Chararcterization of Heterogeneity Style and Permeability Structure in Fluvial Reservoirs

The Cretaceous Acu Formation was investigated as an analog to a heterogeneous group of reservoirs having significant potential for reserve growth in the Potiguar Basin of Brazil. Architectural, lithologic, and petrophysical information was collected from an outcrop exposing a fluvially deposited sandstone body located in the state of Rio Grande do Norte, Brazil. Sedimentologic descriptions of the sandstone body were collected from a series of vertical transects spaced evenly across the outcrop. Stratal surfaces traced between transects were recorded on photomosaics. Measurements of permeability were obtained from each transect by use of a portable probe-style mechanical field permeameter. A cross-section depicting bedding architecture, sedimentologic attributes, and permeability values was constructed, and the information incorporated into a two-dimensional representation of reservoir architecture using Stratamodel's Stratigraphic Geocellular Modeling software (SGM). The SGM technique deterministically interpolates permeability data between transect locations using a lithologic or stratigraphic framework.