Algorithm for Site Selection for Carbon Capture Underground Storage and Brief Overview Geology and Hydrogeology of Louisiana
Douglas Carlson, Louisiana Geological Survey; and Muhammad Zulqarnain, Stephen O. Sears, Mehdi Zeidouni, Richard G. Hughes, Craft and Hawkins Department of Petroleum Engineering, Louisiana State University
Abstract
An important requirement for commercial scale carbon underground sequestration (CUS) site selection process is to identify sites that are safe for injection and retention of carbon dioxide (CO2) over extended time scales. This requires a through evaluation of site-specific surface and subsurface features. An algorithm was developed and used to identify potential sites in south Louisiana. This involved incorporation of surface data: 1) land use, 2) location of legacy oil and gas wells, 3) site proximity to large CO2 stationary sources, 4) state land or other large landowners, and 5) vicinity of large population centers. Study focuses on strata between depths of 3000 ft or USDW, which-ever was deeper, and the top of the geopressured zone at approximately 9,000 to 12,000 feet depth. Regionally for south Louisiana sediments deep towards the south and thicken southwards as a result of prograding deltaic environment during the Cenozoic (focus is on Miocene) which resulted in the deposition of thick packages of fine-grained sandstones suitable for CO2 storage and layers of shale acting as cap rock.
Three sites located south of Interstate 10 are examples of site selection. They are south of large populations centers, in areas that avoid high density of legacy oil and gas wells, and within state lands or state water bodies. In addition to surface concerns subsurface geological features were also considered. The example sites selected were located between 7,500- and 9,500-feet depth, sands were between 304 and 860 feet thick, porosity was approximately 30%, and permeability was approximately 1,000 milli-Darcy. Sands and over lying seals-shales have dips of between 1.4 and 3 degrees. The primary seals are approximately 100feet thick and there were additional thinner seals of 50feet or greater thickness above the primary seal. In summary, sites selected are similar to prospect sites for conventional hydrocarbon production expect there is need to avoid nearby sources. Like hydrocarbons liquified CO2 will float on of brine so it will move up dip into traps. Although formations are normally dipping south locally dips are radial and away from salt domes. Local structures around these domes yield storage sites under various seals. These storage sites are typically a township in size, approximately 36 square miles with storage capacity of billions of cubic feet that can which hold millions of tons of CO2.
The second phase of this study is an evaluation of all of Louisiana and its various formations with criteria developed for site selection in south Louisiana. So, with this in mind a series of top and isopach maps are developed for all units down to the Smackover Formation. A focus is on possible regional confining units such as Anahuac, Cane River, Midway, and Pine Island shales, Ferry Lake Anhydrite and James Limestone. These units cover multiple parishes within Louisiana throughout south, central, or northern Louisiana. Other units mapped include Wilcox Group, Hosston Formation, and Cotton Valley Groups. These units are up to 3,000 feet thick and contain mixtures of sandstone, shale and carbonates acting as seals and reservoirs within a single unit.
BIO:
Douglas’ Areas of expertise include physical hydrogeology, groundwater modeling, groundwater surface water interactions, application of geophysical techniques to hydrogeologic studies, chemical hydrogeology and hydrology.
Douglas has been author or co-author on 74 papers, reports and abstracts