Study on improved efficiency of induced fracture in gas hydrate reservoir depressurization development

Bai, Yajie; Clarke, Matthew A.; Hou, Jirui; Liu, Yongge; Lu, Nu; Zhao, Ermeng; Chen, Litao; Guo, Tiankui

doi:10.1016/j.energy.2023.127853

Cited by 13 publications

(9 citation statements)

References 36 publications

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“…Because the extension direction of the fracture is consistent with the pressure drop direction and the existence of the high permeability fracture provides a rapid flow channel for water and gas, which increases the seepage capacity of the reservoir, there is an obvious low-pressure area near the fracture, and the depressurization front edge has an obvious bulge at the far end of the fracture at day 1, (the end of the fracture away from the well is defined as the far end of the fracture in this paper). The distribution trend of pressure in fractured reservoirs is similar to that of the study of Bai et al After 90 days, the isobar is sunken at the near end of the fracture (the end of the fracture near the well is defined as the near end of the fracture in this paper). Some of the fluid is trapped at the near end of the fracture; therefore, the pressure drops slowly near the fracture.…”

Section: Resultssupporting

confidence: 85%

“…Therefore, the heat compensation of the far reservoir can be presented in the form of this high-temperature region. This phenomenon can also be observed in the study of Bai et al 43 Figure 5 shows the temporal and spatial distribution of hydrate saturation of the hydrate-bearing layer in the fractured reservoir at different exploitation periods (1, 90, 180, and 500 d). With the progress of exploitation, free water and free gas in the reservoir are discharged from the well under the action of pressure difference, and the gas pressure is further reduced.…”

Section: Resultssupporting

confidence: 76%

“…Therefore, the heat compensation of the far reservoir can be presented in the form of this high-temperature region. This phenomenon can also be observed in the study of Bai et al …”

Section: Resultssupporting

confidence: 76%

“…This phenomenon can also be observed in studies. 32,36,43,46 Lv et al 32 have analyzed that this phenomenon is also correlated with the presence of free water in the overburden. Due to the pressure, permeability, and gravity difference, the relatively high-temperature free water seeps into the region and speeds up the hydrate dissociation in this region.…”

Section: End Effect and Its Influence In Fractured Reservoir Exploita...mentioning

confidence: 99%

“…The production well is vertical, and its radius is 0.2 m. The axisymmetric model is shown in Figure . The horizontal penny-shaped fracture is in the middle of the hydrate-bearing layer; this fracture design is widely used in the modeling of fracture systems. ,, The fracture width is set to 0.01 m, and the fracture length is set to 15 m. Through numerical simulation, Zhong made a comparative analysis of cases with fracture permeability of 1, 1.5, and 2 D and cases without fracture. He found that gas production increased when the fracture permeability increased, but the increase rate decreased gradually.…”

Section: Model Construction and Model Parametersmentioning

confidence: 99%

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

Zhao,

Cheng,

Sun

et al. 2024

Energy Fuels

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

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Section: Resultssupporting

confidence: 85%

Section: Resultssupporting

confidence: 76%

“…Therefore, the heat compensation of the far reservoir can be presented in the form of this high-temperature region. This phenomenon can also be observed in the study of Bai et al …”

Section: Resultssupporting

confidence: 76%