High-resolution correlation of coastal plain strata for definition of reservoir attributes
- Colorado School of Mines, Golden, CO (United States)
Three type of stratigraphic cycles are recognized in coastal-plain strata of the MesaVerde Group (Cretaceous) San Juan Basin, Colorado. The cycle types change as a function of accommodation and geographic position. The cycles record oscillations of base level and concomitant oscillations of increasing and decreasing accommodation. Coastal-plain strata were traced physically into shoreface strata to establish temporal equivalency of strata within the two environments, and thus ensure correct recognition of base-level rise and fall hemicycles in coastal-plain strata. Potential reservoir units are channel belt sandstones and backbarrier and bay sandstones which occur in two of the cycle types. These sandstones change geometry, connectivity, and volumes within cycles, reflecting changes in accommodation, the types of original geomorphic elements within environments, and sediment preservation during base-level cycles. The occurrence of different facies successions in the different types of cycles establishes the empirical basis for recognizing such cycles with well-log inversion techniques. One type of stratigraphic cycle, which occurs in the lowest accommodation condition of the Mesa Verde Group, is an alternation between laterally amalgamated channels and either crevasse splay/crevasse channel complexes or floodplain vertical accretion deposits and soils. Laterally amalgamated channel sandstones accumulated during base-level rise hemicycles. The third type of stratigraphic cycle also occurs in the maximum accommodation conditions, but in a more seaward position than the previous type. Like the first, this type of stratigraphic cycle comprises an alternation of two types of facies associations. This type is an alternation between tidally dominated estuarine and bay sandstones and mudstones which accumulated during base-level rise, and shallowing-up and bed-thickening up hummocky cross stratified back-barrier and bay sandstones which accumulated during base-level fall.
- OSTI ID:
- 127664
- Report Number(s):
- CONF-950995-; ISSN 0149-1423; TRN: 95:005942-0219
- Journal Information:
- AAPG Bulletin, Vol. 79, Issue 8; Conference: International conference and exhibition of the American Association of Petroleum Geologists, Inc.: managing change at the turn of the century, Nice (France), 10-13 Sep 1995; Other Information: PBD: Aug 1995
- Country of Publication:
- United States
- Language:
- English
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