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Illustrated Summary of Compartments / Pressure Regimes in Selected North American Basins: Part 2—Western Gulf Coast

By

David E. Powley¹

Search and Discovery Article #60010 (2007)

Posted January 27, 2007

*Compiled from slides prepared by the author for his numerous presentations about the subject of compartments and pressure regimes, for which he was pioneer, advocate, and mentor.  

¹Deceased October 29, 2006. Consultant after retirement from Amoco Production Company.

uJurassic uLouisiana uTexas uReferences                                                         uJurassic uLouisiana uTexas uReferences                                                       uJurassic uLouisiana uTexas uReferences                                                         uJurassic uLouisiana uTexas uReferences

Jurassic in Mississippi Salt Basin Figure 1. Distribution of overpressures in the Smackover and Norphlet formations, Mississippi salt basin.   Tertiary in Louisiana Gulf coast Figure 2. Tectonic map of western Gulf Coast, as index for local maps and cross-sections (after Watkins, 1996). Number on map corresponds to figure number. Figure 3. Cross-section, Bastian Bay Field, Plaquemines Parish, Louisiana, with accumulations in relation to shallowest point of overpressures (arrow). Figure 4. Structure map and schematic cross-section of pressure-enhanced trap, Gibson Field and Humphreys fields, Terrebonne Parish, Louisiana. Pressure parallels stratigraphy. Downthrown-block trap, with production from Sub-Hollywood sands. At Gibson, seal is overpressured shale mass in upthrown block; at Humphreys, seal is shale mass in upthrown block to Lake Hatch fault. Figure 5. Structure map and schematic cross-section of pressure-enhanced trap, Wyandotte Field, St. Mary Parish, Louisiana. Pressure climbs stratigraphy. Upthrown block with production in fault-closure trap above overpressures, which are lower than they are in expanded downthrown block. Figure 6. Cross-section and pressure/depth profile, Ship Shoal Block 28 Field, offshore Louisiana, showing intervals of seal in upthrown and downthrown blocks, along with productive units in relation to shallowest point of overpressures (in the upthrown block at the fault). Figure 7. Structure map and schematic cross-section of pressure-enhanced trap, Bayou Carlin Field, St. Mary Parish, Louisiana. Pressure climbs stratigraphy, Pressure “halo” around shale mass provides western seal for trap. Figure 8. Cross-section, West Bayou Carlin shale mass, St. Mary Parish, Louisiana, showing distribution of low-resistivity shale (overpressure) and of gas reservoirs. Figure 9. Shale resistivities highlighted on log of Amoco No. 1 S.L. 4427, West Bayou Carlin shale mass, St. Mary Parish, Louisiana, with calculation of pressure at base of seal. See Figure 8 for location of well. Figure 10. Pressure/depth profile of the seal calculated from shale resistivities on log of Amoco No. 1 S.L. 4427, West Bayou Carlin shale mass, St. Mary Parish, Louisiana. Figure 11. Structure map and schematic cross-section of pressure-enhanced trap, Jeanerette Field, St. Mary Parish, Louisiana. Pressure climbs stratigraphy. Upthrown block with Panulina production in lower pressured system; downthrown block of expansion fault with overpressure at higher position and non-productive expanded Planulina section. Figure 12. Structure map and schematic cross-section of pressure-enhanced trap, Bayou Pigeon and Bayou Postillion fields, Iberia Parish, Louisiana. Pressure climbs stratigraphy. Updip high-pressured, non-productive sands were encountered in same fault block as productive sands. Pressure is updip seal. Figure 13. Structure map and schematic cross-section of pressure-enhanced trap, Duck Lake Field, St. Martin Parish, Louisiana. Pressure parallels stratigraphy. Overpressure and closure but no production in upthrown block; closure and Discorbis B sand production in expanded downthrown block above overpressures. Figure 14. Structure map and schematic cross-section of pressure-enhanced trap, Pecan Island Field, Vermilion Parish, Louisiana. Pressure climbs stratigraphy. Pressure “halo” forms updip seal for Discorbis B sand accumulation on west flank. Figure 15. Cross-section, Midland Field, Acadia Parish, Louisiana, with normal pressures above overpressures and between normal pressures in the easternmost part of the section (after Fowler et al., 1971).  Figure 16. Structure map and schematic cross-section of pressure-enhanced trap, South Pecan Lake, Cameron Parish, Louisiana. Pressure parallels stratigraphy, following units across faults, with accumulations in lower pressure systems. Figure 17. Cross-section, South Thornwell salt dome, Jefferson Davis and Cameron parishes, Louisiana, showing seal “halo” peripheral to the salt and associated gas accumulation downdip from gas and water (after Roach, 1962). Tertiary in Texas Gulf Coast Figure 18. Cross-section and pressure/depth profile, Alta Loma Field, Galveston County, Texas, showing intervals of seal in upthrown and dowthrown blocks, along with productive units in relation to shallowest point of overpressures (in the upthrown block at the fault). Figure 19. Seismic interval velocity cross-section, Southern Mustang Island, offshore Texas, with seal, determined from well control, approximately paralleling interval velocities over much of the section but highly discordant in the southeasternmost part.   References Roach, C.B., 1962, Intrusive shale dome in South Thornwell Field, Jefferson Davis and Cameron parishes, Louisiana: AAPG Bulletin, v. 46, p. 2121-2132. Fowler, W. A., Boyd, W. A.; Marshall, S. W. and Myers, R. L., 1971, Abnormal Pressures in Midland Field, Louisiana, in Houston Geological Society Abnormal Subsurface Pressure - A Study Group Report.     Return to top.