changes in hydrocarbon composition and quantities over time,and production systems from key trial production wells in lacustrine shale oil areas in China,fine fraction cutting experiments and molecular dynamics numerical simulations were conducted to investigate the effects of changes in shale oil composition on macroscopic fluidity.The concept of“component flow”for shale oil was proposed,and the formation mechanism and conditions of component flow were discussed.The research reveals findings in four aspects.First,a miscible state of light,medium and heavy hydrocarbons form within micropores/nanopores of underground shale according to similarity and intermiscibility principles,which make components with poor fluidity suspended as molecular aggregates in light and medium hydrocarbon solvents,such as heavy hydrocarbons,thereby decreasing shale oil viscosity and enhancing fluidity and outflows.Second,small-molecule aromatic hydrocarbons act as carriers for component flow,and the higher the content of gaseous and light hydrocarbons,the more conducive it is to inhibit the formation of larger aggregates of heavy components such as resin and asphalt,thus increasing their plastic deformation ability and bringing about better component flow efficiency.Third,higher formation temperatures reduce the viscosity of heavy hydrocarbon components,such as wax,thereby improving their fluidity.Fourth,preservation conditions,formation energy,and production system play important roles in controlling the content of light hydrocarbon components,outflow rate,and forming stable“component flow”,which are crucial factors for the optimal compatibility and maximum flow rate of multi-component hydrocarbons in shale oil.The component flow of underground shale oil is significant for improving single-well production and the cumulative ultimate recovery of shale oil.
基金This project was financially supported by the National Natural Science Foundation of China (Grant No. 40502013)
文摘The Linnan subsag is the main oil producer of the Linpan oil zone. Based on the oil group composition,gas chromatography data and biomarker analysis,it was indicated that crude oils from different oilfields varied greatly in group composition and showed obvious heterogeneities in the aspects of precursor type,crude oil maturity and hydrocarbon depositional environment. According to the characteristics of source rocks,three oil populations can be distinguished,i.e.,the southern,northern and transitional oil populations. Furthermore,on the basis of post-reservoir reworking processes,the medium conditions of hydrocarbon-generating environment and differences in maturity,six oil families and twelve sub-families were distinquished. An integrated study suggested that the fac-tors leading to such heterogeneities in crude oil composition mainly include different source rocks,multi-stage oil/gas charging,geo-chromatographic effects during oil/gas migration,reservoir heterogeneities and various post-reservoir secondary alterations.
基金co-supported by the National Key Basic Research and Development Program of China(No.2006CB202300)the National Natural Science Foundation Important Project(No.40739906).
文摘The uplift is a positive structural unit of the crust. It is an important window for continental dynamics owing to its abundant structural phenomena, such as fault, fold, unconformity and denudation of strata. Meanwhile, it is the very place to store important minerals like oil, natural gas, coal and uranium. Giant and large-scale oil and gas fields in China, such as the Daqing Oilfield, Lunnan-Tahe Oilfield, Penglai 19-3 Oilfield, Puguang Gas Field and Jingbian Gas Field, are developed mainly on uplifts. Therefore, it is the main target both for oil and gas exploration and for geological study. The uplift can be either a basement uplift, or one developed only in the sedimentary cover. Extension, compression and wrench or their combined forces may give rise to uplifts. The development process of uplifting, such as formation, development, dwindling and destruction, can be taken as the uplifting cycle. The uplifts on the giant Precambrian cratons are large in scale with less extensive structural deformation. The uplifts on the medium- and small-sized cratons or neo-cratons are formed in various shapes with strong structural deformation and complicated geological structure. Owing to changes in the geodynamic environment, uplift experiences a multi-stage or multi-cycle development process. Its geological structure is characterized in superposition of multi-structural layers. Based on the basement properties, mechanical stratigraphy and development sequence, uplifts can be divided into three basic types-the succession, superposition and destruction ones. The succession type is subdivided into the maintaining type and the lasting type. The superposition type can be subdivided into the composite anticlinal type, the buried-hill draped type, the faulted uplift type and the migration type according to the different scales and superimposed styles of uplifts in different cycles. The destruction type is subdivided into the tilting type and the negative inverted type. The development history of uplifts and their controlling effects on sedimentation and fluids are quite different from one another, although the uplifts with different structural types store important minerals. Uplifts and their slopes are the main areas for oil and gas accumulation. They usually become the composite oil and gas accumulation zones （belts） with multiple productive formations and various types of oil and gas reservoirs.
