Electrical methods offer a potential geophysical approach to determining the sub-bottom distribution of gas hydrate in the deep marine environment. Gas hydrate is essentially nonconductive. Hence, sediments with pore spaces partially filled with hydrate or containing veins filled with hydrate are more resistive than surrounding sediments with pore spaces filled with seawater. To date, attempts ...

6 A two-dimensional model of a passive continental margin was adapted to 7 the simulation of the methane cycle on Siberian continental shelf and 8 slope, attempting to account for the impacts of glacial / interglacial 9 cycles in sea level, alternately exposing the continental shelf to freezing 10 conditions with deep permafrost formation during glacial times, and 11 immersion in the ocean in i...

The kinetics of film growth of hydrates of methane, ethane, and methane-ethane mixtures were studied by exposing a single gas bubble to water. The morphologies, lateral growth rates, and thicknesses of the hydrate films were measured for various gas compositions and degrees of subcooling. A variety of hydrate film textures was revealed. The kinetics of two-dimensional film growth was inferred f...

[1] During sea-level drop, water and gas pressures within oceanic hydrate systems can exceed the total vertical stress and this can drive slope failure and gas venting. We investigate this behavior with a multi-phase fluid and heat flow model. During sea-level drop, fluid pressures drop much less than the total stress due to both the high gas compressibility and hydrate dissociation. In permeab...

In order to investigate the mechanism of gas hydrate deposition and agglomeration in gas dominated flowlines, a high-pressure micromechanical force (MMF) apparatus was applied to directly measure CH4/C2H6 hydrate adhesion/cohesion forces under low temperature and high pressure conditions. A CH4/C2H6 gas mixture was used as the hydrate former. Adhesion forces between hydrate particles and carbon...

Physical property measurements of sediment cores containing natural gas hydrate are typically performed on material exposed at least briefly to non-in situ conditions during recovery. To examine effects of a brief excursion from the gas-hydrate stability field, as can occur when pressure cores are transferred to pressurized storage vessels, we measured physical properties on laboratory-formed s...

As part of an international cooperative research program, the U.S. Geological Survey (USGS) and researchers from the National Gas Hydrate Program (NGHP) of India are studying the physical properties of sediment recovered during the NGHP-01 cruise conducted offshore India during 2006. Here we report on index property, acoustic velocity, and triaxial shear test results for samples recovered from ...

Vast quantities of methane are trapped in oceanic hydrate deposits, and there is concern that a rise in the ocean temperature will induce dissociation of these hydrate accumulations, potentially releasing large amounts of carbon into the atmosphere. Because methane is a powerful greenhouse gas, such a release could have dramatic climatic consequences. The recent discovery of active methane gas ...

Adhesion (cohesion) and agglomeration properties of gas hydrate particles have been a key to hydrate management in flow assurance in natural gas pipelines. Despite its importance, the relevant data in the area, such as the surface energy and the interfacial energy of gas hydrates with gas and/or water, are scarce; presumably due to the experimental difficulties involved in the measurements. Her...

The accumulation of gas hydrates in marine sediments is essentially controlled by the accumulation of particulate organic carbon (POC) which is microbially converted into methane, the thickness of the gas hydrate stability zone (GHSZ) where methane can be trapped, the sedimentation rate (SR) that controls the time that POC and the generated methane stays within the GHSZ, and the delivery of met...