Evaluation of Different CH4-CO2 Replacement Processes in Hydrate-Bearing Sediments by Measuring P-Wave Velocity

Liu, Bei; Pan, Heng; Wang, Xiaohui; Li, Feng-Guang; Sun, Chang‐Yu; Chen, Guangjin

doi:10.3390/en6126242

Cited by 41 publications

(21 citation statements)

References 18 publications

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“…Positive synergy between optimized flow control and guest molecule replacement may therefore be achieved through binary gas injection. However, sonic measurements on samples have detected loss of stiffness during the replacement process [24,39]. This has also been supported by observed resistivity trends [33], which indicates rearrangement or decomposition of hydrates during binary gas injection.…”

Section: Flow Remediation Through Binary Gas Injectionmentioning

confidence: 54%

“…46% recovery was observed after injecting 1 PV CO2, which is 53% higher than observations for samples at 4 °C. Liu et al [24] studied exchange performance at various temperature and reported similar ultimate recovery although (Sw/Sh) the replacement rate was higher at elevated temperature. We have observed both higher exchange rate and final recovery (10%) in this study.…”

Section: Continuous Co2 Mass Transport In Non-fractured Samplesmentioning

confidence: 98%

“…The exchange technology has previously been demonstrated in bulk experiments [14][15][16][17], in sediments [18][19][20][21][22][23][24] and numerically [19,25,26]. This work is part of the laboratory work that was conducted in advance of the Ignik Sikumi field test [27], where the University of Bergen in partnership with ConocoPhillips have studied CO2-CH4 exchange for a range of initial saturations.…”

Section: Figurementioning

confidence: 99%

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Transport Mechanisms for CO2-CH4 Exchange and Safe CO2 Storage in Hydrate-Bearing Sandstone

et al. 2015

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CO2 injection in hydrate-bearing sediments induces methane (CH4) production while benefitting from CO2 storage, as demonstrated in both core and field scale studies. CH4 hydrates have been formed repeatedly in partially water saturated Bentheim sandstones. Magnetic Resonance Imaging (MRI) and CH4 consumption from pump logs have been used to verify final CH4 hydrate saturation. Gas Chromatography (GC) in combination with a Mass Flow Meter was used to quantify CH4 recovery during CO2 injection. The overall aim has been to study the impact of CO2 in fractured and non-fractured samples to determine the performance of CO2-induced CH4 hydrate production. Previous efforts focused on diffusion-driven exchange from a fracture volume. This approach was limited by gas dilution, where free and produced CH4 reduced the CO2 concentration and subsequent driving force for both diffusion and exchange. This limitation was targeted by performing experiments where CO2 was injected continuously into the spacer volume to maintain a high driving force. To evaluate the effect of diffusion length multi-fractured core samples were used, which demonstrated that length was not the dominating effect on core scale. An additional set of experiments is presented on non-fractured samples, where diffusion-limited transportation was assisted by continuous CO2 injection and CH4 displacement. Loss of permeability was addressed through binary gas (N2/CO2) injection, which regained injectivity and sustained CO2-CH4 exchange. OPEN ACCESSEnergies 2015, 8 4074

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Section: Flow Remediation Through Binary Gas Injectionmentioning

confidence: 54%

Section: Continuous Co2 Mass Transport In Non-fractured Samplesmentioning

confidence: 98%

Section: Figurementioning

confidence: 99%

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Transport Mechanisms for CO2-CH4 Exchange and Safe CO2 Storage in Hydrate-Bearing Sandstone

et al. 2015

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“…Wang et al [22] proved that the P-wave velocity and amplitude of the hydrate-bearing sediments behave in the same way and decrease slightly because of the dissociation of CH 4 hydrate when free CH 4 gas is released and CO 2 gas is injected. Liu et al [23] also found that the P-wave velocity continually decreased during all replacement processes. Hyodo et al [24] confirmed that newly formed CO 2 hydrate would keep the reservoir mechanically stable when CH 4 -CO 2 replacement took place in a relatively short period of time in sediments formed by Toyoura sand.…”

Section: Introductionmentioning

confidence: 89%

“…More CH4 hydrate was dissociated than CO2 hydrate due to their dynamic stability differences, which decreased the strength of the sample [31]. show clearly that the failure strength of the CO 2 hydrate-bearing sediments is higher than that of the CH 4 hydrate sediments under different confining pressures, and CH 4 -CO 2 replacement is beneficial to the stability of the reservoir [23,24]. Besides this, in the shear process, the strength of the hydrate-bearing sediments may consist of the strength of ice, hydrate, and sediment matrix and their interaction [29].…”

Section: The Effect Of Confining Pressurementioning

confidence: 94%

Experimental Study on the Mechanical Properties of CH4 and CO2 Hydrate Remodeling Cores in Qilian Mountain

Luo

Liu

et al. 2017

Energies

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Abstract:The CH 4 -CO 2 replacement method has attracted global attention as a new promising method for methane hydrate exploitation. In the replacement process, the mechanical stabilities of CH 4 and CO 2 hydrate-bearing sediments have become problems requiring attention. In this paper, considering the hydrate characteristics and burial conditions of hydrate-bearing cores, sediments matrices were formed by a mixture of kaolin clay and quartz sand, and an experimental study was focused on the failure strength of CH 4 and CO 2 hydrate-bearing sediments under different conditions to verify the mechanical reliability of CH 4 -CO 2 replacement in permafrost-associated natural gas deposits. A series of triaxial shear tests were conducted on the CH 4 and CO 2 hydrate-bearing sediments under temperatures of −20, −10, and −5 • C, confining pressures of 2.5, 3.75, 5, 7.5, and 10 MPa, and a strain rate of 1.0 mm/min. The results indicated that the failure strength of the CO 2 hydrate-bearing sediments was higher than that of the CH 4 hydrate-bearing sediments under different confining pressures and temperatures; the failure strength of the CH 4 and CO 2 hydrate-bearing sediments increased with an increase in confining pressure at a low confining pressure state. Besides that, the failure strength of all hydrate-bearing sediments decreased with an increase in temperature; all the failure strengths of the CO 2 hydrate-bearing sediments were higher than those of the CH 4 hydrate-bearing sediments in different sediment matrices. The experiments proved that the hydrate-bearing sediments would be more stable than that before CH 4 -CO 2 replacement.

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Molecular Dynamics Simulation Study of N₂/CO₂ Displacement Process of Methane Hydrate

et al. 2020

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In this paper, we construct three kinds of hydrate replacement models: N 2 , CO 2 and N 2-CO 2. The molecular dynamics (MD) method is used to study the dynamic process of N 2-CO 2 replacement for natural gas hydrate. The replacement efficiency of N 2 /CO 2 is simulated, and the influence of gas replacement on the stability of the water cage is assessed. The results show that CH 4 molecules in the driving hydrate are all enriched in the gas-liquid interface or gas region. Compared with the replacement of methane hydrate with CO 2 , when N 2-CO 2 mixed gas is used to replace methane hydrate, the diffusion rate of CO 2 is increased by 2 times, and the replacement efficiency of hydrate is significantly improved. The radial distribution function and free energy calculation results show that although the barrier of the water cage is significantly reduced after replacement, the water molecules in the cage still have difficulty jumping over the free energy barrier compared with the thermal motion energy, so the water cage structure remains highly stable.

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Evaluation of Different CH4-CO2 Replacement Processes in Hydrate-Bearing Sediments by Measuring P-Wave Velocity

Cited by 41 publications

References 18 publications

Transport Mechanisms for CO2-CH4 Exchange and Safe CO2 Storage in Hydrate-Bearing Sandstone

Transport Mechanisms for CO2-CH4 Exchange and Safe CO2 Storage in Hydrate-Bearing Sandstone

Experimental Study on the Mechanical Properties of CH4 and CO2 Hydrate Remodeling Cores in Qilian Mountain

Molecular Dynamics Simulation Study of N₂/CO₂ Displacement Process of Methane Hydrate

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Evaluation of Different CH4-CO2 Replacement Processes in Hydrate-Bearing Sediments by Measuring P-Wave Velocity

Cited by 41 publications

References 18 publications

Transport Mechanisms for CO2-CH4 Exchange and Safe CO2 Storage in Hydrate-Bearing Sandstone

Transport Mechanisms for CO2-CH4 Exchange and Safe CO2 Storage in Hydrate-Bearing Sandstone

Experimental Study on the Mechanical Properties of CH4 and CO2 Hydrate Remodeling Cores in Qilian Mountain

Molecular Dynamics Simulation Study of N2/CO2 Displacement Process of Methane Hydrate

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Molecular Dynamics Simulation Study of N₂/CO₂ Displacement Process of Methane Hydrate