STRATIGRAPHIC ANALYSIS OF THE AMSDEN AND BROOM CREEK FORMATIONS (PERMO-CARBONIFEROUS) IN THE WILLISTON BASIN: A STRATIGRAPHIC MODEL FOR A CARBON STORAGE UNIT

This is part of a student-led analysis and assessment of the Broom Creek and Amsden Formations in the subsurface of the Williston Basin in west-central North Dakota. The Broom Creek Formation has been selected as a potential carbon storage unit because of the porosity and permeability of aeolian and nearshore sand facies commonly occurring in the middle and upper part of the formation (which currently functions as a saline aquifer). Project CarbonSAFE was an initiative sponsored by the DOE and local and state agencies and carried out by the EERC, and the initiative resulting in the selection of the Broom Creek. The formation occurs over 6000 ft. down in the subsurface and overlies the Amsden Formation (Pennsylvanian) which consists on many similar facies, and is overlain unconformably by the Opeche Formation wich consists or a thick interval of redish siltstones and anhydrite. The Broom Creek has great potential for carbon storage because of its depth, the high porosity and permeabilityof the aeolian facies, and other interbedded facies functioning as seals (siltstone & anhydrite layers). The Broom Creek lacks detailed stratigraphic assessment as it was never exploited for hydrocarbons. To rectify this lack of knowledge and explore the storage potential of this interval, the EERC supervised the coring of the Broom Creek, the description and analysis of these cores as well as a section of 3D Seismic in Mercer and Oliver Counties in North Dakota (near the potential carbon storage field). The analysis of individual cores combined with analysis of the line of 3D seismic was good for a large-scale assessment of the carbon storage potential of the Broom Creek, but it may fail to recognize and characterize key surfaces that separate genetic packages of facies within the formation. A sequence stratigraphic analysis will recognize these surfaces. Allowing for a high-resolution constraint on the vertical and lateral distribution of key facies. This may reveal more about the geologic history of this formation and provide more information about potential storage volumes of interval of interest.