Petroleum Science最新文献

{"title":"Examining the mechanisms of rebound evolution of various pore types in Longmaxi Formation shale using shale triaxial creep experiments","authors":"Yang Wang ,&nbsp;Han-Yu Zhang ,&nbsp;Yan-Ming Zhu ,&nbsp;Hao-Ran Chen ,&nbsp;Zhi-Xuan Wang ,&nbsp;Jia-Le Li","doi":"10.1016/j.petsci.2025.09.016","DOIUrl":"10.1016/j.petsci.2025.09.016","url":null,"abstract":"<div><div>The Longmaxi Formation shale in the Sichuan Basin has been affected by late-stage tectonic uplift, leading to significant differences in the pore structures of reservoir formations across various structural units and burial depths in development wells. These differences result in variations in gas content and saturation, leading to noticeable disparities in development performance and issues such as unstable production. Therefore, understanding the rebound adjustment mechanisms of pore structures in shale reservoirs is a key scientific question for uncovering the dynamic adjustment and accumulation mechanisms of shale gas. This study employs high-pressure triaxial creep experiments combined with scanning electron microscopy and fractal theory to qualitatively and quantitatively characterize various pore structures in the organic-rich shale of the Longmaxi Formation, disclosing the mechanisms and patterns of rebound response of various pore types. The results indicate that as creep pressure decreases, the rebound adjustment patterns vary among pore types. The complexity and distribution of organic matter pores initially increase and then decrease, while intergranular pores exhibit a trend of first decreasing and then increasing. Furthermore, based on microscopic evolution and changes in fractal dimension characteristics, shale pore rebound adjustment mechanisms can be broadly classified into two types: the plastic and brittle rebound adjustment pathway. This study combines theoretical analysis with experimental results to develop rebound adjustment models and response mechanisms for different pore types. This approach is essential for explaining how late-stage tectonic uplift during geological history regulates dynamic changes in shale pore structures and the process of shale gas accumulation.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 1","pages":"Pages 52-68"},"PeriodicalIF":6.1,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147404518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigating the effect of the shale bedding structure on hydraulic fracture propagation behavior on the basis of a coupled thermal–hydraulic–mechanical numerical model","authors":"Xun Gong ,&nbsp;Zhi-Jun Jin ,&nbsp;Xin-Hua Ma ,&nbsp;Yu-Yang Liu ,&nbsp;Yan-Jun Guo ,&nbsp;Mei-Zhu Wang","doi":"10.1016/j.petsci.2025.10.020","DOIUrl":"10.1016/j.petsci.2025.10.020","url":null,"abstract":"<div><div>The interaction process among hydraulic fractures and natural fractures, bedding planes, and other discontinuities during shale fracturing determines the complexity of the fracture network that is formed. However, the current conclusions and understanding of the mechanisms underlying the interaction between hydraulic and natural fractures, as well as their primary controlling factors, fail to meet the requirements of hydraulic fracturing operations, thereby restricting the efficient development of shale gas resources. Therefore, in this study, a coupled thermal‒hydraulic‒mechanical finite element numerical model that is based on the maximum tensile stress and the Mohr‒Coulomb criterion is established, thereby considering rock deformation, fluid flow, and heat transfer. The reliability of this model is validated on the basis of previous research. This model is subsequently employed to simulate the propagation behavior of hydraulic fractures in shale with well-developed bedding. The results indicate that when hydraulic fractures propagate to the bedding, five propagation modes may occur: arrest, diversion, diversion and crossing, crossing and diversion, and direct crossing. These modes are controlled by factors such as the mechanical properties of the shale matrix and bedding, geostress, bedding dip angle, temperature, and fracturing fluid injection rate. During fracture propagation, increases in the elastic modulus ratio between the rock matrix and the bedding, the bedding dip angle, and the temperature are favorable for hydraulic fractures turning along the bedding, whereas increases in the difference in vertical stress and the injection rate are favorable for hydraulic fractures directly crossing the bedding. Second, on the basis of four influencing factors, namely, the shale matrix and bedding elastic modulus ratio, bedding dip angle, difference in vertical stress, and temperature, propagation criteria for hydraulic fractures along the bedding under various combinations of influencing factors are established. The results provide theoretical reference data for the design and optimization of fracturing in shale with well-developed bedding.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 1","pages":"Pages 297-316"},"PeriodicalIF":6.1,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147404083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unraveling the hydrodynamic effects on calcium carbonate scaling behavior under high-temperature and high-pressure CO2 degassing","authors":"R.S. Maciel ,&nbsp;F.A.R. Pereira ,&nbsp;E.J. Soares ,&nbsp;C. Scandian ,&nbsp;J.R.C. Proveti ,&nbsp;R.P. Cosmo ,&nbsp;R.F. Fejoli ,&nbsp;H.E.P. Schluter ,&nbsp;A.L. Martins","doi":"10.1016/j.petsci.2025.09.040","DOIUrl":"10.1016/j.petsci.2025.09.040","url":null,"abstract":"<div><div>Carbonate scaling in the Brazilian pre-salt oil production systems represents a challenging flow assurance issue driven by the release of CO₂ caused by head loss. This reduction in pressure causes CO₂ degassing, increases the pH and thereby promotes the CaCO₃ precipitation. Recent studies indicate that scaling rates intensify with the inherent flowing fluid turbulence. However, this phenomenon has not been comprehensively studied at elevated temperatures, pressures, and high CO₂ content, typical of pre-salt subsurface environments. This study uses a batch reactor equipped with a rotating cage system (according to the ASTM G184 standard) to investigate the effect of fluid dynamics on CaCO₃ scaling at up to 80 °C, 70 barg, different levels of turbulence and shear stress, being subjected to the effects of CO₂ degassing. Analyses were conducted using 3D profilometry, gravimetry, photomicroscopy, SEM, XRD, and Rockwell C scratch tests. The results reveal that, under oil well conditions, the turbulence distinctly influences the scaling rates compared to bench experiments (room temperature, atmospheric pressure, and without dissolved CO₂). What distinguishes the results of this study from other works is the appearance of a reversal point at sufficiently high turbulence—that is, the scaling rates begin to decrease with increased turbulence—still within the pre-salt oilwell operation range. The material adhered to the rotating cage coupons was investigated to understand this phenomenon, identifying that the calcium carbonate polymorphs contribute to this reversal.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 1","pages":"Pages 434-446"},"PeriodicalIF":6.1,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147404355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interfacial plugging of shale microfractures using functionalized graphene oxide with high dispersion stability under harsh conditions","authors":"Dao-Xiong Li ,&nbsp;Yang Bai ,&nbsp;Cheng Wang ,&nbsp;Na Su ,&nbsp;Ling-Feng Wu ,&nbsp;Deng Gu ,&nbsp;Yu-Fen Zhai ,&nbsp;Ping-Ya Luo","doi":"10.1016/j.petsci.2025.09.030","DOIUrl":"10.1016/j.petsci.2025.09.030","url":null,"abstract":"<div><div>Shale gas development often suffers from wellbore instability due to microfractures in the formation, posing serious challenges to drilling safety and efficiency. This study presents a functionalized graphene oxide (GO-PAA) nanomaterial, prepared by grafting hydrophilic polyacrylic acid (PAA) chains onto GO surfaces to enhance dispersion stability under high salinity, elevated temperature, and wide pH conditions. The results indicate that GO-PAA effectively resists charge-shielding effects under conditions of high salinity, elevated temperature, and a wide pH range, significantly reducing the risk of particle aggregation. Even at high salt concentrations, the zeta potential remains below −32.8 mV, demonstrating good colloidal stability. Plugging performance was evaluated using simulated core experiments. GO-PAA formed a “band-aid” like barrier on shale microfracture surfaces, reducing permeability by up to 57.53%, nearly twice that of conventional spherical nanoparticles. Scanning electron microscope (SEM) and elemental analysis confirmed the formation of a dense and uniform plugging layer. The synergistic interaction between GO’s 2D lamellar structure and the flexible polymer chains facilitated effective surface adhesion and coverage. This adsorption–adhesion plugging mechanism represents a shift from traditional bridging theories, enabling reduced material usage and improved efficiency. The findings provide theoretical and practical support for designing high-performance nanoplugging agents in water-based drilling fluids, contributing to safer and more sustainable shale gas development.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 1","pages":"Pages 422-433"},"PeriodicalIF":6.1,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147404357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impacts of Himalayan tectonism on Eocene gas shale and its pore structure within the Lesser Himalayas, Nepal: Insights for shale gas accumulation and preservation","authors":"Kumar Khadka ,&nbsp;Si-Jie Han ,&nbsp;Shu-Xun Sang ,&nbsp;Jun-Jie He ,&nbsp;Upendra Baral ,&nbsp;Saunak Bhandari ,&nbsp;Debashish Mondal ,&nbsp;Xiao-Zhi Zhou ,&nbsp;Shi-Qi Liu","doi":"10.1016/j.petsci.2025.09.026","DOIUrl":"10.1016/j.petsci.2025.09.026","url":null,"abstract":"<div><div>This study investigates the complex relationship between organic matter (OM), tectonic deformation, and pore structure development in Eocene Bhainskati shale within the Lesser Himalayan foreland basin, Nepal, to assess its implications for shale gas accumulation and preservation. We hypothesize that tectonic deformation and variations in organic matter have a significant impact on pore size distribution, connectivity, and gas retention, thereby influencing shale gas potential. We characterized pore types and quantified pore size distributions using scanning electron microscopy (SEM), mercury intrusion capillary pressure (MICP) techniques, and low-pressure gas adsorption methods. Our findings indicate a predominance of mesopores (1–10 nm range, with a notable peak at 4 nm), suggesting substantial contributions to surface area from micropores and fine mesopores. Thermal maturity negatively impacts porosity and surface area. At the same time, tectonic activity enhances microfracture development, increasing permeability and gas transport, particularly in the Surkhet area, which exhibits higher pore volume and specific surface area than the Tansen area. Tectonic forces shift the shale from brittle to ductile behavior, altering pore connectivity. Himalayan tectonic forces significantly influence shale structure, pore sizes, gas preservation, and migration, enhancing gas adsorption by increasing surface area but posing challenges due to potential gas escape along faults and folds. Understanding the impact of tectonic activity on shale deformation in similar basins within the Himalayas and the adjacent region is vital for assessing shale gas potential and optimizing exploration strategies in tectonically active Nepal Himalayan regions. This study highlights the dual role of tectonics in both promoting and complicating the formation, accumulation, and preservation of shale gas reservoirs, offering critical insights for future exploration efforts.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 1","pages":"Pages 103-126"},"PeriodicalIF":6.1,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147404521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrodynamics characteristics of rough-walled self-propping shale fractures: from microscale morphology to macroscale hydraulic response","authors":"Ming-Yong Zeng ,&nbsp;Hang-Yu Zhou","doi":"10.1016/j.petsci.2025.10.015","DOIUrl":"10.1016/j.petsci.2025.10.015","url":null,"abstract":"<div><div>Self-propping fractures formed during hydraulic fracturing in shale reservoirs constitute a critical component of the hydraulic fractures, with surface roughness serving as a pivotal factor governing their mechanical and hydraulic properties. To examine the regulatory effects and underlying mechanisms of rough morphology on fluid transport behavior within self-propping fractures under closure stress, this study employs the fast Fourier transform (FFT) method to generate synthetic rough fractures characterized by fractal Brownian motion (FBM) features. Subsequently, a coupled mechanical-hydraulic model for single rough self-propping fractures was established to simulate the influence of morphological roughness on their hydrodynamics characteristics. The results demonstrate that under closure stress, the deformation increment of self-propping fractures exhibits a pronounced synchronous relationship with fracture conductivity degradation. The progressive narrowing of fracture aperture induced by increasing closure stress constitutes the primary mechanism driving persistent conductivity deterioration. Furthermore, both high-density “cluster-like” contact micro-asperities and “throat-shaped” constriction structures have been identified as critical morphological factors. Regions dominated by the high-density “cluster-like” contact micro-asperities significantly constrict the flow pathways, inducing specialized flow phenomena such as “transverse flow” and “reverse flow”. Concurrently, the “throat-shaped” constriction structures generate significant throttling effects, precipitating abrupt pressure drops. These combined mechanisms fundamentally degrade the conductivity of self-propping fractures under closure stress. A linear positive correlation exists between fractal dimension and fracture conductivity. While closure stress induces significant reconfiguration of flow pathways, the interplay between fractal roughness characteristics and stress-induced deformation preserves the integrity of favorable flow conduits, resulting in higher conductivity with larger fractal dimensions. Fracture conductivity is governed by the competitive interaction between the roughness-mediated reduction in flow resistance and the throat constriction effect during mechanical compression. The primary flow pathways within self-propping fractures are predominantly dictated by the fundamental large-scale morphological structures. In contrast, small-scale roughness features primarily enhance flow heterogeneity in velocity magnitude and direction. Crucially, these secondary structures do not fundamentally alter the spatial distribution pattern of the primary flow channels in self-propping fractures.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 1","pages":"Pages 245-261"},"PeriodicalIF":6.1,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147404084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance of steam injection process in layered heavy oil reservoirs: An experimental and numerical investigation","authors":"Xiu-Chao Jiang,&nbsp;Xiao-Hu Dong,&nbsp;Hao Zhang,&nbsp;Tian-Yang Yin,&nbsp;Hui-Qing Liu","doi":"10.1016/j.petsci.2025.09.041","DOIUrl":"10.1016/j.petsci.2025.09.041","url":null,"abstract":"<div><div>Layered heavy oil reservoirs are widely distributed hydrocarbon resources and play a crucial role in fulfilling the global increasing demand for energy. Due to the existence of interlayer heterogeneity, however, the traditional commingled steam injection process has been confronted with the challenges of uneven production and poor performance in the field. In this study, to investigate the improvement effects of a separate steam injection process for the layered heavy oil reservoirs, combining the methods of experiments and numerical simulation, the expansion behavior of the heated chamber and production performance of these two steam injection modes (base case and improved case) are compared and analyzed. First, based on the 2D scaling criteria of steam stimulation experiments and actual properties of a typical layered heavy oil reservoir in China, the experimental parameters are obtained. During experiments, to better simulate the field operation condition, a 2D HTHP (high temperature and high pressure) thermal recovery experimental apparatus equipped with a pressure chamber is proposed. From the experimental observations, the advantages of the separate steam injection mode are illustrated from the expansion behavior of the heated chamber and the production performance characteristics. Thereafter, through a history matching of the experimental results, the laboratory-scale numerical simulation model is developed. Then, from the same-scale numerical simulation model, the steam flooding stage of the base case for the layered heavy oil reservoirs is divided into three phases, and the primary features and critical indices of different phases are obtained. Finally, the effects of reservoir properties and operation parameters on production performance and interlayer divergence are discussed. Experimental results show that the separate steam injection mode achieves uniform heated chamber expansion across layers, and the average proportion of heated chamber is 18% higher than that of the commingled steam injection process. Meanwhile, the improved case increases the final oil recovery factor by around 6%. The simulation results of the developed laboratory-scale numerical simulation model are in good agreement with the experimental observations. For the layered reservoirs with an interlayer permeability contrast of the oil layer reaching 3, it is recommended to adopt the separate steam injection mode. In addition, the optimum cyclic steam injection volume for the reservoir is 6000–7000 m³, and the steam injection rate should be no more than 250 m³/d. This paper contributes to a systematic understanding of steam stimulation performance with different steam injection modes for layered heavy oil reservoirs.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 1","pages":"Pages 365-382"},"PeriodicalIF":6.1,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147404445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Insight into the impact of the Al distribution in ZSM-5 zeolite on deep hydrogenation of phenanthrene over Pt/HZSM-5","authors":"Chuan-Hao Zhang ,&nbsp;Qi Dong ,&nbsp;Fei Wang ,&nbsp;Ning-Yue Lu ,&nbsp;Feng Yu ,&nbsp;Bin-Bin Fan ,&nbsp;Rui-Feng Li","doi":"10.1016/j.petsci.2025.09.017","DOIUrl":"10.1016/j.petsci.2025.09.017","url":null,"abstract":"<div><div>Deep hydrogenation of polycyclic aromatic hydrocarbons (PAHs) into jet fuel is an important strategy for the upgrading of light cycle oil (LCO). Zeolite-supported metal catalysts have exhibited good catalytic performance for hydrogenation of PAHs under relatively mild conditions. However, the impacts of acidity variations in zeolite supports, arising from the differences in framework Al (Al_F) distribution on the catalytic behavior of zeolite-supported metal catalysts in the deep hydrogenation of PAHs remains unclear. Herein, two series of mesoporous ZSM-5 samples, that is ZSM-5-E-<em>x</em> and ZSM-5-F-<em>x</em>, with the differences in Al_F distribution but similar Si/Al ratios, were prepared in the crystallization system with or without NaOH. The results of NH₃-TPD, Pyridine-IR, N₂ adsorption-desorption and SEM reveal that two series of HZSM-5 samples have similar acid density and acid strength, textural properties, morphology and particle size. However, the results of XPS, ²⁷Al MAS NMR, 2,6-Ditert-butylpyridine-IR, catalytic cracking of 1,3,5-triisopropylbenzene and the controlled reactions as well as DFT calculation indicate that the higher enrichment degree of Al_F on the external surface and the suitable arrangement mode of Al_F in ten-membered ring (10-MR) of HZSM-5-F-<em>x</em> compared to HZSM-5-E-<em>x</em> in case of the similar Si/Al ratios, result in Pt/HZSM-5-F-<em>x</em> exhibiting remarkably-improved deep hydrogenation performance of phenanthrene (PHE) compared to Pt/HZSM-5-E-<em>x</em>. Particularly, the selectivity to perhydrophenanthrene (PHP) over Pt/HZSM-5-F-50 can reach above 99.0% at a conversion of PHE (&gt;99.0%). Furthermore, Pt/HZSM-5-F-50 exhibits well reusability. This work helps to clarify the impact of Al_F distribution in ZSM-5 on catalytic hydrogenation performance for PAHs, providing valuable guidance for design and development of efficient catalysts for the hydrogenation of PAHs.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 1","pages":"Pages 475-485"},"PeriodicalIF":6.1,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147331753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biomimetic inspired superhydrophobic nanofluids: Enhancing wellbore stability and reservoir protection in shale drilling","authors":"Jin-Sheng Sun ,&nbsp;Ting Liao ,&nbsp;Yu-Xi Ji ,&nbsp;Hang Li ,&nbsp;Yuan-Zhi Qu ,&nbsp;Xian-Bin Huang ,&nbsp;Kai-He Lv ,&nbsp;Yu-Cai Luo ,&nbsp;Bo Zhang ,&nbsp;Jian Li","doi":"10.1016/j.petsci.2025.10.006","DOIUrl":"10.1016/j.petsci.2025.10.006","url":null,"abstract":"<div><div>Shale oil and gas, as typical unconventional resources, have gradually altered the global energy supply and demand landscape, attracting significant attention over recent decades. However, challenges such as wellbore instability and reservoir damage caused by drilling fluids invasion during shale drilling remain unresolved. In this study, we reported the synthesis and preparation of biomimetic inspired superhydrophobic nanofluids (SHN) with multiple functions by utilizing nano-silica, low surface energy fluorinated compounds, and cationic compounds with adsorption capabilities. Firstly, SHN with nano effects could plug micro-nano pores in shale, thereby reducing the filtration loss of drilling fluids (from 24 to 11 mL). Furthermore, SHN could adhere to shale surfaces through electrostatic interactions to increase its roughness from 1.121 to 3.567 μm, thereby transforming the shale surface from hydrophilic (26.4°) to superhydrophobic (152.8°). This not only reduced self-priming by 83.7% and decreased the capillary rise height to 5 mm below the liquid surface but also suppressed hydration expansion and improved the rolling recovery rate by 84.74%. Overall, this study provided new insights into the design and manufacturing of high-performance drilling fluids materials that could support wellbore stability and reservoir protection during shale oil and gas drilling processes.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 1","pages":"Pages 236-244"},"PeriodicalIF":6.1,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147404085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unveiling the role of residual structure in hydrate secondary formation through molecular dynamics simulations","authors":"Yi-Fan Zhang,&nbsp;Sen-Bo Xiao,&nbsp;Zhi-Liang Zhang,&nbsp;Jian-Ying He","doi":"10.1016/j.petsci.2025.11.017","DOIUrl":"10.1016/j.petsci.2025.11.017","url":null,"abstract":"<div><div>The rapid secondary formation of gas hydrate is a potential cause of flowline blockage in deepwater oil and gas production systems, posing serious flow assurance challenges. However, its microscopic formation mechanism remains an area of active research. Recently, the residual structure hypothesis has gained significant attention in explaining the rapid secondary formation of hydrates. In this study, massive molecular dynamics simulations are conducted to investigate the secondary formation of methane hydrates in solutions containing hydrate residual structures of varying sizes. The results indicated that residual structures, owing to their hydrate-like characteristics, facilitate the adsorption and capture of methane molecules, leading to the formation of local gas supersaturation regions. Residual structures promote hydrate formation through two key mechanisms: acting as nucleation sites and supplementing methane concentrations. Particularly, a synergy between residual structures and gas concentration was identified: high gas concentrations stabilize small residual structures, allowing them to serve as nucleation sites, while large stable structures can enrich methane even under low gas concentration.</div><div>This work not only provided a detailed understanding of the mechanisms of hydrate secondary formation but also provided valuable insight for hydrate blockage prediction and control in subsea oil and gas pipelines, contributing to improved flow assurance strategies.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 1","pages":"Pages 514-523"},"PeriodicalIF":6.1,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147404086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}