St. Catharines 2004
Technical Program


SS20:  Ontario Oil and Gas, the joining of two basins 
Organizers / Organisateurs:  Ian Colquhoun, Steven Fletcher
Room / Salle:  TH 245

Date:  05/12/2004
Time:  2:00 PM
Presenter:  Douglas G. Patchen


Evolution of exploration, drilling and completion concepts for Appalachian Basin's Trenton-Black River Play

Patchen, D.G., and Avary, K.L. West Virginia Geological Survey, PO Box 879, Morgantown, WV, USA, 26507, Doug.Patchen@mail.wvu.edu

The hottest play in the Appalachian basin continues to be the deep Trenton-Black River play(Ordovician), a high-tech, high-risk play that began in New York in 1995 with the discovery of the Glodes Corners Road field. High initial potential tests, followed by high, sustained production, attracted national interest, even before the play was extended to West Virginia in 1999.

Early discoveries in New York were based on an exploration model developed by Richard Beardsley, for which he was awarded AAPG's first Outstanding Explorer Award. The first locations were based on seismic where a basement fault was observed beneath a sag on the top of the Trenton, which Beardsley interpreted as being due to a volume reduction as limestone was converted to hydrothermal dolomite (HTD) adjacent to fault zones.

PTTC (Petroleum Technolohy Transfer Council)became involved in the play soon after the discovery of the Cottentree field in West Virginia (1999). The first Trenton-Black River workshop focused on structural and stratigraphic settings and depositional environments, complemented by drilling updates and limited seismic data. Workshop participants gained an appreciation for the high-risk nature of the play, and a realization that basement-deep faults were necessary for the development of HTD reservoirs in both the Trenton Limestone and underlying Black River Formation.

Development continued in New York with additional discoveries and the first horizontal wells being drilled in 2003. Also, some recent exploratory wells have been drilled in Pennsylvania in an attempt to determine if the Trenton-Black River there is more akin to the HTD reservoirs of New York, or to the fractured limestone reservoirs of West Virginia.

As additional discoveries were made, industry requested that PTTC take the lead in technology transfer. Subsequently, four more workshops were held, attracting more than 500 registrants.  During these workshops, it became apparent that: the New York play was different than the West Virginia play; the presence of the basal sandstone could be a key component in a hydrothermal dolomite model; an outcrop model in Kentucky was a good model for the reservoir in New York; various seismic models are necessary to explain the different reservoirs; and there was interest among industry for a detailed study of the Trenton-Black River interval.

Subsequently, a Trenton-Black River research consortium was formed to conduct a regional study of this play. The consortium, consisting of the state geological surveys in Kentucky, New York, Pennsylvania, Ohio and West Virginia, along with their company partners, submitted a successful proposal to the U.S. Department of Energy to prepare a play book and create an interactive website and database for consortium members.