Harrison, William B.¹, Robb Gillespie¹, David A. Barnes¹
(1) Western Michigan University, Kalamazoo, MI

ABSTRACT: Using Core and Log Data to Redesign a Waterflood in the Dundee Limestone Formation (Middle Devonian), South Buckeye Oil Field, Gladwin Co., MI

Nearly 5.5 million barrels of oil have been produced from the South Buckeye oil field since its discovery in 1935. Recovery efficiency was estimated at less than 30% when Wiser Oil initiated a waterflood in the early 1970's. They drilled 40 new wells, acquired modern wire-line logs, and selectively cored 25 of the wells. Little of this new data was used in designing the waterflood that was developed using alternating rows of injector and producer wells. The field changed ownership in the late-1980's, and by the late-1990's, abandonment of the project was being considered due to poor waterflood performance.
Our study evaluated the sedimentary facies using all existing data, identified flow units and formulated a reservoir model with recommendations for redesign of the waterflood. Three facies, identified from core, were found to possess sufficient porosity and permeability to be considered reservoirs. The Stromatoporoid Boundstone; Crinoidal Grainstone; and Dolomitic, Silty Wackestone facies are laterally and vertically discontinuous over the field area. The Stromatoporoid Boundstone facies is the primary reservoir. Key factors in the redesign include structural position, thickness, and lateral continuity of the reservoir facies.
Conclusions of this study are: 1) Stromatoporoid Boundstone reservoir is laterally discontinuous between northern and southern portions of the field; 2) the northern lobe may have the greatest potential for enhanced recovery; 3) injector wells relocated near the periphery in the northern lobe with producer wells in the middle of the lobe should be the most productive pattern.

AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.