Abstract

Horizontal drilling has increased drilling throughout the Williston Basin since September, 1987. This activity has concentrated primarily on the Bakken Formation (Devonian-Mississippian) and the Mission Canyon and Charles formations of the Madison Group (Mississippian). Horizontal activity in the upper Bakken shale in the United States portion of the Williston Basin has been constant since the completion of the first successful well. As of December, 1991, 160 wells have horizontal production throughout North Dakota and Montana.

The Madison Group has been the focus for horizontal activity in the Canadian portion of the Williston Basin. Significant oil production has been obtained from the Mississippian Souris Valley, Tilston, Frobisher-Alida, and Ratcliffe beds in southeastern Saskatchewan and from the Mississippian Lodgepole Formation in southwestern Manitoba. Most successful drilling has been in older fields. Because of this success, attention has been drawn to the Mission Canyon and Charles formations in the United States.