Origin And Preservation Of Organic-Rich Zones And Kukersite Beds Of The Red River Formation (Upper Ordovician), Williston Basin, North Dakota

The Red River Formation is North Dakota’s third most productive hydrocarbon unit. The unit has been interpreted to be self-sourced, but the locations of the source beds has not been thoroughly investigated within the North Dakota portion of the Williston Basin. Using the most current available data, this study investigated the source beds of the Red River Formation. This present study agrees with past studies that there are two source bed types; the first type being a higher organic-rich, thin kukersite bed and the second being a less organic-rich, thicker organic zone. Both types of source beds commonly occur as a series of beds within an area and the beds are not very laterally extensive. Deposition of the two types is believed to be under conditions that favored an isolated or restricted environment that could harbor an algal bloom. Possible conditions could be related to either anoxia or increased salinity. However, after deposition some of the source beds were altered or fully destroyed in some areas by fluid movements associated with the formation of the D Porosity zone. Based on the results of this study, there were two topographic features that assisted in preserving the source beds. The first is the Cedar Creek Anticline and the second appears to be a short-lived, topographic high that trended north-south along the western part of the state. Investigations in the Montana portion of the basin coupled with more data (drilled wells) east of the Nesson Anticline and more core samples taken throughout the state would significantly improve this study and the overall interpretations of the Red River Formation, especially when inspecting the source beds.