Mississippian Oil Reservoirs in Williston Basin1
In the Williston basin, oil occurs principally in carbonate reservoirs of the Mississippian which exhibit structural folding of varying intensity, but facies changes are the basic controlling factor of accumulation. Unconformities also constitute an essential part of the flank habitats. Maps and cross sections of many fields in North Dakota, Saskatchewan, and Manitoba illustrate the controlling factors of accumulation. A lithologic cross section of the Madison group from the outcrop in the Little Rocky Mountains of Montana through the depths of the basin to the eastern wedge edge in North Dakota shows the facies changes in this sequence of rocks.
Figures & Tables
Habitat of Oil
The history of oil exploration in a large basin is very much like the history of research in most fields of investigation. In the history of research into the subject of oil occurrence, however, the rate of increase of knowledge has fluctuated greatly. Sourced from the 1955 AAPG Annual Meeting, this publication contains many of the papers presented at that meeting, which discuss the habitat of most of the oil found in the world prior to 1955.