Testing of pressurised cores containing gas hydrate from deep ocean sediments.

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Description/Abstract

The recent development and deployment of HYACINTH and IODP PCS pressure cores on the JOIDES Resolution during Expedition 1 of the Indian National Gas Hydrate Program (NGHP-1) has provided some of the first “undisturbed” samples of gas hydrate in fine grained marine sediments. Some samples, once recovered from the seafloor, were subject to rapid depressurization and subsequent immersion in liquid nitrogen, at approximately -196oC, for use in subsequent laboratory test programs. This paper describes the techniques used at Southampton University, the difficulties encountered, and the results obtained from geotechnical testing of these samples. The original intention had been to pressurize and unfreeze the material before testing it in the Gas Hydrate Resonant Column (GHRC) Apparatus. Initial CT scanning of the samples showed that the sample quality might be too poor for such testing, and this proved to be the case. Instead a suite of geotechnical testing was carried out, the results of which are reported and interpreted in this paper.