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