Pub Date : 2025-02-05DOI: 10.1021/acs.energyfuels.4c0530610.1021/acs.energyfuels.4c05306
Haodong Hou, Wei Yang*, Rui Yang*, Zhenxue Jiang, Ke Miao, Weihao Sun and Yating Xiao,
Lacustrine fine-grained sedimentary rocks exhibit various lithofacies types and strong multiscale heterogeneity, encouraging us to investigate multistage characteristics of the panoramic pore-microfracture evolution process and potential triggering mechanisms of continental shale reservoirs. We present new results here from organic geochemistry analysis, X-ray diffraction, total organic carbon (TOC) analysis, the R0 test, rock pyrolysis analysis, field emission scanning electron microscopy, low-pressure CO2 and N2 adsorption, high-pressure mercury injection (MIP), nuclear magnetic resonance (NMR), and spontaneous imbibition tests. First, we conducted thermal simulation experiments using low-mature shale samples with an R0 value of 0.67%, aiming to innovatively unravel the entire dynamic evolution process of the micropore-fracture system in continental shales. Multitemperature thermal simulation investigations on naturally low-mature shale samples show that (1) the extensively developed interparticle pores and microfractures are conducive to the formation of complex and heterogeneous pore-fracture network systems. (2) The multistage evolution process of the pore-fracture system in continental shale reservoirs is triggered by differential hydrocarbon generation potential of maceral components, clay mineral transformation, and catalysis processes. (3) Four stages of the pore-fracture system evolution of the shale reservoir were identified, respectively occurring in R0 ≤ 0.9, 0.9% < R0 ≤ 1.6, 1.6% < R0 ≤ 3.0%, and R0 > 3.0%. This study laid a foundation for future research into differential diagenetic and reservoir-forming mechanisms of continental shale reservoirs, offering new insights into accurate prediction and comprehensive evaluation of the lacustrine shale gas “sweet spot”.
{"title":"Formation and Evolution of Complex Pore-Fracture Systems in Shale Gas Reservoirs: Insights into Controlling Mechanisms","authors":"Haodong Hou, Wei Yang*, Rui Yang*, Zhenxue Jiang, Ke Miao, Weihao Sun and Yating Xiao, ","doi":"10.1021/acs.energyfuels.4c0530610.1021/acs.energyfuels.4c05306","DOIUrl":"https://doi.org/10.1021/acs.energyfuels.4c05306https://doi.org/10.1021/acs.energyfuels.4c05306","url":null,"abstract":"<p >Lacustrine fine-grained sedimentary rocks exhibit various lithofacies types and strong multiscale heterogeneity, encouraging us to investigate multistage characteristics of the panoramic pore-microfracture evolution process and potential triggering mechanisms of continental shale reservoirs. We present new results here from organic geochemistry analysis, X-ray diffraction, total organic carbon (TOC) analysis, the <i>R</i><sub>0</sub> test, rock pyrolysis analysis, field emission scanning electron microscopy, low-pressure CO<sub>2</sub> and N<sub>2</sub> adsorption, high-pressure mercury injection (MIP), nuclear magnetic resonance (NMR), and spontaneous imbibition tests. First, we conducted thermal simulation experiments using low-mature shale samples with an <i>R</i><sub>0</sub> value of 0.67%, aiming to innovatively unravel the entire dynamic evolution process of the micropore-fracture system in continental shales. Multitemperature thermal simulation investigations on naturally low-mature shale samples show that (1) the extensively developed interparticle pores and microfractures are conducive to the formation of complex and heterogeneous pore-fracture network systems. (2) The multistage evolution process of the pore-fracture system in continental shale reservoirs is triggered by differential hydrocarbon generation potential of maceral components, clay mineral transformation, and catalysis processes. (3) Four stages of the pore-fracture system evolution of the shale reservoir were identified, respectively occurring in <i>R</i><sub>0</sub> ≤ 0.9, 0.9% < <i>R</i><sub>0</sub> ≤ 1.6, 1.6% < <i>R</i><sub>0</sub> ≤ 3.0%, and <i>R</i><sub>0</sub> > 3.0%. This study laid a foundation for future research into differential diagenetic and reservoir-forming mechanisms of continental shale reservoirs, offering new insights into accurate prediction and comprehensive evaluation of the lacustrine shale gas “sweet spot”.</p>","PeriodicalId":35,"journal":{"name":"Energy & Fuels","volume":"39 6","pages":"3008–3038 3008–3038"},"PeriodicalIF":5.2,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143397343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-04DOI: 10.1021/acs.energyfuels.4c0581010.1021/acs.energyfuels.4c05810
Tingting Zhao, Zhengdong Liu*, Xiaomin Hu, Wancheng Zhu, Shuyuan Liu, Leilei Si, Bao Qu, Chaojie Wang and Yihuai Zhang,
The study of methane diffusion within coal is a critical theoretical foundation for coalbed methane extraction technologies. Currently, the development of coalbed methane resources is significantly constrained by the high-stress and low-permeability characteristics of deep coal seams. This necessitates an urgent focus on investigating the diffusion behavior of methane within the deep coal seams. This study investigates the stepwise diffusion characteristics of methane in coal under high-stress conditions. A series of experiments were carried out using a specially designed experimental apparatus aimed at this purpose to investigate the behavior of methane diffusion and to determine the dominant diffusion patterns in high-stress conditions. A diffusion model was constructed to calculate the diffusion coefficients of coal under high-stress conditions, which were then employed to perform numerical simulations of methane extraction based on the identified stepwise diffusion patterns. This analysis enabled the exploration of more economical and efficient methods of methane extraction. The results indicate that the adoption of a multistep diffusion pathway can effectively enhance methane desorption. When the diffusion pathways are uniform, the amount of desorption in the higher-level diffusion stage surpasses that in the lower-level diffusion stage. Additionally, the methane diffusion coefficient increases with a greater diffusion pressure gradient; however, simply increasing the diffusion pressure gradient does not necessarily lead to a significant increase in the desorption. Based on these findings, an intelligent extraction method was proposed, which enhances methane extraction efficiency while remaining economically viable and effective. The outcomes of this research provide theoretical support for understanding the mechanisms underlying methane extraction in high-stress coal seams.
{"title":"Stepwise Diffusion Characteristics in Coal Mass under In Situ High-Stress Conditions","authors":"Tingting Zhao, Zhengdong Liu*, Xiaomin Hu, Wancheng Zhu, Shuyuan Liu, Leilei Si, Bao Qu, Chaojie Wang and Yihuai Zhang, ","doi":"10.1021/acs.energyfuels.4c0581010.1021/acs.energyfuels.4c05810","DOIUrl":"https://doi.org/10.1021/acs.energyfuels.4c05810https://doi.org/10.1021/acs.energyfuels.4c05810","url":null,"abstract":"<p >The study of methane diffusion within coal is a critical theoretical foundation for coalbed methane extraction technologies. Currently, the development of coalbed methane resources is significantly constrained by the high-stress and low-permeability characteristics of deep coal seams. This necessitates an urgent focus on investigating the diffusion behavior of methane within the deep coal seams. This study investigates the stepwise diffusion characteristics of methane in coal under high-stress conditions. A series of experiments were carried out using a specially designed experimental apparatus aimed at this purpose to investigate the behavior of methane diffusion and to determine the dominant diffusion patterns in high-stress conditions. A diffusion model was constructed to calculate the diffusion coefficients of coal under high-stress conditions, which were then employed to perform numerical simulations of methane extraction based on the identified stepwise diffusion patterns. This analysis enabled the exploration of more economical and efficient methods of methane extraction. The results indicate that the adoption of a multistep diffusion pathway can effectively enhance methane desorption. When the diffusion pathways are uniform, the amount of desorption in the higher-level diffusion stage surpasses that in the lower-level diffusion stage. Additionally, the methane diffusion coefficient increases with a greater diffusion pressure gradient; however, simply increasing the diffusion pressure gradient does not necessarily lead to a significant increase in the desorption. Based on these findings, an intelligent extraction method was proposed, which enhances methane extraction efficiency while remaining economically viable and effective. The outcomes of this research provide theoretical support for understanding the mechanisms underlying methane extraction in high-stress coal seams.</p>","PeriodicalId":35,"journal":{"name":"Energy & Fuels","volume":"39 6","pages":"3110–3118 3110–3118"},"PeriodicalIF":5.2,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143394120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-04DOI: 10.1021/acs.energyfuels.4c0573810.1021/acs.energyfuels.4c05738
Kensaku Kodama*, Shuji Kajiya, Ayako Ohshima, Hajime Murata, Noritoshi Oka and Shigemitsu Nomoto,
High productivity of fuel cell stacks is essential for the widespread adoption of polymer electrolyte fuel cells (PEFCs). The conditioning process (also called break-in) of a PEFC can take several hours, potentially becoming a bottleneck in mass production. In this study, the cause of the long break-in duration in the production of Toyota Mirai fuel cell stacks was identified through electrochemical measurements and sample analyses, and effective protocols were developed to reduce the duration. The primary cause of the extended duration was found to be organic contamination during the cell production process. Synchronizing the timing of electricity generation with the lowering of the cathode potential was found to be effective in promptly washing away contaminants from the Pt surface of the cathode catalyst using produced water. This concept was applied to the break-in process of the second-generation Mirai stacks, enabling a 70% reduction in the duration compared with the protocol for the first-generation Mirai stacks.
{"title":"Reduction of Break-In Duration for Polymer Electrolyte Fuel Cells through an Approach To Accelerate the Removal of Impurities in the Electrode","authors":"Kensaku Kodama*, Shuji Kajiya, Ayako Ohshima, Hajime Murata, Noritoshi Oka and Shigemitsu Nomoto, ","doi":"10.1021/acs.energyfuels.4c0573810.1021/acs.energyfuels.4c05738","DOIUrl":"https://doi.org/10.1021/acs.energyfuels.4c05738https://doi.org/10.1021/acs.energyfuels.4c05738","url":null,"abstract":"<p >High productivity of fuel cell stacks is essential for the widespread adoption of polymer electrolyte fuel cells (PEFCs). The conditioning process (also called break-in) of a PEFC can take several hours, potentially becoming a bottleneck in mass production. In this study, the cause of the long break-in duration in the production of Toyota Mirai fuel cell stacks was identified through electrochemical measurements and sample analyses, and effective protocols were developed to reduce the duration. The primary cause of the extended duration was found to be organic contamination during the cell production process. Synchronizing the timing of electricity generation with the lowering of the cathode potential was found to be effective in promptly washing away contaminants from the Pt surface of the cathode catalyst using produced water. This concept was applied to the break-in process of the second-generation Mirai stacks, enabling a 70% reduction in the duration compared with the protocol for the first-generation Mirai stacks.</p>","PeriodicalId":35,"journal":{"name":"Energy & Fuels","volume":"39 6","pages":"3331–3337 3331–3337"},"PeriodicalIF":5.2,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143394295","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-04DOI: 10.1021/acs.energyfuels.4c0430310.1021/acs.energyfuels.4c04303
Muhammad Ammar Munir, and , Sadia Khalid*,
The world is gradually moving toward more ecological and environmentally friendly energy production and storage mediums to tackle the ever-growing needs. These conventional methods and materials thus are not suitable enough to be continually practiced and consumed. MXenes are the next generation of two-dimensional materials (2DMs) that have been found to be an advanced alternative to the current graphene-based substitutes; however, the predominant method to produce MXene phases has been through fluoride-based precursors, which end up producing fluoride-based products causing significant environmental harm. This review aims to catalogue a number of significant investigations recently conducted with the objective of synthesizing MXenes with fluoride-free precursors and the structural and electrical performance of the resultant phases. Finally, the role of such MXene based electrodes for batteries has been discussed as well. The current challenges in fabrication of high performance MXene based batteries, possible opportunities, and future directions are discussed as well.
{"title":"Focused Review on the Synthesis of Titanium Carbide MXene via Fluorine-Free Methods for Lithium-Ion Batteries","authors":"Muhammad Ammar Munir, and , Sadia Khalid*, ","doi":"10.1021/acs.energyfuels.4c0430310.1021/acs.energyfuels.4c04303","DOIUrl":"https://doi.org/10.1021/acs.energyfuels.4c04303https://doi.org/10.1021/acs.energyfuels.4c04303","url":null,"abstract":"<p >The world is gradually moving toward more ecological and environmentally friendly energy production and storage mediums to tackle the ever-growing needs. These conventional methods and materials thus are not suitable enough to be continually practiced and consumed. MXenes are the next generation of two-dimensional materials (2DMs) that have been found to be an advanced alternative to the current graphene-based substitutes; however, the predominant method to produce MXene phases has been through fluoride-based precursors, which end up producing fluoride-based products causing significant environmental harm. This review aims to catalogue a number of significant investigations recently conducted with the objective of synthesizing MXenes with fluoride-free precursors and the structural and electrical performance of the resultant phases. Finally, the role of such MXene based electrodes for batteries has been discussed as well. The current challenges in fabrication of high performance MXene based batteries, possible opportunities, and future directions are discussed as well.</p>","PeriodicalId":35,"journal":{"name":"Energy & Fuels","volume":"39 6","pages":"2889–2915 2889–2915"},"PeriodicalIF":5.2,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143397289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-04DOI: 10.1021/acs.energyfuels.4c0489510.1021/acs.energyfuels.4c04895
Shichao Zhu, Pengfei Li*, Yan Gao, Guodong Shi, Fan Hu and Zhaohui Liu,
In oxy-fuel combustion systems aimed at carbon capture, reducing the level of NOx emissions is critical for corrosion mitigation and CO2 utilization. Previous studies mostly focused on NOx mechanisms in traditional flame oxy-combustion, while experimental evidence regarding the homogeneous fuel-NO reduction benefits of flameless oxy-combustion is lacking. To fill this gap, this study provides the first systematic investigation into homogeneous fuel-NO formation in flameless oxy-combustion of CH4/NH3 mixtures, combining experimental data with validated numerical simulations. The impacts of combustion mode (flameless vs flame oxy-combustion), initial oxygen concentration (XO2), and equivalence ratio (Φ) are thoroughly investigated. The experiments indicate that at Φ = 0.8 and XO2 = 30%, flameless oxy-combustion reduces homogeneous fuel-NO by 56.8% in comparison with flame oxy-combustion and by 15.8% compared to flameless air combustion. Notably, across varying initial XO2 (25–40%) and Φ (0.6–0.9), the effectiveness of fuel-NO reduction under flameless oxy-combustion remains largely unchanged. Finite-rate combustion modeling with an optimized skeletal mechanism and reaction pathway analysis further reveal that under flameless oxy-combustion of CH4/NH3 mixtures, homogeneous fuel-NO formation through N2O → NO, CN → NO, and NCO → NO pathways is inhibited, whereas the primary NO destruction route, NH2 → N2, is promoted. This research delivers pioneering experimental evidence of the efficacy of flameless oxy-combustion in reducing fuel-NO emissions and offers critical insights into the underlying mechanisms.
{"title":"Homogeneous Fuel-NO Mitigation during Flameless Oxy-Combustion of CH4/NH3 Mixtures","authors":"Shichao Zhu, Pengfei Li*, Yan Gao, Guodong Shi, Fan Hu and Zhaohui Liu, ","doi":"10.1021/acs.energyfuels.4c0489510.1021/acs.energyfuels.4c04895","DOIUrl":"https://doi.org/10.1021/acs.energyfuels.4c04895https://doi.org/10.1021/acs.energyfuels.4c04895","url":null,"abstract":"<p >In oxy-fuel combustion systems aimed at carbon capture, reducing the level of NO<sub><i>x</i></sub> emissions is critical for corrosion mitigation and CO<sub>2</sub> utilization. Previous studies mostly focused on NO<sub><i>x</i></sub> mechanisms in traditional flame oxy-combustion, while experimental evidence regarding the homogeneous fuel-NO reduction benefits of flameless oxy-combustion is lacking. To fill this gap, this study provides the first systematic investigation into homogeneous fuel-NO formation in flameless oxy-combustion of CH<sub>4</sub>/NH<sub>3</sub> mixtures, combining experimental data with validated numerical simulations. The impacts of combustion mode (flameless vs flame oxy-combustion), initial oxygen concentration (<i>X</i><sub>O<sub>2</sub></sub>), and equivalence ratio (Φ) are thoroughly investigated. The experiments indicate that at Φ = 0.8 and <i>X</i><sub>O<sub>2</sub></sub> = 30%, flameless oxy-combustion reduces homogeneous fuel-NO by 56.8% in comparison with flame oxy-combustion and by 15.8% compared to flameless air combustion. Notably, across varying initial <i>X</i><sub>O<sub>2</sub></sub> (25–40%) and Φ (0.6–0.9), the effectiveness of fuel-NO reduction under flameless oxy-combustion remains largely unchanged. Finite-rate combustion modeling with an optimized skeletal mechanism and reaction pathway analysis further reveal that under flameless oxy-combustion of CH<sub>4</sub>/NH<sub>3</sub> mixtures, homogeneous fuel-NO formation through N<sub>2</sub>O → NO, CN → NO, and NCO → NO pathways is inhibited, whereas the primary NO destruction route, NH<sub>2</sub> → N<sub>2</sub>, is promoted. This research delivers pioneering experimental evidence of the efficacy of flameless oxy-combustion in reducing fuel-NO emissions and offers critical insights into the underlying mechanisms.</p>","PeriodicalId":35,"journal":{"name":"Energy & Fuels","volume":"39 6","pages":"3266–3279 3266–3279"},"PeriodicalIF":5.2,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143394122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Accurate prediction of CO2 adsorption isotherms on shale is essential for precisely assessing the CO2 storage capacity of different shale reservoirs. Using the volumetric method, subcritical and supercritical CO2 adsorption isotherms on four different shale samples were measured at temperatures of 308.15, 318.15, and 328.15 K. Recognizing that adsorption-induced swelling of the shale matrix can significantly affect adsorption behavior, we developed three modified adsorption models that account for volumetric changes: modified–Langmuir (M–L), modified Dubinin–Radushkevich (M-D–R), and Dubinin–Astakhov (M-D–A). The findings reveal that the CO2 adsorption capacity estimated by the three modified models is more accurate and reasonable than that of the original models when applied to fit the experimental data. Among them, the M-D–A model provides the most accurate prediction of excess adsorption when incorporating the volume change effect caused by adsorption-induced swelling and offers extensive insight into subcritical and supercritical CO2 adsorption behavior.
{"title":"Enhanced Modeling of CO2 Adsorption on Shale: Incorporating Volumetric Effects for Accurate Isotherm Predictions","authors":"Zhiqiang Dong, Junping Zhou*, Nianjie Kuang, Jinyuan Zhang, Shifeng Tian and Xuefu Xian, ","doi":"10.1021/acs.energyfuels.4c0542010.1021/acs.energyfuels.4c05420","DOIUrl":"https://doi.org/10.1021/acs.energyfuels.4c05420https://doi.org/10.1021/acs.energyfuels.4c05420","url":null,"abstract":"<p >Accurate prediction of CO<sub>2</sub> adsorption isotherms on shale is essential for precisely assessing the CO<sub>2</sub> storage capacity of different shale reservoirs. Using the volumetric method, subcritical and supercritical CO<sub>2</sub> adsorption isotherms on four different shale samples were measured at temperatures of 308.15, 318.15, and 328.15 K. Recognizing that adsorption-induced swelling of the shale matrix can significantly affect adsorption behavior, we developed three modified adsorption models that account for volumetric changes: modified–Langmuir (M–L), modified Dubinin–Radushkevich (M-D–R), and Dubinin–Astakhov (M-D–A). The findings reveal that the CO<sub>2</sub> adsorption capacity estimated by the three modified models is more accurate and reasonable than that of the original models when applied to fit the experimental data. Among them, the M-D–A model provides the most accurate prediction of excess adsorption when incorporating the volume change effect caused by adsorption-induced swelling and offers extensive insight into subcritical and supercritical CO<sub>2</sub> adsorption behavior.</p>","PeriodicalId":35,"journal":{"name":"Energy & Fuels","volume":"39 6","pages":"3188–3202 3188–3202"},"PeriodicalIF":5.2,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143394287","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-03DOI: 10.1021/acs.energyfuels.4c0575010.1021/acs.energyfuels.4c05750
Qi Lv, Jian Hou*, Ziyan Cheng, Jianxun Chen, Yanfeng Ji, Jing Lv, Yang Song, Jianguang Wei and Ying Yang,
The wettability of shale pores is the key factor affecting the effectiveness of fluid–solid interaction. In this paper, two contributions were made. First, the macroscopic shale wettability of different lithofacies is evaluated by the contact angle method, and the microscopic wettability characteristics of the multiscale shale pore structure are elucidated via spontaneous imbibition and two-dimensional nuclear magnetic resonance (NMR) technology. Second, the effect of various factors, including wettability, on the imbibition efficiency of different shale lithofacies is revealed. Results show that (a) the contact angle of oil droplets is greater than 90°, indicating macroscopic hydrophilicity: block A (150.5°) > block C (149.9°) > block B (143.7°). (b) Microscale pores are hydrophilic, with a spontaneous imbibition water–oil ratio of 2.64–4.96; mesoscale pores are lipophilic, with a ratio of 0.08–0.61; macroscale pores are lipophilic, with a ratio of 0.08–0.56. (c) The higher the spontaneous imbibition water–oil ratio, the higher the imbibition recovery rate of small and large pores, and the higher the final imbibition recovery. (d) Compared with fracturing fluid, the overall recovery rate of the imbibition agent increased by 3.2%, and lithology, water–oil ratio, and micropore proportion are the main controlling factors. The research results of this article have important scientific and engineering significance for improving the recovery rate of shale oil.
{"title":"Wettability and Imbibition Mechanism of the Multiscale Pore Structure of Jiyang Shale Oil Formation by NMR","authors":"Qi Lv, Jian Hou*, Ziyan Cheng, Jianxun Chen, Yanfeng Ji, Jing Lv, Yang Song, Jianguang Wei and Ying Yang, ","doi":"10.1021/acs.energyfuels.4c0575010.1021/acs.energyfuels.4c05750","DOIUrl":"https://doi.org/10.1021/acs.energyfuels.4c05750https://doi.org/10.1021/acs.energyfuels.4c05750","url":null,"abstract":"<p >The wettability of shale pores is the key factor affecting the effectiveness of fluid–solid interaction. In this paper, two contributions were made. First, the macroscopic shale wettability of different lithofacies is evaluated by the contact angle method, and the microscopic wettability characteristics of the multiscale shale pore structure are elucidated via spontaneous imbibition and two-dimensional nuclear magnetic resonance (NMR) technology. Second, the effect of various factors, including wettability, on the imbibition efficiency of different shale lithofacies is revealed. Results show that (a) the contact angle of oil droplets is greater than 90°, indicating macroscopic hydrophilicity: block A (150.5°) > block C (149.9°) > block B (143.7°). (b) Microscale pores are hydrophilic, with a spontaneous imbibition water–oil ratio of 2.64–4.96; mesoscale pores are lipophilic, with a ratio of 0.08–0.61; macroscale pores are lipophilic, with a ratio of 0.08–0.56. (c) The higher the spontaneous imbibition water–oil ratio, the higher the imbibition recovery rate of small and large pores, and the higher the final imbibition recovery. (d) Compared with fracturing fluid, the overall recovery rate of the imbibition agent increased by 3.2%, and lithology, water–oil ratio, and micropore proportion are the main controlling factors. The research results of this article have important scientific and engineering significance for improving the recovery rate of shale oil.</p>","PeriodicalId":35,"journal":{"name":"Energy & Fuels","volume":"39 6","pages":"3097–3109 3097–3109"},"PeriodicalIF":5.2,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143397303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Water-alternating-gas (WAG) injection is a promising technique for sequestering greenhouse gases and enhancing oil recovery. However, the pore-scale mass transport physics, carbon capture, utilization, and storage (CCUS) mechanisms, and optimization of WAG injection under reservoir conditions remain poorly understood. To fill this gap, we, by developing the graphics processing unit (GPU)-accelerated lattice Boltzmann method, conduct pore-scale simulations of WAG injection in a water-wet porous medium. Results reveal that in WAG injection, alternately injected water and gas sweep lower and upper regions of the porous medium, thus improving oil recovery compared to sole water flooding or gas injection. In particular, WAG injection that ends with gas injection exhibits significant potential for both enhanced oil recovery (EOR) and CO2 storage. For a fixed number of injection cycles, increasing individual slug size Iss leads to a higher oil recovery; however, when fixing the total injected volume for different Iss, a lower Iss favors the formation of more isolated clusters, which not only hinders the development of preferential flow paths but also decreases the water–gas density difference in the mixing region, thus increasing sweeping efficiency. The isolated and scattered distribution of CO2 reduces the risk of leakage, which is beneficial to CO2 storage. It is also found that the gravitational segregation effect becomes less pronounced with decreasing gravity, which ultimately leads to a higher oil recovery. In reduced gravity conditions, two typical capillary phenomena, namely, multiple displacement and double capillary trapping, are observed, and when the gravity vanishes, WAG injection leads to almost the same oil recovery as sole water flooding. Moreover, increasing the injection rate results in stronger mixing and interaction between injected gas and water, forming more isolated clusters and thus improving oil recovery.
{"title":"Pore-Scale Investigation of Water-Alternating-Gas Injection for CCUS in Water-Wet Porous Media","authors":"Sheng Li, Yifan Zhang, Ningning Wang, Zhiheng Wang* and Haihu Liu*, ","doi":"10.1021/acs.energyfuels.4c0567910.1021/acs.energyfuels.4c05679","DOIUrl":"https://doi.org/10.1021/acs.energyfuels.4c05679https://doi.org/10.1021/acs.energyfuels.4c05679","url":null,"abstract":"<p >Water-alternating-gas (WAG) injection is a promising technique for sequestering greenhouse gases and enhancing oil recovery. However, the pore-scale mass transport physics, carbon capture, utilization, and storage (CCUS) mechanisms, and optimization of WAG injection under reservoir conditions remain poorly understood. To fill this gap, we, by developing the graphics processing unit (GPU)-accelerated lattice Boltzmann method, conduct pore-scale simulations of WAG injection in a water-wet porous medium. Results reveal that in WAG injection, alternately injected water and gas sweep lower and upper regions of the porous medium, thus improving oil recovery compared to sole water flooding or gas injection. In particular, WAG injection that ends with gas injection exhibits significant potential for both enhanced oil recovery (EOR) and CO<sub>2</sub> storage. For a fixed number of injection cycles, increasing individual slug size <i>Iss</i> leads to a higher oil recovery; however, when fixing the total injected volume for different <i>Iss</i>, a lower <i>Iss</i> favors the formation of more isolated clusters, which not only hinders the development of preferential flow paths but also decreases the water–gas density difference in the mixing region, thus increasing sweeping efficiency. The isolated and scattered distribution of CO<sub>2</sub> reduces the risk of leakage, which is beneficial to CO<sub>2</sub> storage. It is also found that the gravitational segregation effect becomes less pronounced with decreasing gravity, which ultimately leads to a higher oil recovery. In reduced gravity conditions, two typical capillary phenomena, namely, multiple displacement and double capillary trapping, are observed, and when the gravity vanishes, WAG injection leads to almost the same oil recovery as sole water flooding. Moreover, increasing the injection rate results in stronger mixing and interaction between injected gas and water, forming more isolated clusters and thus improving oil recovery.</p>","PeriodicalId":35,"journal":{"name":"Energy & Fuels","volume":"39 6","pages":"3039–3055 3039–3055"},"PeriodicalIF":5.2,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143394062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-03DOI: 10.1021/acs.energyfuels.4c0552310.1021/acs.energyfuels.4c05523
Viktor Andersson*, Jan B. C. Pettersson, Thomas Allgurén, Pavleta Knutsson and Klas Andersson,
Recent advancements in combustion-related alkali chemistry have been increasingly driven by the adoption of CO2-neutral fuels, such as bioderived materials and waste, which often contain high amounts of alkali compounds. While alkali compounds may have catalytic effects on, e.g., fuel conversion and tar cracking, they also contribute to fluidized bed agglomeration, ash deposition, and corrosion. A thorough understanding of alkali uptake, release, and emission control is therefore crucial for scaling up and commercializing advanced fuel conversion technologies. This study presents recently developed methods for high-temperature alkali analysis, including (1) a temperature-modulated surface ionization (TMSI) technique for real-time alkali speciation, (2) a laboratory-scale reactor enabling continuous alkali vapor injection into fluidized beds with real-time monitoring of exhaust alkali emissions, and (3) a TMSI-thermogravimetric analysis (TGA) method for monitoring real-time alkali release and mass loss. The summarized results provide valuable insights into high-temperature alkali chemistry processes and their interaction with different oxygen carriers. Oxygen carriers of calcium manganite, manganese oxide, and ilmenite exhibit varying alkali uptake efficiencies based on reactor gas conditions. Ilmenite showed near-complete alkali absorption (>90% uptake of alkali chlorides), particularly in reducing conditions. Alkali speciation analysis revealed that NaCl and KCl were the main alkali species emitted during NaCl and KCl injections, with a similar trend for alkali sulfates. Ilmenite previously used as an oxygen carrier industrially releases alkali at high temperatures in both inert and oxidizing conditions. Furthermore, the TMSI method was applied to study alkali emissions during biomass pyrolysis, where KOH dominated emissions during low-temperature pyrolysis, while both KOH and NaOH were emitted from the remaining char and ash. This real-time characterization of sodium and potassium compounds offers new opportunities to optimize solid fuel conversion processes for fuels such as low-grade biomass, waste, and coal.
{"title":"Alkali Uptake, Release, and Speciation in Fluidized Beds Using Oxygen Carriers","authors":"Viktor Andersson*, Jan B. C. Pettersson, Thomas Allgurén, Pavleta Knutsson and Klas Andersson, ","doi":"10.1021/acs.energyfuels.4c0552310.1021/acs.energyfuels.4c05523","DOIUrl":"https://doi.org/10.1021/acs.energyfuels.4c05523https://doi.org/10.1021/acs.energyfuels.4c05523","url":null,"abstract":"<p >Recent advancements in combustion-related alkali chemistry have been increasingly driven by the adoption of CO<sub>2</sub>-neutral fuels, such as bioderived materials and waste, which often contain high amounts of alkali compounds. While alkali compounds may have catalytic effects on, e.g., fuel conversion and tar cracking, they also contribute to fluidized bed agglomeration, ash deposition, and corrosion. A thorough understanding of alkali uptake, release, and emission control is therefore crucial for scaling up and commercializing advanced fuel conversion technologies. This study presents recently developed methods for high-temperature alkali analysis, including (1) a temperature-modulated surface ionization (TMSI) technique for real-time alkali speciation, (2) a laboratory-scale reactor enabling continuous alkali vapor injection into fluidized beds with real-time monitoring of exhaust alkali emissions, and (3) a TMSI-thermogravimetric analysis (TGA) method for monitoring real-time alkali release and mass loss. The summarized results provide valuable insights into high-temperature alkali chemistry processes and their interaction with different oxygen carriers. Oxygen carriers of calcium manganite, manganese oxide, and ilmenite exhibit varying alkali uptake efficiencies based on reactor gas conditions. Ilmenite showed near-complete alkali absorption (>90% uptake of alkali chlorides), particularly in reducing conditions. Alkali speciation analysis revealed that NaCl and KCl were the main alkali species emitted during NaCl and KCl injections, with a similar trend for alkali sulfates. Ilmenite previously used as an oxygen carrier industrially releases alkali at high temperatures in both inert and oxidizing conditions. Furthermore, the TMSI method was applied to study alkali emissions during biomass pyrolysis, where KOH dominated emissions during low-temperature pyrolysis, while both KOH and NaOH were emitted from the remaining char and ash. This real-time characterization of sodium and potassium compounds offers new opportunities to optimize solid fuel conversion processes for fuels such as low-grade biomass, waste, and coal.</p>","PeriodicalId":35,"journal":{"name":"Energy & Fuels","volume":"39 6","pages":"3280–3294 3280–3294"},"PeriodicalIF":5.2,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/acs.energyfuels.4c05523","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143394197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-03DOI: 10.1021/acs.energyfuels.4c0566810.1021/acs.energyfuels.4c05668
Wenying Li, Jingchun Feng, Kexuan Wu, Si Zhang, Yuelu Jiang and Guozhong Wu*,
Asphaltene blockage and microbiologically induced corrosion (MIC) in oil pipes pose substantial flow assurance challenges, but their interrelationship remains poorly understood despite extensive individual research efforts. This study utilized molecular dynamics simulation and machine learning techniques to elucidate the effects of alginate, a representative biofilm polysaccharide associated with MIC, on asphaltene aggregation. Results underscored the ability of alginates to disperse large asphaltene nanoaggregates into smaller ones with more pronounced dispersion effects at higher concentrations. This was achieved through forming asphaltene–alginate heteroaggregates wherein asphaltene nanoaggregates were tightly wrapped by cross-linked alginate chains stabilized by Na+ bridging. The presence of alginates significantly increased the solvent accessible surface area (SASA) of asphaltenes, while the heteroaggregation process resulted in abundant hydroxyl and carboxyl groups coating the surface of the asphaltene nanoaggregates. Furthermore, this study showed that the time-varying asphaltene aggregation parameters such as nanoaggregate number, intermolecular contact number, and SASA could be accurately predicted by alginate structural properties using optimized random forest models built from 3636 data sets extracted from molecular trajectories (R2 = 0.9628–0.9827). This enabled fast prediction of asphaltene aggregation when the polysaccharide composition and concentration changed during the MIC process. These findings provided theoretical support for developing strategies to address asphaltene-related issues in the presence of a biofilm polysaccharide.
{"title":"Equilibrium and Temporal Evolution of Asphaltene Nanoaggregates during Dynamic Heteroaggregation with Polysaccharides","authors":"Wenying Li, Jingchun Feng, Kexuan Wu, Si Zhang, Yuelu Jiang and Guozhong Wu*, ","doi":"10.1021/acs.energyfuels.4c0566810.1021/acs.energyfuels.4c05668","DOIUrl":"https://doi.org/10.1021/acs.energyfuels.4c05668https://doi.org/10.1021/acs.energyfuels.4c05668","url":null,"abstract":"<p >Asphaltene blockage and microbiologically induced corrosion (MIC) in oil pipes pose substantial flow assurance challenges, but their interrelationship remains poorly understood despite extensive individual research efforts. This study utilized molecular dynamics simulation and machine learning techniques to elucidate the effects of alginate, a representative biofilm polysaccharide associated with MIC, on asphaltene aggregation. Results underscored the ability of alginates to disperse large asphaltene nanoaggregates into smaller ones with more pronounced dispersion effects at higher concentrations. This was achieved through forming asphaltene–alginate heteroaggregates wherein asphaltene nanoaggregates were tightly wrapped by cross-linked alginate chains stabilized by Na<sup>+</sup> bridging. The presence of alginates significantly increased the solvent accessible surface area (SASA) of asphaltenes, while the heteroaggregation process resulted in abundant hydroxyl and carboxyl groups coating the surface of the asphaltene nanoaggregates. Furthermore, this study showed that the time-varying asphaltene aggregation parameters such as nanoaggregate number, intermolecular contact number, and SASA could be accurately predicted by alginate structural properties using optimized random forest models built from 3636 data sets extracted from molecular trajectories (<i>R</i><sup>2</sup> = 0.9628–0.9827). This enabled fast prediction of asphaltene aggregation when the polysaccharide composition and concentration changed during the MIC process. These findings provided theoretical support for developing strategies to address asphaltene-related issues in the presence of a biofilm polysaccharide.</p>","PeriodicalId":35,"journal":{"name":"Energy & Fuels","volume":"39 6","pages":"3056–3068 3056–3068"},"PeriodicalIF":5.2,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143394190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}