The Production-Induced Geomechanical Property Changes during Gas Production from Gas Hydrate Deposits

As a part of a research program aiming to mobilize marine gas hydrate deposits as an energy resource, the worlds' first gas production attempt was performed in early 2013 in the Daini Atsumi Knoll, Eastern Nankai Trough, off Honshu Island, Japan.

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Numerical Simulation of Gas Hydrate Production Using the Cyclic Depressurization Method in the Ulleung Basin of the Korea East Sea

Applied Sciences ◽

10.3390/app11209748 ◽

2021 ◽

Vol 11 (20) ◽

pp. 9748

Author(s):

Taehun Lee ◽

Joo Yong Lee ◽

Taewoong Ahn ◽

Han Am Son

Keyword(s):

Numerical Simulation ◽

Gas Hydrate ◽

Vertical Displacement ◽

Gas Production ◽

East Sea ◽

Ulleung Basin ◽

Production Time ◽

Methane Recovery ◽

Gas Hydrate Deposits ◽

Bottomhole Pressure

The depressurization method is known as the most productive and effective method for successful methane recovery from hydrate deposits. However, this method can cause considerable subsidence because of the increased effective stress. Maintenance of geomechanical stability is necessary for sustainable production of gas from gas hydrate deposits. In this study, the cyclic depressurization method, which uses changing the bottomhole pressure and production time during primary and secondary depressurization stage, was utilized in order to increase stability in the Ulleung Basin of the Korea East Sea. Various case studies were conducted with alternating bottomhole pressure and production time of the primary and secondary depressurization stages over 400 days. Geomechanical stability was significantly enhanced, while cumulative gas production was relatively less reduced or nearly maintained. Specially, the cumulative gas production of the 6 MPa case was more than three times higher than that of the 9 MPa case, while vertical displacement was similar between them. Therefore, it was found that the cyclic depressurization method should be applied for the sake of geomechanical stability.

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Challenges, Uncertainties, and Issues Facing Gas Production From Gas-Hydrate Deposits

SPE Reservoir Evaluation & Engineering ◽

10.2118/131792-pa ◽

2011 ◽

Vol 14 (01) ◽

pp. 76-112 ◽

Cited By ~ 147

Author(s):

G.J.. J. Moridis ◽

T.S.. S. Collett ◽

M.. Pooladi-Darvish ◽

S.. Hancock ◽

C.. Santamarina ◽

...

Keyword(s):

Gas Hydrate ◽

Gas Production ◽

Well Testing ◽

Testing Methods ◽

Well Design ◽

Geophysical Surveys ◽

The Status ◽

Laboratory Investigations ◽

Gas Hydrate Deposits ◽

Hydrate Bearing Sediments

Summary The current paper complements the Moridis et al. (2009) review of the status of the effort toward commercial gas production from hydrates. We aim to describe the concept of the gas-hydrate (GH) petroleum system; to discuss advances, requirements, and suggested practices in GH prospecting and GH deposit characterization; and to review the associated technical, economic, and environmental challenges and uncertainties, which include the following: accurate assessment of producible fractions of the GH resource; development of methods for identifying suitable production targets; sampling of hydrate-bearing sediments (HBS) and sample analysis; analysis and interpretation of geophysical surveys of GH reservoirs; well-testing methods; interpretation of well-testing results; geomechanical and reservoir/well stability concerns; well design, operation, and installation; field operations and extending production beyond sand-dominated GH reservoirs; monitoring production and geomechanical stability; laboratory investigations; fundamental knowledge of hydrate behavior; the economics of commercial gas production from hydrates; and associated environmental concerns.

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