The Rainbow Lake Field is located some 400 miles northwest of Edmonton, Alberta. The main production comes from Middle Devonian reefs which are encased in evaporites. These reefs vary in size from a quarter section to nine sections and range in height to over 800 feet. Additional production comes from overlying units which are structurally draped over the reefs.

These reefs have been interpreted to be ecologic reefs that owe their reservoir qualities to primary fabric and mesodiagenetic processes. To the contrary, we hope to show that these build-ups are “cementation reefs”, i.e. they are primarily products of pervasive cementation of mechanically deposited skeletal debris and that their reservoir characteristics are mainly the result of eodiagenetic processes.