Application of Sequence Stratigraphic Approach to Integrated Field Management Processes: East Fault Block, Hawkins Field, Wood County, Texas

Victor D. Rahmanian, Luis O. Fernandez, Michael, R. Chlebana, Robert H. Davidson

An integrated sequence stratigraphic - engineering study of the Woodbine reservoir in the East Fault Block of the Hawkins Field was undertaken to optimize depletion and operating strategies and profitability of a unique immiscible gas drive/gravity drainage EOR project in a complex fluvially-dominated reservoir system. Specific study objectives were to reduce future development drilling requirements, improve success and performance of all future well workovers, and maximize EOR reserves recovery through enhanced depletion and operating strategies. The study objectives were achieved through a two-phased iterative and integrated work process: 1) delineation and mapping of reservoir geometries and continuities; and 2) integration of production data with the sequence stratigr phic framework of the reservoir.

The 500-foot thick Woodbine reservoir is divisible into two fluvially-dominated sequence sets. The lower sequence set is characterized by sand-prone, high-frequency sequences marked by multi-story, laterally extensive lowstand channels, overlain by thin, laterally discontinuous flood plain mudstones of the transgressive systems tract. The sequences of the upper sequence set contain thinner, laterally discontinuous lowstand channels and are dominated by fine grained flood plain deposits of the transgressive systems tract. The sequences display an overall retrogradational stacking arrangement marked by a progressive upward decrease in overall reservoir net/gross and lateral continuity and a corresponding increase in thickness and continuity of the flood plain mudstone components.

Integration of production data with the sequence stratigraphic framework resulted in definition of complex flow unit geometries and documentation of the movement of fluid contacts through tortuous reservoir pathways over time. Significant results were achieved in all aspects of production operations, including a major reduction in development drilling requirements and a dramatic increase in well workover success rates and performance. EOR project profitability has been increased by improved reserves recovery, accelerated oil production, and reduction of operating costs.

AAPG Search and Discovery Article #91020©1995 AAPG Annual Convention, Houston, Texas, May 5-8, 1995