ABSTRACT: Computer Modeling of Mid-Continent Cyclothems and its Application to the Prediction of Hydrocarbon Reservoirs
John A. French, Lynn W. Watney
A computer model has been developed that generates and correlates multiple one-dimensional stratigraphic sections that resemble lower Missourian cyclic sequences (cyclothems) in the Mid-Continent. The model differs from many other quantitative models currently being developed in that it attempts to recreate fifth- to sixth-order (roughly 50-500 k.a.) cycles in enough detail to allow estimates of facies variations both within and among individual cycles. The replication of large-scale (e.g., seismic) basin-fill architecture, which is the focus of many computer models now being developed, is not currently a goal of this modeling.
Modeling using modified Pleistocene oxygen isotope curves as proxies for sea level curves has resulted in cyclic sequences that closely resemble lower Missourian units in southeastern Kansas. In high-shelf positions, sequences are simple cycles that consist mainly of an upward-shallowing highstand carbonate unit. Relatively complex successions occupy mid-shelf positions where mixed carbonate/siliclastic parasequences occur. Starved-basin shales and lowstand siliciclastic units tend to occur in downdip positions.
The extension of this modeling to time-equivalent, hydrocarbon-bearing strata in central and western Kansas is a major goal of this project. This will be accomplished via the use of values for parameters such as eustasy, subsidence, and sedimentation rates that yield the best match between model results and the stratal succession in southeastern Kansas.
AAPG Search and Discovery Article #91003©1990 AAPG Annual Convention, San Francisco, California, June 3-6, 1990