Chinaʼs continental shale exhibits favorable geological characteristics and substantial resource potential,yet oil recovery for natural energy extraction remains critically low.Investigating the mechanisms of hydrauli...Chinaʼs continental shale exhibits favorable geological characteristics and substantial resource potential,yet oil recovery for natural energy extraction remains critically low.Investigating the mechanisms of hydraulically induced bedding fracture to generate complex fracture networks in continental shale,and establishing effective flow systems,is of utmost importance.This study employs laboratory experiments and numerical simulations to investigate the flow capacity and percolation behavior of hydraulically induced bedding fractures by different fluids in full-diameter shale cores.Hydraulic stimulation using different fluids generates bedding plane fracture networks,establishing effective flow systems.Eroded and detached shale fragments support localized fractures,thereby increasing their opening and enhancing flow capacity.Cetyltrimethylammonium bromide(CTAB)solution and SiO2 solution reduce the hydration of the shale surface,preventing shale fragments from swelling and disintegrating,leading to more stable percolation behavior.Eroded and spalled shale fragments near the injection point are transported to farther locations,where they help support localized fractures.This process differs from conventional hydraulic fracturing.Under a constant injection rate,the velocity in the smaller flow paths near the closure is significantly higher than that in the main flow paths,leading to pronounced bypass flow behavior.This restricts the percolation of fluid during imbibition in shale cores.The results provide valuable insights into the mechanism of hydraulically induced bedding fracture in continental shale,offering guidance for the effective development of shale reservoirs.展开更多
The formation of copper deposits is closely related to hydrothermal processes.Understanding the migration of copper in hydrothermal fluids aids in reconstructing mineralization processes and deciphering deposit genesi...The formation of copper deposits is closely related to hydrothermal processes.Understanding the migration of copper in hydrothermal fluids aids in reconstructing mineralization processes and deciphering deposit genesis.Copper primarily exists as Cu^(+)and Cu^(2+)in hydrothermal solutions,with redox conditions governing their interconversion.In chloride-rich geological fluids,Cu-Cl complexes are considered critical for copper transport.However,the specific types and valence transitions of Cu-Cl complexes under varying hydrothermal conditions remain poorly understood.This study employed in situ Raman spectroscopy to systematically analyze Cu+HCl and CuCl_(2)+K_(2)S_(2)O_(3)/H_(2) systems under saturated vapor pressure at 25-300℃,elucidating the effects of temperature,Cl^(-)concentration,and redox conditions on copper speciation.In the Cu^(+)HCl system,copper dissolved as monovalent Cu-Cl complexes.At high temperatures(>200℃),[CuCl_(2)]^(-)is the dominated species,whereas[CuCl_(3)]^(2-)becomes prevalent at lower temperatures and higher HCl concentrations.For the Cu^(2+)-Cl system,the dominant species transitioned from[Cu(H_(2)O)n]^(2+)(<50℃)to[CuCl_(4)]^(2-)(100℃)and further to[CuCl]^(+)and[CuCl_(2)]^(0) at 300℃.The introduction of reducing agents(K_(2)S_(2)O_(3)/H_(2))facilitated Cu^(2+)→Cu^(+)reduction,thereby stabilizing Cu^(+)-Cl complexes and inducing partial copper precipitation.The behavior of copper in chloriderich hydrothermal fluids observed in this study indicates that high-temperature oxidizing fluids facilitate Cu mobilization,while cooling and redox changes promote deposition and ore minerals formation.展开更多
Supercritical fluids play a crucial role in material transport within Earth's deep interior.Investigating the pressure-dependent atomic structures and transport properties of such fluids is essential for understan...Supercritical fluids play a crucial role in material transport within Earth's deep interior.Investigating the pressure-dependent atomic structures and transport properties of such fluids is essential for understanding their petrological,chemical,and geophysical behaviors.In this study,we employed first-principles molecular dynamics simulations to explore the structures,self-diffusion coefficients(D),and viscosities(η)of supercritical NaAlSi_(3)O_(8)-H_(2)O fluids under conditions of 2000 K and 3-10 GPa,with water contents of 30 wt% and 50 wt%.Our calculations indicate that at a water content of 30 wt%,Q^(2) and Q^(3) exhibit a certain degree of positive and negative pressure dependence,respectively,while other Q^(n) species(n represents the number of bridging oxygens connected to Si/Al)show minimal changes.At a water content of 50 wt%,Q^(2) and Q^(0) exhibit a certain degree of positive and negative pressure dependence,respectively,while other Q^(n) species show minimal changes.At both water contents,Si-O-H and molecular water in the system exhibit negative pressure dependence,suggesting that the migration of supercritical fluids from deep to shallow regions is accompanied by the release of water.The self-diffusion coefficients in the supercritical NaAlSi_(3)O_(8)-H_(2)O fluid follow the order D_(Na)≈D_(H)>D_(O)>D_(Al)≈D_(Si),with an overall weak negative pressure dependence.By comparing the viscosities of anhydrous and hydrous silicate melts from previous studies,we found that the addition of water caused a transition from negative to positive pressure dependence of viscosity,corresponding to a structural change from polymerization to depolymerization.Additionally,we calculated the fluid mobility Δp/η of supercritical NaAlSi_(3)O_(8)-H_(2)O fluids and found that their mobility is several orders of magnitude higher than that of basalt melt and is also significantly greater than that of carbonate melt.As supercritical fluids ascend from deeper to shallower regions,their mobility is further enhanced,significantly contributing to the transport of elements from subducting slabs to the overlying mantle wedge.展开更多
The electric conductivity, dynamic modulus and yield stress of the developed electrorheolo-gical fluid (ERF) are measured at different volume fraction and different electric field strengthusing a modified Rheometrics ...The electric conductivity, dynamic modulus and yield stress of the developed electrorheolo-gical fluid (ERF) are measured at different volume fraction and different electric field strengthusing a modified Rheometrics Mechanical Spectrometer (Model 605). The percolation theory isintroduced to explain electrorheological effect and found that the ERF′s have the similarpercolated network structure as that of other ordinary suspensions with a critical volume fractionvalue independent of electric field strength. A master curve of dimensionless modulus againstdimensionless volume fraction is obtained. which shows that the essence of ER phenomenonactually is one kind of the second ofder phase transition.展开更多
In recent years, the threats posed by computer viruses have become increasingly diverse and complex. While classic percolation theory provides a novel perspective for analyzing epidemics and information dissemination,...In recent years, the threats posed by computer viruses have become increasingly diverse and complex. While classic percolation theory provides a novel perspective for analyzing epidemics and information dissemination, it fails to capture the temporal dynamics of these systems and the effects of virus invasion and governmental regulation. Triadic percolation theory, a recent advancement, addresses these limitations. In this paper, we apply this new percolation mechanism to model the diffusion of computer viruses, deriving a precise mathematical formulation of the triadic percolation model and providing an analytical solution of the triadic percolation threshold. Additionally, we investigate the impact of nonlinear transmission probability characteristics on virus propagation. Numerical simulations demonstrate that reducing the network's average degree(or the positive regulation) or increasing regulatory interventions raises the outbreak threshold for computer viruses while decreasing their final size. Moreover, the study reveals that nonlinear transmission probabilities result in an increased number of solutions for the final size of the computer viruses. Our findings contribute new insights into controlling the spread of computer viruses.展开更多
Universality,encompassing critical exponents,scaling functions,and dimensionless quantities,is fundamental to phase transition theory.In finite systems,universal behaviors are also expected to emerge at the pseudocrit...Universality,encompassing critical exponents,scaling functions,and dimensionless quantities,is fundamental to phase transition theory.In finite systems,universal behaviors are also expected to emerge at the pseudocritical point.Focusing on two-dimensional percolation,we show that the size distribution of the largest cluster asymptotically approaches to a Gumbel form in the subcritical phase,a Gaussian form in the supercritical phase,and transitions within the critical finite-size scaling window.Numerical results indicate that,at consistently defined pseudocritical points,this distribution exhibits a universal form across various lattices and percolation models(bond or site),within error bars,yet differs from the distribution at the critical point.The critical polynomial,universally zero for two-dimensional percolation at the critical point,becomes nonzero at pseudocritical points.Nevertheless,numerical evidence suggests that the critical polynomial,along with other dimensionless quantities such as wrapping probabilities and Binder cumulants,assumes fixed values at the pseudocritical point that are independent of the percolation type(bond or site)but vary with lattice structures.These findings imply that while strict universality breaks down at the pseudocritical point,certain extreme-value statistics and dimensionless quantities exhibit quasi-universality,revealing a subtle connection between scaling behaviors at critical and pseudocritical points.展开更多
Transcritical and supercritical fluids widely exist in aerospace propulsion systems,such as the coolant flow in the regenerative cooling channels of scramjet engines.To numerically simulate the coolant flow,we must ad...Transcritical and supercritical fluids widely exist in aerospace propulsion systems,such as the coolant flow in the regenerative cooling channels of scramjet engines.To numerically simulate the coolant flow,we must address the challenges in solving Riemann problems(RPs)for real fluids under complex flow conditions.In this study,an exact numerical solution for the one-dimensional RP of two-parameter fluids is developed.Due to the comprehensive resolution of fluid thermodynamics,the proposed solution framework is suitable for all forms of the two-parameter equation of state(EoS).The pressure splitting method is introduced to enable parallel calculation of RPs across multiple grid points.Theoretical analysis demonstrates the isentropic nature of weak waves in two-parameter fluids,ensuring that the same mathematical properties as ideal gas could be applied in Newton's iteration.A series of numerical cases validate the effectiveness of the proposed method.A comparative analysis is conducted on the exact Riemann solutions for the real fluid EoS,the ideal gas EoS,and the improved ideal gas EoS under supercritical and transcritical conditions.The results indicate that the improved one produces smaller errors in the calculation of momentum and energy fluxes.展开更多
The Gejiu tin-copper-(tungsten)(Sn-Cu-(W))polymetallic district is located in the southwest of the W-Sn metallogenic belt in the western Youjiang Basin,Yunnan,Southwest China.Abundant W minerals have been identified i...The Gejiu tin-copper-(tungsten)(Sn-Cu-(W))polymetallic district is located in the southwest of the W-Sn metallogenic belt in the western Youjiang Basin,Yunnan,Southwest China.Abundant W minerals have been identified in the region via exploration.However,metallogenic sources and evolution of W remain unclear,and the existing metallogenic model has to be updated to guide further ore prospecting.Elemental and Sr-Nd isotopic data for scheelites assist in the determination of sources and evolution of the W-mineralizing fluids and metals in the district.Based on field geological survey,the scheelites in the Gejiu district can be categorized into three types:altered granite(Type Ⅰ),quartz vein(Type Ⅱ)from the Laochang deposit,and skarn(Type Ⅲ)from the Kafang deposit.Types Ⅰ and Ⅱ scheelites have low molybdenum(Mo)and strontium(Sr)contents,and Type Ⅱ scheelite has lower Sr contents than Type Ⅰ as well as higher Mo and Sr contents than Type Ⅲ scheelites.Varying Mo contents across the scheelite types suggests that the oxygen fugacity varied during ore accumulation.Type Ⅰ and Type Ⅱ scheelites exhibit similar rare earth elements(REE)patterns;Type Ⅲ scheelite contains lower REE content,particularly HREE,compared with the other scheelites.All scheelites exhibit negative Eu anomalies in the chondrite-normalized REE patterns.As the W-mineralization and two-mica granite share close spatial and temporal relationships,the negative Eu anomalies were likely inherited from the two-mica granite.Type Ⅰ and Type Ⅱ scheelites display varied(^(87)Sr/^(86)Sr)_(82 Ma)(0.7090-0.7141)andε_(Nd)(82 Ma)(from−9.9 to−5.4)values,similar to those of granite.However,Type Ⅲ scheelite exhibits lower(^(87)Sr/^(86)Sr)_(82 Ma)(0.7083-0.7087)and lowerε_(Nd)(82 Ma)(from−10.5 to−6.9)values than the two-mica granite.This indicates that the two-mica granite alone did not provide the ore-forming fluids and metals and that the Type Ⅲ scheelite ore-forming fluids likely involved external fluids that were probably derived from carbonate rocks.The implication is that highly differentiated two-mica granites were the source of primary W-bearing metals and fluids,which is consistent with earlier research on the origin of Sn ore-forming materials.展开更多
To investigate the stable chromium(Cr)isotope variations during melt percolation in the mantle,we ana-lyzed the Cr isotopic compositions of fresh ultramafic rocks from the Balmuccia and Baldissero peridotite massifs l...To investigate the stable chromium(Cr)isotope variations during melt percolation in the mantle,we ana-lyzed the Cr isotopic compositions of fresh ultramafic rocks from the Balmuccia and Baldissero peridotite massifs located in the Italian Alps.These massifs represent fragments of the subcontinental lithospheric mantle.The samples collected included lherzolites,harzburgites,dunites,and pyroxenites.Lherzolites,formed through 5%-15%fractional melting of a primitive mantle source,exhibited δ^(53)Crvalues ranging from−0.13‰±0.03‰to−0.03‰±0.03‰.These values correlated negatively with Al_(2)O_(3)content,sug-gesting that partial melting induces Cr isotopic fractionation between the melts and residual peridotites.Harzburgites and dunites,influenced by the silicate melt percolation,displayed distinctδ^(53)Cr values.Notably,dunites not spatially associated with the pyroxenite veins exhibited slightly elevatedδ^(53)Cr val-ues(−0.05‰±0.03‰to 0.10‰±0.03‰)relative to lherzolites.This difference likely resulted from pyroxene dissolution and olivine precipitation during melt percolation processes.However,one dunite sample in direct contact with pyroxenite veins showed lowerδ^(53)Cr values(−0.26‰±0.03‰),possibly owing to the kinetic effects during silicate melt percolation.Pyroxenites are formed through the interac-tion of basaltic melts with the surrounding peridotite via a metasomatic reaction or crystallization in a vein.Most of theirδ^(53)Cr values(−0.26‰±0.03‰to−0.13‰±0.03‰)are positively correlated with MgO contents,suggesting that they were influenced by magmatic differentiation.However,two subsam-ples from a single clinopyroxenite vein exhibit anomalously lowδ^(53)Crvalues(−0.30‰±0.03‰and−0.43‰±0.03‰),which are attributed to kinetic isotopic fractionation during melt-percolation pro-cesses.Our findings suggest that melt percolation processes in the mantle contribute to the Cr isotopic heterogeneity observed within the Earth’s mantle.展开更多
This study presents a theoretical and experimental analysis of laminar flow behavior of high-viscous non-Newtonian power-law and Bingham fluids in multiple structural bifurcation channel distributors.Theoretical model...This study presents a theoretical and experimental analysis of laminar flow behavior of high-viscous non-Newtonian power-law and Bingham fluids in multiple structural bifurcation channel distributors.Theoretical models are derived to describe velocity profiles,shear rate distribution,and pressure drop across specific channels.Modified pressure drop models are proposed based on experiments on 6 kinds of non-Newtonian fluids and 3 types of bifurcation channel distributors with different transition areas.Specifically,the deviations between the theoretical models and the experimental results are systematically analyzed,and models were modified with correction coefficients based on Reynolds number and dimensionless shape factor.The theoretical results,modified results and experimental data are compared and discussed to ensure the accuracy of the modified models,demonstrating a significant improvement in the prediction of pressure drops for high-viscous non-Newtonian fluids in certain types of bifurcation channels.Additional experiments and analyses were carried out to validate the modified models and the results suggest that the models offer a certain degree of universal applicability in bifurcation channel designs.It implies that for other types of bifurcation channel distributors,similar correction methods based on Reynolds number and shape factor may also be applicable even with different coefficients.展开更多
Metallic nanowires have served as novel materials for soft electronics due to their outstanding mechanical compliance and electrical properties.However,weak adhesion and low mechanical robustness of nanowire networks ...Metallic nanowires have served as novel materials for soft electronics due to their outstanding mechanical compliance and electrical properties.However,weak adhesion and low mechanical robustness of nanowire networks to substrates significantly undermine their reliability,necessitating the use of an insulating protective layer,which greatly limits their utility.Herein,we present a versatile and generalized laser-based process that simultaneously achieves strong adhesion and mechanical robustness of nanowire networks on diverse substrates without the need for a protective layer.In this method,the laser-induced photothermal energy at the interface between the nanowire network and the substrate facilitates the interpenetration of the nanowire network and the polymer matrix,resulting in mechanical interlocking through percolation.This mechanism is broadly applicable across different metallic nanowires and thermoplastic substrates,significantly enhancing its universality in diverse applications.Thereby,we demonstrated the mechanical robustness of nanowires in reusable wearable physiological sensors on the skin without compromising the performance of the sensor.Furthermore,enhanced robustness and electrical conductivity by the laser-induced interlocking enables a stable functionalization of conducting polymers in a wet environment,broadening its application into various electrochemical devices.展开更多
Recent advances in statistical physics highlight the significant potential of machine learning for phase transition recognition.This study introduces a deep learning framework based on graph neural network to investig...Recent advances in statistical physics highlight the significant potential of machine learning for phase transition recognition.This study introduces a deep learning framework based on graph neural network to investigate non-equilibrium phase transitions,specifically focusing on the directed percolation process.By converting lattices with varying dimensions and connectivity schemes into graph structures and embedding the temporal evolution of the percolation process into node features,our approach enables unified analysis across diverse systems.The framework utilizes a multi-layer graph attention mechanism combined with global pooling to autonomously extract critical features from local dynamics to global phase transition signatures.The model successfully predicts percolation thresholds without relying on lattice geometry,demonstrating its robustness and versatility.Our approach not only offers new insights into phase transition studies but also provides a powerful tool for analyzing complex dynamical systems across various domains.展开更多
Understanding the thermodynamic behavior of complex fluids in confined environments is critical for various industrial and natural processes including but not limited to polymer flooding enhanced oil recovery(EOR).In ...Understanding the thermodynamic behavior of complex fluids in confined environments is critical for various industrial and natural processes including but not limited to polymer flooding enhanced oil recovery(EOR).In this work,we develop Atif-V2.0,an extended classical density functional theory(cDFT)framework that integrates the interfacial statistical associating fluid theory(iSAFT)to model multicomponent associating fluids composed of water-soluble polymers,alkanes,and water.Building on the original theoretical framework of Atif for modeling nanoconfined inhomogeneous fluids,Atif-V2.0 embeds explicit solvent and captures additional physical interactions-hydrogen bonding,which are critical in associating fluid systems.The other key feature of Atif-V2.0 is its ability to account for polymer topology.We demonstrate its capability by predicting the equilibrium structure and thermodynamic behavior of branched hydrolyzed polyacrylamide solutions near hard walls with various branching topologies,which provides a robust theoretical tool for the rational design of EOR polymers.展开更多
Aiming at the leakage problem in the compact sandstone drilling of the Keziluoyi Formation in South-west Tarim,Nano-core-emulsion was prepared by coating modified nano-SiO_(2) with nano-emulsion,its particle size D50 ...Aiming at the leakage problem in the compact sandstone drilling of the Keziluoyi Formation in South-west Tarim,Nano-core-emulsion was prepared by coating modified nano-SiO_(2) with nano-emulsion,its particle size D50 is about 100 nm,with good dispersion stability.When 0.8%Nano-core-emulsion is added to 5%bentonite slurry,the fluid loss can be reduced by 40%,and the filter cake thickness can be reduced by 84%.Using a Nano-core-emulsion to optimize the plugging performance of potassium pol-ysulfonate drilling fluid can reduce the fluid loss of the drilling fluid by 52%,the resulting filter cake is dense and tough,and the thickness is reduced by 40%.Using the pressure conduction method to evaluate the plugging rate,the plugging rate of the drilling fluid of the Nano-core-emulsion on the core of the Keziluoyi Formation is 63.4%,which is 20.9%higher than that of the field drilling fluid.According to microscopic examination and CT scanning analysis,the material has the plugging characteristics of"inner rigid support+outer soft deformation"and has demonstrated good field application results.展开更多
Millimeter channel reactors(MCRs)have received increasing attention because of their ability to enhance treatment capacity in addition to the advantages of microchannels.In previous studies,less work has been conducte...Millimeter channel reactors(MCRs)have received increasing attention because of their ability to enhance treatment capacity in addition to the advantages of microchannels.In previous studies,less work has been conducted on the micromixing process and enhancement strategies for non-Newtonian fluids in MCRs.In this study,the micromixing efficiency in MCRs was experimentally investigated using CMC(carboxymethyl cellulose sodium)aqueous solution to simulate a non-Newtonian fluid,and the enhanced mechanism of micromixing efficiency by the addition of internals and rotation was analyzed by computational fluid dynamics(CFD)simulations.The results show that in the conventional channel,increasing the flow rate improves the micromixing efficiency when the CMC concentration is low.However,when the CMC concentration is higher,the higher the flow rate,the lower the micromixing efficiency.The highest micromixing efficiency is obtained for the rotationally coupled inner components,followed by the single rotation and the lowest is for the internals only.CFD simulations reveal that the most effective way to improve the micromixing efficiency of non-Newtonian fluids with shear-thinning behavior is to increase the shear force in the reactor,which effectively reduces the apparent viscosity.These results provide the theoretical foundation for enhancing the micromixing process of non-Newtonian fluids in small-size reactors.展开更多
Weathered crust elution-deposited rare earth ores(WREOs)are rich in medium and heavy rare earth.In order to improve the in-situ leaching process,which is prone to landslides and poor permeability,cationic hydroxyethyl...Weathered crust elution-deposited rare earth ores(WREOs)are rich in medium and heavy rare earth.In order to improve the in-situ leaching process,which is prone to landslides and poor permeability,cationic hydroxyethyl cellulose(PQ-10)was used as a novel green swelling inhibitor and percolation promoter and was mixed with conventional leaching agent ammonium sulfate((NH_(4))_(2)SO_(4))to form a composite leaching agent to study the performance and mechanism of swelling inhibition and percolation promotion.Adding PQ-10 can inhibit the hydration swelling of WREOs,promote the percolation effect of the leaching agent,improve the rare earth(RE)leaching efficiency,and reduce the im purity aluminum(Al)leaching efficiency.Compared with the conventional leaching agent 2 wt%(NH_(4))_(2)SO_(4),the percolation time is reduced by 50%by using the composite leaching agent(0.02 wt%PQ-10+2 wt%(NH_(4))_(2)SO_(4)).PQ-10 has positively charged quaternary ammonium groups and hydrophilic group hydroxyl groups,which makes it easy to adsorb on WREOs multiple sites through electrostatic interaction and hydrogen bonding,weakening the electrostatic repulsion between mineral particles,reducing the WREOs interlayer spacing,compressing the double electric layer thickness at the solid-liquid interface,weakening the mineral hydration swelling and increasing the percolation rate.The long carbon chains of the polymer entangle and link the fine mineral particles to agglomerate them,increasing their particle size and reduc ing their hydration dispersion,and preventing blockage of the pe rcolation pores caused by migration of the fine particles through the ore body with the solution.PQ-10 molecules also insert the mine ral interlayer and expulsion of the internal water,further inhibiting the swelling of WREOs.Adding PQ-10 reduces the surface tension of(NH_(4))_(2)SO_(4)solution,improving the spreading and spreading ability of the solution,reducing the adhesion work between molecules in the solid-liquid phase and the adhesion work reduction factor.It proves that PQ-10 promotes the percolation effect of the leaching process of WREOs.In addition,PQ-10 expands the leaching pore size and seepage channels,further improving the percolation rate.展开更多
Drilling operations in carbonate rock heavy oil blocks(e.g.,in the Tahe Oilfield)are challenged by the intrusion of high-viscosity,temperature-sensitive formation heavy oil into the drilling fluid.This phenomenon ofte...Drilling operations in carbonate rock heavy oil blocks(e.g.,in the Tahe Oilfield)are challenged by the intrusion of high-viscosity,temperature-sensitive formation heavy oil into the drilling fluid.This phenomenon often results in wellbore blockage,reduced penetration rates,and compromised well control,thereby significantly limiting drilling efficiency and operational safety.To address this issue,this study conducts a comprehensive investigation into the mechanisms governing heavy oil invasion using a combination of laboratory experiments and field data analysis.Findings indicate that the reservoir exhibits strong heterogeneity and that the heavy oil possesses distinctive physical properties.The intrusion process is governed by multiple interrelated factors,including pressure differentials,pore structure,and the rheological behavior of the heavy oil.Experimental results reveal that the invasion of heavy oil occurs in distinct phases,with temperature playing a critical role in altering its viscosity.Specifically,as temperature increases,the apparent viscosity of the drilling fluid decreases;however,elevated pressures induce a nonlinear increase in viscosity.Furthermore,the compatibility between the drilling fluid and the intruding heavy oil declines markedly with increasing oil concentration,substantially raising the risk of wellbore obstruction.Simulation experiments further confirm that at temperatures exceeding 40℃and injection rates of L/min,the likelihood of wellbore blockage significantly≥0.4increases due to heavy oil infiltration.Based on these insights,a suite of targeted mitigation strategies is proposed.These include the formulation of specialized chemical additives,such as viscosity reducers,dispersants,and plugging removal agents,the real-time adjustment of drilling fluid density,and the implementation of advanced monitoring and early-warning systems.展开更多
Self-propulsion of a deformable ellipse immersed in an unbounded inviscid fluid is discussed in order to explore the effect of the deformation and controlled rotation of the body coupled with the shift of its internal...Self-propulsion of a deformable ellipse immersed in an unbounded inviscid fluid is discussed in order to explore the effect of the deformation and controlled rotation of the body coupled with the shift of its internal mass on the self-motion.The ellipse is capable of symmetric deformation along the two orthogonal axes and endowed with some self-regulation ability via the shift and rotation of its internal mass.From the model,the appropriate velocity potential induced by the motion of the ellipse with the deformation in an otherwise undisturbed fluid is derived,and then the equations of motion are obtained by means of integrals of the unsteady fluid pressure.The equations are utilized to explore self-translational behaviors of the ellipse through the cyclic shift of its internal mass and deformation coupled with its own controllable rotation.Analysis and numerical results show that the ellipse can break the kinematic time-reversal symmetry by properly adjusting its own rotation to coordinate with the deformation and the cyclic shift of the inner mass to meet a forward criterion,and push itself to move persistently forward without a regression at zero system momentum,exhibiting some basic serpentine movements according as the ellipse performs complete revolutions or oscillates between two extreme yaw angles during its self-motion.展开更多
Jadeitites are formed either through direct precipitation from Na-Al-Si rich fluids(P-type),or by replacement of magmatic protoliths(R-type)in subduction zones.They are valuable targets for investigating the mobility ...Jadeitites are formed either through direct precipitation from Na-Al-Si rich fluids(P-type),or by replacement of magmatic protoliths(R-type)in subduction zones.They are valuable targets for investigating the mobility behavior and chemical composition of subduction zone fluids.The Rio San Juan Complex(RSJC)in the northern Dominican Republic hosts both P-and R-type jadeitites and jadeite-rich rocks,which provide ideal samples for addressing such issues.Here,we present trace element and Sr-Nd-O-Si isotope compositions of RSJC jadeitites and related rocks.Most samples show similar REE patterns,trace element distributions and δ^(18)O values to those of plagiogranite protoliths,indicating the predominance of R-type origin in RSJC.The P-type samples exhibit slightly higherδ^(30)Si values(−0.15‰to 0.25‰)than that of R-type samples(−0.20‰to 0.08‰),which place above the igneous array.The low(^(87)Sr/^(86)Sr)_(i)(0.70346 to 0.70505)and highεNd(t)values(4.6 to 6.8)of the P-type jadeitites and quartzites,along with relatively lowδ^(18)O values(4.7‰to 6.4‰)of their forming fluids,indicate that the fluids are likely derived from the altered basaltic crust rather than from oceanic sediment.However,the estimated jadeitite-and quartzite-forming fluids exhibit distinctδ^(30)Si values(0.76‰to 0.99‰and-0.48‰to-0.08‰,respectively),implying an evolution of the fluids that modified the Si isotopic compositions.Since fluid metasomatism and related desilication process could have lowered the whole-rock δ^(30)Si values,the heavy Si isotope compositions of the R-type samples are produced from the external fluids.Combing Rayleigh distillation and binary mixing simulations,we propose that fluids derived from altered oceanic crust obtained high δ^(30)Si values after crystallization of minerals enriched in light Si isotopes.The P-type jadeitites are formed through direct precipitation from this fluid.As the plagiogranite protoliths were continuously replaced by this fluid,the formed R-type samples(jadeitites and quartzites)also exhibit high δ^(30)Si values.Such rocks could significantly alter the Si isotope compositions of local mantle when they are deeply subducted at convergent plate margins.展开更多
The phenomenon of mud volcanism has a connection with the processes of hydrocarbon generation.However,the genesis of sediments is not often taken into consideration.The study of mud volcanoes in the West Kuban margina...The phenomenon of mud volcanism has a connection with the processes of hydrocarbon generation.However,the genesis of sediments is not often taken into consideration.The study of mud volcanoes in the West Kuban marginal marine basin and the Junggar freshwater basin revealed significant isotope-geochemical differences due to various types of sedimentation.The waters from both basins exhibit three principal geochemical facies:Na-HCO_(3),Na-Cl-HCO_(3),and Na-Cl,of which the latter type of water is the dominant.The analysis of genetic coefficients(Cl/Br,Na/Br,and B/Cl)allowed us to distinguish different pathways of mud volcanic water evolution:evaporite dissolution,formation(sedimentation)waters,and waters formed by active water-rock interaction.Through statistical research,we were able to determine that noticeable variations in the behavior of chemical elements in waters from different areas can reflect discrepancies in the geological environment and the evolutionary stage of the diagenetic water transformation.Using thermodynamic modeling,the main directions of mass transfer were shown.It was established that the waters of the Junggar Basin were at a relatively early stage of evolution and had reached equilibrium only with carbonates,while in the formation waters of the West Kuban Basin,element concentrations were also controlled by silicate minerals.The correlations betweenδ^(18)O andδ~2H values and saturation indices of halides,aluminosilicates,sulfates,and borates confirm the enrichment of water with heavy isotopes during interactions with rocks without evaporation or thermal water partition.These reactions are characterized by clay dehydration and water enrichment with^(18)O and B.The data obtained made it possible to clarify the depths of formation of mud-volcanic fluids and their possible stratigraphic sources.展开更多
基金supported by the Frontier and Fundamental Research of Active Nanofluids Flooding for Enhanced Oil Recovery through Discontinuous and Variable-circle Modes in High Temperature and High Salinity Offshore Oilfields(U22B6005)National Natural Science Foundation of China(No.52274037)Study on Key Issues of Enhanced Oil Recovery of Gulong Shale Oil(DQYT-2022-JS-761).
文摘Chinaʼs continental shale exhibits favorable geological characteristics and substantial resource potential,yet oil recovery for natural energy extraction remains critically low.Investigating the mechanisms of hydraulically induced bedding fracture to generate complex fracture networks in continental shale,and establishing effective flow systems,is of utmost importance.This study employs laboratory experiments and numerical simulations to investigate the flow capacity and percolation behavior of hydraulically induced bedding fractures by different fluids in full-diameter shale cores.Hydraulic stimulation using different fluids generates bedding plane fracture networks,establishing effective flow systems.Eroded and detached shale fragments support localized fractures,thereby increasing their opening and enhancing flow capacity.Cetyltrimethylammonium bromide(CTAB)solution and SiO2 solution reduce the hydration of the shale surface,preventing shale fragments from swelling and disintegrating,leading to more stable percolation behavior.Eroded and spalled shale fragments near the injection point are transported to farther locations,where they help support localized fractures.This process differs from conventional hydraulic fracturing.Under a constant injection rate,the velocity in the smaller flow paths near the closure is significantly higher than that in the main flow paths,leading to pronounced bypass flow behavior.This restricts the percolation of fluid during imbibition in shale cores.The results provide valuable insights into the mechanism of hydraulically induced bedding fracture in continental shale,offering guidance for the effective development of shale reservoirs.
基金jointly funded by the Strategic Priority Research Program of the Chinese Academy of Sciences(grant No.XDA0430301)the National Natural Science Foundation of China(grant Nos.42130109,41973059)。
文摘The formation of copper deposits is closely related to hydrothermal processes.Understanding the migration of copper in hydrothermal fluids aids in reconstructing mineralization processes and deciphering deposit genesis.Copper primarily exists as Cu^(+)and Cu^(2+)in hydrothermal solutions,with redox conditions governing their interconversion.In chloride-rich geological fluids,Cu-Cl complexes are considered critical for copper transport.However,the specific types and valence transitions of Cu-Cl complexes under varying hydrothermal conditions remain poorly understood.This study employed in situ Raman spectroscopy to systematically analyze Cu+HCl and CuCl_(2)+K_(2)S_(2)O_(3)/H_(2) systems under saturated vapor pressure at 25-300℃,elucidating the effects of temperature,Cl^(-)concentration,and redox conditions on copper speciation.In the Cu^(+)HCl system,copper dissolved as monovalent Cu-Cl complexes.At high temperatures(>200℃),[CuCl_(2)]^(-)is the dominated species,whereas[CuCl_(3)]^(2-)becomes prevalent at lower temperatures and higher HCl concentrations.For the Cu^(2+)-Cl system,the dominant species transitioned from[Cu(H_(2)O)n]^(2+)(<50℃)to[CuCl_(4)]^(2-)(100℃)and further to[CuCl]^(+)and[CuCl_(2)]^(0) at 300℃.The introduction of reducing agents(K_(2)S_(2)O_(3)/H_(2))facilitated Cu^(2+)→Cu^(+)reduction,thereby stabilizing Cu^(+)-Cl complexes and inducing partial copper precipitation.The behavior of copper in chloriderich hydrothermal fluids observed in this study indicates that high-temperature oxidizing fluids facilitate Cu mobilization,while cooling and redox changes promote deposition and ore minerals formation.
基金funded by National Natural Science Foundation of China(42373033,Yicheng Sun)Fundamental Research Funds for the Central Universities(B240201111,Yicheng Sun)。
文摘Supercritical fluids play a crucial role in material transport within Earth's deep interior.Investigating the pressure-dependent atomic structures and transport properties of such fluids is essential for understanding their petrological,chemical,and geophysical behaviors.In this study,we employed first-principles molecular dynamics simulations to explore the structures,self-diffusion coefficients(D),and viscosities(η)of supercritical NaAlSi_(3)O_(8)-H_(2)O fluids under conditions of 2000 K and 3-10 GPa,with water contents of 30 wt% and 50 wt%.Our calculations indicate that at a water content of 30 wt%,Q^(2) and Q^(3) exhibit a certain degree of positive and negative pressure dependence,respectively,while other Q^(n) species(n represents the number of bridging oxygens connected to Si/Al)show minimal changes.At a water content of 50 wt%,Q^(2) and Q^(0) exhibit a certain degree of positive and negative pressure dependence,respectively,while other Q^(n) species show minimal changes.At both water contents,Si-O-H and molecular water in the system exhibit negative pressure dependence,suggesting that the migration of supercritical fluids from deep to shallow regions is accompanied by the release of water.The self-diffusion coefficients in the supercritical NaAlSi_(3)O_(8)-H_(2)O fluid follow the order D_(Na)≈D_(H)>D_(O)>D_(Al)≈D_(Si),with an overall weak negative pressure dependence.By comparing the viscosities of anhydrous and hydrous silicate melts from previous studies,we found that the addition of water caused a transition from negative to positive pressure dependence of viscosity,corresponding to a structural change from polymerization to depolymerization.Additionally,we calculated the fluid mobility Δp/η of supercritical NaAlSi_(3)O_(8)-H_(2)O fluids and found that their mobility is several orders of magnitude higher than that of basalt melt and is also significantly greater than that of carbonate melt.As supercritical fluids ascend from deeper to shallower regions,their mobility is further enhanced,significantly contributing to the transport of elements from subducting slabs to the overlying mantle wedge.
文摘The electric conductivity, dynamic modulus and yield stress of the developed electrorheolo-gical fluid (ERF) are measured at different volume fraction and different electric field strengthusing a modified Rheometrics Mechanical Spectrometer (Model 605). The percolation theory isintroduced to explain electrorheological effect and found that the ERF′s have the similarpercolated network structure as that of other ordinary suspensions with a critical volume fractionvalue independent of electric field strength. A master curve of dimensionless modulus againstdimensionless volume fraction is obtained. which shows that the essence of ER phenomenonactually is one kind of the second ofder phase transition.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 12101573 and 12022113)the Fundamental Research Program of Shanxi Province,China (Grant Nos. 20210302124381,202203021211213,and 20210302123018)。
文摘In recent years, the threats posed by computer viruses have become increasingly diverse and complex. While classic percolation theory provides a novel perspective for analyzing epidemics and information dissemination, it fails to capture the temporal dynamics of these systems and the effects of virus invasion and governmental regulation. Triadic percolation theory, a recent advancement, addresses these limitations. In this paper, we apply this new percolation mechanism to model the diffusion of computer viruses, deriving a precise mathematical formulation of the triadic percolation model and providing an analytical solution of the triadic percolation threshold. Additionally, we investigate the impact of nonlinear transmission probability characteristics on virus propagation. Numerical simulations demonstrate that reducing the network's average degree(or the positive regulation) or increasing regulatory interventions raises the outbreak threshold for computer viruses while decreasing their final size. Moreover, the study reveals that nonlinear transmission probabilities result in an increased number of solutions for the final size of the computer viruses. Our findings contribute new insights into controlling the spread of computer viruses.
基金supported by the National Natural Science Foundation of China(Grant No.12275263)the Innovation Program for Quantum Science and Technology(Grant No.2021ZD0301900)Natural Science Foundation of Fujian Province of China(Grant No.2023J02032).
文摘Universality,encompassing critical exponents,scaling functions,and dimensionless quantities,is fundamental to phase transition theory.In finite systems,universal behaviors are also expected to emerge at the pseudocritical point.Focusing on two-dimensional percolation,we show that the size distribution of the largest cluster asymptotically approaches to a Gumbel form in the subcritical phase,a Gaussian form in the supercritical phase,and transitions within the critical finite-size scaling window.Numerical results indicate that,at consistently defined pseudocritical points,this distribution exhibits a universal form across various lattices and percolation models(bond or site),within error bars,yet differs from the distribution at the critical point.The critical polynomial,universally zero for two-dimensional percolation at the critical point,becomes nonzero at pseudocritical points.Nevertheless,numerical evidence suggests that the critical polynomial,along with other dimensionless quantities such as wrapping probabilities and Binder cumulants,assumes fixed values at the pseudocritical point that are independent of the percolation type(bond or site)but vary with lattice structures.These findings imply that while strict universality breaks down at the pseudocritical point,certain extreme-value statistics and dimensionless quantities exhibit quasi-universality,revealing a subtle connection between scaling behaviors at critical and pseudocritical points.
基金Project supported by the National Natural Science Foundation of China(No.12525202)。
文摘Transcritical and supercritical fluids widely exist in aerospace propulsion systems,such as the coolant flow in the regenerative cooling channels of scramjet engines.To numerically simulate the coolant flow,we must address the challenges in solving Riemann problems(RPs)for real fluids under complex flow conditions.In this study,an exact numerical solution for the one-dimensional RP of two-parameter fluids is developed.Due to the comprehensive resolution of fluid thermodynamics,the proposed solution framework is suitable for all forms of the two-parameter equation of state(EoS).The pressure splitting method is introduced to enable parallel calculation of RPs across multiple grid points.Theoretical analysis demonstrates the isentropic nature of weak waves in two-parameter fluids,ensuring that the same mathematical properties as ideal gas could be applied in Newton's iteration.A series of numerical cases validate the effectiveness of the proposed method.A comparative analysis is conducted on the exact Riemann solutions for the real fluid EoS,the ideal gas EoS,and the improved ideal gas EoS under supercritical and transcritical conditions.The results indicate that the improved one produces smaller errors in the calculation of momentum and energy fluxes.
基金financed by Yunnan Major Scientific and Technological Projects(Grant No.202202AG050006)the National Natural Science Foundation of China(Grant No.42462011)Projects of Yunnan Province Technology Hall(Grant No.202305AT350004).
文摘The Gejiu tin-copper-(tungsten)(Sn-Cu-(W))polymetallic district is located in the southwest of the W-Sn metallogenic belt in the western Youjiang Basin,Yunnan,Southwest China.Abundant W minerals have been identified in the region via exploration.However,metallogenic sources and evolution of W remain unclear,and the existing metallogenic model has to be updated to guide further ore prospecting.Elemental and Sr-Nd isotopic data for scheelites assist in the determination of sources and evolution of the W-mineralizing fluids and metals in the district.Based on field geological survey,the scheelites in the Gejiu district can be categorized into three types:altered granite(Type Ⅰ),quartz vein(Type Ⅱ)from the Laochang deposit,and skarn(Type Ⅲ)from the Kafang deposit.Types Ⅰ and Ⅱ scheelites have low molybdenum(Mo)and strontium(Sr)contents,and Type Ⅱ scheelite has lower Sr contents than Type Ⅰ as well as higher Mo and Sr contents than Type Ⅲ scheelites.Varying Mo contents across the scheelite types suggests that the oxygen fugacity varied during ore accumulation.Type Ⅰ and Type Ⅱ scheelites exhibit similar rare earth elements(REE)patterns;Type Ⅲ scheelite contains lower REE content,particularly HREE,compared with the other scheelites.All scheelites exhibit negative Eu anomalies in the chondrite-normalized REE patterns.As the W-mineralization and two-mica granite share close spatial and temporal relationships,the negative Eu anomalies were likely inherited from the two-mica granite.Type Ⅰ and Type Ⅱ scheelites display varied(^(87)Sr/^(86)Sr)_(82 Ma)(0.7090-0.7141)andε_(Nd)(82 Ma)(from−9.9 to−5.4)values,similar to those of granite.However,Type Ⅲ scheelite exhibits lower(^(87)Sr/^(86)Sr)_(82 Ma)(0.7083-0.7087)and lowerε_(Nd)(82 Ma)(from−10.5 to−6.9)values than the two-mica granite.This indicates that the two-mica granite alone did not provide the ore-forming fluids and metals and that the Type Ⅲ scheelite ore-forming fluids likely involved external fluids that were probably derived from carbonate rocks.The implication is that highly differentiated two-mica granites were the source of primary W-bearing metals and fluids,which is consistent with earlier research on the origin of Sn ore-forming materials.
基金supported by National Natural Science Foundation of China(Grant No.42473017)Hong Kong RGC grants(JLFS/P-702/24 and 17308023)China Geological Survey project(Grant No.DD20242037).
文摘To investigate the stable chromium(Cr)isotope variations during melt percolation in the mantle,we ana-lyzed the Cr isotopic compositions of fresh ultramafic rocks from the Balmuccia and Baldissero peridotite massifs located in the Italian Alps.These massifs represent fragments of the subcontinental lithospheric mantle.The samples collected included lherzolites,harzburgites,dunites,and pyroxenites.Lherzolites,formed through 5%-15%fractional melting of a primitive mantle source,exhibited δ^(53)Crvalues ranging from−0.13‰±0.03‰to−0.03‰±0.03‰.These values correlated negatively with Al_(2)O_(3)content,sug-gesting that partial melting induces Cr isotopic fractionation between the melts and residual peridotites.Harzburgites and dunites,influenced by the silicate melt percolation,displayed distinctδ^(53)Cr values.Notably,dunites not spatially associated with the pyroxenite veins exhibited slightly elevatedδ^(53)Cr val-ues(−0.05‰±0.03‰to 0.10‰±0.03‰)relative to lherzolites.This difference likely resulted from pyroxene dissolution and olivine precipitation during melt percolation processes.However,one dunite sample in direct contact with pyroxenite veins showed lowerδ^(53)Cr values(−0.26‰±0.03‰),possibly owing to the kinetic effects during silicate melt percolation.Pyroxenites are formed through the interac-tion of basaltic melts with the surrounding peridotite via a metasomatic reaction or crystallization in a vein.Most of theirδ^(53)Cr values(−0.26‰±0.03‰to−0.13‰±0.03‰)are positively correlated with MgO contents,suggesting that they were influenced by magmatic differentiation.However,two subsam-ples from a single clinopyroxenite vein exhibit anomalously lowδ^(53)Crvalues(−0.30‰±0.03‰and−0.43‰±0.03‰),which are attributed to kinetic isotopic fractionation during melt-percolation pro-cesses.Our findings suggest that melt percolation processes in the mantle contribute to the Cr isotopic heterogeneity observed within the Earth’s mantle.
基金the financial support from the National Science and Technology Major Project of China(2024XXXXX2700)the National Natural Science Foundation of China (22408099)+1 种基金the Key Research and Development Program of Xinjiang Uygur Autonomous Region (2022B01032)the National Ten Thousand Talents Program。
文摘This study presents a theoretical and experimental analysis of laminar flow behavior of high-viscous non-Newtonian power-law and Bingham fluids in multiple structural bifurcation channel distributors.Theoretical models are derived to describe velocity profiles,shear rate distribution,and pressure drop across specific channels.Modified pressure drop models are proposed based on experiments on 6 kinds of non-Newtonian fluids and 3 types of bifurcation channel distributors with different transition areas.Specifically,the deviations between the theoretical models and the experimental results are systematically analyzed,and models were modified with correction coefficients based on Reynolds number and dimensionless shape factor.The theoretical results,modified results and experimental data are compared and discussed to ensure the accuracy of the modified models,demonstrating a significant improvement in the prediction of pressure drops for high-viscous non-Newtonian fluids in certain types of bifurcation channels.Additional experiments and analyses were carried out to validate the modified models and the results suggest that the models offer a certain degree of universal applicability in bifurcation channel designs.It implies that for other types of bifurcation channel distributors,similar correction methods based on Reynolds number and shape factor may also be applicable even with different coefficients.
基金supported by the National Research Foundation of Korea(NRF)Grant(RS-2024-00343512,RS-2024-00416938).
文摘Metallic nanowires have served as novel materials for soft electronics due to their outstanding mechanical compliance and electrical properties.However,weak adhesion and low mechanical robustness of nanowire networks to substrates significantly undermine their reliability,necessitating the use of an insulating protective layer,which greatly limits their utility.Herein,we present a versatile and generalized laser-based process that simultaneously achieves strong adhesion and mechanical robustness of nanowire networks on diverse substrates without the need for a protective layer.In this method,the laser-induced photothermal energy at the interface between the nanowire network and the substrate facilitates the interpenetration of the nanowire network and the polymer matrix,resulting in mechanical interlocking through percolation.This mechanism is broadly applicable across different metallic nanowires and thermoplastic substrates,significantly enhancing its universality in diverse applications.Thereby,we demonstrated the mechanical robustness of nanowires in reusable wearable physiological sensors on the skin without compromising the performance of the sensor.Furthermore,enhanced robustness and electrical conductivity by the laser-induced interlocking enables a stable functionalization of conducting polymers in a wet environment,broadening its application into various electrochemical devices.
基金supported by the Fund from the Science and Technology Department of Henan Province,China(Grant Nos.222102210233 and 232102210064)the National Natural Science Foundation of China(Grant Nos.62373169 and 72474086)+5 种基金the Young and Midcareer Academic Leader of Jiangsu Province,China(Grant No.Qinglan Project in 2024)the National Statistical Science Research Project(Grant No.2022LZ03)Shaanxi Provincial Soft Science Project(Grant No.2022KRM111)Shaanxi Provincial Social Science Foundation(Grant No.2022R016)the Special Project for Philosophical and Social Sciences Research in Shaanxi Province,China(Grant No.2024QN018)the Fund from the Henan Office of Philosophy and Social Science(Grant No.2023CJJ112).
文摘Recent advances in statistical physics highlight the significant potential of machine learning for phase transition recognition.This study introduces a deep learning framework based on graph neural network to investigate non-equilibrium phase transitions,specifically focusing on the directed percolation process.By converting lattices with varying dimensions and connectivity schemes into graph structures and embedding the temporal evolution of the percolation process into node features,our approach enables unified analysis across diverse systems.The framework utilizes a multi-layer graph attention mechanism combined with global pooling to autonomously extract critical features from local dynamics to global phase transition signatures.The model successfully predicts percolation thresholds without relying on lattice geometry,demonstrating its robustness and versatility.Our approach not only offers new insights into phase transition studies but also provides a powerful tool for analyzing complex dynamical systems across various domains.
基金financially supported by the Key Technologies R&D Program of China National Offshore Oil Corporation(No.KJGG2021-0504)。
文摘Understanding the thermodynamic behavior of complex fluids in confined environments is critical for various industrial and natural processes including but not limited to polymer flooding enhanced oil recovery(EOR).In this work,we develop Atif-V2.0,an extended classical density functional theory(cDFT)framework that integrates the interfacial statistical associating fluid theory(iSAFT)to model multicomponent associating fluids composed of water-soluble polymers,alkanes,and water.Building on the original theoretical framework of Atif for modeling nanoconfined inhomogeneous fluids,Atif-V2.0 embeds explicit solvent and captures additional physical interactions-hydrogen bonding,which are critical in associating fluid systems.The other key feature of Atif-V2.0 is its ability to account for polymer topology.We demonstrate its capability by predicting the equilibrium structure and thermodynamic behavior of branched hydrolyzed polyacrylamide solutions near hard walls with various branching topologies,which provides a robust theoretical tool for the rational design of EOR polymers.
基金supported by Tarim Oilfield Project“Study on Formation Characteristics and Technical Countermeasures of Drilling Fluid in Yingsha and Yulong Blocks”(Project No.201019121044)the National Natural Science Foundation of China(ZX20200280).
文摘Aiming at the leakage problem in the compact sandstone drilling of the Keziluoyi Formation in South-west Tarim,Nano-core-emulsion was prepared by coating modified nano-SiO_(2) with nano-emulsion,its particle size D50 is about 100 nm,with good dispersion stability.When 0.8%Nano-core-emulsion is added to 5%bentonite slurry,the fluid loss can be reduced by 40%,and the filter cake thickness can be reduced by 84%.Using a Nano-core-emulsion to optimize the plugging performance of potassium pol-ysulfonate drilling fluid can reduce the fluid loss of the drilling fluid by 52%,the resulting filter cake is dense and tough,and the thickness is reduced by 40%.Using the pressure conduction method to evaluate the plugging rate,the plugging rate of the drilling fluid of the Nano-core-emulsion on the core of the Keziluoyi Formation is 63.4%,which is 20.9%higher than that of the field drilling fluid.According to microscopic examination and CT scanning analysis,the material has the plugging characteristics of"inner rigid support+outer soft deformation"and has demonstrated good field application results.
基金supported by the National Natural Science Foundation of China(22078009)National Key Research Program of China(2021YFC3001102,2021YFC3001100).
文摘Millimeter channel reactors(MCRs)have received increasing attention because of their ability to enhance treatment capacity in addition to the advantages of microchannels.In previous studies,less work has been conducted on the micromixing process and enhancement strategies for non-Newtonian fluids in MCRs.In this study,the micromixing efficiency in MCRs was experimentally investigated using CMC(carboxymethyl cellulose sodium)aqueous solution to simulate a non-Newtonian fluid,and the enhanced mechanism of micromixing efficiency by the addition of internals and rotation was analyzed by computational fluid dynamics(CFD)simulations.The results show that in the conventional channel,increasing the flow rate improves the micromixing efficiency when the CMC concentration is low.However,when the CMC concentration is higher,the higher the flow rate,the lower the micromixing efficiency.The highest micromixing efficiency is obtained for the rotationally coupled inner components,followed by the single rotation and the lowest is for the internals only.CFD simulations reveal that the most effective way to improve the micromixing efficiency of non-Newtonian fluids with shear-thinning behavior is to increase the shear force in the reactor,which effectively reduces the apparent viscosity.These results provide the theoretical foundation for enhancing the micromixing process of non-Newtonian fluids in small-size reactors.
基金Project supported by the National Natural Science Foundation of China(U2002215)。
文摘Weathered crust elution-deposited rare earth ores(WREOs)are rich in medium and heavy rare earth.In order to improve the in-situ leaching process,which is prone to landslides and poor permeability,cationic hydroxyethyl cellulose(PQ-10)was used as a novel green swelling inhibitor and percolation promoter and was mixed with conventional leaching agent ammonium sulfate((NH_(4))_(2)SO_(4))to form a composite leaching agent to study the performance and mechanism of swelling inhibition and percolation promotion.Adding PQ-10 can inhibit the hydration swelling of WREOs,promote the percolation effect of the leaching agent,improve the rare earth(RE)leaching efficiency,and reduce the im purity aluminum(Al)leaching efficiency.Compared with the conventional leaching agent 2 wt%(NH_(4))_(2)SO_(4),the percolation time is reduced by 50%by using the composite leaching agent(0.02 wt%PQ-10+2 wt%(NH_(4))_(2)SO_(4)).PQ-10 has positively charged quaternary ammonium groups and hydrophilic group hydroxyl groups,which makes it easy to adsorb on WREOs multiple sites through electrostatic interaction and hydrogen bonding,weakening the electrostatic repulsion between mineral particles,reducing the WREOs interlayer spacing,compressing the double electric layer thickness at the solid-liquid interface,weakening the mineral hydration swelling and increasing the percolation rate.The long carbon chains of the polymer entangle and link the fine mineral particles to agglomerate them,increasing their particle size and reduc ing their hydration dispersion,and preventing blockage of the pe rcolation pores caused by migration of the fine particles through the ore body with the solution.PQ-10 molecules also insert the mine ral interlayer and expulsion of the internal water,further inhibiting the swelling of WREOs.Adding PQ-10 reduces the surface tension of(NH_(4))_(2)SO_(4)solution,improving the spreading and spreading ability of the solution,reducing the adhesion work between molecules in the solid-liquid phase and the adhesion work reduction factor.It proves that PQ-10 promotes the percolation effect of the leaching process of WREOs.In addition,PQ-10 expands the leaching pore size and seepage channels,further improving the percolation rate.
基金Hubei Key Laboratory of Oil and Gas Drilling and Production Engineering(Yangtze University),China(Grant No.YQZC202415)Hubei Province Science and Technology Plan Project(Key R&D Special Project),China(Grant No.2023BCB070)+2 种基金Key R&D Program Project in Xinjiang,China,Grant No.2022B01042Guiding Project of Scientific Research Program of Education Department of Hubei Province,China(Grant No.B2023024)Open Fund of National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation(Southwest Petroleum University),Grant No.PLN2023-03.
文摘Drilling operations in carbonate rock heavy oil blocks(e.g.,in the Tahe Oilfield)are challenged by the intrusion of high-viscosity,temperature-sensitive formation heavy oil into the drilling fluid.This phenomenon often results in wellbore blockage,reduced penetration rates,and compromised well control,thereby significantly limiting drilling efficiency and operational safety.To address this issue,this study conducts a comprehensive investigation into the mechanisms governing heavy oil invasion using a combination of laboratory experiments and field data analysis.Findings indicate that the reservoir exhibits strong heterogeneity and that the heavy oil possesses distinctive physical properties.The intrusion process is governed by multiple interrelated factors,including pressure differentials,pore structure,and the rheological behavior of the heavy oil.Experimental results reveal that the invasion of heavy oil occurs in distinct phases,with temperature playing a critical role in altering its viscosity.Specifically,as temperature increases,the apparent viscosity of the drilling fluid decreases;however,elevated pressures induce a nonlinear increase in viscosity.Furthermore,the compatibility between the drilling fluid and the intruding heavy oil declines markedly with increasing oil concentration,substantially raising the risk of wellbore obstruction.Simulation experiments further confirm that at temperatures exceeding 40℃and injection rates of L/min,the likelihood of wellbore blockage significantly≥0.4increases due to heavy oil infiltration.Based on these insights,a suite of targeted mitigation strategies is proposed.These include the formulation of specialized chemical additives,such as viscosity reducers,dispersants,and plugging removal agents,the real-time adjustment of drilling fluid density,and the implementation of advanced monitoring and early-warning systems.
基金supported by the National Natural Science Foundation of China(Grant No.11672182).
文摘Self-propulsion of a deformable ellipse immersed in an unbounded inviscid fluid is discussed in order to explore the effect of the deformation and controlled rotation of the body coupled with the shift of its internal mass on the self-motion.The ellipse is capable of symmetric deformation along the two orthogonal axes and endowed with some self-regulation ability via the shift and rotation of its internal mass.From the model,the appropriate velocity potential induced by the motion of the ellipse with the deformation in an otherwise undisturbed fluid is derived,and then the equations of motion are obtained by means of integrals of the unsteady fluid pressure.The equations are utilized to explore self-translational behaviors of the ellipse through the cyclic shift of its internal mass and deformation coupled with its own controllable rotation.Analysis and numerical results show that the ellipse can break the kinematic time-reversal symmetry by properly adjusting its own rotation to coordinate with the deformation and the cyclic shift of the inner mass to meet a forward criterion,and push itself to move persistently forward without a regression at zero system momentum,exhibiting some basic serpentine movements according as the ellipse performs complete revolutions or oscillates between two extreme yaw angles during its self-motion.
基金supported by funds from the National Key Research and Development Program of China(Grant No.2024YFF0807302)National Natural Science Foundation of China(42273043,42173003)the International Visiting Professorship of USTC(2024BVR23).
文摘Jadeitites are formed either through direct precipitation from Na-Al-Si rich fluids(P-type),or by replacement of magmatic protoliths(R-type)in subduction zones.They are valuable targets for investigating the mobility behavior and chemical composition of subduction zone fluids.The Rio San Juan Complex(RSJC)in the northern Dominican Republic hosts both P-and R-type jadeitites and jadeite-rich rocks,which provide ideal samples for addressing such issues.Here,we present trace element and Sr-Nd-O-Si isotope compositions of RSJC jadeitites and related rocks.Most samples show similar REE patterns,trace element distributions and δ^(18)O values to those of plagiogranite protoliths,indicating the predominance of R-type origin in RSJC.The P-type samples exhibit slightly higherδ^(30)Si values(−0.15‰to 0.25‰)than that of R-type samples(−0.20‰to 0.08‰),which place above the igneous array.The low(^(87)Sr/^(86)Sr)_(i)(0.70346 to 0.70505)and highεNd(t)values(4.6 to 6.8)of the P-type jadeitites and quartzites,along with relatively lowδ^(18)O values(4.7‰to 6.4‰)of their forming fluids,indicate that the fluids are likely derived from the altered basaltic crust rather than from oceanic sediment.However,the estimated jadeitite-and quartzite-forming fluids exhibit distinctδ^(30)Si values(0.76‰to 0.99‰and-0.48‰to-0.08‰,respectively),implying an evolution of the fluids that modified the Si isotopic compositions.Since fluid metasomatism and related desilication process could have lowered the whole-rock δ^(30)Si values,the heavy Si isotope compositions of the R-type samples are produced from the external fluids.Combing Rayleigh distillation and binary mixing simulations,we propose that fluids derived from altered oceanic crust obtained high δ^(30)Si values after crystallization of minerals enriched in light Si isotopes.The P-type jadeitites are formed through direct precipitation from this fluid.As the plagiogranite protoliths were continuously replaced by this fluid,the formed R-type samples(jadeitites and quartzites)also exhibit high δ^(30)Si values.Such rocks could significantly alter the Si isotope compositions of local mantle when they are deeply subducted at convergent plate margins.
基金partly supported by the NSFC-RSF Joint Research project(Nos.42261134534,23-47-00035)funded by the Chinese Academy of Sciences President’s International Fellowship Initiative(Nos.2024VCA0006,2024VCB0013)the National Natural Science Foundation of China(No.42442006)。
文摘The phenomenon of mud volcanism has a connection with the processes of hydrocarbon generation.However,the genesis of sediments is not often taken into consideration.The study of mud volcanoes in the West Kuban marginal marine basin and the Junggar freshwater basin revealed significant isotope-geochemical differences due to various types of sedimentation.The waters from both basins exhibit three principal geochemical facies:Na-HCO_(3),Na-Cl-HCO_(3),and Na-Cl,of which the latter type of water is the dominant.The analysis of genetic coefficients(Cl/Br,Na/Br,and B/Cl)allowed us to distinguish different pathways of mud volcanic water evolution:evaporite dissolution,formation(sedimentation)waters,and waters formed by active water-rock interaction.Through statistical research,we were able to determine that noticeable variations in the behavior of chemical elements in waters from different areas can reflect discrepancies in the geological environment and the evolutionary stage of the diagenetic water transformation.Using thermodynamic modeling,the main directions of mass transfer were shown.It was established that the waters of the Junggar Basin were at a relatively early stage of evolution and had reached equilibrium only with carbonates,while in the formation waters of the West Kuban Basin,element concentrations were also controlled by silicate minerals.The correlations betweenδ^(18)O andδ~2H values and saturation indices of halides,aluminosilicates,sulfates,and borates confirm the enrichment of water with heavy isotopes during interactions with rocks without evaporation or thermal water partition.These reactions are characterized by clay dehydration and water enrichment with^(18)O and B.The data obtained made it possible to clarify the depths of formation of mud-volcanic fluids and their possible stratigraphic sources.
