Abstract: North Alabama Ferry Field Waterflood Project: Successful Integration of Detailed Geology with Reservoir Engineering

Dennis R. Prezbindowski, David T. Basden, Don G. Bebout, William M. Fitchen

The Alabama Ferry field located in Leon County, East Texas, produces from three partially interconnected, stacked, off-lapping Glenrose "D" carbonate grainstone shoals. Production from more than 160 wells since the field was discovered in 1983 rapidly reduced reservoir pressure far below the bubble point. A detailed geological analysis of more than 20 cored wells correlated to well logs was used to establish a detailed reservoir model for the northern part of the Field. Reservoir porosity (primary and secondary) is sensitive to depositional facies and particularly grainstone types. Detailed, quantitative facies and porosity mapping resulted in the development of a three layer, dual porosity, dual permeability reservoir simulation model used for the evaluation of potential development rograms. Using this quantitative geologic framework a simulation model was constructed to predict hydrocarbon recoveries under many different injection patterns. This reservoir model predicted that under primary depletion 19% (approx. 5.2 MMBO) of the original oil in place would be produced and that a crestal water injection program (which was the initially proposed injection program) would produce approximately 29% (approx. 8 MMBO) of the oil in place. The optimum reservoir model, a pattern waterflood, predicted recovery of approximately 46% (approx. 12.4 MMBO) of the oil in place and, this development program was implemented in 1991. A projected 17% increase in the amount of recoverable oil from the Alabama Ferry North Unit can be attributed to the successful integration of detailed ge logy with reservoir engineering.

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994