Enhanced gas production by forming artificial impermeable barriers from unconfined hydrate deposits in Shenhu area of South China sea

Zhao, Ermeng; Hou, Jirui; Liu, Yongge; Ji, Yunkai; Liu, Wenbin; Lu, Nu; Bai, Yajie

doi:10.1016/j.energy.2020.118826

Cited by 35 publications

(15 citation statements)

References 52 publications

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“…With the compaction and consolidation of the NGH dissociation zone under vertical stress, stratum subsidence appears, and uneven subsidence is bound to cause local HBS instability and wellbore instability (Figure a) . To address the geomechanical stability issues during perforation, fracturing, and production, and to avoid gas leakage from shallow HBS with unconsolidated argillaceous siltstones, a new concept is put forward by forming artificial impermeable barriers from unconfined HBS . However, a feasibility study on the layer of artificially sealed caps is weak.…”

Section: Challenges and Perspectivesmentioning

confidence: 99%

“…391 To address the geomechanical stability issues during perforation, fracturing, and production, and to avoid gas leakage from shallow HBS with unconsolidated argillaceous siltstones, a new concept is put forward by forming artificial impermeable barriers from unconfined HBS. 392 However, a feasibility study on the layer of artificially sealed caps is weak. Furthermore, limited by the ultralow permeability of HBS and lower tensile strength in the NGH dissociation zone, local pore pressure rebound may emerge.…”

Section: Challenges and Perspectivesmentioning

confidence: 99%

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Recent Advances in Methods of Gas Recovery from Hydrate-Bearing Sediments: A Review

et al. 2022

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Safe, efficient, and economical gas recovery from hydrate-bearing sediments (HBS) is a severe issue that determines if natural gas hydrate (NGH), as an alternative energy in the future as fossil fuels approach depletion, is applied. Researchers worldwide are committed to developing a safe, efficient, and economical method of gas recovery from HBS. However, until now, most methods are still being validated and not have not been identified to exploit NGH commercially. Therefore, it is appropriate and significant to discuss researchers’ achievements to exploit NGH and summarize their potential benefits and challenges. This paper introduces nearly all the conventional and latest NGH exploitation methods and reviews field trials’ development characteristics. On the basis of laboratory experiments and field trials, key challenges restricting safe and efficient NGH development, and the existing research gaps reflecting these challenges, are also presented from the gas production, security, and economic aspects. The unfavorable situation mainly comprises the insufficient sensible heat, extremely low thermal conductivity, and ultralow permeability of HBS, lower gas production rate and its intense fluctuations, higher water-to-gas ratio (WGR), geological deformation, and subsidence of HBS attributed to excessive sand production, driving the consideration of some possible solutions. Given this, a new method for enhanced gas production from HBS based on the combination of depressurization (DP) and an in-situ heat generation method is proposed. Benefiting from multiple theoretical enhancement mechanisms such as replenishing energy to HBS with in-situ heat generation powders, cementing and strengthening the HBS skeleton, improving the gas permeability in HBS, decreasing the WGR based on blocking water, and removing gas characteristics of hydration products, this method could be expected to achieve promising long-term performance of gas production, which will be theoretically and practically significant to study commercial gas production.

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Section: Challenges and Perspectivesmentioning

confidence: 99%

Section: Challenges and Perspectivesmentioning

confidence: 99%

Recent Advances in Methods of Gas Recovery from Hydrate-Bearing Sediments: A Review

et al. 2022

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“…The detailed geologic parameters are selected with reference of Shenhu area, South China Sea, are listed in Table . ,− The initial pressure and temperature at the bottom of HBS layer are 15.9 MPa and 288.25 K (no chemical reaction). The initial fluid pressure of the entire model region follows the hydrostatic distribution.…”

Section: Gas Production Strategy and Numerical Modelmentioning

confidence: 99%

“…Overcoming the extreme low permeability of HBS is the main challenge during the production because the depressurization effect is restricted by the low-permeability layer. In order to enlarge the range of pressure-drop zone and promote the depressurization effect, Zhao et al 16 put forward a novel method that forms artificial impermeable barriers from unconfined hydrate deposits that controls the depressurization effect in HBS, and this step avoids invalid dissipation of pressure drop in no-hydrate layers. The numerical simulation results show that the hydrate decomposition rate increases from 8.9 to 45.4% by setting 90 m impermeable barriers.…”

Section: Introductionmentioning

confidence: 99%

Numerical Evaluation of Gas Hydrate Production Performance of the Depressurization and Backfilling with an In Situ Supplemental Heat Method

Zhang

et al. 2021

ACS Omega

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The depressurization and backfilling with an in situ supplemental heat method had been proposed to enhance the gas production of methane hydrate reservoir. This novel method is evaluated by a numerical simulator based on the finite volume method in this work. Based on the typical marine low-permeability hydrate-bearing sediments (HBS), a reservoir model with gas fracturing and CaO powder injection is constructed. The simulation results show that the stimulated fractures could effectively enhance the pressure drop effect. Moreover, the CaO injection could provide in situ heat simultaneously. Based on the sensitivity analysis of the equivalent permeability of fractures and the mass of CaO injection, it is found that a threshold fracture permeability exists for the increasing of gas production. The gas production increases with the equivalent permeability only when the permeability is smaller than the threshold value. Meanwhile, the more CaO are injected into reservoir, the larger volume of gas production. In general, this work theoretically quantifies the potential value of the depressurization and backfilling with an in situ supplemental heat method for marine gas hydrate recovery.

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“…Due to the scarcity of experimental data and the difficulty of making direct measurements, the water-gas relative permeability curves used in the macroscopic numerical simulation of NGH reservoirs are estimated and often described by the van Genuchten equation [20,21], the Corey equation [22,23] and the Modified Stone equation [24][25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Relative permeability of gas and water flow in hydrate-bearing porous media: A micro-scale study by lattice Boltzmann simulation

Kneafsey

Hou

et al. 2022

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Enhanced gas production by forming artificial impermeable barriers from unconfined hydrate deposits in Shenhu area of South China sea

Cited by 35 publications

References 52 publications

Recent Advances in Methods of Gas Recovery from Hydrate-Bearing Sediments: A Review

Recent Advances in Methods of Gas Recovery from Hydrate-Bearing Sediments: A Review

Numerical Evaluation of Gas Hydrate Production Performance of the Depressurization and Backfilling with an In Situ Supplemental Heat Method

Relative permeability of gas and water flow in hydrate-bearing porous media: A micro-scale study by lattice Boltzmann simulation

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