Reservoirs resulting from facies-independent dolomitization: Case histories from the Trenton and Black River carbonate rocks of the Great Lakes area

Abstract

Reservoirs in the Trenton Limestone and the Black River Group (Limestone) (both Upper Ordovician) in Indiana, Michigan, and Ohioformed a major oil province that increased rapidly in importance beginning in 1884. This province became America's first giant oilfieldand has yielded more than 600 MBO,including that produced from the giant Albion-ScipioTrend (120 MBO),which was discovered in 1956. Trenton and Black River carbonates have always excited exploration interest, but very little was known about the nature and distribution of their reservoirs. Recent research on the nature of reservoir development in these units indicates that they do not contain any depositional porosity in the Great Lakes area. Reservoirs are found only where there has been dolomitization or fracturing or some combination of the two.Dolomitization of Trenton and Black River limestones does not conform to facies-related models, such as the sabkha model, but must be related either to fluid movement along fractures associated with tectonic features or to burial dolomitization by some process that is not well understood. The importance of these two general types of dolomitization models can be shown by a comparison of fields where there has been dolomitization and fluid movement along a linear fault (or fracture) zone, and the Lima-Indiana Trend in Ohioand Indiana, where there has been a regional pattern of burial dolomitization. The range of oil recovery of the former is 12,000 to 2500 barrels per acre, and that of the latter is only 1,000 to 540 barrels per acre.

Stress, seismicity and structure of shallow oil reservoirs of Clinton County, Kentucky. Final report

“…10; Keith, 1988). Similar reservoirs have been described from the Tangent Field of northern Alberta (Churcher and Majid, 1989).…”

“…Dolomitized fracture zone in Ordovician limestone, Dover Field, southern Ontario. After Keith (1988). 11: Oil Accumulations of the Cincinnati Arch (after Ryder, 1987).…”

Diagenetic history of the Trenton and Black River Formations in the Michigan Basin

“…Several workers have concluded that at least part of the basin was exposed at the end of Trenton deposition to account for a variety of diagenetic features in the Trenton Formation (Rooney, 1966;DeHaas and Jones, 1984;Churcher, 1986;Taylor and Sibley, 1986). Alternatively, Keith (1985Keith ( , 1988 and Wilson and Sengupta (1985) suggest that alteration at the contact is related to submarine hardground development rather than subaerial exposure. There are well-documented marine hardgrounds reported in Middle Ordovician limestones equivalent to the Trenton Formation in Ontario (Wilkinson and others, 1982) and Indiana (Keith, 1985) that are identical to the mineralized upper surface of the Trenton in the Michigan Basin.…”

“…3A). There is little vertical change in facies within the Trenton Formation and no evidence of peritidal or restricted facies at the top of the formation in Michigan or in surrounding states (Keith, 1985(Keith, , 1988Wickstrom and Gray, 1989 (Howell and Budai, 1989). The central part of the basin during Trenton deposition may have been as much as 100 m deep.…”

“…On the western margin of the Michigan Basin the Trenton and Black River Formations are thin, but exhibit depositional textures similar to the main carbonate platform on the southeast side of the basin. The Trenton and Black River Formations thin to the south in Indiana, where the Trenton Formation appears to record higher energy, shallower water conditions (Keith, 1985). Both formations are thinner in southern Ontario, where the Black River is very shallow subtidal to intertidal and the Trenton records shallow-subtidal, higher energy conditions than those in the Michigan Basin (Brookfield, 1988).…”