Potential Reservoirs for Geologic Sequestration in the East Continent Rift Basin
Drahovzal, James A. and David C. Harris
Kentucky Geological Survey, Lexington, KY
In most areas of the United States, geologic carbon sequestration is not an option in Precambrian rocks due to their crystalline nature and resulting impermeability. Parts of the eastern Midcontinent, like the East Continent Rift Basin, contain thick siliciclastic rocks that could be more permeable. Many of these siliciclastic rocks, however, are dominated by immature lithic arenites, most of which have low porosities and permeabilities. This is certainly the case for the nearly 2,000 feet of Proterozoic Middle Run Formation lithic arenites drilled in the southwest Ohio ODNR DGS No. 2627 well.
The more recent K II No.1 Brooks well drilled in central Kentucky penetrated 1,789 feet of a section very similar and perhaps correlative to the Middle Run Formation of Ohio. The bottom 157 feet of the section, however, encountered an interval of quartzarenite to sublitharenite that shows higher porosity than the section above and that reported shows of gas, indicating measurable permeability. Reflection seismic data at the well and in the area provide additional information on the probable thickness and distribution of the porous unit. The original flow test conducted in the interval was inconclusive, but the well is currently being considered for clean-up and re-testing. If the interval proves not to be gas productive, it may be a candidate for carbon sequestration. The presence of this porous interval begs the question as to how many other similar zones are present in the Proterozoic rocks of the East Continent Rift Basin that could represent potential geologic sequestration targets.
AAPG Search and Discovery Article #90031©2004 AAPG Eastern Section Meeting, Columbus, Ohio, October 3-5, 2004