Experimental Study On the Effect of Hydrate Filling On the Mechanical Properties of Marine Sediments in the Shenhu Area, South China Sea

Energy & Fuels, Journal Year: 2024, Volume and Issue: 38(6), P. 5192 - 5205

Published: March 5, 2024

The basic physical properties of marine sediments are analyzed by in situ sampling the Shenhu area South China Sea. Marine sediment samples containing hydrates were prepared, and triaxial mechanical experiments carried out under different conditions to analyze evolution characteristics stress, strain, porosity during loading. results show that is characterized weak cementation a high mud content. main components quartz, clay minerals, calcite. stress–strain curves HBS nonlinear deformation elasticity strong plasticity. Under low initial pore ratio, effective confining pressure, hydrate saturation, strain softening volume dilatancy evident late loading stage. When pores filled with hydrate, process accompanied fragmentation detachment crystals, resulting higher more severe shear sample, difficulty reaching critical state sediment. With increasing pressure tangential modulus shows linear increase peak strength sample increases nonlinearly. cohesion values internal friction angles an exponential increase. average normal differential stress nearly void ratio decrease.

Language: Английский

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Numerical Investigation of Hydrate Production Characteristics in a Fractured Reservoir via Depressurization: Assessing the Influence of Fractures

Energy & Fuels, Journal Year: 2024, Volume and Issue: 38(11), P. 9467 - 9476

Published: May 14, 2024

The natural gas hydrate reservoir is known for its low permeability, leading to a suboptimal production rate, thus impeding commercial viability. While reservoirs with high permeability fractures exhibit greater seepage capacity, their influence on dissociation characteristics remains unclear. present study introduces coupled thermo-hydrochemical numerical model simulate the exploitation of fractured through depressurization using vertical well. impact fracture characterized as "double-edged sword", termed "fracture end effect", inhibition and promotion at near/far from well, respectively, resulting heterogeneous pressure gradient distribution within adjacent fracture. A relatively high-pressure high-temperature region noted near due thermal compensation distant fracture, potentially reducing risk ice reformation around wellbore during exploitation. Furthermore, presence horizontal can notably enhance cumulative gas-to-water ratio, especially in long-term thereby yielding superior economic benefits reservoir.

Language: Английский

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Impact of Varied Depressurization Rates on Gas Production and Heat Supply in Hydrate Dissociation

Energy & Fuels, Journal Year: 2024, Volume and Issue: 38(11), P. 9734 - 9741

Published: May 15, 2024

Natural gas hydrate is widely recognized as a promising energy source, with depressurization emerging the preferred method due to its simplicity and cost-effectiveness. Employing an appropriate strategy paramount for maximizing production efficiency, especially when faced constraints in reservoir heat supply. However, precise influence of rate on supply remains unclear. In this study, we employ fully coupled thermo-hydro-chemical (THC) model simulate 60 days dissociation using horizontal well under various schemes: decelerating (DD), regular (RD), accelerated (AD). We investigate effects dynamic changes production, multiphysics response Our findings indicate that most pronounced during initial stage. A positive correlation between observed. The amplitude fluctuations more significant at higher rates, these intensify increases. From perspective, sensible ratio increases rate. Gas primarily driven by flow dynamics propelled early stages constant pressure. Subsequently, it controlled ambient transfer. Therefore, additional replenishment can enhance improve economic viability not predominant. Such hold crucial reference value commercial exploitation resources.

Language: Английский

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Creep and Wave Velocity Characterization on Anisotropic Consolidated Methane Hydrate Sediments of the South China Sea

Energy & Fuels, Journal Year: 2024, Volume and Issue: 38(17), P. 16416 - 16425

Published: Aug. 9, 2024

Offshore engineering geological activities can lead to creep behavior in hydrate reservoirs, which, turn, leads reservoir subsidence, seriously affecting the safety of offshore facilities as well long-term stability reservoir. Accurate characterization properties sediment is key predicting reservoirs. Therefore, a series experiments were carried out triaxial pressure chamber, and deformation mechanism was proposed based on acoustic wave data predicted strength The results show that sediments have typical stable characteristics; strain volumetric are positively correlated with stress level effective confining pressure. generally low therefore requires careful consideration. Finally, two different constitutive models compared, Singh–Mitchell empirical model applicable relationship South China Sea established experimental data.

Language: Английский

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Undrained triaxial tests of underconsolidated overlying sediments of hydrate deposits in the South China Sea

Gas Science and Engineering, Journal Year: 2024, Volume and Issue: 131, P. 205442 - 205442

Published: Sept. 13, 2024

Language: Английский

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Enhanced Strategies for Depressurization in Offshore Natural Gas Hydrate Exploitation: An In-Depth Investigation into Pathway Optimization and Production Stability Mechanisms

Marine and Petroleum Geology, Journal Year: 2024, Volume and Issue: unknown, P. 107107 - 107107

Published: Sept. 1, 2024

Language: Английский

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Pore-scale deformation characteristics of hydrate-bearing sediments with gas replacement

The Science of The Total Environment, Journal Year: 2024, Volume and Issue: 954, P. 176464 - 176464

Published: Sept. 23, 2024

Language: Английский

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Permeability Evolution in Hydrate-Bearing Sediments during Hydrate Recovery by Depressurization Combined with Replacement

Energy & Fuels, Journal Year: 2025, Volume and Issue: unknown

Published: May 7, 2025

Language: Английский

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Impact of Layered Heterogeneity on Hydrate Dissociation Dynamics and Fluid Production Behavior of Hydrate-Bearing Sediments

Energy & Fuels, Journal Year: 2025, Volume and Issue: unknown

Published: May 6, 2025

Language: Английский

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Effect of Sediment Stratification on the Mechanical and Acoustic Properties of Hydrate-Bearing Sediments

Energy & Fuels, Journal Year: 2024, Volume and Issue: 38(7), P. 5889 - 5899

Published: March 22, 2024

Natural gas hydrate (NGH) is the commanding height of future energy development strategies. Comprehensively revealing mechanical behavior NGH reservoirs primary guarantee to ensure safe utilization resources. However, due complexity accumulation and deposition, in enrichment area usually not homogeneous. impact layered heterogeneous distribution on properties hydrate-bearing sediment (HBS) remains unclear. In this study, based geological background, several sets triaxial shear tests were carried out, a comprehensive analysis was out by coupling acoustic characteristics tests. The stratification effect sediments changes stress–strain response curve HBS from traditional strain hardening or softening "secondary hardening"; phenomenon only occurs once affected number layers. Also, an increasing would enhance strength dilatancy. will reduce compressional shear-wave velocity HBS. sound increases rapidly during shearing process unchanged after yielding. This study important for exploitation hydrates under conditions.

Language: Английский

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