45015-AC8
Multi-Channel Seismic Analysis of Gas Hydrate and Related Geological Structure in Northwestern Gulf of Mexico
During FY2008, two students worked on the project and both made substantial progress in the interpretation of seismic data. Idris Murad, a graduate student in the Department of Geology and Geophysics, studied seismic data in the Garden Banks and Keathley Canyon leaseblock areas (south of Louisiana). Leslie Nemazi, a graduate student in the Department of Oceanography, examined data in the Alaminos Canyon and Port Isabel leaseblock areas (offshore of south Texas). Both students have followed a similar interpretation path, mapping the depth to the top of the salt layer that is ubiquitous in the region. Both have also mapped faults; although, unambiguous correlation of faults across multiple seismic lines has been hampered by significant changes in the faults over short length scales relative to the spacing of the lines (~ 3 km). In addition, both have charted the locations of apparent fluid escape features, whose complete mapping is hampered by the fact that they are typically smaller than the track line spacing. Despite these difficulties, it is possible to look at regional differences in both faulting and fluid escape features.
Murad has been working on an improved model of the gas hydrate zone thickness in his study area, incorporating the effect of salt on heat flux and gas hydrate stability. His model is currently being evaluated by his committee. As expected, this model suggests that the zone within the sediments that could harbor gas hydrate is smaller than predicted by simpler models. Furthermore, Murad will defend his M.S. thesis in October 2008 and will try to wrap up his studies soon thereafter.
Nemazi has been mapping chaotic layers in the upper part of her seismic sections as indicators of mass wasting of sediments. So far, it appears that many of the slumps and mass wasting events are local (i.e., within certain mini-basins), but she has also found evidence of some larger slumps. Currently we are attempting to acquire biostratigraphic data from industry to constrain the ages of those (and other) layers. If appropriate, we may work with a colleague in Engineering to estimate the size of tsunamis that could have resulted from the larger slumps.
In the future, our goal is to publish both studies in reputable journals. It is still too early to know how this will turn out because both students are focused on finishing their theses and degree requirements.
