Gas hydrate reservoirs of the deepwater Gulf of Mexico : characterization and consequences
Gas hydrate is found in cold, high-pressure, marine sediments around the world. Hydrate is important as a carbon sink, a natural geohazard, and a valuable economic resource. I use classic sedimentologic analyses, well log analysis, X-ray CT, seismic stratigraphy, pore pressure estimation, and basin...
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ftunivtexas:oai:repositories.lib.utexas.edu:2152/115188 2023-05-15T17:12:11+02:00 Gas hydrate reservoirs of the deepwater Gulf of Mexico : characterization and consequences Meazell, Patrick Kevin, II Flemings, Peter Barry, 1960- Covault, Jacob Mohrig, David Summa, Lori 2021-12 application/pdf https://hdl.handle.net/2152/115188 https://doi.org/10.26153/tsw/42089 en eng https://hdl.handle.net/2152/115188 http://dx.doi.org/10.26153/tsw/42089 Gas hydrate Methane hydrate Geology Deepwater sedimentology Pore pressure Mud volcanoes Thesis text 2021 ftunivtexas https://doi.org/10.26153/tsw/42089 2022-08-18T17:27:16Z Gas hydrate is found in cold, high-pressure, marine sediments around the world. Hydrate is important as a carbon sink, a natural geohazard, and a valuable economic resource. I use classic sedimentologic analyses, well log analysis, X-ray CT, seismic stratigraphy, pore pressure estimation, and basin modeling to elucidate the geologic conditions within highly-saturated, natural gas hydrate reservoirs in the deepwater northern Gulf of Mexico. I begin with the characterization of the channel-levee hydrate reservoir in GC-955 with grain size experiments, lithofacies mapping. Hydrate is found in thin-bedded layers of sandy silt that increase in net-to-gross and mean grainsize downhole. I use these results to interpret deposition of overbank sediment gravity flows from a deepwater bypass channel as it becomes increasingly confined by the levees it builds. Next, I use 3D seismic data to identify the relationship between similar channel-levee systems and venting seafloor gas mounds in the Terrebonne Basin of the Walker Ridge protraction area. I estimate the pore pressures, and show that below the hydrate phase boundary, free gas in the levees builds to a critical pressure and creates hydraulic fractures to the seafloor. I describe a conceptual model by which the venting process perturbs the hydrate stability zone, leading to further venting from shallower positions and the formation of distinct rows of gas mounds on the seafloor. Finally, I combine geomechanical properties of the GC-955 reservoir with the structure of the Terrebonne Basin system to show that the pressure estimates are well within reason. Together, these studies provide new insights into where hydrate is found, and how hydrate systems can both control and in turn be controlled by fluid flow, pressure, and stress in the deepwater environment Geological Sciences Thesis Methane hydrate The University of Texas at Austin: Texas ScholarWorks Walker Ridge ENVELOPE(168.367,168.367,-72.567,-72.567) |
institution |
Open Polar |
collection |
The University of Texas at Austin: Texas ScholarWorks |
op_collection_id |
ftunivtexas |
language |
English |
topic |
Gas hydrate Methane hydrate Geology Deepwater sedimentology Pore pressure Mud volcanoes |
spellingShingle |
Gas hydrate Methane hydrate Geology Deepwater sedimentology Pore pressure Mud volcanoes Meazell, Patrick Kevin, II Gas hydrate reservoirs of the deepwater Gulf of Mexico : characterization and consequences |
topic_facet |
Gas hydrate Methane hydrate Geology Deepwater sedimentology Pore pressure Mud volcanoes |
description |
Gas hydrate is found in cold, high-pressure, marine sediments around the world. Hydrate is important as a carbon sink, a natural geohazard, and a valuable economic resource. I use classic sedimentologic analyses, well log analysis, X-ray CT, seismic stratigraphy, pore pressure estimation, and basin modeling to elucidate the geologic conditions within highly-saturated, natural gas hydrate reservoirs in the deepwater northern Gulf of Mexico. I begin with the characterization of the channel-levee hydrate reservoir in GC-955 with grain size experiments, lithofacies mapping. Hydrate is found in thin-bedded layers of sandy silt that increase in net-to-gross and mean grainsize downhole. I use these results to interpret deposition of overbank sediment gravity flows from a deepwater bypass channel as it becomes increasingly confined by the levees it builds. Next, I use 3D seismic data to identify the relationship between similar channel-levee systems and venting seafloor gas mounds in the Terrebonne Basin of the Walker Ridge protraction area. I estimate the pore pressures, and show that below the hydrate phase boundary, free gas in the levees builds to a critical pressure and creates hydraulic fractures to the seafloor. I describe a conceptual model by which the venting process perturbs the hydrate stability zone, leading to further venting from shallower positions and the formation of distinct rows of gas mounds on the seafloor. Finally, I combine geomechanical properties of the GC-955 reservoir with the structure of the Terrebonne Basin system to show that the pressure estimates are well within reason. Together, these studies provide new insights into where hydrate is found, and how hydrate systems can both control and in turn be controlled by fluid flow, pressure, and stress in the deepwater environment Geological Sciences |
author2 |
Flemings, Peter Barry, 1960- Covault, Jacob Mohrig, David Summa, Lori |
format |
Thesis |
author |
Meazell, Patrick Kevin, II |
author_facet |
Meazell, Patrick Kevin, II |
author_sort |
Meazell, Patrick Kevin, II |
title |
Gas hydrate reservoirs of the deepwater Gulf of Mexico : characterization and consequences |
title_short |
Gas hydrate reservoirs of the deepwater Gulf of Mexico : characterization and consequences |
title_full |
Gas hydrate reservoirs of the deepwater Gulf of Mexico : characterization and consequences |
title_fullStr |
Gas hydrate reservoirs of the deepwater Gulf of Mexico : characterization and consequences |
title_full_unstemmed |
Gas hydrate reservoirs of the deepwater Gulf of Mexico : characterization and consequences |
title_sort |
gas hydrate reservoirs of the deepwater gulf of mexico : characterization and consequences |
publishDate |
2021 |
url |
https://hdl.handle.net/2152/115188 https://doi.org/10.26153/tsw/42089 |
long_lat |
ENVELOPE(168.367,168.367,-72.567,-72.567) |
geographic |
Walker Ridge |
geographic_facet |
Walker Ridge |
genre |
Methane hydrate |
genre_facet |
Methane hydrate |
op_relation |
https://hdl.handle.net/2152/115188 http://dx.doi.org/10.26153/tsw/42089 |
op_doi |
https://doi.org/10.26153/tsw/42089 |
_version_ |
1766068972922339328 |