Continual revision of geologic reservoir description is an important component of reservoir management. New data should be incorporated into existing reservoir models in light of evolving geologic concepts. Revisions may have significant impacts on the approach and success of reservoir management strategies. A reevaluation of Bindley field (Mississippian), Hodgeman County, Kansas, serves as an illustration of this process.

Prior study of this field suggested that the reservoir interval is comprised of a single, relatively uniform facies (bryozoan dolomite) having no apparent internal structure. A waterflood attempt based on this concept of reservoir architecture resulted in minimal response.

A revised model of reservoir architecture and petrophysics resulted from integration of new core data, a new stratigraphic correlation scheme, updated well production histories, and capillary pressure data. The principal reservoir interval is vertically segregated into six stratal units, each consisting of storm-winnowed, normal marine carbonates at the base and capped by low permeability, restricted dolomudstones. The reservoir is confined to grain-supported dolostones in the normal marine portion of four of the stratal units (flow-unit type I; k>=10 md). Each grain-supported dolostone grades laterally into low permeability mud-supported fabrics and is vertically isolated by the intervening restricted dolomudstones. Reservoir quality is primarily determined by matrix permeability, which is not covariant with porosity. Permeability variation within flow-unit type I rocks is caused by variation in pore-throat size distribution. Cumulative primary fluid production is proportional to the transmissivity (kh) of flow-unit type I rocks that are in communication with the well bore.

The revised geologic model reveals specific methods to improve primary recovery and rectify the poor waterflood performance. These methods include selective perforation of all oil-saturated type I flow units to optimize primary recovery, and remedial waterflood design to assure continuity of fluid flow between injection and production wells. The revised model demonstrates the benefit of revising geologic reservoir models regardless of field size or maturity.