A parasequence within the fluvial-deltaic Cretaceous Ferron Sandstone Member of the Mancos Shale is the focus of an integrated, detailed (0.6 km x 0.6 km x 100 m) characterization and flow simulation study of delta-front deposits. Photomosaics, drill holes, and permeability transects collocated with stratigraphic sections provide the characterization data. Prograding delta-front clinoforms, the main architectural element observed in outcrop, show a systematic decrease in permeability from proximal deposits (k_avg ª 20 md) to distal deposits (k_avg ª 2 md). This trend correlates with corresponding trends in sedimentary structures and grain size. High resolution 2-D and 3-D petrophysical models illustrate the impact of clinoform architecture on two-phase (oil and water) flow in the subsurface. The 2-D (vertical cross-section) models illustrate how flow is affected by permeability trends within clinoforms and by the thin (typically < 15 cm), shaley, lower permeability bounding layers separating individual clinoforms. Bounding layers retard the progress of a simulated waterflood, as expected. Although individual clinoforms are not preserved in the 3-D model, the prograding nature of the deposits is represented by assigning permeabilities on the basis of sedimentary facies. One set of 3-D simulations includes permeability anisotropy estimated from a more detailed 2-D permeability model. Computed cumulative oil recovery in the anisotropic case is higher than in the isotropic case (ª30% OOIP vs. ª20% OOIP after ten years), but oil produced/water injected is lower (0.3 vs. 0.5 after ten years).

AAPG Search and Discovery Article #90937©1998 AAPG Annual Convention and Exhibition, Salt Lake City, Utah