Sign in to use this feature.

Years

Between: -

Subjects

remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline
remove_circle_outline

Journals

Article Types

Countries / Regions

Search Results (275)

Search Parameters:
Keywords = methane gas hydrate

Order results
Result details
Results per page
Select all
Export citation of selected articles as:
21 pages, 1252 KiB  
Article
Research and Performance Evaluation of Low-Damage Plugging and Anti-Collapse Water-Based Drilling Fluid Gel System Suitable for Coalbed Methane Drilling
by Jian Li, Zhanglong Tan, Qian Jing, Wenbo Mei, Wenjie Shen, Lei Feng, Tengfei Dong and Zhaobing Hao
Gels 2025, 11(7), 473; https://doi.org/10.3390/gels11070473 - 20 Jun 2025
Viewed by 415
Abstract
Coalbed methane (CBM), a significant unconventional natural gas resource, holds a crucial position in China’s ongoing energy structure transformation. However, the inherent low permeability, high brittleness, and strong sensitivity of CBM reservoirs to drilling fluids often lead to severe formation damage during drilling [...] Read more.
Coalbed methane (CBM), a significant unconventional natural gas resource, holds a crucial position in China’s ongoing energy structure transformation. However, the inherent low permeability, high brittleness, and strong sensitivity of CBM reservoirs to drilling fluids often lead to severe formation damage during drilling operations, consequently impairing well productivity. To address these challenges, this study developed a novel low-damage, plugging, and anti-collapse water-based drilling fluid gel system (ACWD) specifically designed for coalbed methane drilling. Laboratory investigations demonstrate that the ACWD system exhibits superior overall performance. It exhibits stable rheological properties, with an initial API filtrate loss of 1.0 mL and a high-temperature, high-pressure (HTHP) filtrate loss of 4.4 mL after 16 h of hot rolling at 120 °C. It also demonstrates excellent static settling stability. The system effectively inhibits the hydration and swelling of clay and coal, significantly reducing the linear expansion of bentonite from 5.42 mm (in deionized water) to 1.05 mm, and achieving high shale rolling recovery rates (both exceeding 80%). Crucially, the ACWD system exhibits exceptional plugging performance, completely sealing simulated 400 µm fractures with zero filtrate loss at 5 MPa pressure. It also significantly reduces core damage, with an LS-C1 core damage rate of 7.73%, substantially lower than the 19.85% recorded for the control polymer system (LS-C2 core). Field application in the JX-1 well of the Ordos Basin further validated the system’s effectiveness in mitigating fluid loss, preventing wellbore instability, and enhancing drilling efficiency in complex coal formations. This study offers a promising, relatively environmentally friendly, and cost-effective drilling fluid solution for the safe and efficient development of coalbed methane resources. Full article
(This article belongs to the Special Issue Chemical and Gels for Oil Drilling and Enhanced Recovery)
Show Figures

Figure 1

12 pages, 476 KiB  
Article
Study of the Formation and Dissociation of Methane Hydrate System in the Presence of Pure Water
by Ashkan Arfanejad, Vladimir Poplygin and Xian Shi
Energies 2025, 18(11), 2849; https://doi.org/10.3390/en18112849 - 29 May 2025
Viewed by 406
Abstract
This study investigated methane hydrate formation and dissociation within a temperature range of 280 to 290 K and a pressure range of 5.5 to 13 MPa. These conditions are relevant to natural gas systems, where methane is the primary component of natural gas. [...] Read more.
This study investigated methane hydrate formation and dissociation within a temperature range of 280 to 290 K and a pressure range of 5.5 to 13 MPa. These conditions are relevant to natural gas systems, where methane is the primary component of natural gas. Either experimental or thermodynamic models were used to predict the conditions of formation of gas hydrates. The Van der Waals–Platteeuw model based on statistical thermodynamics is the basis of the existing thermodynamic models for predicting the conditions of hydrate formation. In this work, the stepwise heating method was applied to determine the thermodynamic equilibrium points of methane gas in a constant volume system. The CPA (Cubic Plus Association) equation of state and the Van der Waals–Platteeuw model were employed to simulate hydrate formation conditions. Experimental equilibrium data for pure methane were compared with results from previous studies (Deaton and Frost, Nakamura, Jhaveri and Robinson, De Roo, and others). The results showed excellent agreement, with an average absolute temperature error of less than 0.1%. This high level of accuracy confirms the reliability of the experimental procedures and thermodynamic modeling approaches used in the study to accurately predict hydrate formation conditions, being critical for designing and operating natural gas systems in order to avoid hydrate accumulation. Full article
(This article belongs to the Section K: State-of-the-Art Energy Related Technologies)
Show Figures

Figure 1

18 pages, 4920 KiB  
Article
Geometric Characterizations of Non-Uniform Structure I Methane Hydrate Behaviors Under Pressure
by Samuel Mathews, Xiaodan Zhu, André Guerra, Phillip Servio and Alejandro Rey
Crystals 2025, 15(6), 518; https://doi.org/10.3390/cryst15060518 - 29 May 2025
Viewed by 393
Abstract
Gas hydrates have been identified as one of the leading candidates for future energy sources. According to conservative estimates, the energy contained in natural hydrates is double that of the fossil fuel that has been explored. This substantial energy storage motivates the investigation [...] Read more.
Gas hydrates have been identified as one of the leading candidates for future energy sources. According to conservative estimates, the energy contained in natural hydrates is double that of the fossil fuel that has been explored. This substantial energy storage motivates the investigation of natural hydrates. Prior research on mechanical/material properties has assumed that the lattice would be the smallest unit and averaged all the features within the lattice, disregarding smaller-scale geometric properties. We investigated the geometric features of sI methane hydrate under pressure. The sI methane hydrate is made up of two kinds of cages (polyhedrons) with two kinds of faces (polygons), and the vertices of the polygons are occupied by water oxygen atoms. Based on these three categories, we examined the cage integrity, face deformation, and water oxygen atom bond lengths and angles within and beyond the stability limits. The presence of forbidden zones was confirmed in bond length and angle distributions, validating the effects of geometric features. The predictive nature of water molecule angular displacement with pressure was validated. This multiscale computational materials science methodology describes and defines the range of the elastic stability of gas hydrates, a crucial contribution to energy materials science and engineering. Full article
Show Figures

Graphical abstract

13 pages, 3915 KiB  
Article
Mechanical Strength Degradation in Deep Coal Seams Due to Drilling Fluid Invasion
by Qin Zhang, Weiliang Wang, Mingming Zhu, Yanbing Zhang, Qingchen Wang, Huan Sun and Jiping She
Processes 2025, 13(4), 1222; https://doi.org/10.3390/pr13041222 - 17 Apr 2025
Viewed by 405
Abstract
With the rapid development of the coalbed methane (CBM) industry in China, coal seam No. 8 of the Benxi Formation in the Ordos Basin has emerged as a key target for CBM development due to its abundant deep reserves. However, wellbore instability during [...] Read more.
With the rapid development of the coalbed methane (CBM) industry in China, coal seam No. 8 of the Benxi Formation in the Ordos Basin has emerged as a key target for CBM development due to its abundant deep reserves. However, wellbore instability during deep CBM extraction has become increasingly problematic, with the degradation of coal mechanical strength caused by drilling fluid invasion being identified as a critical factor affecting drilling safety and operational efficiency. This study focuses on coal seam No. 8 of the Benxi Formation in the Sulige Gas Field, Ordos Basin. Through experimental analyses of the coal’s mineral composition, microstructure, hydration expansion properties, and mechanical strength variations, the mechanism underlying drilling fluid invasion-induced mechanical strength degradation is elucidated. The experimental results reveal that coal seam No. 8 of the Benxi Formation exhibits a high carbon content and a low absolute clay mineral content (approximately 6.11%), with minimal expansive minerals (e.g., mixed-layer illite–smectite accounts for 26.4%). Consequently, the coal demonstrates a low linear expansion rate and weak hydration dispersion properties, indicating that hydration expansion is not the dominant mechanism driving mechanical strength degradation. However, drilling fluid invasion significantly reduced coal’s Young’s modulus (from 1988.1 MPa to 1676.1 MPa, a 15.69% decrease) and compressive strength (from 7.9 MPa to 6.5 MPa, a 17.72% drop), while markedly affecting its internal friction angle. Friction coefficient tests further demonstrate that the synergistic action of water molecules and additives decreases microcrack sliding resistance by 19.22% with simulated formation water and by 25.00% with drilling fluid, thereby promoting microcrack propagation and failure. This process ultimately leads to a degradation in mechanical strength. Hence, the enhancement of sliding effects induced by drilling fluid invasion is identified as the primary factor contributing to coal mechanical strength degradation, whereas hydration expansion plays a secondary role. To mitigate these effects, optimizing the design of drilling fluid systems and selecting suitable anti-collapse additives to reduce sliding effects are critical for minimizing wellbore instability risks in coal seams. These measures will ensure safer and more efficient drilling operations for deep CBM extraction. Full article
Show Figures

Figure 1

18 pages, 6428 KiB  
Article
Mohr–Coulomb-Model-Based Study on Gas Hydrate-Bearing Sediments and Associated Variance-Based Global Sensitivity Analysis
by Chenglang Li, Jie Yuan, Jie Cui, Yi Shan and Shuman Yu
J. Mar. Sci. Eng. 2025, 13(3), 440; https://doi.org/10.3390/jmse13030440 - 26 Feb 2025
Viewed by 545
Abstract
Different gas hydrate types, such as methane hydrate and carbon dioxide hydrate, exhibit distinct geomechanical responses and hydrate morphologies in gas-hydrate-bearing sediments (GHBSs). However, most constitutive models for GHBSs focus on methane-hydrate-bearing sediments (MHBSs), while largely overlooking carbon-dioxide-hydrate-bearing sediments (CHBSs). This paper proposes [...] Read more.
Different gas hydrate types, such as methane hydrate and carbon dioxide hydrate, exhibit distinct geomechanical responses and hydrate morphologies in gas-hydrate-bearing sediments (GHBSs). However, most constitutive models for GHBSs focus on methane-hydrate-bearing sediments (MHBSs), while largely overlooking carbon-dioxide-hydrate-bearing sediments (CHBSs). This paper proposes a modified Mohr–Coulomb (M-C) model for GHBSs that incorporates the geomechanical effects of both MHBSs and CHBSs. The model integrates diverse hydrate morphologies—cementing, load-bearing, and pore-filling—into hydrate saturation and incorporates an effective confining pressure. Its validity was demonstrated through simulations of reported triaxial compression tests for both MHBSs and CHBSs. Moreover, a variance-based sensitivity analysis using Sobol’s method evaluated the effects of hydrate-related soil properties on the geomechanical behavior of GHBSs. The results indicate that the shear modulus influences the yield axial strain of the CHBSs and could be up to 1.15 times more than that of the MHBSs. Similarly, the bulk modulus showed an approximate 5% increase in its impact on the yield volumetric strain of the CHBSs compared with the MHBSs. These findings provide a unified framework for modeling GHBSs and have implications for CO2-injection-induced methane production from deep sediments, advancing the understanding and simulation of GHBS geomechanical behavior. Full article
(This article belongs to the Section Geological Oceanography)
Show Figures

Figure 1

28 pages, 9216 KiB  
Review
Current Status and Reflections on Ocean CO2 Sequestration: A Review
by Shanling Zhang, Sheng Jiang, Hongda Li, Peiran Li, Xiuping Zhong, Chen Chen, Guigang Tu, Xiang Liu and Zhenhua Xu
Energies 2025, 18(4), 942; https://doi.org/10.3390/en18040942 - 16 Feb 2025
Viewed by 1246
Abstract
Climate change has become one of the most pressing global challenges, with greenhouse gas emissions, particularly carbon dioxide (CO2), being the primary drivers of global warming. To effectively address climate change, reducing carbon emissions has become an urgent task for countries [...] Read more.
Climate change has become one of the most pressing global challenges, with greenhouse gas emissions, particularly carbon dioxide (CO2), being the primary drivers of global warming. To effectively address climate change, reducing carbon emissions has become an urgent task for countries worldwide. Carbon capture, utilization, and storage (CCUS) technologies are regarded as crucial measures to combat climate change, among which ocean CO2 sequestration has emerged as a promising approach. Recent reports from the International Energy Agency (IEA) indicate that by 2060, CCUS technologies could contribute up to 14% of global cumulative carbon reductions, highlighting their significant potential in mitigating climate change. This review discusses the main technological pathways for ocean CO2 sequestration, including oceanic water column sequestration, CO2 oil and gas/coal seam geological sequestration, saline aquifer sequestration, and seabed methane hydrate sequestration. The current research status and challenges of these technologies are reviewed, with a particular focus on the potential of seabed methane hydrate sequestration, which offers a storage density of approximately 0.5 to 1.0 Gt per cubic kilometer of hydrate. This article delves into the formation mechanisms, stability conditions, and storage advantages of CO2 hydrates. CO2 sequestration via hydrates not only offers high storage density but also ensures long-term stability in the low-temperature, high-pressure conditions of the seabed, minimizing leakage risks. This makes it one of the most promising ocean CO2 sequestration technologies. This paper also analyzes the difficulties faced by ocean CO2 sequestration technologies, such as the kinetic limitations of hydrate formation and leakage monitoring during the sequestration process. Finally, this paper looks ahead to the future development of ocean CO2 sequestration technologies, providing theoretical support and practical guidance for optimizing their application and promoting a low-carbon economy. Full article
(This article belongs to the Section H: Geo-Energy)
Show Figures

Figure 1

25 pages, 5642 KiB  
Article
Effect of Methane Gas Hydrate Content of Marine Sediment on Ocean Wave-Induced Oscillatory Excess Pore Water Pressure and Geotechnical Implications
by Adango Miadonye and Mumuni Amadu
Fuels 2025, 6(1), 4; https://doi.org/10.3390/fuels6010004 - 8 Jan 2025
Viewed by 1459
Abstract
Methane gas hydrate-bearing sediments hold substantial natural gas reserves, and to understand their potential roles in the energy sector as the next generation of energy resources, considerable research is being conducted in industry and academia. Consequently, safe and economically feasible extraction methods are [...] Read more.
Methane gas hydrate-bearing sediments hold substantial natural gas reserves, and to understand their potential roles in the energy sector as the next generation of energy resources, considerable research is being conducted in industry and academia. Consequently, safe and economically feasible extraction methods are being vigorously researched, as are methods designed to estimate site-specific reserves. In addition, the presence of methane gas hydrates and their dissociation have been known to impact the geotechnical properties of submarine foundation soils and slopes. In this paper, we advance research on gas hydrate-bearing sediments by theoretically studying the effect of the hydromechanical coupling process related to ocean wave hydrodynamics. In this regard, we have studied two geotechnically and theoretically relevant situations related to the oscillatory wave-induced hydromechanical coupling process. Our results show that the presence of initial methane gas pressure leads to excessively high oscillatory pore pressure, which confirms the instability of submarine slopes with methane gas hydrate accumulation originally reported in the geotechnical literature. In addition, our results show that neglecting the presence of initial methane gas pressure in gas hydrate-bearing sediments in the theoretical description of the oscillatory excess pore pressure can lead to improper geotechnical planning. Moreover, the theoretical evolution of oscillatory excess pore water pressure with depth indicates a damping trend in magnitude, leading to a stable value with depth. Full article
(This article belongs to the Special Issue Feature Papers in Fuels)
Show Figures

Figure 1

25 pages, 10233 KiB  
Article
Advanced Insights into Methane Hydrate Production: Influence of Pressure, Saturation, and Permeability Dynamics
by Yunjian Zhou, Yufa He, Yu Chen and Shihui Sun
Processes 2025, 13(1), 80; https://doi.org/10.3390/pr13010080 - 1 Jan 2025
Viewed by 1271
Abstract
The decomposition of hydrate during hydrate mining can reduce the strength of the formation and induce engineering geological disasters. Clarifying the decomposition characteristics of geological hydrate during hydrate mining is of great significance for preventing marine geological disasters. This study comprehensively examines the [...] Read more.
The decomposition of hydrate during hydrate mining can reduce the strength of the formation and induce engineering geological disasters. Clarifying the decomposition characteristics of geological hydrate during hydrate mining is of great significance for preventing marine geological disasters. This study comprehensively examines the effects of various extraction conditions, including production pressure, hydrate saturation, and permeability, on methane hydrate decomposition during depressurization-based extraction. Key findings show that reduced production pressure significantly increases gas and water production rates due to an enhanced pressure differential, albeit at the cost of potential geomechanical instability. Variations in hydrate saturation reveal that lower-saturation reservoirs initially exhibit higher production due to faster pressure propagation and greater porosity, whereas high-saturation layers may sustain production in the later stages. Permeability changes impact pressure diffusion and heat transfer within the formation; higher permeability leads to faster initial production but causes rapid energy depletion, requiring supplementary energy inputs to maintain production. These findings provide essential insights for optimizing methane hydrate extraction, ensuring high productivity while mitigating formation stability risks. Full article
(This article belongs to the Special Issue Modeling, Control, and Optimization of Drilling Techniques)
Show Figures

Figure 1

16 pages, 6328 KiB  
Article
Gas Transport Arising from the Decomposition of Methane Hydrates in the Sediments of the Arctic Shelf to the Atmosphere: Numerical Modeling
by Mariia Trimonova, Nikolay Baryshnikov and Sergey Turuntaev
Atmosphere 2025, 16(1), 9; https://doi.org/10.3390/atmos16010009 - 26 Dec 2024
Viewed by 816
Abstract
This study investigates the transport of methane released from gas hydrate decomposition through sedimentary layers to quantify its flux into the atmosphere, a critical process given methane’s role as a major greenhouse gas. A novel methodology was developed to model two-phase, unsteady gas [...] Read more.
This study investigates the transport of methane released from gas hydrate decomposition through sedimentary layers to quantify its flux into the atmosphere, a critical process given methane’s role as a major greenhouse gas. A novel methodology was developed to model two-phase, unsteady gas flow in regions of hydrate decomposition, incorporating key factors such as relative permeability curves, capillary pressure, hydrostatics, and gas diffusion. Numerical simulations revealed that to achieve a gas front rise rate of 7 m/year, the gas accumulation rate must not exceed 10−8 kg/m3·s. At higher accumulation rates (10−6 kg/m3·s), gas diffusion has minimal impact on the saturation front movement, whereas at lower rates (10−8 kg/m3·s), diffusion significantly affects the front’s behavior. The study also established that the critical gas accumulation rate required to trigger sediment blowout in the hydrate decomposition zone is approximately 10−6 kg/m3·s, several orders of magnitude greater than typical bubble gas fluxes observed at the ocean surface. The proposed model improves the ability to predict the contribution of Arctic shelf methane hydrate decomposition to atmospheric methane concentrations. Full article
(This article belongs to the Section Atmospheric Techniques, Instruments, and Modeling)
Show Figures

Figure 1

15 pages, 15237 KiB  
Article
Uncertainty Analysis of Biogas Generation and Gas Hydrate Accumulations in the Baiyun Sag, South China Sea
by Pibo Su, Jinqiang Liang, Huai Cheng, Yaoyao Lv, Wei Zhang and Zuofei Zhu
Microorganisms 2025, 13(1), 5; https://doi.org/10.3390/microorganisms13010005 - 24 Dec 2024
Viewed by 695
Abstract
In this study, we use petroleum systems modeling (PSM) to quantitatively simulate the uncertainty of biogenic gas generation modes and their impact on the spatial distribution and resource assessment of gas hydrates in the Baiyun Sag, South China Sea. The results are as [...] Read more.
In this study, we use petroleum systems modeling (PSM) to quantitatively simulate the uncertainty of biogenic gas generation modes and their impact on the spatial distribution and resource assessment of gas hydrates in the Baiyun Sag, South China Sea. The results are as follows: (1) Biogenic gas generation is significantly affected by thermal state and organic matter type. Low temperature is a primary reason for gas hydrate occurrence in shallower sediments when sufficient methane gas is present. This may be due to higher thermal conductivity of the overlying sediments, slower sediment burial rates, or other geological processes. (2) Natural gas hydrate resources are significantly controlled by biogenic gas generation. In addition to the thermal conditions of the source rock or sediment, the nature of the organic matter is another crucial factor. Generally, low-temperature methanogens produce more methane gas because they require less energy, whereas high-temperature methanogens require more energy and thus produce less methane gas. (3) The biogas generation thermal model is key to controlling the location and quantity of natural gas hydrate resources. The three possible gas-phase models, K0, K1, and K2 (representing different methanogens), produce varying amounts of methane gas over time, resulting in different amounts of natural gas hydrate resources. Additionally, the preservation of various methanogens in biogas source rocks can alter reservoir formation locations, influencing the scale and genetic model of natural gas hydrate resources. Full article
(This article belongs to the Section Environmental Microbiology)
Show Figures

Figure 1

16 pages, 7979 KiB  
Article
Hydrate-Based Methane Storage in Biodegradable Hydrogels Absorbing Dilute Sodium P-Styrenesulfonate Solution
by Fangzheng Hua, Kang Tan, Jingyu Lv, Fei Wang and Mengting Sun
Gels 2025, 11(1), 1; https://doi.org/10.3390/gels11010001 - 24 Dec 2024
Viewed by 840
Abstract
Developing an exceptional reaction medium with high promotion efficiency, desirable biodegradability and good recyclability is necessary for hydrate-based methane storage. In this work, a kind of eco-friendly hydrogel, polyvinyl alcohol-co-acrylic acid (PVA-co-PAA), was utilized to absorb dilute sodium p-styrenesulfonate (SS) solution, for constructing [...] Read more.
Developing an exceptional reaction medium with high promotion efficiency, desirable biodegradability and good recyclability is necessary for hydrate-based methane storage. In this work, a kind of eco-friendly hydrogel, polyvinyl alcohol-co-acrylic acid (PVA-co-PAA), was utilized to absorb dilute sodium p-styrenesulfonate (SS) solution, for constructing a hybrid reaction medium for methane hydrate formation. Hydrogels or dilute SS solutions (1–4 mmol L−1) had weak or even no promoting effects on hydrate formation kinetics, while the combination of them could synergistically promote methane hydrate formation. In hydrogel-SS hybrid media containing 1, 2, 3 and 4 mmol L−1 of SS solutions, the storage capacity reached 121.2 ± 1.6, 121.5 ± 3.1, 122.6 ± 1.9 and 120.6 ± 1.6 v/v, respectively. In this binary reaction system, the large surface area of hydrogels provided hydrate formation with sufficient nucleation sites and an enlarged gas–liquid interface, and in the meantime, the dilute SS solution produced an adequate capillary effect, which together enhanced mass transfer and accelerated hydrate formation kinetics. Additionally, the hybrid medium could relieve wall-climbing hydrate growth and improve poor hydrate compactness resulting from the bulk SS promoter. Moreover, the hybrid medium exhibited a preferable recyclability and could be reused at least 10 times. Therefore, the hydrogel-SS hybrid medium can serve as an effective and eco-friendly packing medium for methane hydrate storage tanks, which holds great application potential in hydrate-based methane storage technology. Full article
Show Figures

Graphical abstract

14 pages, 4728 KiB  
Article
Experimental Analysis of Elastic Property Variations in Methane Hydrate-Bearing Sediments with Different Porosities
by Weiping Xu, Bangrang Di, Haifeng Chen and Jianxin Wei
J. Mar. Sci. Eng. 2024, 12(12), 2370; https://doi.org/10.3390/jmse12122370 - 23 Dec 2024
Cited by 1 | Viewed by 822
Abstract
Natural gas hydrates, a promising clean energy resource, hold substantial potential. Porosity plays a crucial role in hydrate systems by influencing formation processes and physical properties. To clarify the effects of porosity on hydrate elasticity, we examined methane hydrate formation and its acoustic [...] Read more.
Natural gas hydrates, a promising clean energy resource, hold substantial potential. Porosity plays a crucial role in hydrate systems by influencing formation processes and physical properties. To clarify the effects of porosity on hydrate elasticity, we examined methane hydrate formation and its acoustic characteristics. Experiments were conducted on sediment samples with porosities of 23%, 32%, and 37%. P- and S-wave velocities were measured to assess acoustic responses. Results show that as hydrate saturation increases, sample acoustic velocity also rises. However, high-porosity samples consistently exhibit lower acoustic velocities compared to low-porosity samples and reach a lower maximum hydrate saturation. This behavior is attributed to rapid pore filling in high-porosity samples, which blocks flow pathways and limits further hydrate formation. In contrast, hydrate formation in low-porosity sediments progresses more gradually, maintaining clearer pore channels and resulting in relatively higher hydrate saturation. Higher porosity also accelerates the shift of hydrates from cementing to load-bearing morphologies. These findings underscore porosity’s significant influence on hydrate formation and provide insights into observed variations in hydrate saturation and acoustic velocity across different experimental conditions. Full article
(This article belongs to the Section Marine Energy)
Show Figures

Figure 1

21 pages, 7616 KiB  
Article
Numerical Simulation of a Marine Landslide in Gas Hydrate-Bearing Sediments Using L-GSM
by Da Hui, Guangyao Wang, Yilin Huang, Guixun Zhu and Wenming Li
J. Mar. Sci. Eng. 2024, 12(12), 2274; https://doi.org/10.3390/jmse12122274 - 11 Dec 2024
Viewed by 792
Abstract
The marine gas hydrates within seabed sediments and their subsequent extraction may cause landslides. Predicting landslides in hydrate-bearing sediments is particularly challenging due to the intricate nature of the marine environment. To address this issue, we have developed a Lagrangian gradient smoothing method [...] Read more.
The marine gas hydrates within seabed sediments and their subsequent extraction may cause landslides. Predicting landslides in hydrate-bearing sediments is particularly challenging due to the intricate nature of the marine environment. To address this issue, we have developed a Lagrangian gradient smoothing method (L-GSM) based on gradient smoothing techniques. This approach effectively eliminates the tensile instability inherent in the original Smoothed Particle Hydrodynamics (SPH) method used for modeling solid flow. Then, we applied the L-GSM to investigate the mechanics of hydrate-bearing sediments by integrating a constitutive equation specific to these sediments, which were modeled based on the artificial methane-hydrate-bearing sediment. The robustness and precision of the L-GSM were verified through various numerical examples. Furthermore, we modeled the landslides associated with hydrate-bearing sediments under varying hydrate saturation levels. The numerical findings revealed that hydrate saturation significantly affects the dynamics of landslide movement. These satisfactory results suggest that the L-GSM has the potential to be applied to geotechnical problems associated with hydrate-bearing sediment. Full article
Show Figures

Figure 1

18 pages, 2817 KiB  
Article
A Comparative Study on Acoustic Characteristics of Methane and Tetrahydrofuran Hydrate-Bearing Sediments
by Wengao Zhao, Qingtao Bu, Zihao Wang, Tong Liu, Qingguo Meng, Yapeng Zhao and Gaowei Hu
J. Mar. Sci. Eng. 2024, 12(12), 2239; https://doi.org/10.3390/jmse12122239 - 5 Dec 2024
Viewed by 958
Abstract
Laboratory acoustic measurements of hydrate-bearing sediments serve as an important reference for the geological interpretation of seismic exploration data. Tetrahydrofuran (THF) hydrates are relatively easy to form with precise control of hydrate saturation, and they overcome the long time it takes for methane [...] Read more.
Laboratory acoustic measurements of hydrate-bearing sediments serve as an important reference for the geological interpretation of seismic exploration data. Tetrahydrofuran (THF) hydrates are relatively easy to form with precise control of hydrate saturation, and they overcome the long time it takes for methane in sediments to form hydrate. However, when THF hydrates are used as a substitute for methane hydrate, their acoustic properties yield different results. This study reports the results of a series of laboratory experiments on the formation of methane and THF hydrate in quartz sand and the evaluation of their acoustic properties. It compares the experimental results with the results of calculations from micro-distribution models of the four hydrates using effective medium theory (EMT). Methane hydrate formed by the excess gas method has higher acoustic velocities than THF hydrate at 0–80% saturation, but at 80–100% saturation, the situation reverses, with THF hydrate having a higher wave velocity. The methane hydrate synthesis process follows a mixed micro-distribution, with grain coating predominating at low saturations, the pore-filling mixing mode dominating at medium saturations, and grain coating dominating at high saturations. In addition, THF hydrate has a slow-velocity growth at low saturation and is dominated by a pore-filling model and a load-bearing model at high saturation. We compared our experimental data with a compilation of similar published results to confirm their reliability and support our conclusions. Both hydrate types exhibit distinct micro-distributions across different saturations. Therefore, when testing the elastic characteristics of hydrate sediments, the distinct hydrate synthesis methods and micro-distribution should be considered, especially when using THF hydrate as an alternative to methane hydrate. Full article
(This article belongs to the Section Geological Oceanography)
Show Figures

Figure 1

15 pages, 4237 KiB  
Article
Damage Mechanism of Deep Coalbed Methane Reservoir and Novel Anti-Waterblocking Protection Technology
by Wei Wang, Jiafeng Jin, Jiang Xin, Kaihe Lv, Kang Ren, Jie Xu, Zhenyi Cao and Ran Zhuo
Processes 2024, 12(12), 2735; https://doi.org/10.3390/pr12122735 - 3 Dec 2024
Cited by 1 | Viewed by 939
Abstract
Coalbed Methane (CBM) accounts for about 5% of China’s domestic gas supply, which has been regarded as one of the most promising energies for alleviating the energy supply–demand imbalance. Deep CBM reservoirs have the characteristics of low permeability, low porosity, and low water [...] Read more.
Coalbed Methane (CBM) accounts for about 5% of China’s domestic gas supply, which has been regarded as one of the most promising energies for alleviating the energy supply–demand imbalance. Deep CBM reservoirs have the characteristics of low permeability, low porosity, and low water saturation, which easily experience reservoir damage during the drilling process, further affecting the gas productivity. Based on the analysis of coal mineral composition, pore structure distribution, and the surface micromorphology change in coal surface before and after hydration, a possible mechanism for CBM formation damage was revealed. It was found that the damage caused by drilling fluid intrusion can be divided into three stages: stripping, migration, and plugging. Based on the water-sensitive, acid-sensitive, and stress-sensitive evaluation tests, a novel anti-waterblocking agent with both wettability alteration and surface tension reduction was developed; then a reservoir protection drilling fluid for deep coal formation in Daning-Jixian block was constructed; then the reservoir protection performance of drilling fluid was evaluated. The results show that as the concentration of the anti-waterblocking agent FSS increases from 0% to 1%, the surface tension of the water phase is significantly reduced from 72.15 mN/m to 26.58 mN/m, while the maximum contact angle of water on the surface reaches 117°. This enhancement in wettability leads to an improvement in the permeability recovery rate from 56.6% to 80.0%, indicating a substantial reduction in waterblocking effects and better fluid mobility within the reservoir. These findings highlight the efficacy of FSS in mitigating formation damage and optimizing gas production in coalbed methane reservoirs. The drilling fluid has good wettability alteration, inhibition, and sealing performance, which is of great significance for protecting gas well productivity. Full article
(This article belongs to the Special Issue Advanced Nano-Materials for Oil and Natural Gas Exploration)
Show Figures

Figure 1

Back to TopTop