From Bureau of Economic Geology, The
University of Texas at Austin (www.beg.utexas.edu).
For more information, please contact the author.
Methane hydrates, ice-like compounds that consist of water and methane, abound on continental margins and constitute one of the largest carbon reservoirs on Earth. Interest in methane hydrates is currently surging not only because methane hydrates represent a potentially enormous energy resource but also because hydrates may play a critical role in Earth's climate. At present, both the quantity of methane hydrates and the role hydrates play in climate change remains uncertain and therefore a topic of significant on-going study. After three decades of burgeoning gas hydrates research, several fundamental questions remain unanswered, including: What is the global inventory of methane hydrates? What are the key geologic factors impacting hydrate stability? Is hydrate in-part responsible for slope failure and past/present climate change?
In this presentation I demonstrate how recently acquired high-resolution 3D seismic images combined with 3D heat-flow models of gas hydrate systems are beginning to answer these questions while simultaneously opening the door to exciting new areas of geoscience research. Specifically, I demonstrate using recently collected, processed, and interpreted 3D seismic data how dynamic geomorphology along continental margins drives thermal instability that leads to hydrate instability and slope failure. Additionally, using two overlapping 3D seismic volumes collected at Hydrate Ridge, I show that where the methane hydrate phase boundary appears dynamic (ie. not in steady state) we can use it to (1) detect and quantify methane hydrate in unprecedented detail, (2) constrain the location of fluid advection across the margin, and (3) determine the location and timing of both slope failure and recent tectonic processes on continental margins. The analysis suggests a much richer fluid flow regime exists beneath continental margins then previous studies indicate and implies recent global estimates of methane hydrate are low by an order of magnitude.
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