Pub Date : 2026-03-01Epub Date: 2025-12-22DOI: 10.1016/j.geoen.2025.214353
Yuanxiu Sun , Zhengyang Jia , Jianchao Li , Ming Li , Yangfan Tang
With the excessive consumption of fossil fuels and the further increase in CO2 emissions, the global demand for energy is gradually rising. Vigorously developing renewable energy has become a crucial measure in the energy industry. As a kind of green renewable resource with huge reserves, geothermal energy is considered to be one of the most promising renewable resources. In the quest for efficient methods of geothermal energy extraction, CO2 has demonstrated unique advantages. Compared to traditional systems that use water as the working medium, CO2 exhibits superior fluidity, enabling it to circulate more efficiently within geothermal reservoirs. All of which can accelerate heat transfer, thereby significantly improving the efficiency of geothermal energy extraction. The types of geothermal reservoirs are summerized in this article, including three categories: hot dry rock, deep aquifers and depleted oil and gas reservoirs. Moreover, the study provides a review of the physicochemical phenomena that occur after CO2 injection into geothermal reservoirs. These phenomena mainly include salt precipitation, CO2-brine-rock geochemical reactions, and thermosiphon effects. Furthermore, the factors affecting CO2 heat recovery are clarified. Finally, the obstacles and challenges faced by CO2 heat recovery technology are pointed out, and the future research work is clarified.
{"title":"The progress of CO2 geothermal extraction based on different reservoir types: physicochemical effects and multi-factors influence","authors":"Yuanxiu Sun , Zhengyang Jia , Jianchao Li , Ming Li , Yangfan Tang","doi":"10.1016/j.geoen.2025.214353","DOIUrl":"10.1016/j.geoen.2025.214353","url":null,"abstract":"<div><div>With the excessive consumption of fossil fuels and the further increase in CO<sub>2</sub> emissions, the global demand for energy is gradually rising. Vigorously developing renewable energy has become a crucial measure in the energy industry. As a kind of green renewable resource with huge reserves, geothermal energy is considered to be one of the most promising renewable resources. In the quest for efficient methods of geothermal energy extraction, CO<sub>2</sub> has demonstrated unique advantages. Compared to traditional systems that use water as the working medium, CO<sub>2</sub> exhibits superior fluidity, enabling it to circulate more efficiently within geothermal reservoirs. All of which can accelerate heat transfer, thereby significantly improving the efficiency of geothermal energy extraction. The types of geothermal reservoirs are summerized in this article, including three categories: hot dry rock, deep aquifers and depleted oil and gas reservoirs. Moreover, the study provides a review of the physicochemical phenomena that occur after CO<sub>2</sub> injection into geothermal reservoirs. These phenomena mainly include salt precipitation, CO<sub>2</sub>-brine-rock geochemical reactions, and thermosiphon effects. Furthermore, the factors affecting CO<sub>2</sub> heat recovery are clarified. Finally, the obstacles and challenges faced by CO<sub>2</sub> heat recovery technology are pointed out, and the future research work is clarified.</div></div>","PeriodicalId":100578,"journal":{"name":"Geoenergy Science and Engineering","volume":"258 ","pages":"Article 214353"},"PeriodicalIF":4.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145840568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2025-12-11DOI: 10.1016/j.geoen.2025.214316
Yang Long , Jin Yang , Chao Fu , Qishuai Yin
The presence of natural gas hydrates (NGHs) in deep-water shallow sediments may pose potential risks to the bearing capacity of submarine piles. In this study, a numerical simulation model was developed for the bearing capacity of piles serving deep-sea NGH-bearing sediments (NBSs) with the decomposition of NGHs, which is based on the dynamic decomposition model of NGH, constitutive model of NBS, theoretical model of pile bearing capacity and theory of negative pile friction resistance. The research analysed the variation in the pile bearing capacity with NGH saturation in the overall decomposition process and with NGH decomposition thickness in the layer-by-layer decomposition process. The Q–s curve and pile ultimate bearing capacity in the NGH decomposition process under different soil conditions were numerically simulated and compared. This study also investigated the contribution of the dilatancy angle to pile stability and the sensitivity of the pile bearing capacity to various parameters. Further analyses utilised numerical simulations to evaluate the pile bearing capacity in multi-layered NGH-bearing soil on-site for a layer-by-layer NGH decomposition process scenario.
{"title":"Study on the influence of hydrate decomposition on pile bearing capacity in deep-water hydrate-bearing sediments by numerical simulation","authors":"Yang Long , Jin Yang , Chao Fu , Qishuai Yin","doi":"10.1016/j.geoen.2025.214316","DOIUrl":"10.1016/j.geoen.2025.214316","url":null,"abstract":"<div><div>The presence of natural gas hydrates (NGHs) in deep-water shallow sediments may pose potential risks to the bearing capacity of submarine piles. In this study, a numerical simulation model was developed for the bearing capacity of piles serving deep-sea NGH-bearing sediments (NBSs) with the decomposition of NGHs, which is based on the dynamic decomposition model of NGH, constitutive model of NBS, theoretical model of pile bearing capacity and theory of negative pile friction resistance. The research analysed the variation in the pile bearing capacity with NGH saturation in the overall decomposition process and with NGH decomposition thickness in the layer-by-layer decomposition process. The Q–s curve and pile ultimate bearing capacity in the NGH decomposition process under different soil conditions were numerically simulated and compared. This study also investigated the contribution of the dilatancy angle to pile stability and the sensitivity of the pile bearing capacity to various parameters. Further analyses utilised numerical simulations to evaluate the pile bearing capacity in multi-layered NGH-bearing soil on-site for a layer-by-layer NGH decomposition process scenario.</div></div>","PeriodicalId":100578,"journal":{"name":"Geoenergy Science and Engineering","volume":"258 ","pages":"Article 214316"},"PeriodicalIF":4.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145790970","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2025-12-26DOI: 10.1016/j.geoen.2025.214350
Michael Kwofie , Richard Djimasbe , Mikhail A. Varfolomeev , Ilfat Z. Rakhmatullin , Vladimir V. Klochkov , Almaz L. Zinnatullin , Ameen A. Al-Muntaser , Muneer A. Suwaid , Rustam R. Davletshin , Anastasia N. Mikhailova , Yulia A. Duglav , Liliya K. Galiakhmetova
The present article investigates the effect of water and a bimetallic catalyst (Ni-Co/Al2O3) on the hydrothermal upgrading of crude oil including the conversion of asphaltenes and hydrogen production in discontinuous autoclave reactor at the conditions of 300 °C, 24 h and 92 bars. The catalyst was synthesized and characterized locally using XRD, SEM-EDX, and BET techniques. The reaction products were analyzed employing GC, FTIR, 13C NMR, and CHNS/O elemental analysis methods. The results indicate that, after the thermal and the hydrothermal upgrading process of crude oil, the production of gas increased from 4.22 to 6.39 wt%, respectively. Thereby, use of catalytic further raised the gas yield up to 8.77 wt%. Beside, it was found that, the optimal yields of the upgraded oil and hydrogen of 93.51 wt% and 23.52 mol%, were respectively obtained using 1.0 wt% and 0.5 wt% of catalyst. It was observed that using 0.5 wt% of catalyst resulted in negligible coke deposition, less than 1 wt% including 9.14 wt% sulfur in the solid phase contained, while around 1.29 mol% of H2S was detected in the gaseous products. Additionally, the asphaltenes structure of the sample containing 1 wt% catalyst appeared to be deficient in hydrogen, which is consistent with the observed sulfur removal from the asphaltenes structures due to the cleavage of C-S, C-C, and C-H bonds. Moreover, the NMR indicates that the molar content of Cp, Cs,q, Ct groups increases and the mean chain length (MCL) decreases to minimum for samples of asphaltenes 1 wt% of catalyst. The viscosity of the crude oil reduced 2.7 times after the hydrothermal upgrading process without using a catalyst. XRD analysis shows that adding 10 % SiO2 improves catalyst stability by preventing AlO(OH) formation. Overall, thermal upgrading increases mono-aromatics in asphaltenes, water inhibits their condensation via hydrolysis, and the catalyst enhances hydrogen production through the water-gas shift reaction.
{"title":"Experimental study of hydrogen generation through thermal and hydrothermal upgrading of crude oil in the presence of heterogeneous bimetallic catalyst with support","authors":"Michael Kwofie , Richard Djimasbe , Mikhail A. Varfolomeev , Ilfat Z. Rakhmatullin , Vladimir V. Klochkov , Almaz L. Zinnatullin , Ameen A. Al-Muntaser , Muneer A. Suwaid , Rustam R. Davletshin , Anastasia N. Mikhailova , Yulia A. Duglav , Liliya K. Galiakhmetova","doi":"10.1016/j.geoen.2025.214350","DOIUrl":"10.1016/j.geoen.2025.214350","url":null,"abstract":"<div><div>The present article investigates the effect of water and a bimetallic catalyst (Ni-Co/Al<sub>2</sub>O<sub>3</sub>) on the hydrothermal upgrading of crude oil including the conversion of asphaltenes and hydrogen production in discontinuous autoclave reactor at the conditions of 300 °C, 24 h and 92 bars. The catalyst was synthesized and characterized locally using XRD, SEM-EDX, and BET techniques. The reaction products were analyzed employing GC, FTIR, <sup>13</sup>C NMR, and CHNS/O elemental analysis methods. The results indicate that, after the thermal and the hydrothermal upgrading process of crude oil, the production of gas increased from 4.22 to 6.39 wt%, respectively. Thereby, use of catalytic further raised the gas yield up to 8.77 wt%. Beside, it was found that, the optimal yields of the upgraded oil and hydrogen of 93.51 wt% and 23.52 mol%, were respectively obtained using 1.0 wt% and 0.5 wt% of catalyst. It was observed that using 0.5 wt% of catalyst resulted in negligible coke deposition, less than 1 wt% including 9.14 wt% sulfur in the solid phase contained, while around 1.29 mol% of H<sub>2</sub>S was detected in the gaseous products. Additionally, the asphaltenes structure of the sample containing 1 wt% catalyst appeared to be deficient in hydrogen, which is consistent with the observed sulfur removal from the asphaltenes structures due to the cleavage of C-S, C-C, and C-H bonds. Moreover, the NMR indicates that the molar content of C<sub>p</sub>, C<sub>s</sub>,<sub>q</sub>, C<sub>t</sub> groups increases and the mean chain length (MCL) decreases to minimum for samples of asphaltenes 1 wt% of catalyst. The viscosity of the crude oil reduced 2.7 times after the hydrothermal upgrading process without using a catalyst. XRD analysis shows that adding 10 % SiO<sub>2</sub> improves catalyst stability by preventing AlO(OH) formation. Overall, thermal upgrading increases mono-aromatics in asphaltenes, water inhibits their condensation via hydrolysis, and the catalyst enhances hydrogen production through the water-gas shift reaction.</div></div>","PeriodicalId":100578,"journal":{"name":"Geoenergy Science and Engineering","volume":"258 ","pages":"Article 214350"},"PeriodicalIF":4.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2025-12-08DOI: 10.1016/j.geoen.2025.214341
Bin Zou , Huanqiang Yang , Cunpeng Liu , Haidan Lv , Zhihe Ma , Menglu Liu
The toughness and strength of the cement sheath are critical factors in ensuring wellbore sealing integrity of underground gas storage (UGS) wells. Based on this, a two-phase mesoscopic numerical model for the cube compressive and splitting tensile of fiber-reinforced cement(FRC) was established. Through investigate the failure characteristics of FRC under mechanical loading, and integrating theoretical analysis with micro-structural characterization, the toughening and strengthening mechanisms of inorganic fibers in cement matrices were elucidated. Simultaneously, by comprehensively considering the characteristics of the cement stone before and after the peak stress, the toughness of FRC was characterized by the envelop area under the stress-strain curve, and combined with the equivalent plastic strain(PEEQ) cloud diagram of the cement matrix, the influence of key controlling factors(mf, type, and aspect ratio)on the toughness and strength of the cement stone was investigated. The results indicate: (1)The core of fiber toughening and strengthening mechanism lies in the synergistic effect of two-phase interface adhesion, bridging effect and energy dissipation. (2) As the basalt fiber mf increases (from 0 % to 2.5 %), both the cube compressive and splitting tensile strengths of FRC gradually improve. (3) High-performance carbon fibers can achieve high strength and high pre-peak toughness for FRC even at low mf. (4) The toughness and strength of FRC tend to increase and then decrease with the increasing fiber aspect ratio.
{"title":"Numerical simulation of the toughening behavior of fiber-reinforced cement sheath in underground gas storage wells","authors":"Bin Zou , Huanqiang Yang , Cunpeng Liu , Haidan Lv , Zhihe Ma , Menglu Liu","doi":"10.1016/j.geoen.2025.214341","DOIUrl":"10.1016/j.geoen.2025.214341","url":null,"abstract":"<div><div>The toughness and strength of the cement sheath are critical factors in ensuring wellbore sealing integrity of underground gas storage (UGS) wells. Based on this, a two-phase mesoscopic numerical model for the cube compressive and splitting tensile of fiber-reinforced cement(FRC) was established. Through investigate the failure characteristics of FRC under mechanical loading, and integrating theoretical analysis with micro-structural characterization, the toughening and strengthening mechanisms of inorganic fibers in cement matrices were elucidated. Simultaneously, by comprehensively considering the characteristics of the cement stone before and after the peak stress, the toughness of FRC was characterized by the envelop area under the stress-strain curve, and combined with the equivalent plastic strain(PEEQ) cloud diagram of the cement matrix, the influence of key controlling factors(<em>m</em><sub><em>f</em></sub>, type, and aspect ratio)on the toughness and strength of the cement stone was investigated. The results indicate: (1)The core of fiber toughening and strengthening mechanism lies in the synergistic effect of two-phase interface adhesion, bridging effect and energy dissipation. (2) As the basalt fiber <em>m</em><sub><em>f</em></sub> increases (from 0 % to 2.5 %), both the cube compressive and splitting tensile strengths of FRC gradually improve. (3) High-performance carbon fibers can achieve high strength and high pre-peak toughness for FRC even at low <em>m</em><sub><em>f</em></sub>. (4) The toughness and strength of FRC tend to increase and then decrease with the increasing fiber aspect ratio.</div></div>","PeriodicalId":100578,"journal":{"name":"Geoenergy Science and Engineering","volume":"258 ","pages":"Article 214341"},"PeriodicalIF":4.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145738718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2025-12-09DOI: 10.1016/j.geoen.2025.214328
JiaHui Gao , HanYi Wang
With the continuous development of oil exploration and extraction technologies, the role of fracturing fluids in enhancing oil and gas production and promoting reservoir development has become increasingly important. In recent years, nanofluids, as a new type of fracturing fluid additive, have gradually become a research hotspot due to their unique advantages in improving rheological properties and other aspects. This study mainly uses molecular dynamics (MD) simulations to explore the effects of nanoparticles on fluid viscosity and flow resistance. The results indicate that the addition of nanoparticles significantly improves the viscosity of fracturing fluid mixture and exerts a pronounced influence on the lubrication, flow performance and friction resistance of shale surface. By studying the viscosity, surface wettability, friction and nanoflow of the system, it was found that Al2O3 and CNFs exhibited the most significant effect on viscosity enhancement, while CNT and ZnO demonstrated excellent comprehensive properties in enhancing viscosity, reducing resistance and improving nanoflow velocity. Specifically, the addition of zinc oxide (ZnO) and carbon nanotubes (CNT) increased the viscosity of the oil-gas mixture by more than 8 %, and the friction values within the 0–20 g Å/fs 2 range accounted for over 80 % of the total friction value. In summary, nanoparticles exhibit broad application prospects in oil and gas production, especially in increasing viscosity, reducing friction and improving fluid mobility. This study provides a theoretical foundation for the design and performance optimization of nanofluids, and provides new insights into the selection of suitable nanofluids to optimize fracturing fluid formula and improve oil and gas production efficiency.
随着石油勘探开采技术的不断发展，压裂液在提高油气产量、促进储层开发方面的作用越来越重要。近年来，纳米流体作为一种新型压裂液添加剂，因其在改善流变性能等方面的独特优势，逐渐成为研究热点。本研究主要利用分子动力学（MD）模拟来探讨纳米颗粒对流体粘度和流动阻力的影响。结果表明，纳米颗粒的加入显著提高了压裂液混合物的粘度，对页岩表面的润滑、流动性能和摩擦阻力有显著影响。通过对体系的粘度、表面润湿性、摩擦力和纳米流的研究，发现Al2O3和CNFs对粘度的增强效果最为显著，而CNT和ZnO在增强粘度、降低阻力和提高纳米流速度方面表现出优异的综合性能。具体而言，氧化锌（ZnO）和碳纳米管（CNT）的加入使油气混合物的粘度提高了8%以上，0-20 g Å/fs 2范围内的摩擦值占总摩擦值的80%以上。综上所述，纳米颗粒在油气生产中具有广阔的应用前景，特别是在增加粘度、减少摩擦和改善流体流动性方面。该研究为纳米流体的设计和性能优化提供了理论基础，为优化压裂液配方、提高油气生产效率选择合适的纳米流体提供了新的见解。
{"title":"Molecular dynamics simulation study on the viscosity increasing and drag reducing properties of nanoparticles-enhanced fracturing fluid","authors":"JiaHui Gao , HanYi Wang","doi":"10.1016/j.geoen.2025.214328","DOIUrl":"10.1016/j.geoen.2025.214328","url":null,"abstract":"<div><div>With the continuous development of oil exploration and extraction technologies, the role of fracturing fluids in enhancing oil and gas production and promoting reservoir development has become increasingly important. In recent years, nanofluids, as a new type of fracturing fluid additive, have gradually become a research hotspot due to their unique advantages in improving rheological properties and other aspects. This study mainly uses molecular dynamics (MD) simulations to explore the effects of nanoparticles on fluid viscosity and flow resistance. The results indicate that the addition of nanoparticles significantly improves the viscosity of fracturing fluid mixture and exerts a pronounced influence on the lubrication, flow performance and friction resistance of shale surface. By studying the viscosity, surface wettability, friction and nanoflow of the system, it was found that Al<sub>2</sub>O<sub>3</sub> and CNFs exhibited the most significant effect on viscosity enhancement, while CNT and ZnO demonstrated excellent comprehensive properties in enhancing viscosity, reducing resistance and improving nanoflow velocity. Specifically, the addition of zinc oxide (ZnO) and carbon nanotubes (CNT) increased the viscosity of the oil-gas mixture by more than 8 %, and the friction values within the 0–20 g Å/fs <sup>2</sup> range accounted for over 80 % of the total friction value. In summary, nanoparticles exhibit broad application prospects in oil and gas production, especially in increasing viscosity, reducing friction and improving fluid mobility. This study provides a theoretical foundation for the design and performance optimization of nanofluids, and provides new insights into the selection of suitable nanofluids to optimize fracturing fluid formula and improve oil and gas production efficiency.</div></div>","PeriodicalId":100578,"journal":{"name":"Geoenergy Science and Engineering","volume":"258 ","pages":"Article 214328"},"PeriodicalIF":4.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145790953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2025-12-08DOI: 10.1016/j.geoen.2025.214322
Haoran Jing , Yili Kang , Chengyuan Xu , Lei Liu , Xiaopeng Yan , Zhenjiang You
Addressing lost circulation during drilling operations typically involves the utilization of lost circulation materials (LCMs) to create a fracture plugging zone (FPZ), which effectively decouples the wellbore fluid column pressure (Pw) from the formation pressure (Pf). This FPZ, comprised of aggregated granular LCM particles, frequently succumbs to shear stress, with shear failure being the predominant mode of structural failure, leading to ongoing fluid losses. To illuminate the failure mechanisms of the FPZ under conditions of escalating drilling differential pressure (Pw - Pf), we utilized photoelastic experiments to capture and visualize the evolving mesoscopic mechanical structure of the FPZ. Photoelastic images were analyzed using the modified ten-step phase-shift method to calculate the shear stress distribution within the FPZ. Results indicated that shear failure is characterized by recurrent bidirectional shearing interactions between the FPZ and the fracture surface, accompanied by a significant increase in stress concentration at the initiation of shear failure. To augment the shear stability of the FPZ, a methodology inspired by the composite nature of concrete—comprising sand, stone, and cementitious materials—was adopted. The integration of adhesive particles within the FPZ resulted in a marked reduction in internal shear stress and an enhancement of its load-bearing capacity. These findings substantiate that the incorporation of adhesives effectively bolsters the mechanical stability of the FPZ across both mesoscopic and macroscopic scales.
{"title":"Shear stability enhancement in fracture plugging zones: Unveiling failure mechanisms and adhesive benefits through photoelastic analysis","authors":"Haoran Jing , Yili Kang , Chengyuan Xu , Lei Liu , Xiaopeng Yan , Zhenjiang You","doi":"10.1016/j.geoen.2025.214322","DOIUrl":"10.1016/j.geoen.2025.214322","url":null,"abstract":"<div><div>Addressing lost circulation during drilling operations typically involves the utilization of lost circulation materials (LCMs) to create a fracture plugging zone (FPZ), which effectively decouples the wellbore fluid column pressure (<em>P</em><sub><em>w</em></sub>) from the formation pressure (<em>P</em><sub><em>f</em></sub>). This FPZ, comprised of aggregated granular LCM particles, frequently succumbs to shear stress, with shear failure being the predominant mode of structural failure, leading to ongoing fluid losses. To illuminate the failure mechanisms of the FPZ under conditions of escalating drilling differential pressure (<em>P</em><sub><em>w</em></sub> - <em>P</em><sub><em>f</em></sub>), we utilized photoelastic experiments to capture and visualize the evolving mesoscopic mechanical structure of the FPZ. Photoelastic images were analyzed using the modified ten-step phase-shift method to calculate the shear stress distribution within the FPZ. Results indicated that shear failure is characterized by recurrent bidirectional shearing interactions between the FPZ and the fracture surface, accompanied by a significant increase in stress concentration at the initiation of shear failure. To augment the shear stability of the FPZ, a methodology inspired by the composite nature of concrete—comprising sand, stone, and cementitious materials—was adopted. The integration of adhesive particles within the FPZ resulted in a marked reduction in internal shear stress and an enhancement of its load-bearing capacity. These findings substantiate that the incorporation of adhesives effectively bolsters the mechanical stability of the FPZ across both mesoscopic and macroscopic scales.</div></div>","PeriodicalId":100578,"journal":{"name":"Geoenergy Science and Engineering","volume":"258 ","pages":"Article 214322"},"PeriodicalIF":4.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145790955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Foaming of non-aqueous liquids, particularly in the energy sector, presents significant challenges due to the transient stability of these systems. Despite being free of surfactants, non-aqueous liquids are observed to foam in practice. This phenomenon is observed during the simultaneous production of gas and liquids, affecting transportation and separation processes. The stability of foams can impact pressure drops, production efficiency, and safety.
The study of foam stability in organic liquids has focused on understanding the factors that enhance stability within liquid films. Solid or solid-like particles within the liquid film, such as fat crystals or asphaltenes, can stabilize oil foams. Recent advancement on particle-free liquids has also shown that blends of organic liquids, even when totally miscible, can produce surfactant like effects stabilizing foams.
Experimental methods, including depressurization tests and surface tension measurements, were employed to study the foaming behavior of various crude oils, and the results were compared with the learnings from the literature.
It is observed that higher viscosity fluids generally produce more stable foams, however viscosity alone cannot explain the increase of stability. Other parameters can greatly enhance foam stability and depend on the precise formulation of liquids, such as the presence of solid particles or the thermodynamics of blends. In the latter case, the foam stability can be predicted from simple surface tension measurements.
In conclusion, advances in the theoretical understanding of foam stability in organic liquids have led to practical applications in the energy sector, such as the use of simple surface tension measurements of blends of crude oils to anticipate the stability of the foams through depressurization. By identifying and mitigating foaming issues, it is possible to improve production efficiency, safety, and overall performance in various industrial processes.
{"title":"Advancements in the forecasting of foaming of organic liquids for flow assurance studies","authors":"Nicolas Passade-Boupat , Léa Delance , Hoai-Phuong Tran , Mélanie Arangalage , Roel Belt , Didier Lauranson , Francois Lequeux , Laurence Talini , Emilie Verneuil","doi":"10.1016/j.geoen.2025.214321","DOIUrl":"10.1016/j.geoen.2025.214321","url":null,"abstract":"<div><div>Foaming of non-aqueous liquids, particularly in the energy sector, presents significant challenges due to the transient stability of these systems. Despite being free of surfactants, non-aqueous liquids are observed to foam in practice. This phenomenon is observed during the simultaneous production of gas and liquids, affecting transportation and separation processes. The stability of foams can impact pressure drops, production efficiency, and safety.</div><div>The study of foam stability in organic liquids has focused on understanding the factors that enhance stability within liquid films. Solid or solid-like particles within the liquid film, such as fat crystals or asphaltenes, can stabilize oil foams. Recent advancement on particle-free liquids has also shown that blends of organic liquids, even when totally miscible, can produce surfactant like effects stabilizing foams.</div><div>Experimental methods, including depressurization tests and surface tension measurements, were employed to study the foaming behavior of various crude oils, and the results were compared with the learnings from the literature.</div><div>It is observed that higher viscosity fluids generally produce more stable foams, however viscosity alone cannot explain the increase of stability. Other parameters can greatly enhance foam stability and depend on the precise formulation of liquids, such as the presence of solid particles or the thermodynamics of blends. In the latter case, the foam stability can be predicted from simple surface tension measurements.</div><div>In conclusion, advances in the theoretical understanding of foam stability in organic liquids have led to practical applications in the energy sector, such as the use of simple surface tension measurements of blends of crude oils to anticipate the stability of the foams through depressurization. By identifying and mitigating foaming issues, it is possible to improve production efficiency, safety, and overall performance in various industrial processes.</div></div>","PeriodicalId":100578,"journal":{"name":"Geoenergy Science and Engineering","volume":"258 ","pages":"Article 214321"},"PeriodicalIF":4.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145791483","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2025-12-10DOI: 10.1016/j.geoen.2025.214323
Ronald Mejia , Cristian Mejia , Deane Roehl
The hydrocarbon industry is one of the leading energy sources influencing the global economy. However, hydrocarbon recovery produces high CO2 content, particularly in carbonate reservoirs. An attractive method to mitigate carbon emissions is the reinjection of water alternating CO2 under reservoir conditions. One of the main concerns about CO2 reinjection is predicting the interaction between injected CO2 and rock. This work proposes a multispecies reactive transport simulator by coupling the Geo Modeling Analysis (GeMA) framework and PhreeqC to simulate geochemical problems. The simulator couples physical and geochemical interactions between injected fluid and rock matrix in the solid-liquid interface. The geochemical software PhreeqC evaluates equilibrium and kinetics reactions, while the GeMA framework solves the multispecies transport problem. The proposed coupling workflow combines the relevant features of the GeMA framework and PhreeqC geochemical code. The Engesgaard validation benchmark for mineral precipitation/dissolution considering kinetic and equilibrium reactions is compared with excellent agreement. In addition, a case study of water alternating CO2 injection into a Brazilian carbonate reservoir is investigated. The validation of coupled GeMA-PhreeqC simulators considering geochemical equilibrium and kinetically controlled reactions is essential to investigate fluid-rock interaction and alteration in petrophysics properties induced by CO2 injection in saturated carbonate reservoirs.
{"title":"A coupled strategy for multispecies reactive transport modeling in saturated porous media","authors":"Ronald Mejia , Cristian Mejia , Deane Roehl","doi":"10.1016/j.geoen.2025.214323","DOIUrl":"10.1016/j.geoen.2025.214323","url":null,"abstract":"<div><div>The hydrocarbon industry is one of the leading energy sources influencing the global economy. However, hydrocarbon recovery produces high CO<sub>2</sub> content, particularly in carbonate reservoirs. An attractive method to mitigate carbon emissions is the reinjection of water alternating CO<sub>2</sub> under reservoir conditions. One of the main concerns about CO<sub>2</sub> reinjection is predicting the interaction between injected CO<sub>2</sub> and rock. This work proposes a multispecies reactive transport simulator by coupling the Geo Modeling Analysis (GeMA) framework and PhreeqC to simulate geochemical problems. The simulator couples physical and geochemical interactions between injected fluid and rock matrix in the solid-liquid interface. The geochemical software PhreeqC evaluates equilibrium and kinetics reactions, while the GeMA framework solves the multispecies transport problem. The proposed coupling workflow combines the relevant features of the GeMA framework and PhreeqC geochemical code. The Engesgaard validation benchmark for mineral precipitation/dissolution considering kinetic and equilibrium reactions is compared with excellent agreement. In addition, a case study of water alternating CO2 injection into a Brazilian carbonate reservoir is investigated. The validation of coupled GeMA-PhreeqC simulators considering geochemical equilibrium and kinetically controlled reactions is essential to investigate fluid-rock interaction and alteration in petrophysics properties induced by CO<sub>2</sub> injection in saturated carbonate reservoirs.</div></div>","PeriodicalId":100578,"journal":{"name":"Geoenergy Science and Engineering","volume":"258 ","pages":"Article 214323"},"PeriodicalIF":4.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2025-12-10DOI: 10.1016/j.geoen.2025.214334
Han Wang , Dong Chen , Zhihui Ye
In modern drilling operations, precise wellbore placement is increasingly challenging in thin reservoirs and geologically complex formations. This study proposes an intelligent trajectory optimization framework integrating third-order Bézier curve modeling with Proximal Policy Optimization (PPO)-based reinforcement learning. Real-time logging-while-drilling (LWD) data are used to reconstruct reservoir models and dynamically adjust control points, enabling smooth, curvature-constrained trajectories that adhere to drilling limits. A multi-objective reward function balances geosteering accuracy, curvature minimization, and mechanical load reduction. Field applications on three horizontal wells in the Shengli shale oil block showed that the optimized trajectories reduced average TVD deviation by over 40 %, significantly lowered curvature, and decreased cumulative torque by 30 %–60 % compared with historical drilled paths. These results confirm the method's adaptability, robustness, and engineering applicability, offering a practical solution for intelligent, automated drilling in thin-target reservoirs.
{"title":"Intelligent drilling trajectory optimization method based on azimuth logging while drilling data","authors":"Han Wang , Dong Chen , Zhihui Ye","doi":"10.1016/j.geoen.2025.214334","DOIUrl":"10.1016/j.geoen.2025.214334","url":null,"abstract":"<div><div>In modern drilling operations, precise wellbore placement is increasingly challenging in thin reservoirs and geologically complex formations. This study proposes an intelligent trajectory optimization framework integrating third-order Bézier curve modeling with Proximal Policy Optimization (PPO)-based reinforcement learning. Real-time logging-while-drilling (LWD) data are used to reconstruct reservoir models and dynamically adjust control points, enabling smooth, curvature-constrained trajectories that adhere to drilling limits. A multi-objective reward function balances geosteering accuracy, curvature minimization, and mechanical load reduction. Field applications on three horizontal wells in the Shengli shale oil block showed that the optimized trajectories reduced average TVD deviation by over 40 %, significantly lowered curvature, and decreased cumulative torque by 30 %–60 % compared with historical drilled paths. These results confirm the method's adaptability, robustness, and engineering applicability, offering a practical solution for intelligent, automated drilling in thin-target reservoirs.</div></div>","PeriodicalId":100578,"journal":{"name":"Geoenergy Science and Engineering","volume":"258 ","pages":"Article 214334"},"PeriodicalIF":4.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145738694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Accurate geological modeling is essential for reservoir characterization, yet traditional methods struggle with complex subsurface heterogeneity and the conditioning of data to observed values. This study introduces Pix2Geomodel, a novel conditional generative adversarial network (cGAN) framework based on the Pix2Pix architecture, designed to predict key reservoir properties (facies, porosity, permeability, and water saturation) from the Rotliegend reservoir of the Groningen gas field. Utilizing a 7.6 million-cell dataset from the Nederlandse Aardolie Maatschappij, accessed via EPOS-NL, the methodology included data preprocessing, augmentation to generate 2,350 images per property, and training with a U-Net generator and PatchGAN discriminator over 19,000 steps. Evaluation metrics include pixel accuracy (PA), mean intersection over union (mIoU), and frequency-weighted intersection over union (FWIoU). Performance was evaluated in two tasks: (i) masked property prediction and (ii) property-to-property translation. Results demonstrated high accuracy for facies (PA 0.88, FWIoU 0.85) and water saturation (PA 0.96, FWIoU 0.95), with moderate success for porosity (PA 0.70, FWIoU 0.55) and permeability (PA 0.74, FWIoU 0.60), and robust transferability performance (e.g., facies-to-Sw PA 0.98, FWIoU 0.97). The framework captured spatial variability and geological realism, as validated by variogram analysis, and calculated the training loss curves for the generator and discriminator for each property. Compared to traditional methods, Pix2Geomodel provides more accurate and more time- and resource-efficient property mapping. While the current model is trained to perform 2D geomodeling, future work will be developed to involve 3D geomodeling and also consider microstructural heterogeneity in the geology of the area, with extensions to multi-modal inputs planned for Pix2Geomodel v2.0. This study advances the application of generative AI in geoscience, supporting improved reservoir management and open science initiatives.
{"title":"Pix2Geomodel: A next-generation reservoir geomodeling with property-to-property translation","authors":"Abdulrahman Al-Fakih , Ardiansyah Koeshidayatullah , Nabil A. Saraih , Tapan Mukerji , Rayan Kanfar , Abdulmohsen Alali , SanLinn I. Kaka","doi":"10.1016/j.geoen.2025.214342","DOIUrl":"10.1016/j.geoen.2025.214342","url":null,"abstract":"<div><div>Accurate geological modeling is essential for reservoir characterization, yet traditional methods struggle with complex subsurface heterogeneity and the conditioning of data to observed values. This study introduces Pix2Geomodel, a novel conditional generative adversarial network (cGAN) framework based on the Pix2Pix architecture, designed to predict key reservoir properties (facies, porosity, permeability, and water saturation) from the Rotliegend reservoir of the Groningen gas field. Utilizing a 7.6 million-cell dataset from the Nederlandse Aardolie Maatschappij, accessed via EPOS-NL, the methodology included data preprocessing, augmentation to generate 2,350 images per property, and training with a U-Net generator and PatchGAN discriminator over 19,000 steps. Evaluation metrics include pixel accuracy (PA), mean intersection over union (mIoU), and frequency-weighted intersection over union (FWIoU). Performance was evaluated in two tasks: (i) masked property prediction and (ii) property-to-property translation. Results demonstrated high accuracy for facies (PA 0.88, FWIoU 0.85) and water saturation (PA 0.96, FWIoU 0.95), with moderate success for porosity (PA 0.70, FWIoU 0.55) and permeability (PA 0.74, FWIoU 0.60), and robust transferability performance (e.g., facies-to-Sw PA 0.98, FWIoU 0.97). The framework captured spatial variability and geological realism, as validated by variogram analysis, and calculated the training loss curves for the generator and discriminator for each property. Compared to traditional methods, Pix2Geomodel provides more accurate and more time- and resource-efficient property mapping. While the current model is trained to perform 2D geomodeling, future work will be developed to involve 3D geomodeling and also consider microstructural heterogeneity in the geology of the area, with extensions to multi-modal inputs planned for Pix2Geomodel v2.0. This study advances the application of generative AI in geoscience, supporting improved reservoir management and open science initiatives.</div></div>","PeriodicalId":100578,"journal":{"name":"Geoenergy Science and Engineering","volume":"258 ","pages":"Article 214342"},"PeriodicalIF":4.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145790952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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