IN SITU SAMPLING, MONITORING AND SUB SAMPLING OF MARINE GAS HYDRATES AND DEEP SEA FLOOR LIFE PROCESSES

Hans Amann, Eric Anders, Hans-Jürgen Hohnberg, Holger Hüning, Michael Maggiulli, Thjunjoto
FG Maritime Technik, Technische Universitat, Berlin, Germany

Phenomena in extreme environments must be accessed and studied in extreme environments, in-situ, e.g. in the deep sea, under ground, in polar areas and even more so in extraterrestrial situations. The new engineering topic of in-situ technology is creating methods and tools to comply with this requirement. Recent examples are successfully tested high pressure coring equipment for gas hydrates and the benthic ecology and ongoing development on pressurised sub sampling methods.

HYACE and HYACINTH are consecutive research and development projects of European research partnerships launched by MAT in 1997 and sponsored by the European Commission since 1998. Pressurised coring methods for deep ocean drilling were developed and successfully pilot used on ODP Leg 204, offshore Oregon in July and August 2002. They are being further amended in the US JIP Project, Gas Hydrates in the Gulf of Mexico, in 2004 and 2005. Autoclave coring tools are the HRC, HYACE Rotary Corer, and the FPC, Fugro Percussion Corer. Downstream sub sampling methods and tools are being added. Methods, tools and products of cutting or probing core sections, in a contamination controlled way, core plugs, pore water, and gas are being presented. Those tools operate under in-situ pressure, 25 MPa, to be eventually increased to 40 and even 60 MPa. Temperature control by deep sea water insulation is an integral feature.

Pressurised systems are being developed concomitantly to take pressurised samples and sub samples from the seafloor surface as well. Process conditions of gas hydrates at the sea floor are different from deeply buried gas hydrates. Differences need to be assessed by in-situ sampling, pressurized sub sampling and analysis. MAC, the Multi Autoclave Corer and DAPC, the Dynamic Autoclave Piston Corer were developed in the German project OMEGA and successfully pilot used offshore Oregon in August 2002 and, again, in the Gulf of Mexico in October/November 2003. Water depth was 1000 to 1500 m, RV Sonne was the research platform. Those novel system concepts are being adapted and upgraded in the EC project ANAXIMANDER to research gas hydrates on the ANAXIMANDER Sea Mount in the Eastern Mediterranean, in greater water depth of 2000 to 2500 m. Sub sampling by pressurised rod gauging is being added. Further applications are planned for gas hydrate research in the South China Sea and in the Gulf of Mexico in 2004/2005.