Assessment of the Miocene Petroleum System of the Northern Gulf of Mexico Basin: Implications for CO2 Sequestration in Offshore Texas State Waters
Jordan-Leigh Taylor, David L. Carr, Timothy A. Meckel, and Ramon H. Trevino
Bureau of Economic Geology, The University of Texas at Austin
The northern Gulf of Mexico Basin coastal Miocene petroleum system from Texas to Alabama was evaluated using integrated published data and digital databases of major Miocene oil and gas fields. Regional knowledge of trapping mechanisms and fluid migration in this province provided insights for CO2 storage potential of the sand-bearing Miocene section. Use of GIS data allowed evaluation of relationships between specific field parameters and multiple geologic features. Regional structural features exert primary control on trapping and distribution of Miocene hydrocarbons. In salt basins, traps frequently occur as part of vertically stacked complexes; where salt is negligible, traps are typically associated with listric-normal growth faulting. Approximately shore-parallel, early Miocene fault zones typically mark the landward extent of the voluminous Miocene gas play and likely prevented large updip, onshore accumulations. These Miocene fault zones partially reside in the offshore Texas State Waters, suggesting high potential for regional entrapment of injected CO2.
Occurrence of favorable sandstone reservoirs is a secondary control on Miocene petroleum accumulation trap types and geographic distribution. Major Miocene fields occur primarily in more homogenous deltaic and shore-zone depositional systems. Northeastward migration of sand-rich depocenters during the Miocene is evident in age-specific reservoir maps.
Miocene fields are the volumetrically minor apexes of their respective, and typically much larger structural fetch areas; therefore, existing Miocene fields represent injected CO2 capacity minima. Known reservoir volumes alone lack adequate capacity for commercial CO2 sequestration, requiring investigation of quantitative CO2 capacity relationships between Miocene fields and their respective fetch areas.
AAPG Search and Discovery Article #90182©2013 AAPG/SEG Student Expo, Houston, Texas, September 16-17, 2013