Organic electrochemical transistor(OECT)devices demonstrate great promising potential for reservoir computing(RC)systems,but their lack of tunable dynamic characteristics limits their application in multi-temporal sca...Organic electrochemical transistor(OECT)devices demonstrate great promising potential for reservoir computing(RC)systems,but their lack of tunable dynamic characteristics limits their application in multi-temporal scale tasks.In this study,we report an OECT-based neuromorphic device with tunable relaxation time(τ)by introducing an additional vertical back-gate electrode into a planar structure.The dual-gate design enablesτreconfiguration from 93 to 541 ms.The tunable relaxation behaviors can be attributed to the combined effects of planar-gate induced electrochemical doping and back-gateinduced electrostatic coupling,as verified by electrochemical impedance spectroscopy analysis.Furthermore,we used theτ-tunable OECT devices as physical reservoirs in the RC system for intelligent driving trajectory prediction,achieving a significant improvement in prediction accuracy from below 69%to 99%.The results demonstrate that theτ-tunable OECT shows a promising candidate for multi-temporal scale neuromorphic computing applications.展开更多
Neuromorphic devices have garnered significant attention as potential building blocks for energy-efficient hardware systems owing to their capacity to emulate the computational efficiency of the brain.In this regard,r...Neuromorphic devices have garnered significant attention as potential building blocks for energy-efficient hardware systems owing to their capacity to emulate the computational efficiency of the brain.In this regard,reservoir computing(RC)framework,which leverages straightforward training methods and efficient temporal signal processing,has emerged as a promising scheme.While various physical reservoir devices,including ferroelectric,optoelectronic,and memristor-based systems,have been demonstrated,many still face challenges related to compatibility with mainstream complementary metal oxide semiconductor(CMOS)integration processes.This study introduced a silicon-based schottky barrier metal-oxide-semiconductor field effect transistor(SB-MOSFET),which was fabricated under low thermal budget and compatible with back-end-of-line(BEOL).The device demonstrated short-term memory characteristics,facilitated by the modulation of schottky barriers and charge trapping.Utilizing these characteristics,a RC system for temporal data processing was constructed,and its performance was validated in a 5×4 digital classification task,achieving an accuracy exceeding 98%after 50 training epochs.Furthermore,the system successfully processed temporal signal in waveform classification and prediction tasks using time-division multiplexing.Overall,the SB-MOSFET's high compatibility with CMOS technology provides substantial advantages for large-scale integration,enabling the development of energy-efficient reservoir computing hardware.展开更多
Understanding water chemistry in karst regions is crucial for improving global water resource management and deepening our knowledge of the biogeochemical cycles shaping these sensitive environments.Despite advance-me...Understanding water chemistry in karst regions is crucial for improving global water resource management and deepening our knowledge of the biogeochemical cycles shaping these sensitive environments.Despite advance-ments in karst hydrology,significant gaps remain in long-term trends,underlying processes,and quantitative effects of environmental changes.This is especially true in areas like the Wujiang River(WJ)in China,where human activities such as reservoir construction and land use/cover changes have accelerated hydrochemical changes.We combined recent and historical monitoring data to provide a detailed analysis of the spatial and temporal characteristics,evolution,and controlling factors of major ions in WJ.These findings are important for local water management and contribute to global efforts to manage similar karst systems facing human-induced pressures.Our research shows clear seasonal differences in solute concentrations,with higher levels during the dry season.WJ’s water is rich in calcium,with Ca-HCO_(3) ion pairs being the most common.Reservoir monitor-ing stations show much higher levels of NO_(3)^(−)and SO_(4)^(2−)compared to river-type stations,likely due to longer hydraulic retention time and increased acid deposition.The study confirms the significant role of pH and water temperature in rock weathering processes.Land use/cover changes were identified as the primary drivers of solute variations(46.37%),followed by lithology(13.92%)and temperature(8.35%).Over the past two decades,in-tense carbonate weathering has been observed,especially during wet seasons.Among karstic provinces,Guizhou Province stands out with the highest ion concentrations,indicative of its extensive karst coverage and heightened weathering processes.展开更多
Microbial communities play indispensable roles in the biogeochemical cycling of river ecosystems.However,the response patterns of microbial community diversity,niche breadth,and assembly to rainfall disturbances in co...Microbial communities play indispensable roles in the biogeochemical cycling of river ecosystems.However,the response patterns of microbial community diversity,niche breadth,and assembly to rainfall disturbances in complex mountainous riverine reservoirs remain inadequately understood.We employed high-throughput sequencing of 16S and 18S ribosomal RNA genes,along with multivariate statistical methods to systematically investigate prokaryotic and eukaryotic microorganisms in the riverine Zhaoshandu Reservoir,Wenzhou,Zhejiang,East China.Results show significant temporal heterogeneity in both prokaryotic and eukaryotic microbial communities,with eukaryotic microbes showing more pronounced temporal variation.Canonical correspondence analysis revealed that rainfall and water temperature were the key drivers shaping microbial communities.Additionally,eukaryotic microorganisms exhibited a more pronounced response to rainfall and water temperature compared to prokaryotes.Modified stochasticity ratio model indicated that deterministic processes predominantly governed microbial community assembly,with stronger deterministic processes in eukaryotic compared to prokaryotic microorganisms.Rainfall has significantly altered water quality,notably increasing phosphorus concentration in the water column.Total phosphorus and total nitrogen showed significant correlations with the niche breadth of prokaryotic and eukaryotic microorganisms,and phosphorus nutrients served as keystones and playing indispensable roles in their co-occurrence networks.A structural equation model confirmed the notable impacts of rainfall and water temperature on microbial community diversity,further revealing that rainfall indirectly influenced the niche breadth and co-occurrence relationships of microbial communities by altering phosphorus concentrations.The findings underscore the influence of rainfall and water temperature on microbial distribution,highlighting the sensitivity of riverine reservoir ecosystems to climate change.展开更多
In recent years,significant breakthroughs have been achieved in the exploration of deep volcanic rocks in the Junggar Basin,highlighting their substantial exploration potential.The complex distribution of volcanic res...In recent years,significant breakthroughs have been achieved in the exploration of deep volcanic rocks in the Junggar Basin,highlighting their substantial exploration potential.The complex distribution of volcanic reservoirs is attributed to the multi-phase tectonic evolution within the basin,with their superior reservoir properties playing a crucial role in natural gas formation.However,due to the combined effects of multi-cyclic volcanic eruptions and tectonic activities,predicting volcanic facies distribution and favorable reservoirs remains highly challenging.This study focuses on the third member of the Jiamuhe Formation in the Zhongguai Uplift.By integrating drilling and petrophysical data with well-seismic analysis techniques,a seismic identification model for volcanic reservoirs has been established.The findings reveal that different facies exhibit distinct seismic response characteristics.Andesite,rhyolite,volcanic breccia,and volcanic clastic rocks show variability in amplitude,frequency,and continuity.Using structural-guided filtering,high-resolution coherence analysis,and 3D body carving techniques,the locations of volcanic craters and eruption centers were successfully identified,further clarifying the distribution patterns of volcanic facies.By combining multi-attribute clustering analysis and seismic attribute extraction,a volcanic facies zone distribution map was generated,and favorable exploration directions for volcanic reservoirs were proposed.The study provides technical guidance for the exploration of deep volcanic oil and gas reservoirs in the Junggar Basin and holds significant application value.展开更多
With the efficient and intelligent development of computer-based big data processing,applying machine learning methods to the processing and interpretation of logging data in the field of geophysical well logging has ...With the efficient and intelligent development of computer-based big data processing,applying machine learning methods to the processing and interpretation of logging data in the field of geophysical well logging has broad potential for improving production efficiency.Currently,the Jiyuan Oilfield in the Ordos Basin relies mainly on manual reprocessing and interpretation of old well logging data to identify different fluid types in low-contrast reservoirs,guiding subsequent production work.This study uses well logging data from the Chang 1 reservoir,partitioning the dataset based on individual wells for model training and testing.A deep learning model for intelligent reservoir fluid identification was constructed by incorporating the focal loss function.Comparative validations with five other models,including logistic regression(LR),naive Bayes(NB),gradient boosting decision trees(GBDT),random forest(RF),and support vector machine(SVM),show that this model demonstrates superior identification performance and significantly improves the accuracy of identifying oil-bearing fluids.Mutual information analysis reveals the model's differential dependency on various logging parameters for reservoir fluid identification.This model provides important references and a basis for conducting regional studies and revisiting old wells,demonstrating practical value that can be widely applied.展开更多
Coal mine underground reservoirs help address the severe water imbalance in ecologically fragile mining regions of western China,but evaluating their storage capacity remains challenging due to the coupled effects of ...Coal mine underground reservoirs help address the severe water imbalance in ecologically fragile mining regions of western China,but evaluating their storage capacity remains challenging due to the coupled effects of gangue deformation,saturation,and goaf geometry.This study investigates the deformation and void evolution of fragmented gangue with varying lithologies,particle sizes,and water contents through an independent-developed testing system and theoretical model.A planar micro-unit model and a three-dimensional spatial structure model are proposed to quantify the storage coefficient and total reservoir capacity of underground water storage structures.These models incorporate the effects of stratified lithologies,saturation-induced softening,and spatially distributed stress conditions.The methodology is applied to the underground reservoir in Chahasu coal mine,and the results show that under increasing stress,storage coefficients decline exponentially,with pronounced differences between single-and double-lithology structures.The storage coefficient in the spatial model demonstrate greater resilience to stress concentration compared to planar models,and further analysis identifies critical thresholds in roof fracture distances and stress-recovery times affecting long-term storage performance.This research provides a comprehensive framework for evaluating underground reservoir storage potential,offering theoretical support and engineering guidance for the sustainable utilization of mine water.展开更多
The strong vertical discontinuities pose a fundamental challenge to optimizing stimulated reservoir volume(SRV)in multilayered reservoirs.This research proposes a radial borehole-assisted horizontal well fracturing te...The strong vertical discontinuities pose a fundamental challenge to optimizing stimulated reservoir volume(SRV)in multilayered reservoirs.This research proposes a radial borehole-assisted horizontal well fracturing technology,which is expected to achieve effective vertical stimulation and commingled production across multiple pay zones.Under different geological and engineering conditions,the vertical propagation behavior of hydraulic fractures guided by radial boreholes can be determined by adjusting the interlayered lithologies and radial borehole configurations in experimental samples.Experimental results reveal four fracture network patterns:passivated,cross-layer,skip-layer,and hybrid fractures in the radial borehole fracturing.The radial boreholes perform better fracture guiding performances in the high-brittleness interlayers,which form cross-layer and hybrid fracture networks to improve the growth height.Hydraulic fractures tend to propagate from high-strength to low-strength layers under radial borehole guidance.When radial boreholes interconnect multiple lithology layers,hydraulic fractures initiate preferentially in lower-strength zones rather than remaining confined to borehole root ends.Increased radial borehole length and diameter facilitate fracture skip-layer initiation and cross-layer propagation,while multiple borehole branches enhance fracture penetration across high-strength interlayers.Radial boreholes with inclination angles below 30°enhance fracture height by generating cross-layer and hybrid fracture networks.Furthermore,an inter-borehole phase angle of less than 180°facilitates single-wing fracture cross-layer propagation.Fracture height is primarily governed by radial borehole length,followed by quantity,inclination angle,and diameter.Based on the geometric similarity criteria,the recommended parameters for radial borehole-assisted fracturing in a 5 1/2-inch horizontal well include a length>15 m,an inclination angle<30°,and a diameter>52 mm to ensure effective stimulation across three or more pay zones.Finally,the field-scale numerical model was developed to simulate the optimized radial borehole fracturing and demonstrate the technical superiority.These findings are expected to provide an in-depth understanding of the effective stimulation in multilayered reservoirs.展开更多
This paper discusses the characteristics and formation mechanism of thin dolomite reservoirs in the lower submember of the second member of the Permian Maokou Formation(lower Mao 2 Member)in the Wusheng-Tongnan area o...This paper discusses the characteristics and formation mechanism of thin dolomite reservoirs in the lower submember of the second member of the Permian Maokou Formation(lower Mao 2 Member)in the Wusheng-Tongnan area of the Sichuan Basin,SW China,through comprehensive analysis of geological,geophysical and geochemical data.The reservoir rocks of the lower Mao 2 Member are dominated by porphyritic vuggy dolomite and calcareous dolomite or dolomitic limestone,which have typical karst characteristics of early diagenetic stage.The dolomites at the edge of the karst system and in the fillings have dissolved estuaries,and the dolomite breccia has micrite envelope and rim cement at the edge,indicating that dolomitization is earlier than the early diagenetic karstification.The shoal facies laminated dolomite is primarily formed by the seepage reflux dolomitization of moderate-salinity seawater.The key factors of reservoir formation are the bioclastic shoal deposition superimposed with seepgae reflux dolomitization and the karstification of early diagenetic stage,which are locally reformed by fractures and hydrothermal processes.The development of dolomite vuggy reservoir is closely related to the upward-shallowing sequence,and mainly occurs in the late highstand of the fourth-order cycle.Moreover,the size of dolomite is closely related to formation thickness,and it is concentrated in the formation thickness conversion area,followed by the thinner area.According to the understanding of insufficient accommodation space in the geomorphic highland and the migration of granular shoal to geomorphic lowland in the late highstand of the third-order cycle,it is proposed that the large-scale shoal-controlled dolomite reservoirs are distributed along structural highs and slopes,and the reservoir-forming model with shoal,dolomitization and karstification jointly controlled by the microgeomorphy and sea-level fluctuation in the sedimentary period is established.On this basis,the paleogeomorphology in the lower Mao 2 Member is restored using well-seismic data,and the reservoir distribution is predicted.The prediction results have been verified by the latest results of exploration wells and tests,which provide an important reference for the prediction of thin dolomite reservoirs under similar geological setting.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 increased frequency and intensity of heavy rainfall events due to climate change could potentially influence the movement of nutrients from land-based regions into recipient rivers.However,little information is av...The increased frequency and intensity of heavy rainfall events due to climate change could potentially influence the movement of nutrients from land-based regions into recipient rivers.However,little information is available on how the rainfall affect nutrient dynamics in subtropicalmontane rivers with complex land use.This study conducted high-frequency monitoring to study the effects of rainfall on nutrients dynamics in an agricultural river draining to Lake Qiandaohu,a montane reservoir of southeast China.The results showed that riverine total nitrogen(TN)and total phosphorus(TP)concentrations increased continuously with increasing rainfall intensity,while TN:TP decreased.The heavy rainfall and rainstorm drove more than 30%of the annual N and P loading in only 5.20%of the total rainfall period,indicating that increased storm runoff is likely to exacerbate eutrophication in montane reservoirs.NO_(3)^(−)-N is the primary nitrogen form lost,while particulate phosphorus(PP)dominated phosphorus loss.Themain source of N is cropland,and themain source of P is residential area.Spatially,forestedwatersheds have better drainage quality,while it is still a potential source of nonpoint pollution during rainfall events.TN and TP concentrations were significantly higher at sites dominated by cropland and residential area,indicating their substantial contributions to deteriorating river water quality.Temporally,TN and TP concentrations reached high values in May-August when rainfall was most intense,while they were lower in autumn and winter than that in spring and summer under the same rainfall intensities.The results emphasize the influence of rainfall-runoff and land use on dynamics of riverine N and P loads,providing guidance for nutrient load reduction planning for Lake Qiandaohu.展开更多
Optoelectronic memristor is generating growing research interest for high efficient computing and sensing-memory applications.In this work,an optoelectronic memristor with Au/a-C:Te/Pt structure is developed.Synaptic ...Optoelectronic memristor is generating growing research interest for high efficient computing and sensing-memory applications.In this work,an optoelectronic memristor with Au/a-C:Te/Pt structure is developed.Synaptic functions,i.e.,excita-tory post-synaptic current and pair-pulse facilitation are successfully mimicked with the memristor under electrical and optical stimulations.More importantly,the device exhibited distinguishable response currents by adjusting 4-bit input electrical/opti-cal signals.A multi-mode reservoir computing(RC)system is constructed with the optoelectronic memristors to emulate human tactile-visual fusion recognition and an accuracy of 98.7%is achieved.The optoelectronic memristor provides potential for developing multi-mode RC system.展开更多
The origin of tight reservoirs in the Yanchang Formation of the Ordos Basin and their relationship with hydrocarbon charging remain unclear.Based on petrological observations,physical property analysis,fluid inclusion...The origin of tight reservoirs in the Yanchang Formation of the Ordos Basin and their relationship with hydrocarbon charging remain unclear.Based on petrological observations,physical property analysis,fluid inclusion system analysis and in situ U-Pb dating,the sequence of tight sandstone reservoir densification and oil charging was determined.Through petrological observations,fluid inclusion analysis and physical property analysis,it is concluded that compaction and cementation are the primary causes of reservoir densification.When the content of calcite cement is less than or equal to 7%,compaction dominates densification;otherwise,cementation becomes more significant.However,determining the exact timing of compaction densification proved challenging.Microscopic observations revealed that oil charging likely occurred either before or during the densification of the reservoir.According to in situ U-Pb dating and the porosity evolution curve,cementation densification occurred between 167.0±20.0 Ma and 151.8 Ma.Temperature measurements of the aqueous inclusions indicate that oil charging occurred between 125.0 and 96.0 Ma,suggesting that densification preceded oil charging.This study provides valuable insights for the future exploration of tight oil reservoirs in the Ordos Basin.展开更多
Photonic platforms are gradually emerging as a promising option to encounter the ever-growing demand for artificial intelligence,among which photonic time-delay reservoir computing(TDRC)is widely anticipated.While suc...Photonic platforms are gradually emerging as a promising option to encounter the ever-growing demand for artificial intelligence,among which photonic time-delay reservoir computing(TDRC)is widely anticipated.While such a computing paradigm can only employ a single photonic device as the nonlinear node for data processing,the performance highly relies on the fading memory provided by the delay feedback loop(FL),which sets a restriction on the extensibility of physical implementation,especially for highly integrated chips.Here,we present a simplified photonic scheme for more flexible parameter configurations leveraging the designed quasi-convolution coding(QC),which completely gets rid of the dependence on FL.Unlike delay-based TDRC,encoded data in QC-based RC(QRC)enables temporal feature extraction,facilitating augmented memory capabilities.Thus,our proposed QRC is enabled to deal with time-related tasks or sequential data without the implementation of FL.Furthermore,we can implement this hardware with a low-power,easily integrable vertical-cavity surface-emitting laser for high-performance parallel processing.We illustrate the concept validation through simulation and experimental comparison of QRC and TDRC,wherein the simpler-structured QRC outperforms across various benchmark tasks.Our results may underscore an auspicious solution for the hardware implementation of deep neural networks.展开更多
Accurate prediction of water level changes in reservoirs is crucial for optimizing the operation of reservoir projects and ensuring their safety.This study proposed a method for reservoir water level prediction based ...Accurate prediction of water level changes in reservoirs is crucial for optimizing the operation of reservoir projects and ensuring their safety.This study proposed a method for reservoir water level prediction based on CEEMDAN-FE and RUN-SVM-RBFNN algorithms.By integrating the adaptive complete ensemble empirical mode decomposition with adaptive noise(CEEMDAN)method and fuzzy entropy(FE)with the new and highly efficient Runge–Kuta optimizer(RUN),adaptive parameter optimization for the support vector machine(SVM)and radial basis function neural network(RBFNN)algorithms was achieved.Regression prediction was conducted on the two reconstructed sequences using SVM and RBFNN according to their respective features.This approach improved the accuracy and stability of predictions.In terms of accuracy,the combined model outperformed single models,with the determination coefficient,root mean square error,and mean absolute error values of 0.9975,0.2418 m,and 0.1616 m,respectively.In terms of stability,the model predicted more consistently in training and testing periods,with stable overall prediction accuracy and a better adaptive ability to complex datasets.The case study demonstrated that the combined prediction model effectively addressed the environmental factors affecting reservoir water levels,leveraged the strength of each predictive method,compensated for their limitations,and clarified the impacts of environmental factors on reservoir water levels.展开更多
The 10000-m ultradeep dolomite reservoir holds significant potential as a successor field for future oil and gas exploration in China's marine craton basin.However,major challenges such as the genesis of dolomite,...The 10000-m ultradeep dolomite reservoir holds significant potential as a successor field for future oil and gas exploration in China's marine craton basin.However,major challenges such as the genesis of dolomite,the formation time of high-quality reservoirs,and the preservation mechanism of reservoirs have always limited exploration decision-making.This research systematically elaborates on the genesis and reservoir-forming mechanisms of Sinian-Cambrian dolomite,discussing the ancient marine environment where microorganisms and dolomite develop,which controls the formation of large-scale Precambrian-Cambrian dolomite.The periodic changes inMg isotopes and sedimentary cycles show that the thick-layered dolomite is the result of different dolomitization processes superimposed on a spatiotemporal scale.Lattice defects and dolomite embryos can promote dolomitization.By simulating the dissolution of typical calcite and dolomite crystal faces in different solution systems and calculating their molecular weights,the essence of heterogeneous dissolution and pore formation on typical calcite and dolomite crystal faces was revealed,and the mechanism of dolomitization was also demonstrated.The properties of calcite and dolomite(104)/(110)grain boundaries and their dissolution mechanism in carbonate solution were revealed,showing the limiting factors of the dolomitization process and the preservation mechanism of deep buried dolomite reservoirs.The in situ laser U-Pb isotope dating technique has demonstrated the timing of dolomitization and pore formation in ancient carbonate rocks.This research also proposed that dolomitization occurred during the quasi-contemporaneous or shallow-burial periods within 50Ma after deposition and pores formed during the quasi-contemporaneous to the early diagenetic periods.And it was clear that the quasi-contemporaneous dolomitization was the key period for reservoir formation.The systematic characterization of the spatial distribution of the deepest dolomite reservoirs in multiple sets of the Sinian and the Cambrian in the Chinese craton basins provides an important basis for the distribution prediction of large-scale dolomite reservoirs.It clarifies the targets for oil and gas exploration at depths over 10000 m.The research on dolomite in this study will greatly promote China's ultradeep oil and gas exploration and lead the Chinese petroleum industry into a new era of 10000-m deep oil exploration.展开更多
The development of shale reservoirs is important in ensuring China’s national energy security by achiev-ing energy independence.Among the key technologies for shale oil production,CO_(2) fracturing is an effec-tive m...The development of shale reservoirs is important in ensuring China’s national energy security by achiev-ing energy independence.Among the key technologies for shale oil production,CO_(2) fracturing is an effec-tive method that can not only enhance oil recovery but also promote large amounts of CO_(2) storage,thereby supporting China’s goals of achieving a carbon peak and carbon neutrality.This research paper aims to study the impacts and prospective applications of CO_(2) fracturing in shale reservoirs,using real exploitation parameters from the Gulong shale reservoir well 1(GYYP1)well in the Songliao Basin.By utilizing numerical simulation,the dynamics of CO_(2) production are analyzed.Adsorption and diffusion are identified as pivotal mechanisms for CO_(2) storage in shale reservoirs.After the analysis of the fractur-ing process,approximately 22.13%of CO_(2) is found to be adsorbed,which decreases to 11.06%after ten years due to pressure decline.Diffusion increases the volume of CO_(2) interacting with a greater extent of shale,thereby enhancing the adsorption mechanism.Over time,the diffusion process results in a remarkable increase of 26.02%in CO_(2) adsorption,ensuring the long-term and stable storage of CO_(2) within the shale reservoir.This investigation delves into the contribution of these two crucial mechanisms of CO_(2) storage in shale reservoirs,ultimately predicting that,by 2030,approximately two million tons of CO_(2) can be effectively stored in the Daqing Oilfield through CO_(2) fracturing in shale oil reservoirs.Such an achievement will undoubtedly contribute to the sustainable development of the energy sector and foster the transformation and upgrading of China’s energy structure.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
This study comprehensively uses various methods such as production dynamic analysis,fluid inclusion thermometry and carbon-oxygen isotopic compositions testing,based on outcrop,core,well-logging,3D seismic,geochemistr...This study comprehensively uses various methods such as production dynamic analysis,fluid inclusion thermometry and carbon-oxygen isotopic compositions testing,based on outcrop,core,well-logging,3D seismic,geochemistry experiment and production test data,to systematically explore the control mechanisms of structure and fluid on the scale,quality,effectiveness and connectivity of ultra-deep fault-controlled carbonate fractured-vuggy reservoirs in the Tarim Basin.The results show that reservoir scale is influenced by strike-slip fault scale,structural position,and mechanical stratigraphy.Larger faults tend to correspond to larger reservoir scales.The reservoir scale of contractional overlaps is larger than that of extensional overlaps,while pure strike-slip segments are small.The reservoir scale is enhanced at fault intersection,bend,and tip segments.Vertically,the heterogeneity of reservoir development is controlled by mechanical stratigraphy,with strata of higher brittleness indices being more conducive to the development of fractured-vuggy reservoirs.Multiple phases of strike-slip fault activity and fluid alterations contribute to fractured-vuggy reservoir effectiveness evolution and heterogeneity.Meteoric water activity during the Late Caledonian to Early Hercynian period was the primary phase of fractured-vuggy reservoir formation.Hydrothermal activity in the Late Hercynian period further intensified the heterogeneity of effective reservoir space distribution.The study also reveals that fractured-vuggy reservoir connectivity is influenced by strike-slip fault structural position and present in-situ stress field.The reservoir connectivity of extensional overlaps is larger than that of pure strike-slip segments,while contractional overlaps show worse reservoir connectivity.Additionally,fractured-vuggy reservoirs controlled by strike-slip faults that are nearly parallel to the present in-situ stress direction exhibit excellent connectivity.Overall,high-quality reservoirs are distributed at the fault intersection of extensional overlaps,the central zones of contractional overlaps,pinnate fault zones at intersection,bend,and tip segments of pure strike-slip segments.Vertically,they are concentrated in mechanical stratigraphy with high brittleness indices.展开更多
Accurate capture and presentation of the interactive feedback relationships among various objectives in multi-objective reservoir operation is essential for maximizing operational benefits.In this study,the niche theo...Accurate capture and presentation of the interactive feedback relationships among various objectives in multi-objective reservoir operation is essential for maximizing operational benefits.In this study,the niche theory of ecology was innovatively applied to the field of reservoir operation,and a novel state-relationship(S-R)measurement analysis method was developed for multi-objective reservoir operation.This method enables the study of interaction among multiple objectives.This method was used to investigate the relationship among the objectives of power generation,water supply,and ecological protection for cascade reservoir operation in the Wujiang River Basin in China.The results indicated that the ecological protection objective was the most competitive in acquiring and capturing resources like flow and water level,while the water supply objective was the weakest.Power generation competed most strongly with ecological protection and relatively weakly with water supply.These findings facilitate decision-making throughout the reservoir operation process in the region.The S-R method based on the niche theory is convenient,efficient,and intuitive,allowing for the quantification of feedback relationships among objectives without requiring the solution of the Pareto frontier of a multi-objective problem in advance.This method provides a novel and feasible idea for studying multi-objective interactions.展开更多
基金supported by the National Key Research and Development Program of China under Grant 2022YFB3608300in part by the National Nature Science Foundation of China(NSFC)under Grants 62404050,U2341218,62574056,62204052。
文摘Organic electrochemical transistor(OECT)devices demonstrate great promising potential for reservoir computing(RC)systems,but their lack of tunable dynamic characteristics limits their application in multi-temporal scale tasks.In this study,we report an OECT-based neuromorphic device with tunable relaxation time(τ)by introducing an additional vertical back-gate electrode into a planar structure.The dual-gate design enablesτreconfiguration from 93 to 541 ms.The tunable relaxation behaviors can be attributed to the combined effects of planar-gate induced electrochemical doping and back-gateinduced electrostatic coupling,as verified by electrochemical impedance spectroscopy analysis.Furthermore,we used theτ-tunable OECT devices as physical reservoirs in the RC system for intelligent driving trajectory prediction,achieving a significant improvement in prediction accuracy from below 69%to 99%.The results demonstrate that theτ-tunable OECT shows a promising candidate for multi-temporal scale neuromorphic computing applications.
基金supported in part by the Chinese Academy of Sciences(No.XDA0330302)NSFC program(No.22127901)。
文摘Neuromorphic devices have garnered significant attention as potential building blocks for energy-efficient hardware systems owing to their capacity to emulate the computational efficiency of the brain.In this regard,reservoir computing(RC)framework,which leverages straightforward training methods and efficient temporal signal processing,has emerged as a promising scheme.While various physical reservoir devices,including ferroelectric,optoelectronic,and memristor-based systems,have been demonstrated,many still face challenges related to compatibility with mainstream complementary metal oxide semiconductor(CMOS)integration processes.This study introduced a silicon-based schottky barrier metal-oxide-semiconductor field effect transistor(SB-MOSFET),which was fabricated under low thermal budget and compatible with back-end-of-line(BEOL).The device demonstrated short-term memory characteristics,facilitated by the modulation of schottky barriers and charge trapping.Utilizing these characteristics,a RC system for temporal data processing was constructed,and its performance was validated in a 5×4 digital classification task,achieving an accuracy exceeding 98%after 50 training epochs.Furthermore,the system successfully processed temporal signal in waveform classification and prediction tasks using time-division multiplexing.Overall,the SB-MOSFET's high compatibility with CMOS technology provides substantial advantages for large-scale integration,enabling the development of energy-efficient reservoir computing hardware.
基金supported by Guangdong Basic and Applied Basic Research Foundation(Nos.2023A1515110824 and 2025A1515011839)Shenzhen Science and Technology Program(No.RCBS20231211090638066).
文摘Understanding water chemistry in karst regions is crucial for improving global water resource management and deepening our knowledge of the biogeochemical cycles shaping these sensitive environments.Despite advance-ments in karst hydrology,significant gaps remain in long-term trends,underlying processes,and quantitative effects of environmental changes.This is especially true in areas like the Wujiang River(WJ)in China,where human activities such as reservoir construction and land use/cover changes have accelerated hydrochemical changes.We combined recent and historical monitoring data to provide a detailed analysis of the spatial and temporal characteristics,evolution,and controlling factors of major ions in WJ.These findings are important for local water management and contribute to global efforts to manage similar karst systems facing human-induced pressures.Our research shows clear seasonal differences in solute concentrations,with higher levels during the dry season.WJ’s water is rich in calcium,with Ca-HCO_(3) ion pairs being the most common.Reservoir monitor-ing stations show much higher levels of NO_(3)^(−)and SO_(4)^(2−)compared to river-type stations,likely due to longer hydraulic retention time and increased acid deposition.The study confirms the significant role of pH and water temperature in rock weathering processes.Land use/cover changes were identified as the primary drivers of solute variations(46.37%),followed by lithology(13.92%)and temperature(8.35%).Over the past two decades,in-tense carbonate weathering has been observed,especially during wet seasons.Among karstic provinces,Guizhou Province stands out with the highest ion concentrations,indicative of its extensive karst coverage and heightened weathering processes.
基金Supported by the Zhejiang Provincial Natural Science Foundation of China(No.LD21C030001)the Key Research and Development Program of National Natural Science Foundation of China(No.2021YFE0112000)+1 种基金the National Natural Science Foundation of China(Nos.32371634,31970219)the Scientific Research Project of the Shanghai Municipal Bureau of Ecology and Environment(No.202409)。
文摘Microbial communities play indispensable roles in the biogeochemical cycling of river ecosystems.However,the response patterns of microbial community diversity,niche breadth,and assembly to rainfall disturbances in complex mountainous riverine reservoirs remain inadequately understood.We employed high-throughput sequencing of 16S and 18S ribosomal RNA genes,along with multivariate statistical methods to systematically investigate prokaryotic and eukaryotic microorganisms in the riverine Zhaoshandu Reservoir,Wenzhou,Zhejiang,East China.Results show significant temporal heterogeneity in both prokaryotic and eukaryotic microbial communities,with eukaryotic microbes showing more pronounced temporal variation.Canonical correspondence analysis revealed that rainfall and water temperature were the key drivers shaping microbial communities.Additionally,eukaryotic microorganisms exhibited a more pronounced response to rainfall and water temperature compared to prokaryotes.Modified stochasticity ratio model indicated that deterministic processes predominantly governed microbial community assembly,with stronger deterministic processes in eukaryotic compared to prokaryotic microorganisms.Rainfall has significantly altered water quality,notably increasing phosphorus concentration in the water column.Total phosphorus and total nitrogen showed significant correlations with the niche breadth of prokaryotic and eukaryotic microorganisms,and phosphorus nutrients served as keystones and playing indispensable roles in their co-occurrence networks.A structural equation model confirmed the notable impacts of rainfall and water temperature on microbial community diversity,further revealing that rainfall indirectly influenced the niche breadth and co-occurrence relationships of microbial communities by altering phosphorus concentrations.The findings underscore the influence of rainfall and water temperature on microbial distribution,highlighting the sensitivity of riverine reservoir ecosystems to climate change.
文摘In recent years,significant breakthroughs have been achieved in the exploration of deep volcanic rocks in the Junggar Basin,highlighting their substantial exploration potential.The complex distribution of volcanic reservoirs is attributed to the multi-phase tectonic evolution within the basin,with their superior reservoir properties playing a crucial role in natural gas formation.However,due to the combined effects of multi-cyclic volcanic eruptions and tectonic activities,predicting volcanic facies distribution and favorable reservoirs remains highly challenging.This study focuses on the third member of the Jiamuhe Formation in the Zhongguai Uplift.By integrating drilling and petrophysical data with well-seismic analysis techniques,a seismic identification model for volcanic reservoirs has been established.The findings reveal that different facies exhibit distinct seismic response characteristics.Andesite,rhyolite,volcanic breccia,and volcanic clastic rocks show variability in amplitude,frequency,and continuity.Using structural-guided filtering,high-resolution coherence analysis,and 3D body carving techniques,the locations of volcanic craters and eruption centers were successfully identified,further clarifying the distribution patterns of volcanic facies.By combining multi-attribute clustering analysis and seismic attribute extraction,a volcanic facies zone distribution map was generated,and favorable exploration directions for volcanic reservoirs were proposed.The study provides technical guidance for the exploration of deep volcanic oil and gas reservoirs in the Junggar Basin and holds significant application value.
基金supported by a project of the Shaanxi Youth Science and Technology Star(2021KJXX-87)public welfare geological survey projects of Shaanxi Institute of Geologic Survey(20180301,201918 and 202103)。
文摘With the efficient and intelligent development of computer-based big data processing,applying machine learning methods to the processing and interpretation of logging data in the field of geophysical well logging has broad potential for improving production efficiency.Currently,the Jiyuan Oilfield in the Ordos Basin relies mainly on manual reprocessing and interpretation of old well logging data to identify different fluid types in low-contrast reservoirs,guiding subsequent production work.This study uses well logging data from the Chang 1 reservoir,partitioning the dataset based on individual wells for model training and testing.A deep learning model for intelligent reservoir fluid identification was constructed by incorporating the focal loss function.Comparative validations with five other models,including logistic regression(LR),naive Bayes(NB),gradient boosting decision trees(GBDT),random forest(RF),and support vector machine(SVM),show that this model demonstrates superior identification performance and significantly improves the accuracy of identifying oil-bearing fluids.Mutual information analysis reveals the model's differential dependency on various logging parameters for reservoir fluid identification.This model provides important references and a basis for conducting regional studies and revisiting old wells,demonstrating practical value that can be widely applied.
基金supported by the National Natural Science Foundation of China(Nos.52404153,52504157 and 52504156)the Natural Science Foundation of Jiangsu Province(No.BK20241649).
文摘Coal mine underground reservoirs help address the severe water imbalance in ecologically fragile mining regions of western China,but evaluating their storage capacity remains challenging due to the coupled effects of gangue deformation,saturation,and goaf geometry.This study investigates the deformation and void evolution of fragmented gangue with varying lithologies,particle sizes,and water contents through an independent-developed testing system and theoretical model.A planar micro-unit model and a three-dimensional spatial structure model are proposed to quantify the storage coefficient and total reservoir capacity of underground water storage structures.These models incorporate the effects of stratified lithologies,saturation-induced softening,and spatially distributed stress conditions.The methodology is applied to the underground reservoir in Chahasu coal mine,and the results show that under increasing stress,storage coefficients decline exponentially,with pronounced differences between single-and double-lithology structures.The storage coefficient in the spatial model demonstrate greater resilience to stress concentration compared to planar models,and further analysis identifies critical thresholds in roof fracture distances and stress-recovery times affecting long-term storage performance.This research provides a comprehensive framework for evaluating underground reservoir storage potential,offering theoretical support and engineering guidance for the sustainable utilization of mine water.
基金supported by the National Natural Science Foundation of China(Nos.U24B6001,52421002,52474016,and 52020105001)Research on Key Technologies for Exploration and Development of Dry Geothermal Resources(No.2022DJ5503)Deep-land National Science and Technology Major Project of China(No.2024ZD1003504).
文摘The strong vertical discontinuities pose a fundamental challenge to optimizing stimulated reservoir volume(SRV)in multilayered reservoirs.This research proposes a radial borehole-assisted horizontal well fracturing technology,which is expected to achieve effective vertical stimulation and commingled production across multiple pay zones.Under different geological and engineering conditions,the vertical propagation behavior of hydraulic fractures guided by radial boreholes can be determined by adjusting the interlayered lithologies and radial borehole configurations in experimental samples.Experimental results reveal four fracture network patterns:passivated,cross-layer,skip-layer,and hybrid fractures in the radial borehole fracturing.The radial boreholes perform better fracture guiding performances in the high-brittleness interlayers,which form cross-layer and hybrid fracture networks to improve the growth height.Hydraulic fractures tend to propagate from high-strength to low-strength layers under radial borehole guidance.When radial boreholes interconnect multiple lithology layers,hydraulic fractures initiate preferentially in lower-strength zones rather than remaining confined to borehole root ends.Increased radial borehole length and diameter facilitate fracture skip-layer initiation and cross-layer propagation,while multiple borehole branches enhance fracture penetration across high-strength interlayers.Radial boreholes with inclination angles below 30°enhance fracture height by generating cross-layer and hybrid fracture networks.Furthermore,an inter-borehole phase angle of less than 180°facilitates single-wing fracture cross-layer propagation.Fracture height is primarily governed by radial borehole length,followed by quantity,inclination angle,and diameter.Based on the geometric similarity criteria,the recommended parameters for radial borehole-assisted fracturing in a 5 1/2-inch horizontal well include a length>15 m,an inclination angle<30°,and a diameter>52 mm to ensure effective stimulation across three or more pay zones.Finally,the field-scale numerical model was developed to simulate the optimized radial borehole fracturing and demonstrate the technical superiority.These findings are expected to provide an in-depth understanding of the effective stimulation in multilayered reservoirs.
基金Supported by the National Natural Science Foundation of China(42172166)National Natural Science Foundation and CNPC Joint Fund Project(U23B20154)CNPC-Southwest Petroleum University Science and Technology Cooperation Project(2020CX010000).
文摘This paper discusses the characteristics and formation mechanism of thin dolomite reservoirs in the lower submember of the second member of the Permian Maokou Formation(lower Mao 2 Member)in the Wusheng-Tongnan area of the Sichuan Basin,SW China,through comprehensive analysis of geological,geophysical and geochemical data.The reservoir rocks of the lower Mao 2 Member are dominated by porphyritic vuggy dolomite and calcareous dolomite or dolomitic limestone,which have typical karst characteristics of early diagenetic stage.The dolomites at the edge of the karst system and in the fillings have dissolved estuaries,and the dolomite breccia has micrite envelope and rim cement at the edge,indicating that dolomitization is earlier than the early diagenetic karstification.The shoal facies laminated dolomite is primarily formed by the seepage reflux dolomitization of moderate-salinity seawater.The key factors of reservoir formation are the bioclastic shoal deposition superimposed with seepgae reflux dolomitization and the karstification of early diagenetic stage,which are locally reformed by fractures and hydrothermal processes.The development of dolomite vuggy reservoir is closely related to the upward-shallowing sequence,and mainly occurs in the late highstand of the fourth-order cycle.Moreover,the size of dolomite is closely related to formation thickness,and it is concentrated in the formation thickness conversion area,followed by the thinner area.According to the understanding of insufficient accommodation space in the geomorphic highland and the migration of granular shoal to geomorphic lowland in the late highstand of the third-order cycle,it is proposed that the large-scale shoal-controlled dolomite reservoirs are distributed along structural highs and slopes,and the reservoir-forming model with shoal,dolomitization and karstification jointly controlled by the microgeomorphy and sea-level fluctuation in the sedimentary period is established.On this basis,the paleogeomorphology in the lower Mao 2 Member is restored using well-seismic data,and the reservoir distribution is predicted.The prediction results have been verified by the latest results of exploration wells and tests,which provide an important reference for the prediction of thin dolomite reservoirs under similar geological setting.
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.
基金supported by the National Natural Science Foundation of China(Nos.U2340209,and 42271126)the NIGLAS Foundation(No.NIGLAS2022GS03)+1 种基金the Natural Science Foundation of Jiangsu Province(No.BK20220041)the US National Science Foundation Projects(Nos.1831096,1803697,and 2108917).
文摘The increased frequency and intensity of heavy rainfall events due to climate change could potentially influence the movement of nutrients from land-based regions into recipient rivers.However,little information is available on how the rainfall affect nutrient dynamics in subtropicalmontane rivers with complex land use.This study conducted high-frequency monitoring to study the effects of rainfall on nutrients dynamics in an agricultural river draining to Lake Qiandaohu,a montane reservoir of southeast China.The results showed that riverine total nitrogen(TN)and total phosphorus(TP)concentrations increased continuously with increasing rainfall intensity,while TN:TP decreased.The heavy rainfall and rainstorm drove more than 30%of the annual N and P loading in only 5.20%of the total rainfall period,indicating that increased storm runoff is likely to exacerbate eutrophication in montane reservoirs.NO_(3)^(−)-N is the primary nitrogen form lost,while particulate phosphorus(PP)dominated phosphorus loss.Themain source of N is cropland,and themain source of P is residential area.Spatially,forestedwatersheds have better drainage quality,while it is still a potential source of nonpoint pollution during rainfall events.TN and TP concentrations were significantly higher at sites dominated by cropland and residential area,indicating their substantial contributions to deteriorating river water quality.Temporally,TN and TP concentrations reached high values in May-August when rainfall was most intense,while they were lower in autumn and winter than that in spring and summer under the same rainfall intensities.The results emphasize the influence of rainfall-runoff and land use on dynamics of riverine N and P loads,providing guidance for nutrient load reduction planning for Lake Qiandaohu.
基金supported by the"Science and Technology Development Plan Project of Jilin Province,China"(Grant No.20240101018JJ)the Fundamental Research Funds for the Central Universities(Grant No.2412023YQ004)the National Natural Science Foundation of China(Grant Nos.52072065,52272140,52372137,and U23A20568).
文摘Optoelectronic memristor is generating growing research interest for high efficient computing and sensing-memory applications.In this work,an optoelectronic memristor with Au/a-C:Te/Pt structure is developed.Synaptic functions,i.e.,excita-tory post-synaptic current and pair-pulse facilitation are successfully mimicked with the memristor under electrical and optical stimulations.More importantly,the device exhibited distinguishable response currents by adjusting 4-bit input electrical/opti-cal signals.A multi-mode reservoir computing(RC)system is constructed with the optoelectronic memristors to emulate human tactile-visual fusion recognition and an accuracy of 98.7%is achieved.The optoelectronic memristor provides potential for developing multi-mode RC system.
基金supported by the project of the Exploration Department of the Huabei Oilfield Company of Sinopec(No.34550008-20-ZC0609-0031).
文摘The origin of tight reservoirs in the Yanchang Formation of the Ordos Basin and their relationship with hydrocarbon charging remain unclear.Based on petrological observations,physical property analysis,fluid inclusion system analysis and in situ U-Pb dating,the sequence of tight sandstone reservoir densification and oil charging was determined.Through petrological observations,fluid inclusion analysis and physical property analysis,it is concluded that compaction and cementation are the primary causes of reservoir densification.When the content of calcite cement is less than or equal to 7%,compaction dominates densification;otherwise,cementation becomes more significant.However,determining the exact timing of compaction densification proved challenging.Microscopic observations revealed that oil charging likely occurred either before or during the densification of the reservoir.According to in situ U-Pb dating and the porosity evolution curve,cementation densification occurred between 167.0±20.0 Ma and 151.8 Ma.Temperature measurements of the aqueous inclusions indicate that oil charging occurred between 125.0 and 96.0 Ma,suggesting that densification preceded oil charging.This study provides valuable insights for the future exploration of tight oil reservoirs in the Ordos Basin.
基金National Natural Science Foundation of China(62171305,62405206,62004135,62001317,62111530301)Natural Science Foundation of Jiangsu Province(BK20240778,BK20241917)+3 种基金State Key Laboratory of Advanced Optical Communication Systems and Networks,China(2023GZKF08)China Postdoctoral Science Foundation(2024M752314)Postdoctoral Fellowship Program of CPSF(GZC20231883)Innovative and Entrepreneurial Talent Program of Jiangsu Province(JSSCRC2021527).
文摘Photonic platforms are gradually emerging as a promising option to encounter the ever-growing demand for artificial intelligence,among which photonic time-delay reservoir computing(TDRC)is widely anticipated.While such a computing paradigm can only employ a single photonic device as the nonlinear node for data processing,the performance highly relies on the fading memory provided by the delay feedback loop(FL),which sets a restriction on the extensibility of physical implementation,especially for highly integrated chips.Here,we present a simplified photonic scheme for more flexible parameter configurations leveraging the designed quasi-convolution coding(QC),which completely gets rid of the dependence on FL.Unlike delay-based TDRC,encoded data in QC-based RC(QRC)enables temporal feature extraction,facilitating augmented memory capabilities.Thus,our proposed QRC is enabled to deal with time-related tasks or sequential data without the implementation of FL.Furthermore,we can implement this hardware with a low-power,easily integrable vertical-cavity surface-emitting laser for high-performance parallel processing.We illustrate the concept validation through simulation and experimental comparison of QRC and TDRC,wherein the simpler-structured QRC outperforms across various benchmark tasks.Our results may underscore an auspicious solution for the hardware implementation of deep neural networks.
基金supported by the National Key R&D Program of China(Grant No.2022YFC3005401)the National Natural Science Foundation of China(Grant No.52239009)。
文摘Accurate prediction of water level changes in reservoirs is crucial for optimizing the operation of reservoir projects and ensuring their safety.This study proposed a method for reservoir water level prediction based on CEEMDAN-FE and RUN-SVM-RBFNN algorithms.By integrating the adaptive complete ensemble empirical mode decomposition with adaptive noise(CEEMDAN)method and fuzzy entropy(FE)with the new and highly efficient Runge–Kuta optimizer(RUN),adaptive parameter optimization for the support vector machine(SVM)and radial basis function neural network(RBFNN)algorithms was achieved.Regression prediction was conducted on the two reconstructed sequences using SVM and RBFNN according to their respective features.This approach improved the accuracy and stability of predictions.In terms of accuracy,the combined model outperformed single models,with the determination coefficient,root mean square error,and mean absolute error values of 0.9975,0.2418 m,and 0.1616 m,respectively.In terms of stability,the model predicted more consistently in training and testing periods,with stable overall prediction accuracy and a better adaptive ability to complex datasets.The case study demonstrated that the combined prediction model effectively addressed the environmental factors affecting reservoir water levels,leveraged the strength of each predictive method,compensated for their limitations,and clarified the impacts of environmental factors on reservoir water levels.
基金National Natural Science Foundation of China,Grant/Award Number:42230812。
文摘The 10000-m ultradeep dolomite reservoir holds significant potential as a successor field for future oil and gas exploration in China's marine craton basin.However,major challenges such as the genesis of dolomite,the formation time of high-quality reservoirs,and the preservation mechanism of reservoirs have always limited exploration decision-making.This research systematically elaborates on the genesis and reservoir-forming mechanisms of Sinian-Cambrian dolomite,discussing the ancient marine environment where microorganisms and dolomite develop,which controls the formation of large-scale Precambrian-Cambrian dolomite.The periodic changes inMg isotopes and sedimentary cycles show that the thick-layered dolomite is the result of different dolomitization processes superimposed on a spatiotemporal scale.Lattice defects and dolomite embryos can promote dolomitization.By simulating the dissolution of typical calcite and dolomite crystal faces in different solution systems and calculating their molecular weights,the essence of heterogeneous dissolution and pore formation on typical calcite and dolomite crystal faces was revealed,and the mechanism of dolomitization was also demonstrated.The properties of calcite and dolomite(104)/(110)grain boundaries and their dissolution mechanism in carbonate solution were revealed,showing the limiting factors of the dolomitization process and the preservation mechanism of deep buried dolomite reservoirs.The in situ laser U-Pb isotope dating technique has demonstrated the timing of dolomitization and pore formation in ancient carbonate rocks.This research also proposed that dolomitization occurred during the quasi-contemporaneous or shallow-burial periods within 50Ma after deposition and pores formed during the quasi-contemporaneous to the early diagenetic periods.And it was clear that the quasi-contemporaneous dolomitization was the key period for reservoir formation.The systematic characterization of the spatial distribution of the deepest dolomite reservoirs in multiple sets of the Sinian and the Cambrian in the Chinese craton basins provides an important basis for the distribution prediction of large-scale dolomite reservoirs.It clarifies the targets for oil and gas exploration at depths over 10000 m.The research on dolomite in this study will greatly promote China's ultradeep oil and gas exploration and lead the Chinese petroleum industry into a new era of 10000-m deep oil exploration.
基金funded by the General Program of the National Natural Science Foundation of China(52274058,52174052,52474058)the Central Program of Basic Science of the National Natural Science Foundation of China(72088101)the"Enlisting and Leading"Science and Technology Project of Heilongjiang Province(RIPED-2022-JS-1740 and RIPED-2022-JS-1853).
文摘The development of shale reservoirs is important in ensuring China’s national energy security by achiev-ing energy independence.Among the key technologies for shale oil production,CO_(2) fracturing is an effec-tive method that can not only enhance oil recovery but also promote large amounts of CO_(2) storage,thereby supporting China’s goals of achieving a carbon peak and carbon neutrality.This research paper aims to study the impacts and prospective applications of CO_(2) fracturing in shale reservoirs,using real exploitation parameters from the Gulong shale reservoir well 1(GYYP1)well in the Songliao Basin.By utilizing numerical simulation,the dynamics of CO_(2) production are analyzed.Adsorption and diffusion are identified as pivotal mechanisms for CO_(2) storage in shale reservoirs.After the analysis of the fractur-ing process,approximately 22.13%of CO_(2) is found to be adsorbed,which decreases to 11.06%after ten years due to pressure decline.Diffusion increases the volume of CO_(2) interacting with a greater extent of shale,thereby enhancing the adsorption mechanism.Over time,the diffusion process results in a remarkable increase of 26.02%in CO_(2) adsorption,ensuring the long-term and stable storage of CO_(2) within the shale reservoir.This investigation delves into the contribution of these two crucial mechanisms of CO_(2) storage in shale reservoirs,ultimately predicting that,by 2030,approximately two million tons of CO_(2) can be effectively stored in the Daqing Oilfield through CO_(2) fracturing in shale oil reservoirs.Such an achievement will undoubtedly contribute to the sustainable development of the energy sector and foster the transformation and upgrading of China’s energy structure.
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(U21B2062).
文摘This study comprehensively uses various methods such as production dynamic analysis,fluid inclusion thermometry and carbon-oxygen isotopic compositions testing,based on outcrop,core,well-logging,3D seismic,geochemistry experiment and production test data,to systematically explore the control mechanisms of structure and fluid on the scale,quality,effectiveness and connectivity of ultra-deep fault-controlled carbonate fractured-vuggy reservoirs in the Tarim Basin.The results show that reservoir scale is influenced by strike-slip fault scale,structural position,and mechanical stratigraphy.Larger faults tend to correspond to larger reservoir scales.The reservoir scale of contractional overlaps is larger than that of extensional overlaps,while pure strike-slip segments are small.The reservoir scale is enhanced at fault intersection,bend,and tip segments.Vertically,the heterogeneity of reservoir development is controlled by mechanical stratigraphy,with strata of higher brittleness indices being more conducive to the development of fractured-vuggy reservoirs.Multiple phases of strike-slip fault activity and fluid alterations contribute to fractured-vuggy reservoir effectiveness evolution and heterogeneity.Meteoric water activity during the Late Caledonian to Early Hercynian period was the primary phase of fractured-vuggy reservoir formation.Hydrothermal activity in the Late Hercynian period further intensified the heterogeneity of effective reservoir space distribution.The study also reveals that fractured-vuggy reservoir connectivity is influenced by strike-slip fault structural position and present in-situ stress field.The reservoir connectivity of extensional overlaps is larger than that of pure strike-slip segments,while contractional overlaps show worse reservoir connectivity.Additionally,fractured-vuggy reservoirs controlled by strike-slip faults that are nearly parallel to the present in-situ stress direction exhibit excellent connectivity.Overall,high-quality reservoirs are distributed at the fault intersection of extensional overlaps,the central zones of contractional overlaps,pinnate fault zones at intersection,bend,and tip segments of pure strike-slip segments.Vertically,they are concentrated in mechanical stratigraphy with high brittleness indices.
基金supported by the National Key Research&Development Project of China(Grant No.2016YFC0402209)and the China Scholarship Council.
文摘Accurate capture and presentation of the interactive feedback relationships among various objectives in multi-objective reservoir operation is essential for maximizing operational benefits.In this study,the niche theory of ecology was innovatively applied to the field of reservoir operation,and a novel state-relationship(S-R)measurement analysis method was developed for multi-objective reservoir operation.This method enables the study of interaction among multiple objectives.This method was used to investigate the relationship among the objectives of power generation,water supply,and ecological protection for cascade reservoir operation in the Wujiang River Basin in China.The results indicated that the ecological protection objective was the most competitive in acquiring and capturing resources like flow and water level,while the water supply objective was the weakest.Power generation competed most strongly with ecological protection and relatively weakly with water supply.These findings facilitate decision-making throughout the reservoir operation process in the region.The S-R method based on the niche theory is convenient,efficient,and intuitive,allowing for the quantification of feedback relationships among objectives without requiring the solution of the Pareto frontier of a multi-objective problem in advance.This method provides a novel and feasible idea for studying multi-objective interactions.
