The LArge Reservoir Simulator (LARS) was developed to investigate various processes during gas hydrate formation and dissociation under simulated in situ conditions of relatively high pressure and low temperature (close to natural conditions). To monitor the spatial hydrate distribution during hydrate formation and the mobility of the free gas phase generated during hydrate dissociation, a cyli...

[1] Log and core data document gas saturations as high as 90% in a coarse-grained turbidite sequence beneath the gas hydrate stability zone (GHSZ) at south Hydrate Ridge, in the Cascadia accretionary complex. The geometry of this gassaturated bed is defined by a strong, negative-polarity reflection in 3D seismic data. Because of the gas buoyancy, gas pressure equals or exceeds the overburden st...

Long offsets and subsea tie-backs are becoming attractive scenarios for exploration and production of offshore hydrocarbon resources. Flow assurance associated with these field development scenarios is critical. As offshore oil and gas production pushes into deeper water, the risk of hydrate plugging of pipelines and flowlines continues to grow, as does the cost of remediating any such plugs. C...

Concerns about the potential effects of rising carbon dioxide levels in the atmosphere have stimulated interest in a number of carbon dioxide sequestration studies. One suggestion is the sequestration of carbon dioxide as clathrate hydrates by injection of carbon dioxide into methane hydrate. Energy-supply research estimates indicate that natural gas hydrates in arctic and sub-seafloor formatio...

During Ocean Drilling Program (ODP) Leg 204, we will drill a transect of sites through the gas hydrate stability zone on the southern part of Hydrate Ridge on the Cascadia accretionary margin offshore Oregon. Massive hydrates are present at the seafloor there, and high-resolution threedimensional seismic data indicate a complicated subsurface plumbing system. The transect will cover two distinc...

The small hydrate concept (SHC) was proposed to predict the generated excess pore water pressure due to dissociation of gas hydrate within sandy soils. This concept was then used to calculate excess pore water pressure in the Storegga slide of which gas hydrate dissociation may have contributed. Since the excess pore water pressure calculated by the SHC resulted in the considerable loss of stif...

Gas hydrate can precipitate in pore space of marine sediment when gas concentrations exceed solubility conditions within a gas hydrate stability zone (GHSZ). Here we present analytical expressions that relate the top of the GHSZ and the amount of gas hydrate within the GHSZ to the depth of the sulfate-methane transition (SMT). The expressions are strictly valid for steady-state systems in which...