scholarly journals Experimental Investigation of Gas Flow and Hydrate Formation Within the Hydrate Stability Zone

2018 ◽  
Vol 123 (7) ◽  
pp. 5350-5371 ◽  
Author(s):  
Dylan W. Meyer ◽  
Peter B. Flemings ◽  
David DiCarlo ◽  
Kehua You ◽  
Stephen C. Phillips ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Gas Flow ◽  
Hydrate Formation ◽  
Stability Zone ◽  
Hydrate Stability

scholarly journals Effect of Gas Flow Rate on Hydrate Formation Within the Hydrate Stability Zone

2018 ◽  
Vol 123 (8) ◽  
pp. 6263-6276 ◽  
Author(s):  
Dylan W. Meyer ◽  
Peter B. Flemings ◽  
David DiCarlo
Keyword(s):  
Flow Rate ◽  
Gas Flow ◽  
Hydrate Formation ◽  
Stability Zone ◽  
Gas Flow Rate ◽  
Hydrate Stability

scholarly journals Numerical Modeling of Gas Migration and Hydrate Formation in Heterogeneous Marine Sediments

2019 ◽  
Vol 7 (10) ◽  
pp. 348 ◽  
Author(s):  
Keqi Bei ◽  
Tianfu Xu ◽  
Songhua Shang ◽  
Zilin Wei ◽  
Yilong Yuan ◽  
...  
Keyword(s):  
South China Sea ◽  
South China ◽  
Hydrate Formation ◽  
Stable Region ◽  
Gas Migration ◽  
Stability Zone ◽  
Shenhu Area ◽  
China Sea ◽  
Porosity And Permeability ◽  
Hydrate Stability

The formation of marine gas hydrates is controlled by gas migration and accumulation from lower sediments and by the conditions of the hydrate stability zone. Permeability and porosity are important factors to evaluate the gas migration capacity and reservoir sealing capacity, and to determine the distribution of hydrates in the stable region. Based on currently available geological data from field measurements in the Shenhu area of Baiyun Sag in the northern South China Sea, numerical simulations were conducted to estimate the influence of heterogeneities in porosity and permeability on the processes of hydrate formation and accumulation. The simulation results show that: (1) The heterogeneity of the hydrate stability zone will affect the methane migration within it and influence the formation and accumulation of hydrates. This is one of the reasons for the formation of heterogeneous hydrates. (2) When the reservoir is layered heterogeneously, stratified differences in gas lateral migration and hydrate formation will occur in the sediment, and the horizontal distribution range of the hydrate in a high porosity and permeability reservoir is wider. (3) To determine the dominant enrichment area of hydrate in a reservoir, we should consider both vertical and lateral conditions of the sedimentary layer, and the spatial coupling configuration relationships among the hydrate stability region, reservoir space and gas migration and drainage conditions should be considered comprehensively. The results are helpful to further understand the rules of hydrate accumulation in the Shenhu area on the northern slope of the South China Sea, and provide some references for future hydrate exploration and the estimation of reserves.

scholarly journals Probable patterns of gas flow and hydrate accretion at the base of the hydrate stability zone

Geology ◽  
2014 ◽  
Vol 42 (12) ◽  
pp. 1055-1058 ◽  
Author(s):  
Richard J. Davies ◽  
Jinxiu Yang ◽  
Richard Hobbs ◽  
Ang Li
Keyword(s):  
Gas Flow ◽  
Stability Zone ◽  
Hydrate Stability

scholarly journals Gas Flow by Invasion Percolation Through the Hydrate Stability Zone

2020 ◽  
Vol 47 (3) ◽  
Author(s):  
Dylan W. Meyer ◽  
Peter B. Flemings ◽  
Kehua You ◽  
David A. DiCarlo
Keyword(s):  
Gas Flow ◽  
Invasion Percolation ◽  
Stability Zone ◽  
Hydrate Stability

Methane hydrate saturations at the Southern Hikurangi margin (New Zealand) estimated from seismic and rock physics inversion

2020 ◽  
Author(s):  
Francesco Turco ◽  
Andrew Gorman ◽  
Gareth Crutchley ◽  
Leonardo Azevedo ◽  
Dario Grana ◽  
...  
Keyword(s):  
New Zealand ◽  
Gas Hydrate ◽  
Methane Hydrate ◽  
Waveform Inversion ◽  
Hydrate Formation ◽  
Rock Physics ◽  
Stability Zone ◽  
Hydrate Saturation ◽  
Physics Model ◽  
Hydrate Stability

<p>Geophysical data indicate that the Hikurangi subduction margin on New Zealand’s East Coast contains a large gas hydrate province. Gas hydrates are widespread in shallow sediments across the margin, and locally intense fluid seepage associated with methane hydrate is observed in several areas. Glendhu and Honeycomb ridges lie at the toe of the Hikurangi deformation wedge at depths ranging from 2100 to 2800 m. These two parallel four-way closure systems host concentrated methane hydrate deposits. The control on hydrate formation at these ridges is governed by steeply dipping permeable strata and fractures, which allow methane to flow upwards into the gas hydrate stability zone. Hydrate recycling at the base of the hydrate stability zone may contribute to the accumulation of highly concentrated hydrate in porous layers.<br>To improve the characterisation of the hydrate systems at Glendhu and Honeycomb ridges, we estimate hydrate saturation and porosity of the concentrated hydrate deposits. We first estimate elastic properties (density, compressional and shear-wave velocities) of the gas hydrate stability zone through full-waveform inversion and <span>iterative geostatistical seismic amplitude versus angle (AVA) inversion</span>. We then perform a petrophysical inversion based on a rock physics model to predict gas hydrate saturation and porosity of the hydrate bearing sediments along the two ridges.<br>Our results indicate that the high seismic amplitudes correspond to the top interface of highly concentrated hydrate deposit, with peak saturations around 35%. Because of the resolution of the seismic data we assume that the estimated properties are averaged over layers of 10 to 20 meters thickness. These saturation values are in agreement with studies conducted in other areas of concentrated hydrate accumulations in similar geologic settings.</p>

scholarly journals Crustal fingering facilitates free-gas methane migration through the hydrate stability zone

2020 ◽  
Vol 117 (50) ◽  
pp. 31660-31664
Author(s):  
Xiaojing Fu ◽  
Joaquin Jimenez-Martinez ◽  
Thanh Phong Nguyen ◽  
J. William Carey ◽  
Hari Viswanathan ◽  
...  
Keyword(s):  
Hydrate Formation ◽  
Elevated Pressure ◽  
Water Mixture ◽  
Gas Migration ◽  
Stability Zone ◽  
Critical Gap ◽  
Methane Seepage ◽  
Field Evidence ◽  
Hydrate Bearing Sediments ◽  
Hydrate Stability

Widespread seafloor methane venting has been reported in many regions of the world oceans in the past decade. Identifying and quantifying where and how much methane is being released into the ocean remains a major challenge and a critical gap in assessing the global carbon budget and predicting future climate [C. Ruppel, J. D. Kessler. Rev. Geophys. 55, 126–168 (2017)]. Methane hydrate (CH4⋅5.75H2O) is an ice-like solid that forms from methane–water mixture under elevated-pressure and low-temperature conditions typical of the deep marine settings (>600-m depth), often referred to as the hydrate stability zone (HSZ). Wide-ranging field evidence indicates that methane seepage often coexists with hydrate-bearing sediments within the HSZ, suggesting that hydrate formation may play an important role during the gas-migration process. At a depth that is too shallow for hydrate formation, existing theories suggest that gas migration occurs via capillary invasion and/or initiation and propagation of fractures (Fig. 1). Within the HSZ, however, a theoretical mechanism that addresses the way in which hydrate formation participates in the gas-percolation process is missing. Here, we study, experimentally and computationally, the mechanics of gas percolation under hydrate-forming conditions. We uncover a phenomenon—crustal fingering—and demonstrate how it may control methane-gas migration in ocean sediments within the HSZ.

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