Mapping Key Subsurface Boundaries to Determine Maximum Thickness of Methane Hydrate within the Blake Ridge Region of Offshore North Carolina, USA, Constrained with Three-Dimensional Seismic Data and Well Logs
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My undergraduate thesis was mapping key subsurface boundaries to determine the maximum possible thickness of methane hydrate within the hydrate stability zone contained in marine sediment within the Blake Ridge region of offshore North Carolina, USA. Blake Ridge is approximately 385 miles ESE of Savannah, Georgia in water depths ranging from 1935 meters to 2513 meters. Methane hydrates are an ice with a crystalline structure consisting of interlocking water molecules surrounding a methane molecule forming in a delicate zone of low temperatures and high pressures within the Arctic permafrost or ocean sediments. Using the software packages IHS Kingdom Suite, ArcGIS, and Adobe Illustrator I analyzed three-dimensional seismic data in order to map the two key subsurface boundaries for this study: the sea floor and the bottom simulating reflector (BSR). I produced contoured structural maps and amplitude maps of each surface to correlate how to identify the BSR and at what depth it should be appearing. Comparing my results to a past study in this area, my seafloor bathymetry was similar and my BSR was also subparallel to the seafloor, however the depth of my BSR was shallower by 500 meters to 600 meters. The reason for this difference is not yet established. This general procedure has been applied in other hydrate provinces and is also applied in current mainstream oil and gas industry. Given that methane hydrates are potentially a global significant reservoir of natural gas, mapping is vital for quantifying the potential energy resource that may be extractable in the future.