Diffusion of methane and ethane through the reservoir cap rock: Implications for the timing and duration of categenesis: Discussion
Nelson and Simmons (1995) concluded that entrapped gas accumulations are continuously reduced by diffusion leakage through cap rocks, and that to maintain the reserve the rocks must constantly be replenished by infusion of catagenically generated gas. To satisfy this conclusion one must accept long-duration catagenic generation of gas and long-distance gas migration over an extended time span. These sweeping conclusions on fundamental petroleum geological processes demand more comprehensive support than that provided by the analysis of the McClave field. The McClave field is a small (57 Gcf*), stratigraphically trapped gas accumulation in the Morrowan (Pennsylvanian) at 4860 ft (1480 m) on the Las Animas arch in southeastern Colorado. If cap rocks are ineffective seals in a stratigraphic trap of this type, we must presume that loss will occur by diffusion through both lateral and vertical seals and, lacking overlying or lateral traps, would presumably become dispersed in the overlying rocks before reaching the surface. A logical first step to test such conclusions would be to apply them to other stratigraphically trapped gas accumulations that have been thoroughly described in published papers.
- OSTI ID:
- 411874
- Report Number(s):
- CONF-9610180-; ISSN 0149-1423; TRN: 96:005901-0006
- Journal Information:
- AAPG Bulletin, Vol. 80, Issue 9; Conference: American Association of Petroleum Geologists (AAPG) gulf coast association of geological societies meeting, San Antonio, TX (United States), 2-4 Oct 1996; Other Information: PBD: Sep 1996
- Country of Publication:
- United States
- Language:
- English
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Diffusion of methane and ethane through the reservoir cap rock: Implications for the timing and duration of catagenesis
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