In view of the shortcomings of the existing CO2 pipeline leakage and diffusion models, such as large fluctuations in prediction errors, insufficient depiction of heavy gas effects, and poor adaptability to phase states, this paper constructs a phase-state adaptive leakage rate model, an SLAB model adapted to CO2 properties, and an improved Gaussian plume model, achieving more accurate predictions of leakage rate and hazardous distance. Experimental validation showed that the average relative error of the leakage rate model in predicting density and leakage rate is respectively <= 5.20% and 6.90%. The prediction error under all verification conditions is <= 15%, which is higher than that of the existing models. The SLAB model based on CO2 physical properties exhibited an average relative error of <= 14.90% in concentration-distance predictions, while the improved Gaussian plume model showed average relative errors of 15.20% and 12.40% for 4% medium-risk and 1% low-risk concentration-distance predictions, respectively. Under most operating conditions, the model prediction errors were <= 20%, outperforming traditional Gaussian plume models and the Phast model. Engineering case study results indicate that the dense-phase CO2 leakage rate is the highest for the same leakage orifice diameter. For a 100 mm leakage orifice, the leakage rates for the dense-phase, supercritical, and gas-phase states are 500.39 kg/s, 370.47 kg/s, and 96.19 kg/s, respectively; For a 100 mm leak aperture, the maximum low-risk, medium-risk, and high-risk distances predictedby the diffusion model for dense-phase CO2 reached 952.50 m, 342.10 m, and 138.70 m, respectively. These research findings provide reliable model data support for CO2 pipeline safety design, risk assessment, and emergency response.

The mechanical properties of hydrates within deep-sea oil and gas pipelines significantly influence their deposition, detachment, and remediation within the pipelines. This study systematically investigates the evolution patterns and mechanisms of hydrate adhesion strength in pipelines under various subcooling degrees and different thermal dissociation conditions. Research has revealed that the adhesion strength of hydrates increases significantly with rising subcooling. Hydrates formed below 273.15 K exhibit high-strength brittle fracture characteristics, with adhesion forces an order of magnitude higher than those formed above 273.15 K. The adhesion force exhibits a two-stage decay characteristic under thermal decomposition conditions. During the initial 30 min, the adhesive strength undergoes a precipitous decline accounting for 78.75% of the total reduction. Thereafter, the adhesion force enters a low-value stabilization period. The variation in maximum shear strength of hydrates induced by temperature changes can be divided into three distinct zones: the solid softening zone, the phase transition critical zone, and the liquid film-dominated zone. It was noted that the decomposition mechanism is jointly governed by a bottom-up macroscopic decomposition process primarily driven by wall-surface heat conduction, and a top-down microscopic decomposition process induced by thermal droplet erosion, leading to honeycombed volumetric failure of the hydrate. This study reveals the mechanical evolution pathway of hydrate deposits from structural strengthening to interfacial failure under thermo-mechanical coupling.

Understanding multiphase flow behavior in the shale matrix is essential for evaluating shale gas reservoirs. The objective of this study is to establish a multiscale simulation model that captures fluid flow mechanisms under nanoconfined conditions, which is achieved by developing a single-nanopore flow equation, and incorporates it into reservoir simulation through pore network model. Based on this approach, an integrated simulation model combining nanoporous matrix, fracture zones, and hydraulic fractures is developed. Field data validate the model's effectiveness, demonstrating its ability to accurately predict early-stage productivity decline due to fracturing fluid flow within shale matrix. Simulation results indicate that the shale gas production rate declines from an initial peak of 2.15 & times; 105 m3/d to a stable lower rate, while the water flowback rate decreases from 310 m3/d to near zero over time. The permeability of matrix, fracture zone width, reservoir wettability, and capillary entry pressure are discussed. Matrix permeability exerts a significant influence on the gas production rate during the early production, but its impact diminishes to negligible levels in the later period. Additionally, the peak gas production rate increases by approximately 25.0% when the fracture zone width expands from 4 ft to 5 ft, while the growth rate reduces to about 14.3% for an increase from 7 ft to 8 ft. Regarding wettability, a homogeneous condition is found to enhance production, whereas increasing the contact angle from 40 degrees to 80 degrees markedly reduces the gas production rate. Besides, increasing the capillary entry pressure further diminishes gas production rate as well. In contrast to conventional models that consider only single-phase gas flow in the matrix, the proposed model incorporates water flowback in shale matrix, providing a theoretical foundation and optimization strategies for efficient shale gas development.

[Objective]Amid the global energy transition and the"dual-carbon"goals,hydrogen energy,as a clean energy carrier,holds significant application potential.However,hydrogen leakage in pure hydrogen and hydrogen-blended natural gas pipeline transportation systems poses a high explosion risk.Therefore,it is imperative to advance comprehensive hydrogen elimination,explosion prevention,and explosion suppression technologies to ensure safe transportation.[Methods]Through literature research and review analysis,the scientific principles of hydrogen elimination,passive and active protection,and explosion suppression technologies were systematically summarized.The effectiveness,applicable scenarios,and limitations of these technologies were evaluated.The innovative model of multi-medium collaborative hydrogen elimination and explosion suppression was analyzed in detail,alongside a compilation of the latest domestic and international research findings and engineering cases.[Results]In terms of hydrogen elimination technologies,ventilation in open spaces was found to have limited effectiveness.While inerting provided effective explosion suppression,it involved high costs and safety risks.Catalytic hydrogen elimination demonstrated high efficiency but faced challenges with catalyst poisoning.A multi-stage collaborative hydrogen elimination system(such as ventilation combined with inerting and catalysis)significantly improved both safety and efficiency.For explosion-proof and pressure-relief technologies,active explosion-proof systems offered rapid response but required high equipment reliability,while passive systems needed structural optimization for hydrogen characteristics.Pressure-relief effectiveness was significantly influenced by relief outlet size and gas concentration,and secondary explosions needed to be prevented.Each single explosion suppression technology had limitations:inert gas suppression required high concentrations,liquid-phase suppression risked equipment corrosion,powder suppression was less effective in pure hydrogen,and porous material suppression faced issues with material selection and adaptability.Collaborative explosion suppression technologies significantly enhanced effectiveness through the synergistic action of multiple suppressants.[Conclusion]Current hydrogen elimination,explosion prevention,and explosion suppression technologies face challenges including high costs,limited material adaptability,and poor stability under complex conditions.Future efforts should focus on developing a collaborative model of efficient hydrogen elimination combined with multi-medium explosion suppression.This includes developing low-cost,anti-poisoning catalysts,intelligent control systems,and targeted hydrogen-absorbing materials,optimizing explosion suppression formulations,and establishing scenario-based safety standards to guide the safe operation of hydrogen pipeline transportation systems.(4 Tables,79 References)

[Objective]The rapid expansion of oil and gas pipeline construction in China,coupled with accelerating urbanization,has heightened safety concerns from stratum settlement,posing significant risks to buried pipeline operations.Stratum settlement is a time-dependent process;although similar settlement outcomes may arise from varying development patterns,current safety evaluations overlook how these differing settlement processes affect the mechanical response of buried pipelines.[Methods]Finite element numerical simulation was employed.By varying settlement counts and sequences across different areas,simulations of buried pipeline settlement under various modes were conducted and validated experimentally.The simulation results enabled a quantitative comparison and analysis of the mechanical responses of buried pipelines under different settlement modes.[Results]Under reverse-order,step-by-step settlement,the maximum surface settlement above the pipeline exceeded that of the one-time overall settlement mode.Although soil separation beneath the pipeline center was severe,the pipeline's mechanical response remained lower than in the one-time overall settlement.When settlement counts were equal,differences in pipeline mechanical response due to settlement sequence exceeded 50％,highlighting the significant impact of settlement processes.For the same settlement amount,the one-time overall mode caused more than twice the maximum displacement and longitudinal tensile strain compared to multi-step settlement.Consequently,one-time overall settlement induced a more intense mechanical response,increasing the risk of damage to buried steel pipelines.[Conclusion]Large-scale local stratum settlement has limited impact on the overall mechanical response of buried pipelines.A comprehensive analysis of the settlement development across the entire area is necessary.To minimize pipeline mechanical response for a given settlement range and amount,it is recommended to first analyze large-scale settlement in the center of the area,followed by multiple smaller settlements toward the boundaries.These findings are crucial for accurately assessing the safety of buried pipelines under stratum settlement.(25 Figures,7 Tables,23 References)

Integrating hydrogen into urban gas pipeline networks is a pivotal technology for energy transition yet poses critical safety threats, thus necessitating comprehensive risk assessment of hydrogen-blended natural gas pipelines. This study performs full quantitative risk assessment of leakage failure and accident evolution by proposing a novel framework that integrates causal inference (Bow-Tie analysis) with probabilistic machine learning (Bayesian networks), enabling systematic failure factor identification and dynamic accident progression simulation. Key findings indicate human factors and pipeline material degradation as primary triggers. The studied pipeline exhibits a low baseline failure probability, with dispersion emerging as the most likely consequence of leakage. Higher hydrogen blending ratios significantly elevate jet fire risk due to hydrogen’s low ignition energy, while hydrogen’s inherent buoyancy and high diffusivity notably mitigate the likelihood of flash fire and vapor cloud explosion. The case study verifies the model’s practicability, and macro-micro analyses provide holistic insights, offering a reliable method to guide pipeline safety and reliability improvement amid energy transition.

High-speed sand-laden fluids can cause severe erosion of the packer mandrel in downhole packer systems. However, predictive models for packer systems under coupled thermo-mechanical stresses remain underdeveloped, and no research has been conducted on the multiphase flow erosion of the packer mandrel with temperature considerations. This study applies a coupled CFD–DPM framework to systematically investigate multiphase flow–particle interactions and erosion behavior in a retrievable test-treat-squeeze (RTTS) packer mandrel. The computational framework employs Lagrangian particle tracking coupled with turbulent flow modeling, enabling precise quantification of erosion patterns influenced by five key operational parameters: fluid velocity (5-35m/s), temperature (160-220°C), silica particle size (0.2-4.0mm), solids loading (0.5-5.0kg/s), and diameter ratio (0.35-0.80). The results show that the maximum erosion rate increases by up to 25.5 -fold as flow velocity increases, and by 8.27-fold as solids loading increases. Particle size exhibited a non-monotonic effect on erosion. Temperature exhibits a limited influence on erosion, contributing less than 2% variation under the assumption of constant fluid properties. Flow field analysis reveals that vortex intensity and particle impact localization are highly sensitive to flow acceleration and geometric contraction. The research results can provide a reference for the structural optimization design and failure position prediction of packer, in order to improve the service life and reliability of packer.

This study systematically investigates the hydrogen embrittlement (HE) behavior of X65 pipeline steel base metal (BM) and weld metal (WM) in gaseous hydrogen environments. The hydrogen permeation characteristics, fatigue properties and fracture behaviour of both the BM and WM under various hydrogen partial pressure environments were considered intensively. Electron backscatter scanning diffraction (EBSD) was employed to characterize crystallographic features of the BM and WM. The results indicate that the BM exhibits no pronounced texture and contains a low proportion of high angle grain boundaries (HAGBs). The WM shows distinct texture and possesses relatively low dislocation density. Under in-situ gaseous hydrogen charging conditions, the hydrogen diffusivity for various regions of WM are about half an order of magnitude greater than that of the BM. With the increase of hydrogen partial pressure, the correlation between partial pressure and the fatigue crack growth rate (FCGR) weakens. At the hydrogen partial pressure of 1.26 MPa, the FCGRR of WM is approximately 1.4 times that of the BM, which is more susceptible to hydrogen effects. Macroscopic and microscopic analyzes of the specimen fracture surfaces were conducted using a 3D super depth of field microscope and a scanning electron microscope (SEM). Comparing with BM specimens, WM specimens accompany more abundant brittle fracture characteristics and exhibit lower fracture toughness. Under the identical hydrogen partial pressure, the embrittlement index (EI) of BM and WM are comparable, whereas the fracture toughness of WM was approximately 37.7 % and 14.6 % lower than those of BM respectively.

ObjectiveThe formation of hydrogen atoms on the surface of hydrogen pipeline steel serves as the critical link between the external hydrogen environment and internal hydrogen-induced damage. While existing research predominantly concentrate on hydrogen diffusion, hydrogen trapping, and macroscopic mechanical property degradation, systematic reviews regarding the dissociative adsorption of hydrogen on pipeline steel surfaces remain insufficient, which fails to supply direct theoretical basis for safety assessment of operational hydrogen pipelines. MethodsCentering on of the dissociative adsorption of hydrogen, recent research regarding gaseous hydrogen embrittlement and hydrogen behavior in pipeline steel was summarized across three dimensions: theoretical foundations, experimental testing, and numerical simulations. The application scopes of multiple methodologies were systematically compared, including surface characterization, hydrogen permeation testing, densityfunctional theory, ab initio molecular dynamics, and the finite element method. Furthermore, influencing factors such as surface states, corrosion product films and passive films, impurity gases, alloying elements, temperature, and stress were integrated into a unified analytical framework. ResultsStatistical analysis indicated that in the field of gaseous hydrogen embrittlement, studies on macroscopic mechanical properties and hydrogen embrittlement mechanisms accounted for approximately 72％, those on hydrogen diffusion in steel accounted for roughly 15％, and only around 8％ directly addressed surface dissociative adsorption—revealing insufficient research on this initial process. Comparative analysis of typical numerical simulation methods revealed that density functional theory was applicable to analyzing stable adsorption sites, adsorption energy, and dissociation energy barriers at a scale of 0.1–10.0 nm. Ab initio molecular dynamics described dynamic interfacial processes at finite temperatures for scales of 0.1–20.0 nm, though it was limited by system size and time scale. The finite element method could reach micrometer scales and even component scales, but it relied on atomic-scale input parameters. Experimental results further demonstrated that surface roughness, grain boundaries, dislocation emergences, and inclusion interfaces increased local active site density. The integrity and compactness of corrosion product films/passive films significantly affect hydrogen ingress, and compact films generally show a hydrogen-barrier effect, gas impurities introduced distinct chemical behaviors: O2 and CO primarily induced competitive adsorption and surface poisoning, CO2 exhibited environment-dependent characteristics, and H2S tended to facilitate the ingress of atomic hydrogen into the steel matrix. ConclusionThe dissociative adsorption of hydrogen on pipeline steel surfaces should not be regarded as an isolated surface reaction, but rather as the starting point of the entire degradation sequence: surface hydrogen generation – interfacial hydrogen ingress – bulk hydrogen diffusion – hydrogen trapping and enrichment – damage evolution. Future research should focus on in-situ characterization under high-pressure gas phases, standardized gaseous hydrogen permeation testing, and multi-scale coupling models to provide quantitative benchmarks for material selection, gas quality management, and the safety evaluation of in-service hydrogen pipelines.

Dense phase / supercritical CO2 pipeline transportation is a critical component of CCUS (Carbon Capture, Utilization, and Storage), where impurity content significantly affects the phase state and stability of CO2 pipeline transportation. To address the challenge that the influence mechanisms of various impurities on the phase characteristics of CO2 under pipeline conditions are complex and difficult to predict, a phase equilibrium theoretical model was developed. Additionally, the equation of state (EOS) suitable for impurity-containing CO2 systems was optimized through experimental validation. Based on this, the sensitivities of the bubble point, dew point, and critical point during pipeline transportation were studied. The following conclusions were drawn: the preferred Peng-Robinson (PR) equation of state is the most suitable for CO2 systems containing impurities, with an average deviation of 4.835 %. From the perspective of impurity molecular polarity and intermolecular forces, the phase characteristics of CO2 systems were analyzed. By defining a deviation degree, the average deviations of CO2 systems with N2, CO, H2, Ar, and CH4 impurities were 0.337, 0.364, 0.671, 0.268, and 0.211, respectively. Therefore, the influence of impurities on the phase envelope region, i.e., the impact per unit impurity, follows the order: H2 > CO > N2 > Ar > CH4. Based on pipeline transportation conditions, the effects of changes in bubble point, dew point, and critical point shifts on pipeline transport were analyzed. This research provides a foundation for establishing impurity content limits in CO2 systems under pipeline transportation conditions.

Gravity-induced stratification of hydrogen–methane(H₂–CH₄) mixtures remains a debated safety concern in hydrogen-blended natural gas pipelines, particularly in vertical and quiescent sections. In this work, a unified thermodynamic–transport framework is developed to quantitatively evaluate both the equilibrium distribution and the transient timescale of H₂–CH₄ mixtures under gravity. The framework integrates(i) a minimum-energy model based on Helmholtz free energy minimization with the Peng–Robinson real-gas equation of state and(ii) a transient convection–diffusion model coupling gravitational drift with molecular diffusion. Model predictions agree with benchmark literature and experimental data within 2%. Results show that temperature accelerates diffusion, pressure delays equilibration without altering steady-state distributions, and pipe height primarily controls the stratification timescale rather than its magnitude. Even under extreme conditions (−10°C, 10 MPa, 30 vol% H₂, 1 km height), the steady-state top–bottom hydrogen volume fraction difference remains below 1.5%, while more than 2.7 × 10³ years are required to reach equilibrium. Under typical urban gas conditions, the concentration difference after 10 days is below 0.01%. These findings demonstrate that gravity-induced stratification of H₂–CH₄ mixtures is physically possible but engineering-irrelevant within practical pipeline lifetimes, providing a time-explicit and quantitatively justified basis for pipeline design and safety assessment.

With growing global recognition of methanol as a versatile energy carrier, establishing safe and efficient transnational supply chains is urgent. Pipeline transportation, known for its economy and efficiency, is pivotal in this context. Repurposing existing refined oil pipelines for green methanol transport offers a strategic solution, improving infrastructure utilization and avoiding the high costs of new construction. Despite this potential, systematic reviews on large-scale green methanol transport infrastructure, particularly pipeline repurposing, remain scarce. Based on a comprehensive survey of the literature, this review synthesizes key findings on establishing a large-scale green methanol pipeline infrastructure, covering material compatibility, equipment adaptability, and operational safety for green methanol pipeline transport. A primary conclusion is that repurposing existing refined oil pipelines, integrated with multimodal transportation methods offers a viable path to enhance pipeline utilization and ensure a stable supply. However, significant technical challenges must be addressed. Material compatibility studies indicate that impurities can induce corrosion and swelling; equipment requires specialized designs for safety; Leakage dispersion behavior is complex, and during sequential transport, mixing lacks efficient predictive models. Compounding these hurdles is the absence of dedicated national standards. By identifying these key knowledge gaps, this review proposes a methodology for assessing the feasibility of converting refined oil pipelines to transport green methanol, considering process, technical, economic, and environmental safety aspects. It provides a research roadmap for future technological innovation and strategic planning to support the emerging green methanol economy. (230 words)

With the continuous development of global trade and shipping industry, the total amount of carbon dioxide emitted by ships has increased significantly. The removal and regeneration of carbon dioxide in ship exhaust and the liquefaction and recycling of regenerated carbon dioxide can effectively alleviate the greenhouse effect. However, for the treatment of large flow ship flue gas, the larger gas flow rate when using a single rotating packed bed will make the rotating packed bed too large, increasing energy consumption and vibration. It is a feasible method to use rotating packed bed in series or in parallel for carbon dioxide removal and regeneration of large flow natural gas. In this paper, the simulation of carbon dioxide removal and regeneration of natural gas was carried out in HYSYS, and the simulation results were compared with the experimental results. At the same time, the rotating packed bed is enlarged, and the same rotating packed bed is simulated in series and parallel. In this paper, the effects of operating parameters and structural parameters on carbon dioxide removal and regeneration in series rotating packed bed and parallel rotating packed bed are analyzed. The simulation results show that the series rotating packed bed has a good absorption effect on carbon dioxide, and the parallel rotating packed bed has a good regeneration effect, and its regeneration effect is better than the first and second stages of the series rotating packed bed.

Due to its unique advantages-including light weight, low density, high porosity, large specific surface area, and favorable mechanical properties-metal foam packing has been increasingly adopted, gradually supplanting traditional packings such as metal mesh. Currently, however, research on foam metal packings is limited, and numerical simulations have been confined to two-dimensional analyses. Unlike metal mesh packings, foam metal packings possess a complex structure, rendering two-dimensional simulations inadequate for capturing the detailed flow phenomena within. Therefore, conducting three-dimensional simulations of their interior is essential. In this study, three-dimensional modeling and numerical simulation of metal foam packing were performed. The effects of operating parameters (e.g., rotational speed and liquid flow rate) and structural parameters (e.g., porosity and packing aperture) on key performance indicators-including liquid holdup, effective interfacial area, droplet diameter, droplet velocity, and droplet volume percentage-were analyzed. The results indicate that higher porosity and moderate packing aperture facilitate liquid flow within the metal foam packing, thereby promoting heat and mass transfer. Furthermore, the mechanisms underlying flooding in foam metal packings are analyzed. The findings of this study contribute to the broader understanding and practical application of foam metal packings.

An indoor horizontal experimental flow loop was constructed to investigate safe restart strategies for gathering pipelines in high-water-cut oil fields following unplanned shutdowns. The system enables cyclic shutdown-restart operations of oil-gas-water three-phase flow under varying conditions, with synchronous flow pattern visualization and high-frequency pressure/temperature data acquisition. Experiments revealed that a distinct horizontal oil-water stratification develops during shutdown. Based on this observation, a temperature drop prediction model was developed, which couples the external soil temperature field and explicitly accounts for the three-phase distribution. During restart, the reduction in flow area due to the gelled oil layer and its non‑Newtonian shear-shedding behavior are identified as the key mechanisms governing the pressure transients. Accordingly, a three-phase restart pressure prediction model was established by decomposing the total pressure into frictional pressure drop, gelled oil layer shear pressure drop, and inertial pressure drop. Experimental validation demonstrates that the coupled model can effectively predict the post‑shutdown temperature distribution and the full restart pressure evolution, including the peak pressure and subsequent decay.

Constructing new hydrogen pipelines and repurposing existing oil and gas pipelines represent two typical modes of hydrogen transportation. While repurposing existing pipelines offers greater economic benefits, both approaches face safety challenges due to the flammable and explosive properties of hydrogen. In this study, the evolution behavior of hydrogen under various venting conditions was investigated using numerical simulations. The results show that a vent diameter of 30 mm leads to higher peak temperatures and pressures inside the vent pipeline compared to diameters of 5 mm, 10 mm, and 20 mm, and also results in a slower rate of energy dissipation. From the perspective of preventing spontaneous ignition, selecting a smaller valve passage diameter is more effective in reducing the ignition risk. When the downstream pipeline is filled with a hydrogen-air premixed gas, a localized high-temperature zone forms within the valve pipe and extends throughout the entire high-temperature region. However, the annular high-temperature band at the pressure wavefront lacks sufficient energy to ignite the downstream mixture. No combustion occurs at the wavefront, and only localized slowburning reactions are observed at the valve outlet. The findings provide valuable insights into the safety considerations associated with converting in-service natural gas pipelines for hydrogen transport.

This work presents an experimental investigation of hydrogen-induced degradation in X52 pipeline steel, evaluating both base metal and weld metal behavior under varying hydrogen pressures. Through in-situ hydrogen-charged mechanical testing combining fatigue crack growth analysis and single-point J₀ toughness measurements, the research quantifies hydrogen's impact on fracture resistance. Advanced microstructural characterization techniques, including EBSD and SEM fractography, provide mechanistic insights into embrittlement phenomena. The results reveal two critical hydrogen effects: first, a pressure-dependent acceleration of fatigue crack propagation, with weld metal showing 25-40% faster growth rates than base metal at equivalent pressures. Second, substantial toughness reduction occurs through hydrogen's selective impairment of plastic deformation mechanisms, decreasing J₀ values by up to 85% at 4MPa H₂ pressure. The vulnerability of the weld zone may be linked to its characteristic grain boundary structure. Observations indicate a significantly higher proportion (estimated at 30-50%) of high-angle boundaries compared to the base metal. As these boundaries are widely hypothesized to be effective hydrogen traps, they could be a key factor contributing to the observed higher hydrogen embrittlement susceptibility.

Hydrate deposition in stratified multiphase flows poses a major challenge to flow assurance in deep-water energy systems. Existing models often neglect the dynamic interplay between hydrate particle suspension, aggregation, and bed formation under complex flow regimes. This study proposes a coupled hydrate deposition model that integrates a critical suspension particle-size module, derived from energy conservation principles, with a Population Balance Model (PBM) and a four-layer stratified flow framework. The model captures the full evolution of hydrate particles—from generation and aggregation to bed accumulation—and enables accurate prediction of deposition height and risk zones along the pipeline. To evaluate the model, simulations were conducted on a deep-water mixed-transportation pipeline under laminar flow conditions. Results revealed that hydrate deposition risk concentrates in three key regions: downstream horizontal sections, the end of uphill segments, and pipeline terminations. Importantly, during production decline stages, reduced flow carrying capacity exacerbated hydrate accumulation, with high-risk zones extending to over 30% of the pipeline length. Compared to existing stratified flow models, the proposed framework enhances spatial resolution of hydrate bed formation and risk localization. The model's modular coupling strategy also allows for flexible extension to different flow regimes. These findings offer both theoretical insights and practical tools for predicting hydrate plugging risk, supporting safer and more efficient flow assurance strategies in deep-water oil and gas development.