The seepage characteristics of shale reservoirs are influenced not only by multi-field coupling effects such as stress field,temperature field,and seepage field but also exhibit evident creep characteristics during oi...The seepage characteristics of shale reservoirs are influenced not only by multi-field coupling effects such as stress field,temperature field,and seepage field but also exhibit evident creep characteristics during oil and gas exploitation.The complex fluid flow in such reservoirs is analyzed using a combination of theoretical modeling and numerical simulation.This study develops a comprehensive mathematical model that integrates the impact of creep on the seepage process,with consideration of factors including stress,strain,and time-dependent deformation.The model is validated through a series of numerical experiments,which demonstrate the significant influence of creep on the seepage behavior.The results indicate that the rock mechanical parameters and creep constitutive model were determined through triaxial compression tests and uniaxial creep tests.A creep-seepage coupling control equation for shale was established based on the Burgers creep model.The absolute value of the volumetric strain of shale increases rapidly in the initial creep stage,and the increase in vertical stress accelerates the rock’s creep deformation.During the deceleration creep stage,the volumetric strain of the reservoir increases rapidly,leading to a significant decrease in permeability.In the stable creep stage,the pores and fractures in the rock are further compressed,causing a gradual reduction in permeability,which eventually stabilizes.展开更多
Accurately predicting relative permeability is an important issue in the research of multiphase flow in tight reservoirs.Existing predictive models typically rely on the capillary tube bundle model featuring circular ...Accurately predicting relative permeability is an important issue in the research of multiphase flow in tight reservoirs.Existing predictive models typically rely on the capillary tube bundle model featuring circular cross-sections,often overlooking the impact of pore geometry on fluid flow behavior within reservoirs.In this work,the intermingled fractal theory of porous media is introduced to characterize the intricate local features within the internal space of tight rocks.Initially,iterative rules for diverse fractal units are skillfully designed to capture the actual characteristics of pore cross-sectional shapes.Subsequently,analytical relationships are derived between the iterative parameters and the area,wetted perimeter,and hydraulic diameter of pores generated by these units,followed by the establishment of a relative permeability model that considers pore geometry.The model's validity is confirmed through comparisons with experimental data and published relative permeability models,with correlation coefficients exceeding 0.996.Finally,various factors affecting two-phase flow characteristics are analyzed.The results reveal that pore geometry has a significant impact on flow behavior in porous media.Assuming that the flow channels are cylindrical typically leads to an overestimation of permeability,with the maximum relative error reaching 46.91%.Additionally,the tortuosity fractal dimension is a determinant factor influencing the relative permeability of both wetting and nonwetting fluids,and the phase permeability is sensitive to variations in solid particle size and porosity.The proposed intermingled fractal model enhances the accuracy of evaluating fluid flow characteristics in microscale pore channels and offers a novel framework for simulating porous media with complex geometries.展开更多
The precision of dynamic reserve calculations in gas reservoirs is crucial for the rational and efficient development of oil and gas fields and the formulation of gas well production plans.The Shaximiao gas reservoir ...The precision of dynamic reserve calculations in gas reservoirs is crucial for the rational and efficient development of oil and gas fields and the formulation of gas well production plans.The Shaximiao gas reservoir in the ZT block of northwestern Sichuan is densely packed and highly heterogeneous,featuring complex gas-water distribution,substantial variations in test production among gas wells,and a rapid decline rate.To precisely determine the dynamic reserves of these tight water-bearing gas wells,this study focuses on the water-tight gas reservoirs in the ZT block of northwestern Sichuan,conducting core X-ray diffraction,constant-rate mercury injection,and reservoir rock stress sensitivity experiments.Utilizing the experimental findings,the porosity and permeability of the rock samples under effective stress conditions are adjusted via binary linear regression.These adjusted parameters are then incorporated into the water-sealed gas material balance method,thereby establishing a novel approach for calculating dynamic reserves in water-tight gas reservoirs under stress sensitivity conditions.The results show that:(1)the rock porosity ranges from 6.08%to 10.22%,permeability ranges from 0.035 mD to 0.547 mD,clay mineral content ranges from 6.58%to 19.14%,pore radius distribution ranges from 90μm to 180μm,throat radius distribution ranges from 0.61μm to 3.41μm,with significant differences in throat distribution,indicating poor reservoir fluid flow capacity and strong tightness;(2)after aging experiments,rock samples exhibit plastic deformation,with porosity and permeability unable to fully recover after pressure relief.The stress sensitivity curve of rock samples shows a two-stage characteristic,with moderate to strong stress sensitivity;(3)porosity stress sensitivity is mainly influenced by pore radius and mineral composition-larger pore radius and higher clay content lead to stronger stress sensitivity,with porosity loss rates ranging from 8.26%to 23.69%.Permeability stress sensitivity is mainly influenced by throat radius and mineral composition-smaller throat radius and higher clay content result in stronger stress sensitivity,with permeability loss rates ranging from 47.91%to 62.03%;(4)a comparative analysis between the traditional dynamic reserve calculation method for gas wells and the new method considering stress sensitivity shows a relative error between 0.90%and 2.41%,with the new method demonstrating better accuracy.This study combines physical experimental results with an effective stress model of reservoir rocks to develop a new method for calculating dynamic reserves of water-bearing tight gas reservoirs under effective stress conditions,providing experimental data and example calculation results to support subsequent dynamic evaluation of gas reservoirs and the establishment of rational well allocation plans.展开更多
Gastric cancer(GC)is the fifth most prevalent malignancy worldwide and remains a leading cause of cancer-related mortality.Major risk factors for GC include Helicobacter pylori infection,increasing age,high dietary sa...Gastric cancer(GC)is the fifth most prevalent malignancy worldwide and remains a leading cause of cancer-related mortality.Major risk factors for GC include Helicobacter pylori infection,increasing age,high dietary salt intake,and diets deficient in vegetables and fruits.Due to the often subtle and nonspecific early symptoms,coupled with the lack of routine screening programs,a significant proportion of GC cases are diagnosed at advanced stages.The etiology of GC is multifactorial,and diagnosis is confirmed histologically through endoscopic biopsy,followed by staging via computed tomography,positron emission tomography,staging laparoscopy,and endoscopic ultrasound.Treatment strategies typically involve a multidisciplinary approach including chemotherapy,surgical resection,radiotherapy,and emerging immunotherapeutic options.Despite advances in diagnostic and therapeutic modalities,the prognosis of advanced GC remains poor,with high rates of recurrence and metastasis.In recent years,increasing attention has been given to the role of tight junction(TJ)proteins in the pathogenesis and progression of GC.TJ proteins,critical components of epithelial barrier function,have been implicated in various stages of gastric carcinogenesis,from intestinal metaplasia to invasion and metastasis.Infection and inflammation,particularly due to Helicobacter pylori,disrupt TJ integrity,compromising the gastric mucosal barrier and facilitating neoplastic transformation.This review synthesizes current evidence from PubMed,EMBASE,Google Scholar,ScienceDirect,SpringerLink,and other reputable databases to provide a comprehensive overview of the involvement of TJ proteins in GC.By elucidating the molecular interplay between TJ dysregulation and gastric tumorigenesis,this work aims to highlight the potential of TJ proteins as novel diagnostic biomarkers and therapeutic targets in GC management.展开更多
Threshold pressure gradient has great importance in efficient tight gas field development as well as for research and laboratory experiments.This experimental study is carried out to investigate the threshold pressure...Threshold pressure gradient has great importance in efficient tight gas field development as well as for research and laboratory experiments.This experimental study is carried out to investigate the threshold pressure gradient in detail.Experiments are carried out with and without back pressure so that the effect of pore pressure on threshold pressure gradient may be observed.The trend of increasing or decreasing the threshold pressure gradient is totally opposite in the cases of considering and not considering the pore pressure.The results demonstrate that the pore pressure of tight gas reservoirs has great influence on threshold pressure gradient.The effects of other parameters like permeability and water saturation,in the presence of pore pressure,on threshold pressure gradient are also examined which show that the threshold pressure gradient increases with either a decrease in permeability or an increase in water saturation.Two new correlations of threshold pressure gradient on the basis of pore pressure and permeability,and pore pressure and water saturation,are also introduced.Based on these equations,new models for tight gas production are proposed.The gas slip correction factor is also considered during derivation of this proposed tight gas production models.Inflow performance relationship curves based on these proposed models show that production rates and absolute open flow potential are always be overestimated while ignoring the threshold pressure gradients.展开更多
AIM:To investigate the effect of side-stream smoking on gut microflora composition,intestinal inflammation and expression of tight junction proteins.METHODS:C57BL/6 mice were exposed to side-stream cigarette smoking f...AIM:To investigate the effect of side-stream smoking on gut microflora composition,intestinal inflammation and expression of tight junction proteins.METHODS:C57BL/6 mice were exposed to side-stream cigarette smoking for one hour daily over eight weeks.Cecal contents were collected for microbial composition analysis.Large intestine was collected for immunoblotting and quantitative reverse transcriptase polymerase chain reaction analyses of the inflammatory pathway and tight junction proteins.RESULTS:Side-stream smoking induced significant changes in the gut microbiota with increased mouse intestinal bacteria,Clostridium but decreased Fermicutes(Lactoccoci and Ruminococcus),Enterobacteriaceae family and Segmented filamentous baceteria compared to the control mice.Meanwhile,side-stream smoking inhibited the nuclear factor-κB pathway with reduced phosphorylation of p65 and IκBα,accompanied with unchanged mRNA expression of tumor necrosis factor-α or interleukin-6.The contents of tight junction proteins,claudin3 and ZO2 were up-regulated in the large intestine of mice exposed side-stream smoking.In addition,side-stream smoking increased c-Jun N-terminal kinase and p38 MAPK kinase signaling,while inhibiting AMPactivated protein kinase in the large intestine.CONCLUSION:Side-stream smoking altered gut microflora composition and reduced the inflammatory response,which was associated with increased expression of tight junction proteins.展开更多
A mathematical model for the gas-water two-phase flow in tight gas reservoirs is elaborated.The model can account for the gas slip effect,stress sensitivity,and high-speed non-Darcy factors.The related equations are s...A mathematical model for the gas-water two-phase flow in tight gas reservoirs is elaborated.The model can account for the gas slip effect,stress sensitivity,and high-speed non-Darcy factors.The related equations are solved in the framework of a finite element method.The results are validated against those obtained by using the commercial software CMG(Computer Modeling Group software for advanced recovery process simulation).It is shown that the proposed method is reliable.It can capture the fracture rejection characteristics of tight gas reservoirs better than the CMG.A sensitivity analysis of various control factors(initial water saturation,reservoir parameters,and fracturing parameters)affecting the production in tight gas wells is conducted accordingly.Finally,a series of theoretical arguments are provided for a rational and effective development/exploitation of tight sandstone gas reservoirs.展开更多
The physical properties of hydrocarbon reservoirs are important factors affecting the percolation ability of the reservoirs.Tight-sand reservoirs exhibit complex pore throat connectivity due to the extensive developme...The physical properties of hydrocarbon reservoirs are important factors affecting the percolation ability of the reservoirs.Tight-sand reservoirs exhibit complex pore throat connectivity due to the extensive development of micro-and nano-scale pore and throat systems.Characterizing the microscopic properties of these reservoirs using nondestructive,quantitative methods serves as an important means to determine the characteristics of microscopic pores and throats in tight-sand reservoirs and the mechanism behind the influence of these characteristics on reservoir porosity and permeability.In this study,a low-permeability sandstone sample and two tight sandstone samples collected from the Ordos Basin were nondestructively tested using high-resolution nano-CT technology to quantitively characterize their microscopic pore throat structures and model them three-dimensionally(in 3D)based on CT threshold differences and gray models.A thorough analysis and comparison reveal that the three samples exhibit a certain positive correlation between their porosity and permeability but the most important factor affecting both porosity and permeability is the microscopic pore throat structure.Although the number of pores in tight sandstones shows a minor impact on their porosity,large pores(more than 20μm)contribute predominantly to porosity,suggesting that the permeability of tight sandstones is controlled primarily by large pore throats.For these samples,higher permeability corresponds to larger average throat sizes.Therefore,throats with average radii greater than 2μm can significantly improve the permeability of tight sandstones.展开更多
The tight sandstone reservoirs in the first sub-member of Chang 7 member(Chang 71)of Triassic Yanchang Formation in the Jiyuan area,Ordos Basin,show significant variations in microscopic pore-throat structure(PTS)and ...The tight sandstone reservoirs in the first sub-member of Chang 7 member(Chang 71)of Triassic Yanchang Formation in the Jiyuan area,Ordos Basin,show significant variations in microscopic pore-throat structure(PTS)and fluid mobility due to the influences of the northeast and northwest dual provenance systems.This study performed multiple experimental analyses on nine samples from the area to determine the petrological and petrophysical properties,as well as the PTS characteristics of reservoirs in different provenance-controlled regions.On this basis,the pore-throat size distribution(PSD)obtained from high-pressure mercury injection(HPMI)was utilized to convert the NMR movable fluid T2spectrum,allowing for quantitative characterization of the full PSD and the occurrence characteristics of movable fluids.A systematic analysis was conducted on the primary controlling factors affecting fluid mobility in the reservoir.The results indicated that the lithology in the eastern and western regions is lithic arkose.The eastern sandstones,being farther from the provenance,exhibit higher contents of feldspar and lithic fragments,along with the development of more dissolution pores.The reservoir possesses good petrophysical properties,low displacement pressure,and high pore-throat connectivity and homogeneity,indicating strong fluid mobility.In contrast,the western sandstones,being nearer to the provenance,exhibit poor grain sorting,high contents of lithic fragments,strong compaction and cementation effects,resulting in poor petrophysical properties,and strong pore-throat heterogeneity,revealing weak fluid mobility.The range of full PSD in the eastern reservoir is wider than that in the western reservoir,with relatively well-developed macropores.The macropores are the primary space for occurrence of movable fluids,and controls the fluid mobility of the reservoir.The effective porosity of movable fluids(EPMF)quantitatively represents the pore space occupied by movable fluids within the reservoir and correlates well with porosity,permeability,and PTS parameters,making it a valuable parameter for evaluating fluid mobility.Under the multi-provenance system,the eastern and western reservoirs underwent different sedimentation and diagenesis processes,resulting in differential distribution of reservoir mineral components and pore types,which in turn affects the PTS heterogeneity and reservoir quality.The composition and content of reservoir minerals are intrinsic factors influencing fluid mobility,while the microscopic PTS is the primary factor controlling it.Low clay mineral content,welldeveloped macropores,and weak pore-throat heterogeneity all contribute to the storage and seepage of reservoir fluids.展开更多
Supercritical CO_(2)(SC-CO_(2))fracturing stands out a promising waterless stimulation technique in the development of unconventional resources.While numerous studies have delved into the inducedfracture mechanism of ...Supercritical CO_(2)(SC-CO_(2))fracturing stands out a promising waterless stimulation technique in the development of unconventional resources.While numerous studies have delved into the inducedfracture mechanism of SC-CO_(2),the small scale of rock samples and synthetic materials used in many studies have limited a comprehensive understanding of fracture propagation in unconventional formations.In this study,cubic tight sandstone samples with dimensions of 300 mm were employed to conduct SC-CO_(2)fractu ring experiments under true-triaxial stre ss conditions.The spatial morphology and quantitative attributes of fracture induced by water and SC-CO_(2)fracturing were compared,while the impact of in-situ stress on fracture propagation was also investigated.The results indicate that the SCCO_(2)fracturing takes approximately ten times longer than water fracturing.Furthermore,under identical stress condition,the breakdown pressure(BP)for SC-CO_(2)fracturing is nearly 25%lower than that for water fracturing.A quantitative analysis of fracture morphology reveals that water fracturing typically produces relatively simple fracture pattern,with the primary fracture distribution predominantly controlled by bedding planes.In contrast,SC-CO_(2)fracturing results in a more complex fracture morphology.As the differential of horizontal principal stress increases,the BP for SC-CO_(2)fractured rock exhibits a downward trend,and the induced fracture morphology becomes more simplified.Moreover,the presence of abnormal in-situ stress leads to a further increase in the BP for SC-CO_(2)fracturing,simultaneously enhancing the development of a more conductive fracture network.These findings provide critical insights into the efficiency and behavior of SC-CO_(2)fracturing in comparison to traditional water-based fracturing,offering valuable implication for its potential applications in unconventional reservoirs.展开更多
Understanding the storage mechanisms in CO_(2)flooding is crucial,as many carbon capture,utilization,and storage(CCUS)projects are related to enhanced oil recovery(EOR).CO_(2)storage in reservoirs across large timesca...Understanding the storage mechanisms in CO_(2)flooding is crucial,as many carbon capture,utilization,and storage(CCUS)projects are related to enhanced oil recovery(EOR).CO_(2)storage in reservoirs across large timescales undergoes the two storage stages of oil displacement and well shut-in,which cover mul-tiple replacement processes of injection-production synchronization,injection only with no production,and injection-production stoppage.Because the controlling mechanism of CO_(2)storage in different stages is unknown,the evolution of CO_(2)storage mechanisms over large timescales is not understood.A math-ematical model for the evaluation of CO_(2)storage,including stratigraphic,residual,solubility,and mineral trapping in low-permeability tight sandstone reservoirs,was established using experimental and theoret-ical analyses.Based on a detailed geological model of the Huaziping Oilfield,calibrated with reservoir permeability and fracture characteristic parameters obtained from well test results,a dynamic simulation of CO_(2)storage for the entire reservoir life cycle under two scenarios of continuous injection and water-gas alternation were considered.The results show that CO_(2)storage exhibits the significant stage charac-teristics of complete storage,dynamic storage,and stable storage.The CO_(2)storage capacity and storage rate under the continuous gas injection scenario(scenario 1)were 6.34×10^(4)t and 61%,while those under the water-gas alternation scenario(scenario 2)were 4.62×10^(4)t and 46%.The proportions of stor-age capacity under scenarios 1 and 2 for structural or stratigraphic,residual,solubility,and mineral trap-ping were 33.36%,33.96%,32.43%,and 0.25%;and 15.09%,38.65%,45.77%,and 0.49%,respectively.The evolution of the CO_(2)storage mechanism showed an overall trend:stratigraphic and residual trapping first increased and then decreased,whereas solubility trapping gradually decreased,and mineral trapping continuously increased.Based on these results,an evolution diagram of the CO_(2)storage mechanism of low-permeability tight sandstone reservoirs across large timescales was established.展开更多
Taking the second member of the Xujiahe Formation of the Upper Triassic in the Xinchang structural belt as an example,based on data such as logging,production,seismic interpretation and test,a systematic analysis was ...Taking the second member of the Xujiahe Formation of the Upper Triassic in the Xinchang structural belt as an example,based on data such as logging,production,seismic interpretation and test,a systematic analysis was conducted on the structural characteristics and evolution,reservoir diagenesis and densification processes,and types and stages of faults/fractures,and revealing the multi-stage and multi-factor dynamic coupled enrichment mechanisms of tight gas reservoirs.(1)In the early Yanshan period,the paleo-structural traps were formed with low-medium maturity hydrocarbons accumulating in structural highs driven by buoyancy since reservoirs were not fully densified in this stage,demonstrating paleo-structure control on traps and early hydrocarbon accumulation.(2)In the middle-late Yanshan period,the source rocks became mature to generate and expel a large quantity of hydrocarbons.Grain size and type of sandstone controlled the time of reservoir densification,which restricted the scale of hydrocarbon charging,allowing for only a small-scale migration through sand bodies near the fault/fracture or less-densified matrix reservoirs.(3)During the Himalayan period,the source rocks reached overmaturity,and the residual oil cracking gas was efficiently transported along the late-stage faults/fractures.Wells with high production capacity were mainly located in Type I and II fault/fracture zones comprising the late-stage north-south trending fourth-order faults and the late-stage fractures.The productivity of the wells was controlled by the transformation of the late-stage faults/fractures.(4)The Xinchang structural belt underwent three stages of tectonic evolution,two stages of reservoir formation,and three stages of fault/fractures development.Hydrocarbons mainly accumulated in the paleo-structure highs.After reservoir densification and late fault/fracture adjustment,a complex gas-water distribution pattern was formed.Thus,it is summarized as the model of“near-source and low-abundance hydrocarbon charging in the early stage,and differential enrichment of natural gas under the joint control of fault-fold-fracture complex,high-quality reservoirs and structural highs in the late stage”.Faults/fractures with well-coupled fault-fold-fracture-pore are favorable exploration targets with high exploration effectiveness.展开更多
The Triassic Xujiahe Formation in the slope zone of the Sichuan foreland basin is a new field of continental tight gas exploration in recent years.The fourth member of the Xujiahe Formation(Xu4 Member),the major inter...The Triassic Xujiahe Formation in the slope zone of the Sichuan foreland basin is a new field of continental tight gas exploration in recent years.The fourth member of the Xujiahe Formation(Xu4 Member),the major interval in the Jianyang Block of the Tianfu gas field in the basin,is characterized by considerable buried depth,tight reservoirs,and strong heterogeneity.By using cast thin section,X-ray diffraction(XRD),scanning electron microscopy(SEM),fluid inclusion thermometry,and core analysis,the reservoir rock types,dominant diageneses,diagenetic history,and controls on high-graded reservoirs were investigated.It is found that the Xu4 Member in Jianyang mainly consists of lithic feldspar sandstones and feldspar lithic sandstones,followed by lithic quartz sandstones.High-energy hydrodynamic conditions in the microfacies of underwater distributary channels and mouth bars are beneficial to the preservation of primary pores and the occurrence of secondary pores,and there are no significant differences in petrophysical properties between these two microfacies.Compaction and calcareous cementation are the dominant controls on reservoir porosity decrease in the Xujiahe Formation;corrosion is the major contributor to porosity increase by generating secondary dissolved pores,e.g.intragranular dissolved pores and intergranular dissolved pores,as major reservoir space in the study area.Fracture zones around the faults inside the Xujiahe Formation(fourth‒order faults)are favorable for proximal tight gas accumulation,preservation,and production.The research findings have been successfully applied to explore the Xujiahe Formation in the slope zone of the Sichuan foreland basin.They can be referential for other similar tight sandstone gas accumulations.展开更多
In order to identify the development characteristics of fracture network in tight conglomerate reservoir of Mahu after hydraulic fracturing,a hydraulic fracturing test site was set up in the second and third members o...In order to identify the development characteristics of fracture network in tight conglomerate reservoir of Mahu after hydraulic fracturing,a hydraulic fracturing test site was set up in the second and third members of Triassic Baikouquan Formation(T1b2 and T1b3)in Ma-131 well area,which learned from the successful experience of hydraulic fracturing test sites in North America(HFTS-1).Twelve horizontal wells and a high-angle coring well MaJ02 were drilled.The orientation,connection,propagation law and major controlling factors of hydraulic fractures were analyzed by comparing results of CT scans,imaging logs,direct observation of cores from Well MaJ02,and combined with tracer monitoring data.Results indicate that:(1)Two types of fractures have developed by hydraulic fracturing,i.e.tensile fractures and shear fractures.Tensile fractures are approximately parallel to the direction of the maximum horizontal principal stress,and propagate less than 50 m from perforation clusters.Shear fractures are distributed among tensile fractures and mainly in the strike-slip mode due to the induced stress field among tensile fractures,and some of them are in conjugated pairs.Overall,tensile fractures alternate with shear fractures,with shear fractures dominated and activated after tensile ones.(2)Tracer monitoring results indicate that communication between wells was prevalent in the early stage of production,and the static pressure in the fracture gradually decreased and the connectivity between wells reduced as production progressed.(3)Density of hydraulic fractures is mainly affected by the lithology and fracturing parameters,which is smaller in the mudstone than the conglomerate.Larger fracturing scale and smaller cluster spacing lead to a higher fracture density,which are important directions to improve the well productivity.展开更多
Tricellulin,a key tricellular tight junction(TJ)protein,is essential for maintaining the barrier integrity of acinar epithelia against macromolecular passage in salivary glands.This study aims to explore the role and ...Tricellulin,a key tricellular tight junction(TJ)protein,is essential for maintaining the barrier integrity of acinar epithelia against macromolecular passage in salivary glands.This study aims to explore the role and regulatory mechanism of tricellulin in the development of salivary gland hypofunction in Sjögren’s syndrome(SS).Employing a multifaceted approach involving patient biopsies,non-obese diabetic(NOD)mice as a SS model,salivary gland acinar cell-specific tricellulin conditional knockout(TricCKO)mice,and IFN-γ-stimulated salivary gland epithelial cells,we investigated the role of tricellulin in SS-related hyposalivation.Our data revealed diminished levels of tricellulin in salivary glands of SS patients.Similarly,NOD mice displayed a reduction in tricellulin expression from the onset of the disease,concomitant with hyposecretion and an increase in salivary albumin content.Consistent with these findings,TricCKO mice exhibited both hyposecretion and leakage of macromolecular tracers when compared to control animals.Mechanistically,the JAK/STAT1/miR-145 axis was identified as mediating the IFN-γ-induced downregulation of tricellulin.Treatment with AT1001,a TJ sealer,ameliorated epithelial barrier dysfunction,restored tricellulin expression,and consequently alleviated hyposalivation in NOD mice.Importantly,treatment with miR-145 antagomir to specifically recover the expression of tricellulin in NOD mice significantly alleviated hyposalivation and macromolecular leakage.Collectively,we identified that tricellulin deficiency in salivary glands contributed to hyposalivation in SS.Our findings highlight tricellulin as a potential therapeutic target for hyposecretion,particularly in the context of reinforcing epithelial barrier function through preventing leakage of macromolecules in salivary glands.展开更多
In contrast to conventional reservoirs,tight formations have more complex pore structures and significant boundary layer effect,making it difficult to determine the effective permeability.To address this,this paper fi...In contrast to conventional reservoirs,tight formations have more complex pore structures and significant boundary layer effect,making it difficult to determine the effective permeability.To address this,this paper first proposes a semi-empirical model for calculating boundary layer thickness based on dimensional analysis,using published experimental data on microcapillary flow.Furthermore,considering the non-uniform distribution of fluid viscosity in the flow channels of tight reservoirs,a theoretical model for boundary layer thickness is established based on fractal theory,and permeability predictions are conducted through Monte Carlo simulations.Finally,sensitivity analyses of various influencing parameters are performed.The results show that,compared to other fractal-based analytical models,the proposed permeability probabilistic model integrates parameters affecting fluid flow with random numbers,reflecting both the fractal and randomness characteristics of capillary size distribution.The computational results exhibit the highest consistency with experimental data.Among the factors affecting the boundary layer,in addition to certain conventional physical and mechanical parameters,different microstructure parameters significantly influence the boundary layer as well.A higher tortuosity fractal dimension results in a thicker boundary layer,while increases in pore fractal dimension,porosity,and maximum capillary size help mitigate the boundary layer effect.It is also observed that the permeability of large pores exhibits greater sensitivity to changes in various influencing parameters.Considering micro-scale flow effects,the proposed model enhances the understanding of the physical mechanisms of fluid transport in dense porous media.展开更多
The pore structures of the Majiagou Formation in the Ordos Basin are complex,featuring micro-and nano-scale intra-crystalline and inter-crystalline pores that significantly impact hydrocarbon storage and flow.Precisel...The pore structures of the Majiagou Formation in the Ordos Basin are complex,featuring micro-and nano-scale intra-crystalline and inter-crystalline pores that significantly impact hydrocarbon storage and flow.Precisely characterizing the rock internal structures is crucial for reservoir exploration and development.However,it is difficult to accurately characterize the pore structure of rock using traditional imaging methods to meet the simulation requirements.In this context,this study focuses on high-resolution 3D digital core reconstruction using the SliceGAN model.Specifically,the Modular Automated Processing System(MAPS)image and Quanti-tative Evaluation of Minerals by Scanning Electron Microscopy(QEMSCAN)image were combined to divide MAPS into three categories:pore,dolomite,and calcite.Then,through the SliceGAN algorithm,the 3D digital core was reconstructed.To evaluate the reconstruction,the auto-correlation function,two-point probability function,porosity,mineral content,and specific surface area were employed.The results show that the SliceGAN can effectively capture the micro-features in the core,and the internal structure of the generated core was consistent with that of the original core.This study provided a new sight for reconstructing cores with complex pore structures and strong heterogeneity and innovatively supports tight carbonate reservoir characterization and evaluation.展开更多
Tight oil is the most viable target for unconventional oil and gas exploration, but the complexity of micro-/nanopore throat systems significantly affects the oil content of reservoirs. To investigate the causes of he...Tight oil is the most viable target for unconventional oil and gas exploration, but the complexity of micro-/nanopore throat systems significantly affects the oil content of reservoirs. To investigate the causes of heterogeneity in oil-bearing reservoirs, a high-pressure mercury injection experiment combined with fractal theory was conducted to analyze the micro pore throat structure characteristics of the tight sandstone of Chang 7 Member reservoirs in the Ordos Basin. The factors controlling the variations in oil content among tight sandstone samples were identified based on mineral composition characteristics. The results indicate that the pore throat radius distribution is mainly unimodal an bimodal. In oil-bearing samples, the pore throat distributions align well with the corresponding permeability contribution curves, while in oil-free samples, there is a clear deviation from these curves. Mesopore throats exert the greatest influence on seepage capacity. Differences in fractal characteristics are primarily reflected in D1 values, with oil-free samples exhibiting D1 values close to 3, indicating an extremely nonuniform pore throat structure at this scale. The content of quartz, plagioclase, and chlorite is significantly higher in oil-bearing samples than in oil-free samples, whereas calcite content is lower in oil-bearing samples. There is a positive correlation between the contents of quartz, plagioclase, and chlorite with D1;their increased presence contributes to a more favorable pore throat structure.Conversely, the calcite contents show an inverse relationship with D1. Cementation increases the complexity of pore throat structures, while multiple diagenetic processes simultaneously control these characteristics, leading to variations in oil content.展开更多
In the context of complex tectonic evolution,due to the control of tectonic compression stress and faults on tectonic fractures,the formation and development of tectonic fractures in the T_3x~2 tight reservoirs presen...In the context of complex tectonic evolution,due to the control of tectonic compression stress and faults on tectonic fractures,the formation and development of tectonic fractures in the T_3x~2 tight reservoirs present significant variations across different tectonic segments in the Western Sichuan Foreland Basin.We clarified the control of differential tectonic evolution on the formation and development of tectonic fractures in different tectonic segments through field-based observations,core samples,image logging,as well as fluid inclusion petrography and temperature determinations of fracture-filling materials,combined with 2D balanced cross-section restoration.The study area primarily manifests two types of tectonic fractures in the tight reservoirs:orogen-related fractures(regional fractures)and fault-related fractures.The orientations of these fractures are predominantly E-W,nearly N-S,NE,and NW.Specifically,the northern segment area only shows the development of regional fractures,while the southern and middle segments exhibit the development of both regional and tectonic fractures.There are three phases of tectonic fractures in different tectonic segments,and their formation times are relatively consistent.The Mesozoic tectonic events had a significant impact on the northern and central segments,with the amount of tectonic shortening and the rate of stratigraphic shortening gradually decreasing from the northeast to the southwest.The compressional stress resulting from tectonic compression also decreases from the northeast to the southwest.As a result,the development of first-phase and second-phase tectonic shear fractures is more pronounced in the northern and middle segments compared to the southern segment.Under the significant control of faults,the development of N-S-and NE-oriented fault-related fractures is more pronounced in the southern segment,while the development of NE-oriented fault-related fractures is relatively higher in the middle segment.Overall,there is an increased density of fractures and an increasing trend in fracture scale from the northern to the middle and then to the southern segment.展开更多
High saturation pressure reservoirs experience rapid pressure decline during exploitation,leading to significant changes in crude oil phase behavior and a continuous increase in viscosity after degassing,which adverse...High saturation pressure reservoirs experience rapid pressure decline during exploitation,leading to significant changes in crude oil phase behavior and a continuous increase in viscosity after degassing,which adversely affects oil recovery.This challenge is particularly acute in tight sandstone reservoirs.To optimize the development strategy for such reservoirs,a series of experiments were conducted using core samples from a high saturation tight sandstone reservoir in the JS oilfield.Gas-dissolved crude oil was prepared by mixing wellhead oil and gas samples,enabling the identification of the critical point where viscosity changes as pressure decreases.Oil-water relative permeability experiments under varying viscosities revealed crude oilmobility trends with declining production pressure.Additionally,physical and numerical simulations of water huff-n-puff processeswere performed,while nuclear magnetic resonance methods explored the effects of soaking time on oil-water imbibition.Key findings include the following optimal parameters for water huff-n-puff:(1)initiating the process when formation pressure is 75%of its original level,(2)a soaking time of 48 h,(3)an injection volume of 0.6 pore volumes per cycle,and(4)a 5 MPa pressure reduction per production stage.Numerical simulations further recommend initiating water injection after one year of depletion,with an optimal cumulative injection volume of 18,000 cubic meters,a soaking time of 10 days,and a producing pressure difference of 5 MPa.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.42472195 and 42272153)the Research Fund of PetroChina Tarim Oilfield Company(Grant No.671023060003)Technology Projects of China National Petroleum Corporation(Grant No.2023ZZ16YJ02).
文摘The seepage characteristics of shale reservoirs are influenced not only by multi-field coupling effects such as stress field,temperature field,and seepage field but also exhibit evident creep characteristics during oil and gas exploitation.The complex fluid flow in such reservoirs is analyzed using a combination of theoretical modeling and numerical simulation.This study develops a comprehensive mathematical model that integrates the impact of creep on the seepage process,with consideration of factors including stress,strain,and time-dependent deformation.The model is validated through a series of numerical experiments,which demonstrate the significant influence of creep on the seepage behavior.The results indicate that the rock mechanical parameters and creep constitutive model were determined through triaxial compression tests and uniaxial creep tests.A creep-seepage coupling control equation for shale was established based on the Burgers creep model.The absolute value of the volumetric strain of shale increases rapidly in the initial creep stage,and the increase in vertical stress accelerates the rock’s creep deformation.During the deceleration creep stage,the volumetric strain of the reservoir increases rapidly,leading to a significant decrease in permeability.In the stable creep stage,the pores and fractures in the rock are further compressed,causing a gradual reduction in permeability,which eventually stabilizes.
基金financially supported by the Hebei Provincial Natural Science Foundation of China(No.D2023402012)the Major Science and Technology Project of China National Petroleum Corporation(No.2024DJ87)。
文摘Accurately predicting relative permeability is an important issue in the research of multiphase flow in tight reservoirs.Existing predictive models typically rely on the capillary tube bundle model featuring circular cross-sections,often overlooking the impact of pore geometry on fluid flow behavior within reservoirs.In this work,the intermingled fractal theory of porous media is introduced to characterize the intricate local features within the internal space of tight rocks.Initially,iterative rules for diverse fractal units are skillfully designed to capture the actual characteristics of pore cross-sectional shapes.Subsequently,analytical relationships are derived between the iterative parameters and the area,wetted perimeter,and hydraulic diameter of pores generated by these units,followed by the establishment of a relative permeability model that considers pore geometry.The model's validity is confirmed through comparisons with experimental data and published relative permeability models,with correlation coefficients exceeding 0.996.Finally,various factors affecting two-phase flow characteristics are analyzed.The results reveal that pore geometry has a significant impact on flow behavior in porous media.Assuming that the flow channels are cylindrical typically leads to an overestimation of permeability,with the maximum relative error reaching 46.91%.Additionally,the tortuosity fractal dimension is a determinant factor influencing the relative permeability of both wetting and nonwetting fluids,and the phase permeability is sensitive to variations in solid particle size and porosity.The proposed intermingled fractal model enhances the accuracy of evaluating fluid flow characteristics in microscale pore channels and offers a novel framework for simulating porous media with complex geometries.
基金supported by CNPC Southwest Oil and Gas Field Branch's 2023 Scientific Research Program Project(20230303-14).
文摘The precision of dynamic reserve calculations in gas reservoirs is crucial for the rational and efficient development of oil and gas fields and the formulation of gas well production plans.The Shaximiao gas reservoir in the ZT block of northwestern Sichuan is densely packed and highly heterogeneous,featuring complex gas-water distribution,substantial variations in test production among gas wells,and a rapid decline rate.To precisely determine the dynamic reserves of these tight water-bearing gas wells,this study focuses on the water-tight gas reservoirs in the ZT block of northwestern Sichuan,conducting core X-ray diffraction,constant-rate mercury injection,and reservoir rock stress sensitivity experiments.Utilizing the experimental findings,the porosity and permeability of the rock samples under effective stress conditions are adjusted via binary linear regression.These adjusted parameters are then incorporated into the water-sealed gas material balance method,thereby establishing a novel approach for calculating dynamic reserves in water-tight gas reservoirs under stress sensitivity conditions.The results show that:(1)the rock porosity ranges from 6.08%to 10.22%,permeability ranges from 0.035 mD to 0.547 mD,clay mineral content ranges from 6.58%to 19.14%,pore radius distribution ranges from 90μm to 180μm,throat radius distribution ranges from 0.61μm to 3.41μm,with significant differences in throat distribution,indicating poor reservoir fluid flow capacity and strong tightness;(2)after aging experiments,rock samples exhibit plastic deformation,with porosity and permeability unable to fully recover after pressure relief.The stress sensitivity curve of rock samples shows a two-stage characteristic,with moderate to strong stress sensitivity;(3)porosity stress sensitivity is mainly influenced by pore radius and mineral composition-larger pore radius and higher clay content lead to stronger stress sensitivity,with porosity loss rates ranging from 8.26%to 23.69%.Permeability stress sensitivity is mainly influenced by throat radius and mineral composition-smaller throat radius and higher clay content result in stronger stress sensitivity,with permeability loss rates ranging from 47.91%to 62.03%;(4)a comparative analysis between the traditional dynamic reserve calculation method for gas wells and the new method considering stress sensitivity shows a relative error between 0.90%and 2.41%,with the new method demonstrating better accuracy.This study combines physical experimental results with an effective stress model of reservoir rocks to develop a new method for calculating dynamic reserves of water-bearing tight gas reservoirs under effective stress conditions,providing experimental data and example calculation results to support subsequent dynamic evaluation of gas reservoirs and the establishment of rational well allocation plans.
文摘Gastric cancer(GC)is the fifth most prevalent malignancy worldwide and remains a leading cause of cancer-related mortality.Major risk factors for GC include Helicobacter pylori infection,increasing age,high dietary salt intake,and diets deficient in vegetables and fruits.Due to the often subtle and nonspecific early symptoms,coupled with the lack of routine screening programs,a significant proportion of GC cases are diagnosed at advanced stages.The etiology of GC is multifactorial,and diagnosis is confirmed histologically through endoscopic biopsy,followed by staging via computed tomography,positron emission tomography,staging laparoscopy,and endoscopic ultrasound.Treatment strategies typically involve a multidisciplinary approach including chemotherapy,surgical resection,radiotherapy,and emerging immunotherapeutic options.Despite advances in diagnostic and therapeutic modalities,the prognosis of advanced GC remains poor,with high rates of recurrence and metastasis.In recent years,increasing attention has been given to the role of tight junction(TJ)proteins in the pathogenesis and progression of GC.TJ proteins,critical components of epithelial barrier function,have been implicated in various stages of gastric carcinogenesis,from intestinal metaplasia to invasion and metastasis.Infection and inflammation,particularly due to Helicobacter pylori,disrupt TJ integrity,compromising the gastric mucosal barrier and facilitating neoplastic transformation.This review synthesizes current evidence from PubMed,EMBASE,Google Scholar,ScienceDirect,SpringerLink,and other reputable databases to provide a comprehensive overview of the involvement of TJ proteins in GC.By elucidating the molecular interplay between TJ dysregulation and gastric tumorigenesis,this work aims to highlight the potential of TJ proteins as novel diagnostic biomarkers and therapeutic targets in GC management.
基金supported by the National Science Foundation(51674279,51804328)Major National Science and Technology Project(2017ZX05009-001,2017ZX05069,2017ZX05072)+4 种基金Shandong Province Key Research and Development Program(2018GSF116004)Shandong Province Natural Science Foundation(ZR2018BEE008,ZR2018BEE018)Fundamental Research Funds for the Central Universities(18CX02168A)China Postdoctoral Science Foundation(2018M630813)Postdoctoral Applied Research Project Foundation of Qingdao city(BY201802003)。
文摘Threshold pressure gradient has great importance in efficient tight gas field development as well as for research and laboratory experiments.This experimental study is carried out to investigate the threshold pressure gradient in detail.Experiments are carried out with and without back pressure so that the effect of pore pressure on threshold pressure gradient may be observed.The trend of increasing or decreasing the threshold pressure gradient is totally opposite in the cases of considering and not considering the pore pressure.The results demonstrate that the pore pressure of tight gas reservoirs has great influence on threshold pressure gradient.The effects of other parameters like permeability and water saturation,in the presence of pore pressure,on threshold pressure gradient are also examined which show that the threshold pressure gradient increases with either a decrease in permeability or an increase in water saturation.Two new correlations of threshold pressure gradient on the basis of pore pressure and permeability,and pore pressure and water saturation,are also introduced.Based on these equations,new models for tight gas production are proposed.The gas slip correction factor is also considered during derivation of this proposed tight gas production models.Inflow performance relationship curves based on these proposed models show that production rates and absolute open flow potential are always be overestimated while ignoring the threshold pressure gradients.
基金Supported by INBRE P20RR016474USDA-NRI 200835203-19084USDA-AFRI 2009-65203-05716
文摘AIM:To investigate the effect of side-stream smoking on gut microflora composition,intestinal inflammation and expression of tight junction proteins.METHODS:C57BL/6 mice were exposed to side-stream cigarette smoking for one hour daily over eight weeks.Cecal contents were collected for microbial composition analysis.Large intestine was collected for immunoblotting and quantitative reverse transcriptase polymerase chain reaction analyses of the inflammatory pathway and tight junction proteins.RESULTS:Side-stream smoking induced significant changes in the gut microbiota with increased mouse intestinal bacteria,Clostridium but decreased Fermicutes(Lactoccoci and Ruminococcus),Enterobacteriaceae family and Segmented filamentous baceteria compared to the control mice.Meanwhile,side-stream smoking inhibited the nuclear factor-κB pathway with reduced phosphorylation of p65 and IκBα,accompanied with unchanged mRNA expression of tumor necrosis factor-α or interleukin-6.The contents of tight junction proteins,claudin3 and ZO2 were up-regulated in the large intestine of mice exposed side-stream smoking.In addition,side-stream smoking increased c-Jun N-terminal kinase and p38 MAPK kinase signaling,while inhibiting AMPactivated protein kinase in the large intestine.CONCLUSION:Side-stream smoking altered gut microflora composition and reduced the inflammatory response,which was associated with increased expression of tight junction proteins.
基金supported by the China Postdoctoral Science Foundation(2021M702304)and Natural Science Foundation of Shandong Province(ZR2021QE260).
文摘A mathematical model for the gas-water two-phase flow in tight gas reservoirs is elaborated.The model can account for the gas slip effect,stress sensitivity,and high-speed non-Darcy factors.The related equations are solved in the framework of a finite element method.The results are validated against those obtained by using the commercial software CMG(Computer Modeling Group software for advanced recovery process simulation).It is shown that the proposed method is reliable.It can capture the fracture rejection characteristics of tight gas reservoirs better than the CMG.A sensitivity analysis of various control factors(initial water saturation,reservoir parameters,and fracturing parameters)affecting the production in tight gas wells is conducted accordingly.Finally,a series of theoretical arguments are provided for a rational and effective development/exploitation of tight sandstone gas reservoirs.
文摘The physical properties of hydrocarbon reservoirs are important factors affecting the percolation ability of the reservoirs.Tight-sand reservoirs exhibit complex pore throat connectivity due to the extensive development of micro-and nano-scale pore and throat systems.Characterizing the microscopic properties of these reservoirs using nondestructive,quantitative methods serves as an important means to determine the characteristics of microscopic pores and throats in tight-sand reservoirs and the mechanism behind the influence of these characteristics on reservoir porosity and permeability.In this study,a low-permeability sandstone sample and two tight sandstone samples collected from the Ordos Basin were nondestructively tested using high-resolution nano-CT technology to quantitively characterize their microscopic pore throat structures and model them three-dimensionally(in 3D)based on CT threshold differences and gray models.A thorough analysis and comparison reveal that the three samples exhibit a certain positive correlation between their porosity and permeability but the most important factor affecting both porosity and permeability is the microscopic pore throat structure.Although the number of pores in tight sandstones shows a minor impact on their porosity,large pores(more than 20μm)contribute predominantly to porosity,suggesting that the permeability of tight sandstones is controlled primarily by large pore throats.For these samples,higher permeability corresponds to larger average throat sizes.Therefore,throats with average radii greater than 2μm can significantly improve the permeability of tight sandstones.
文摘The tight sandstone reservoirs in the first sub-member of Chang 7 member(Chang 71)of Triassic Yanchang Formation in the Jiyuan area,Ordos Basin,show significant variations in microscopic pore-throat structure(PTS)and fluid mobility due to the influences of the northeast and northwest dual provenance systems.This study performed multiple experimental analyses on nine samples from the area to determine the petrological and petrophysical properties,as well as the PTS characteristics of reservoirs in different provenance-controlled regions.On this basis,the pore-throat size distribution(PSD)obtained from high-pressure mercury injection(HPMI)was utilized to convert the NMR movable fluid T2spectrum,allowing for quantitative characterization of the full PSD and the occurrence characteristics of movable fluids.A systematic analysis was conducted on the primary controlling factors affecting fluid mobility in the reservoir.The results indicated that the lithology in the eastern and western regions is lithic arkose.The eastern sandstones,being farther from the provenance,exhibit higher contents of feldspar and lithic fragments,along with the development of more dissolution pores.The reservoir possesses good petrophysical properties,low displacement pressure,and high pore-throat connectivity and homogeneity,indicating strong fluid mobility.In contrast,the western sandstones,being nearer to the provenance,exhibit poor grain sorting,high contents of lithic fragments,strong compaction and cementation effects,resulting in poor petrophysical properties,and strong pore-throat heterogeneity,revealing weak fluid mobility.The range of full PSD in the eastern reservoir is wider than that in the western reservoir,with relatively well-developed macropores.The macropores are the primary space for occurrence of movable fluids,and controls the fluid mobility of the reservoir.The effective porosity of movable fluids(EPMF)quantitatively represents the pore space occupied by movable fluids within the reservoir and correlates well with porosity,permeability,and PTS parameters,making it a valuable parameter for evaluating fluid mobility.Under the multi-provenance system,the eastern and western reservoirs underwent different sedimentation and diagenesis processes,resulting in differential distribution of reservoir mineral components and pore types,which in turn affects the PTS heterogeneity and reservoir quality.The composition and content of reservoir minerals are intrinsic factors influencing fluid mobility,while the microscopic PTS is the primary factor controlling it.Low clay mineral content,welldeveloped macropores,and weak pore-throat heterogeneity all contribute to the storage and seepage of reservoir fluids.
基金funded by the National Natural Scientific Foundation of China(Nos.52304008,52404038,52474043)the China Postdoctoral Science Foundation(No.2023MD734223)+1 种基金the Key Laboratory of Well Stability and Fluid&Rock Mechanics in Oil and Gas Reservoir of Shaanxi Province(No.23JS047)the Youth Talent Lifting Program of Xi'an Science and Technology Association(No.959202413078)。
文摘Supercritical CO_(2)(SC-CO_(2))fracturing stands out a promising waterless stimulation technique in the development of unconventional resources.While numerous studies have delved into the inducedfracture mechanism of SC-CO_(2),the small scale of rock samples and synthetic materials used in many studies have limited a comprehensive understanding of fracture propagation in unconventional formations.In this study,cubic tight sandstone samples with dimensions of 300 mm were employed to conduct SC-CO_(2)fractu ring experiments under true-triaxial stre ss conditions.The spatial morphology and quantitative attributes of fracture induced by water and SC-CO_(2)fracturing were compared,while the impact of in-situ stress on fracture propagation was also investigated.The results indicate that the SCCO_(2)fracturing takes approximately ten times longer than water fracturing.Furthermore,under identical stress condition,the breakdown pressure(BP)for SC-CO_(2)fracturing is nearly 25%lower than that for water fracturing.A quantitative analysis of fracture morphology reveals that water fracturing typically produces relatively simple fracture pattern,with the primary fracture distribution predominantly controlled by bedding planes.In contrast,SC-CO_(2)fracturing results in a more complex fracture morphology.As the differential of horizontal principal stress increases,the BP for SC-CO_(2)fractured rock exhibits a downward trend,and the induced fracture morphology becomes more simplified.Moreover,the presence of abnormal in-situ stress leads to a further increase in the BP for SC-CO_(2)fracturing,simultaneously enhancing the development of a more conductive fracture network.These findings provide critical insights into the efficiency and behavior of SC-CO_(2)fracturing in comparison to traditional water-based fracturing,offering valuable implication for its potential applications in unconventional reservoirs.
基金supported by the National Key Research and Development Program of China(2022YFE0206700).
文摘Understanding the storage mechanisms in CO_(2)flooding is crucial,as many carbon capture,utilization,and storage(CCUS)projects are related to enhanced oil recovery(EOR).CO_(2)storage in reservoirs across large timescales undergoes the two storage stages of oil displacement and well shut-in,which cover mul-tiple replacement processes of injection-production synchronization,injection only with no production,and injection-production stoppage.Because the controlling mechanism of CO_(2)storage in different stages is unknown,the evolution of CO_(2)storage mechanisms over large timescales is not understood.A math-ematical model for the evaluation of CO_(2)storage,including stratigraphic,residual,solubility,and mineral trapping in low-permeability tight sandstone reservoirs,was established using experimental and theoret-ical analyses.Based on a detailed geological model of the Huaziping Oilfield,calibrated with reservoir permeability and fracture characteristic parameters obtained from well test results,a dynamic simulation of CO_(2)storage for the entire reservoir life cycle under two scenarios of continuous injection and water-gas alternation were considered.The results show that CO_(2)storage exhibits the significant stage charac-teristics of complete storage,dynamic storage,and stable storage.The CO_(2)storage capacity and storage rate under the continuous gas injection scenario(scenario 1)were 6.34×10^(4)t and 61%,while those under the water-gas alternation scenario(scenario 2)were 4.62×10^(4)t and 46%.The proportions of stor-age capacity under scenarios 1 and 2 for structural or stratigraphic,residual,solubility,and mineral trap-ping were 33.36%,33.96%,32.43%,and 0.25%;and 15.09%,38.65%,45.77%,and 0.49%,respectively.The evolution of the CO_(2)storage mechanism showed an overall trend:stratigraphic and residual trapping first increased and then decreased,whereas solubility trapping gradually decreased,and mineral trapping continuously increased.Based on these results,an evolution diagram of the CO_(2)storage mechanism of low-permeability tight sandstone reservoirs across large timescales was established.
基金Supported by the National Natural Science Foundation of China(42302141).
文摘Taking the second member of the Xujiahe Formation of the Upper Triassic in the Xinchang structural belt as an example,based on data such as logging,production,seismic interpretation and test,a systematic analysis was conducted on the structural characteristics and evolution,reservoir diagenesis and densification processes,and types and stages of faults/fractures,and revealing the multi-stage and multi-factor dynamic coupled enrichment mechanisms of tight gas reservoirs.(1)In the early Yanshan period,the paleo-structural traps were formed with low-medium maturity hydrocarbons accumulating in structural highs driven by buoyancy since reservoirs were not fully densified in this stage,demonstrating paleo-structure control on traps and early hydrocarbon accumulation.(2)In the middle-late Yanshan period,the source rocks became mature to generate and expel a large quantity of hydrocarbons.Grain size and type of sandstone controlled the time of reservoir densification,which restricted the scale of hydrocarbon charging,allowing for only a small-scale migration through sand bodies near the fault/fracture or less-densified matrix reservoirs.(3)During the Himalayan period,the source rocks reached overmaturity,and the residual oil cracking gas was efficiently transported along the late-stage faults/fractures.Wells with high production capacity were mainly located in Type I and II fault/fracture zones comprising the late-stage north-south trending fourth-order faults and the late-stage fractures.The productivity of the wells was controlled by the transformation of the late-stage faults/fractures.(4)The Xinchang structural belt underwent three stages of tectonic evolution,two stages of reservoir formation,and three stages of fault/fractures development.Hydrocarbons mainly accumulated in the paleo-structure highs.After reservoir densification and late fault/fracture adjustment,a complex gas-water distribution pattern was formed.Thus,it is summarized as the model of“near-source and low-abundance hydrocarbon charging in the early stage,and differential enrichment of natural gas under the joint control of fault-fold-fracture complex,high-quality reservoirs and structural highs in the late stage”.Faults/fractures with well-coupled fault-fold-fracture-pore are favorable exploration targets with high exploration effectiveness.
基金supported by the China National Petroleum Corporation Science and Technology Project(Study on genesis mechanism and distribution law of high quality reservoir of the fourth Member of Xujiahe Formation in middle and west Sichuan area,20230301-23)。
文摘The Triassic Xujiahe Formation in the slope zone of the Sichuan foreland basin is a new field of continental tight gas exploration in recent years.The fourth member of the Xujiahe Formation(Xu4 Member),the major interval in the Jianyang Block of the Tianfu gas field in the basin,is characterized by considerable buried depth,tight reservoirs,and strong heterogeneity.By using cast thin section,X-ray diffraction(XRD),scanning electron microscopy(SEM),fluid inclusion thermometry,and core analysis,the reservoir rock types,dominant diageneses,diagenetic history,and controls on high-graded reservoirs were investigated.It is found that the Xu4 Member in Jianyang mainly consists of lithic feldspar sandstones and feldspar lithic sandstones,followed by lithic quartz sandstones.High-energy hydrodynamic conditions in the microfacies of underwater distributary channels and mouth bars are beneficial to the preservation of primary pores and the occurrence of secondary pores,and there are no significant differences in petrophysical properties between these two microfacies.Compaction and calcareous cementation are the dominant controls on reservoir porosity decrease in the Xujiahe Formation;corrosion is the major contributor to porosity increase by generating secondary dissolved pores,e.g.intragranular dissolved pores and intergranular dissolved pores,as major reservoir space in the study area.Fracture zones around the faults inside the Xujiahe Formation(fourth‒order faults)are favorable for proximal tight gas accumulation,preservation,and production.The research findings have been successfully applied to explore the Xujiahe Formation in the slope zone of the Sichuan foreland basin.They can be referential for other similar tight sandstone gas accumulations.
基金Supported by the National Natural Science Foundation of China(52274051)CNPC-China University of Petroleum(Beijing)Strategic Cooperative Project(ZLZX2020-01).
文摘In order to identify the development characteristics of fracture network in tight conglomerate reservoir of Mahu after hydraulic fracturing,a hydraulic fracturing test site was set up in the second and third members of Triassic Baikouquan Formation(T1b2 and T1b3)in Ma-131 well area,which learned from the successful experience of hydraulic fracturing test sites in North America(HFTS-1).Twelve horizontal wells and a high-angle coring well MaJ02 were drilled.The orientation,connection,propagation law and major controlling factors of hydraulic fractures were analyzed by comparing results of CT scans,imaging logs,direct observation of cores from Well MaJ02,and combined with tracer monitoring data.Results indicate that:(1)Two types of fractures have developed by hydraulic fracturing,i.e.tensile fractures and shear fractures.Tensile fractures are approximately parallel to the direction of the maximum horizontal principal stress,and propagate less than 50 m from perforation clusters.Shear fractures are distributed among tensile fractures and mainly in the strike-slip mode due to the induced stress field among tensile fractures,and some of them are in conjugated pairs.Overall,tensile fractures alternate with shear fractures,with shear fractures dominated and activated after tensile ones.(2)Tracer monitoring results indicate that communication between wells was prevalent in the early stage of production,and the static pressure in the fracture gradually decreased and the connectivity between wells reduced as production progressed.(3)Density of hydraulic fractures is mainly affected by the lithology and fracturing parameters,which is smaller in the mudstone than the conglomerate.Larger fracturing scale and smaller cluster spacing lead to a higher fracture density,which are important directions to improve the well productivity.
基金supported by the National Natural Science Foundation of China(grants 31972908,81991500,81991502,and 32030010)Beijing Natural Science Foundation(grant 7202082).
文摘Tricellulin,a key tricellular tight junction(TJ)protein,is essential for maintaining the barrier integrity of acinar epithelia against macromolecular passage in salivary glands.This study aims to explore the role and regulatory mechanism of tricellulin in the development of salivary gland hypofunction in Sjögren’s syndrome(SS).Employing a multifaceted approach involving patient biopsies,non-obese diabetic(NOD)mice as a SS model,salivary gland acinar cell-specific tricellulin conditional knockout(TricCKO)mice,and IFN-γ-stimulated salivary gland epithelial cells,we investigated the role of tricellulin in SS-related hyposalivation.Our data revealed diminished levels of tricellulin in salivary glands of SS patients.Similarly,NOD mice displayed a reduction in tricellulin expression from the onset of the disease,concomitant with hyposecretion and an increase in salivary albumin content.Consistent with these findings,TricCKO mice exhibited both hyposecretion and leakage of macromolecular tracers when compared to control animals.Mechanistically,the JAK/STAT1/miR-145 axis was identified as mediating the IFN-γ-induced downregulation of tricellulin.Treatment with AT1001,a TJ sealer,ameliorated epithelial barrier dysfunction,restored tricellulin expression,and consequently alleviated hyposalivation in NOD mice.Importantly,treatment with miR-145 antagomir to specifically recover the expression of tricellulin in NOD mice significantly alleviated hyposalivation and macromolecular leakage.Collectively,we identified that tricellulin deficiency in salivary glands contributed to hyposalivation in SS.Our findings highlight tricellulin as a potential therapeutic target for hyposecretion,particularly in the context of reinforcing epithelial barrier function through preventing leakage of macromolecules in salivary glands.
基金supported by the Hebei Provincial Natural Science Foundation of China(No.D2023402012)the Major Science and Technology Project of China National Petroleum Corporation(No.2024DJ87).
文摘In contrast to conventional reservoirs,tight formations have more complex pore structures and significant boundary layer effect,making it difficult to determine the effective permeability.To address this,this paper first proposes a semi-empirical model for calculating boundary layer thickness based on dimensional analysis,using published experimental data on microcapillary flow.Furthermore,considering the non-uniform distribution of fluid viscosity in the flow channels of tight reservoirs,a theoretical model for boundary layer thickness is established based on fractal theory,and permeability predictions are conducted through Monte Carlo simulations.Finally,sensitivity analyses of various influencing parameters are performed.The results show that,compared to other fractal-based analytical models,the proposed permeability probabilistic model integrates parameters affecting fluid flow with random numbers,reflecting both the fractal and randomness characteristics of capillary size distribution.The computational results exhibit the highest consistency with experimental data.Among the factors affecting the boundary layer,in addition to certain conventional physical and mechanical parameters,different microstructure parameters significantly influence the boundary layer as well.A higher tortuosity fractal dimension results in a thicker boundary layer,while increases in pore fractal dimension,porosity,and maximum capillary size help mitigate the boundary layer effect.It is also observed that the permeability of large pores exhibits greater sensitivity to changes in various influencing parameters.Considering micro-scale flow effects,the proposed model enhances the understanding of the physical mechanisms of fluid transport in dense porous media.
基金financially supported by the open fund of Key Lab-oratory of Exploration Technologies for Oil and Gas Resources(Yangtze University),Ministry of Education,NO PI2023-03the open foundation of the National Engineering Laboratory for Exploration and Develop-ment of Low-Permeability Oil&Gas Fields and the National Natural Science Foundation of China(No.42474159).
文摘The pore structures of the Majiagou Formation in the Ordos Basin are complex,featuring micro-and nano-scale intra-crystalline and inter-crystalline pores that significantly impact hydrocarbon storage and flow.Precisely characterizing the rock internal structures is crucial for reservoir exploration and development.However,it is difficult to accurately characterize the pore structure of rock using traditional imaging methods to meet the simulation requirements.In this context,this study focuses on high-resolution 3D digital core reconstruction using the SliceGAN model.Specifically,the Modular Automated Processing System(MAPS)image and Quanti-tative Evaluation of Minerals by Scanning Electron Microscopy(QEMSCAN)image were combined to divide MAPS into three categories:pore,dolomite,and calcite.Then,through the SliceGAN algorithm,the 3D digital core was reconstructed.To evaluate the reconstruction,the auto-correlation function,two-point probability function,porosity,mineral content,and specific surface area were employed.The results show that the SliceGAN can effectively capture the micro-features in the core,and the internal structure of the generated core was consistent with that of the original core.This study provided a new sight for reconstructing cores with complex pore structures and strong heterogeneity and innovatively supports tight carbonate reservoir characterization and evaluation.
基金supported by the National Natural Science Foundation of China (Grant No. 42002139)the Basic Prospective Project of SINOPEC (Grant No. P23240-3)。
文摘Tight oil is the most viable target for unconventional oil and gas exploration, but the complexity of micro-/nanopore throat systems significantly affects the oil content of reservoirs. To investigate the causes of heterogeneity in oil-bearing reservoirs, a high-pressure mercury injection experiment combined with fractal theory was conducted to analyze the micro pore throat structure characteristics of the tight sandstone of Chang 7 Member reservoirs in the Ordos Basin. The factors controlling the variations in oil content among tight sandstone samples were identified based on mineral composition characteristics. The results indicate that the pore throat radius distribution is mainly unimodal an bimodal. In oil-bearing samples, the pore throat distributions align well with the corresponding permeability contribution curves, while in oil-free samples, there is a clear deviation from these curves. Mesopore throats exert the greatest influence on seepage capacity. Differences in fractal characteristics are primarily reflected in D1 values, with oil-free samples exhibiting D1 values close to 3, indicating an extremely nonuniform pore throat structure at this scale. The content of quartz, plagioclase, and chlorite is significantly higher in oil-bearing samples than in oil-free samples, whereas calcite content is lower in oil-bearing samples. There is a positive correlation between the contents of quartz, plagioclase, and chlorite with D1;their increased presence contributes to a more favorable pore throat structure.Conversely, the calcite contents show an inverse relationship with D1. Cementation increases the complexity of pore throat structures, while multiple diagenetic processes simultaneously control these characteristics, leading to variations in oil content.
基金financially supported by the National Natural Science Foundation of China(No.42402171)the China Postdoctoral Science Foundation(No.2023MD744255)+6 种基金the Natural Science Basic Research Program of Shaanxi(No.2024JC-YBQN-0353)the Scientific Research Program Funded by Shaanxi Provincial Education Department(No.23JK0600)the Shaanxi Postdoctoral Science Foundation(No.2023BSHEDZZ324)the project of Theory of Hydrocarbon Enrichment under Multi-Spheric Interactions of the Earth(No.THEMSIE04010107)the Key Research and Development Program of Shaanxi(No.2021KW-10)the Innovation Capability Support Program of Shaanxi(No.2022PT-08)the SINOPEC CCUS Fund Project(No.33550000-22ZC0613-0326)。
文摘In the context of complex tectonic evolution,due to the control of tectonic compression stress and faults on tectonic fractures,the formation and development of tectonic fractures in the T_3x~2 tight reservoirs present significant variations across different tectonic segments in the Western Sichuan Foreland Basin.We clarified the control of differential tectonic evolution on the formation and development of tectonic fractures in different tectonic segments through field-based observations,core samples,image logging,as well as fluid inclusion petrography and temperature determinations of fracture-filling materials,combined with 2D balanced cross-section restoration.The study area primarily manifests two types of tectonic fractures in the tight reservoirs:orogen-related fractures(regional fractures)and fault-related fractures.The orientations of these fractures are predominantly E-W,nearly N-S,NE,and NW.Specifically,the northern segment area only shows the development of regional fractures,while the southern and middle segments exhibit the development of both regional and tectonic fractures.There are three phases of tectonic fractures in different tectonic segments,and their formation times are relatively consistent.The Mesozoic tectonic events had a significant impact on the northern and central segments,with the amount of tectonic shortening and the rate of stratigraphic shortening gradually decreasing from the northeast to the southwest.The compressional stress resulting from tectonic compression also decreases from the northeast to the southwest.As a result,the development of first-phase and second-phase tectonic shear fractures is more pronounced in the northern and middle segments compared to the southern segment.Under the significant control of faults,the development of N-S-and NE-oriented fault-related fractures is more pronounced in the southern segment,while the development of NE-oriented fault-related fractures is relatively higher in the middle segment.Overall,there is an increased density of fractures and an increasing trend in fracture scale from the northern to the middle and then to the southern segment.
基金supported by the Innovation Fund of China National Petroleum Corporation(2020D-5007-0209).
文摘High saturation pressure reservoirs experience rapid pressure decline during exploitation,leading to significant changes in crude oil phase behavior and a continuous increase in viscosity after degassing,which adversely affects oil recovery.This challenge is particularly acute in tight sandstone reservoirs.To optimize the development strategy for such reservoirs,a series of experiments were conducted using core samples from a high saturation tight sandstone reservoir in the JS oilfield.Gas-dissolved crude oil was prepared by mixing wellhead oil and gas samples,enabling the identification of the critical point where viscosity changes as pressure decreases.Oil-water relative permeability experiments under varying viscosities revealed crude oilmobility trends with declining production pressure.Additionally,physical and numerical simulations of water huff-n-puff processeswere performed,while nuclear magnetic resonance methods explored the effects of soaking time on oil-water imbibition.Key findings include the following optimal parameters for water huff-n-puff:(1)initiating the process when formation pressure is 75%of its original level,(2)a soaking time of 48 h,(3)an injection volume of 0.6 pore volumes per cycle,and(4)a 5 MPa pressure reduction per production stage.Numerical simulations further recommend initiating water injection after one year of depletion,with an optimal cumulative injection volume of 18,000 cubic meters,a soaking time of 10 days,and a producing pressure difference of 5 MPa.
