Application of fiber optic temperature and strain sensing technology to gas hydrates

Authors: S.M. Ulrich, M.E. Elwood Madden, C.J. Rawn, P. Szymcek, and T.J. Phelps

Venue: 6th International Conference on Gas Hydrates, Fairmont Hotel, Vancouver, Canada July 6-10, 2008. http://www.icgh.org/ [external site].

Abstract: Gas hydrates may have a significant influence on global carbon cycles due to their large carbon storage capacity in the form of greenhouse gases and their sensitivity to small perturbations in local conditions. Characterizing existing gas hydrate and the formation of new hydrate within sediment systems and their response to small changes in temperature and pressure is imperative to understanding how this dynamic system functions. Fiber optic sensing technology offers a way to precisely measure temperature and strain in harsh environments such as the seafloor. Recent large-scale experiments using Oak Ridge National Laboratory’s Seafloor Process Simulator were designed to evaluate the potential of fiber optic sensors to study the formation and dissociation of gas hydrates in 4-D within natural sediments. Results indicate that the fiber optic sensors are so sensitive to experimental perturbations (e.g. refrigeration cycles) that small changes due to hydrate formation or dissociation can be overshadowed.

Related NETL Project
This presentation is related to the NETL project FEAB111, “Hydration Formation and Dissociation via Depressurization in Simulated and Field Samples”. The results of physical property measurements will be made available to other researchers for integration with studies related to resource evaluation and mechanical modeling of seafloor sites relative to drilling in the offshore. It is anticipated that natural gas hydrate cores from ODP, and DOE sponsored cruises will provide core samples for analyses to compare with the synthetic samples used to develop the technology and instrumentation to understand the behavior of these unconventional gas reservoirs. The plan was to obtain and analyze samples from the Gulf of Mexico in FY2005.

Project Contacts
NETL – Robert Vagnetti (robert.vagnetti@netl.doe.gov or 304-285-13341)
Oak Ridge National Laboratory – Tommy Joe Phelps (phelpstj@ornl.gov or (865) 574-7290)