Abstract: Horizontal Drilling for Oil and Gas in the Michigan Basin

HARRISON, WILLIAM B., III
Michigan Basin Core Research Laboratory, Department of Geology, Western Michigan University, Kalamazoo, Michigan 49008

The first horizontal well was drilled in Michigan in 1985. As of December 1, 1997 there have been 214 horizontal wells drilled and completed. Another 140 wells are pending, having been permitted and are in various stages of planning, drilling, or waiting on completion. All horizontal wells have been drilled in known fields in previously productive reservoir zones. Most of these fields were considered to be depleted or approaching an economic productivity limit with respect to their existing vertical wells. About 93 % of the completed horizontal are considered to be successful. Only about 7 % have been declared as dry holes.

Horizontal wells in Michigan are mainly being used as a secondary recovery technology to improve productivity in Michigan's aging fields. A few horizontal wells have also been drilled in gas storage reservoirs to greatly enhance injection or withdrawal rates.

Twelve different Michigan reservoirs have, thus far, been targets of horizontal wells. They range in age from Ordovician to Mississippian and include sandstone, carbonate, and shale lithologies. The most prolifically drilled horizon is the Niagaran pinnacle reefs. Approximately 60% of currently completed horizontal wells are in this formation.

Productivity of these horizontal wells has been variable. Few of the wells have a long history of production by which to evaluate their performance. However, preliminary production data suggests that horizontal drilling in Michigan can provide the opportunity for recovery of additional hydrocarbon reserves from Michigan's aging oil and gas reservoirs.

AAPG Search and Discovery Article #90930©1998 AAPG Eastern Section, Columbus, Ohio