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Title: Support of Gulf of Mexico Hydrate Research Consortium: Activities of Support Establishment of a Sea Floor Monitoring Station Project

Technical Report ·
DOI:https://doi.org/10.2172/966438· OSTI ID:966438

The Gulf of Mexico Hydrates Research Consortium (GOM-HRC) was established in 1999 to assemble leaders in gas hydrates research that shared the need for a way to conduct investigations of gas hydrates and their stability zone in the Gulf of Mexico in situ on a more-or-less continuous basis. The primary objective of the group is to design and emplace a remote monitoring station or sea floor observatory (SFO) on the sea floor in the northern Gulf of Mexico, in an area where gas hydrates are known to be present at, or just below, the sea floor and to discover the configuration and composition of the subsurface pathways or 'plumbing' through which fluids migrate into and out of the hydrate stability zone (HSZ) to the sediment-water interface. Monitoring changes in this zone and linking them to coincident and perhaps consequent events at the seafloor and within the water column is the eventual goal of the Consortium. This mission includes investigations of the physical, chemical and biological components of the gas hydrate stability zone - the sea-floor/sediment-water interface, the near-sea-floor water column, and the shallow subsurface sediments. The eventual goal is to monitor changes in the hydrate stability zone over time. Establishment of the Consortium succeeded in fulfilling the critical need to coordinate activities, avoid redundancies and communicate effectively among those involved in gas hydrates research. Complementary expertise, both scientific and technical, has been assembled to promote innovative methods and construct necessary instrumentation. Following extensive investigation into candidate sites, Mississippi Canyon 118 (MC118) was chosen by consensus of the Consortium at their fall, 2004, meeting as the site most likely to satisfy all criteria established by the group. Much of the preliminary work preceding the establishment of the site - sensor development and testing, geophysical surveys, and laboratory studies - has been reported in agency documents including the Final Technical Report to DOE covering Cooperative Agreement DEFC26-00NT40920 and Semiannual Progress Reports for this award, DE-FC26-02NT41628. Initial components of the observatory, a probe that collects pore-fluid samples and another that records sea floor temperatures, were deployed in MC118 in May of 2005. Follow-up deployments, planned for fall 2005, had to be postponed due to the catastrophic effects of Hurricane Katrina (and later, Rita) on the Gulf Coast. SFO completion, now anticipated for 2009-10, has, therefore, been delayed. Although delays caused scheduling and deployment difficulties, many sensors and instruments were completed during this period. Software has been written that will accommodate the data that the station retrieves, when it begins to be delivered. In addition, new seismic data processing software has been written to treat the peculiar data to be received by the vertical line array (VLA) and additional software has been developed that will address the horizontal line array (HLA) data. These packages have been tested on data from the test deployments of the VLA and on data from other, similar, areas of the Gulf (in the case of the HLA software). During the life of this Cooperative Agreement (CA), the CMRET conducted many cruises. Early in the program these were executed primarily to survey potential sites and test sensors and equipment being developed for the SFO. When MC118 was established as the observatory site, subsequent cruises focused on this location. Beginning in 2005 and continuing to the present, 13 research cruises to MC118 have been conducted by the Consortium. During September, 2006, the Consortium was able to secure 8 days aboard the R/V Seward Johnson with submersible Johnson SeaLink, a critical chapter in the life of the Observatory project as important documentation, tests, recoveries and deployments were accomplished during this trip (log appended). Consortium members have participated materially in a number of additional cruises including several of the NIUST autonomous underwater vehicle (AUV), Eagle Ray. Activities reports summarize cruise activities, including objectives, how they were met or not met, and challenges. Deployment cruises are scheduled for 2009 that are designed to complete installation of the major observatory components.

Research Organization:
Univ. of Mississippi, Oxford, MS (United States)
Sponsoring Organization:
USDOE
DOE Contract Number:
FC26-02NT41628
OSTI ID:
966438
Country of Publication:
United States
Language:
English