Dundee Field Production History and Reservoir Performance in Relation to Reservoir Type

W. B. Harrison III
Department of Geosciences, Western Michigan University, Kalamazoo, MI

Shallow shelf carbonate reservoirs in the Dundee Formation of Michigan are the most prolific oil producers in the basin’s history. Cumulative oil production exceeds 350 million barrels from about 100 fields since the play’s discovery in 1930. The two primary Dundee reservoir types are most easily distinguished by their lithology. One is mainly composed of dolomite the other is predominately limestone. Each of these two main types has two or more subtypes distinguished by depositional fabrics and diagenetic overprints. Although each primary type or subtype of reservoir is generally found in a specific portion of the basin, there are notable exceptions of where these reservoir types are mixed in the same geographic area.

Analysis of initial flow data, cumulative oil production/decline curves, and water production history provides useful information about reservoir performance in this play. Examination of core samples and conventional porosity and permeability data confirm the reservoir type and subtype for selected fields.

Limestone reservoir types maintain much of their original depositional fabric. The pore structure is dominated by intergranular and intraparticle porosity. Grainstone shoal/sand bodies, patch reef complexes, and vertically and horizontally-fenestral, peritidal,packstones and wackestones are three known subtypes in the limestone reservoirs. IP rates are usually in the 10s to 100s of barrels per day.Water production is generally low throughout the life of the field. The drive mechanism is probably solution/expansion gas. Reservoir pressures decline continuously during production.

Dolomite reservoirs may be pervasively dolomitized examples of the same depositional fabrics seen in the limestones, or the more common highly-fractured and mineralized hydrothermal dolomite reservoirs (HTDR). Increased permeability and porosity give the dolomite reservoirs higher IPs (100s to 1000s bbl/day).Water production is abundant and early in the life of the field and reservoir pressures drop little due to strong water drive.

AAPG Search and Discovery Article #90900©2001 AAPG Eastern Section Meeting, Kalamazoo, Michigan