Gas hydrate blockage in pipelines during offshore production becomes a major problem with increasing water depth. In this work, a series of experiments on gas hydrate formation in a flow loop was performed with low flow rates of 0.33, 0.66, and 0.88 m/s; the effects of the initial subcooling, flow rate, pressure, and morphology were investigated for methane hydrate formation in the flow loop. T...

Clathrate hydrates are crystalline compounds composed of hydrogen-bonded water molecules that form polyhedral cavities and trap small guest molecules such as methane, carbon dioxide, cyclopentane (CP), and tetrahydrofuran (THF). Understanding the formation and dissociation of clathrate hydrates is of significant importance to addressing some global challenges such as greenhouse gas mitigation a...

Seismic analyses of methane hydrate data from the Blake Outer Ridge indicate high Pwave velocity and anomalously low S-wave velocity in sediments containing methane hydrates. In an attempt to explain this observed P-wave and S-wave velocity structure at the transition from gas to hydrates, the effect of different hydrate models on elastic moduli and velocities are explored. After construction o...

Prospective industrial applications of clathrate hydrates as materials for gas separation require further knowledge of cavity distortion, cavity selectivity, and defects induction by guest-host interactions. The results presented in this contribution show that under certain temperature conditions the guest combination of CH3F and a large polar molecule induces defects on the clathrate hydrate f...

An isobaric flow loop added to the Gas Hydrate And Sediment Test Laboratory Instrument (GHASTLI) is being investigated as a means of rapidly forming methane hydrate in watersaturated sand from methane dissolved in water. Water circulates through a relatively warm source chamber, dissolving granular methane hydrate that was pre-made from seed ice, then enters a colder hydrate growth chamber wher...

Clathrate hydrates are of great importance in many aspects. However, hydrate formation and dissociation mechanisms, essential to all hydrate applications, are still not well understood due to the limitations of experimental techniques capable of providing dynamic and structural information on a molecular level. NMR has been shown to be a powerful tool to noninvasively measure molecular level dy...

Airaksinen, S.T.T., 2005. Role of excipients in moisture sorption and physical stability of solid pharmaceutical formulations. Dissertationes bioscientiarum molecularium Universitatis Helsingiensis in Viikki, 20/2005, pp. 57, ISBN 952-10-2733-9 (print) ISBN 952-10-2734-7 (pdf) ISSN 1795-7079 The interaction of moisture with pharmaceutical solids is crucial to an understanding of water-based pro...

This proposal is for an IODP program to constrain models for the formation of deep sea gas hydrate in subduction zone accretionary prisms. The objectives include the deep origin of the methane, its upward transport, its incorporation in gas hydrate, and its subsequent loss to the seafloor. The main attention is on the widespread seafloor-parallel layer of dispersed hydrate located just above th...

In this work we investigated the behavior of methane hydrates dispersed in crude oils from different fields at temperatures below 0°C. In case of crude oil emulsion the size of water droplets is in the range of 50÷100μm. The size of hydrate particles formed from droplets is the same. The self-preservation is not expected in this field. However, the self-preservation of hydrates with the size of...

This paper describes a one-dimensional numerical model for natural gas production from the dissociation of methane hydrate in hydrate-capped gas reservoir under depressurization and thermal stimulation. Some of the hydrate reservoirs discovered are overlying a free-gas layer, known as hydrate-capped gas reservoirs. These reservoirs are thought to be easiest and probably the first type of hydrat...