Failure to launch: Fate of the Second White Specks as a resource play was preordained by its Late Cretaceous depositional setting

We compare the Second White Specks and Belle Fourche For-mations (2WS/BF) of Alberta, Canada to the Eagle Ford Forma-tion shale (EF) of southern Texas and, to a lesser extent, the Tuscaloosa marine shale (TMS) of Louisiana and Mississippi. These units were deposited during the same Late Cretaceous (Cenomanian-Turonian) eustatic rise and highstand, and all are prolific source rocks. Our aim was to define the reasons why attempts to develop the 2WS/BF as a resource play were unsuccessful. We propose that failure was controlled by the combined effects of three geologic factors-reservoir quality, organic richness, and completion quality-all of which stem from the depositional setting and history of the interval. Because it was deposited in close proximity to a major source of fine-grained siliciclastic sediments, the 2WS/BF has a higher clay-mineral con-tent than the EF, the latter being deposited in a relatively clastics-starved setting. Porosity loss, through compaction, was therefore greater in the 2WS/BF, and the higher clay-mineral content of that play, combined with the stratigraphic stacking, led to com-pletion problems such as proppant embedment and out-of-zone growth of hydraulic fractures. The TMS was likewise challenged as a resource play because of its high clay content. The original organic content of the 2WS/BF was neither as high nor as oil prone as that of the EF because of paleoenvironmental conditions at the seafloor at the time of deposition. This retrospective analy-sis identifies depositional setting as a first-order control on the potential of a source rock to form a resource play.