Paul Post (MMS) - PETROLEUM SYSTEMS OF THE U.S. CENTRAL ATLANTIC MARGIN
Paul J. Post is a geologist with the Minerals Management Service (MMS) in New Orleans, LA. He has over 30 years of diverse exploration experience with major and independent companies, as a consultant, and with MMS in basins throughout the U.S., Canada, Latin America, the Far East, Australasia, North Africa, the Middle East, and northern Europe. His primary technical expertise is in regional synthesis, new venture/play development, petroleum systems, basin analysis, basin modeling, economic analysis, and risk assessment. Paul has a B.Sc. in geology from Virginia Polytechnic Institute.
ABSTRACT
PETROLEUM SYSTEMS OF THE U.S. CENTRAL ATLANTIC MARGIN
Post, Paul J1; Sassen, Roger2
1MMS 1201 Elmwood Park Blvd., New Orleans, LA, 70123, United States; 2Dept. of Geology & Geophysics - Geochemical & Environmental Research Group - Texas A&M University, College Station, TX, 77845, United States
From 1975–1988, a single stage of expensive, disappointing hydrocarbon exploration took place on the U.S. Atlantic margin (USAM). Fifty-one wells (5 COST – 46 industry) were drilled in the Georges Bank basin, Baltimore Canyon Trough (BCT), and Southeast Georgia Embayment: none were drilled in the Carolina Trough.
Tested play types included drape/compaction structures, amplitude anomalies, listric fault traps, a dyke-swarm cored uplift, various carbonate margin plays, and slope-apron siliciclastics. The only positive results in the USAM were the gas encountered and/or tested in the eight wells drilled in the four-block Hudson Canyon (HC) 598 area, a listric fault trap in the BCT.
Analogs previously applied to USAM basins are inappropriate. While the same geologic age, they differ in regional and local setting. Carbonate and clean/mature siliciclastic reservoir analogs in the Gulf of Mexico Mesozoic basins are located on salt rollers, or related to salt-cored or salt-withdrawal structures. Other than in the Carolina Trough, similar structures are not widely recognized in USAM basins. The productive Sable sub-basin siliciclastic depocenter is located basinward from the carbonate margin and reservoirs are often overpressured, preserving porosity and permeability. In USAM basins, siliciclastic depocenters are generally landward from the margin and reservoirs encountered to date are not overpressured.
Throughout the USAM, issues regarding petroleum system elements include: generally degrading siliciclastic reservoir quality with depth, poorly developed carbonate reservoir facies, identification and areal distribution of source rocks, and timing of seal deposition/lithification in carbonate margin tests drilled to date. Petroleum system processes; i.e., timing of hydrocarbon generation–migration–accumulation are also poorly understood and appreciated.
Assessment of these basins using a forensic petroleum system approach may provide guidance for future exploration strategies.
