Assessing an offshore carbon storage opportunity at Chandeleur Sound, Louisiana

Carbon Capture and Storage (CCS) is considered a crucial technology for climate change mitigation. Its primary objective is to reduce CO₂ emissions caused by human activities by capturing gas from large point sources or from direct air capture and injecting it into deep geologic formations. This study focuses on the geological characterization and CO₂ storage capacity estimation for an offshore state water site – Chandeleur Sound, Louisiana. Form literature review, the storage window is narrowed to Middle and Upper Miocene. 3-D seismic data was used for fault and horizon picking, stratal slicing and attribute mapping. Three attributes/methods were used in the stratal slices: Sum Negative Amplitude, RMS amplitude, and Spectral Decomposition. The slices give a qualitative overview of the depositional trends and faulting in Chandeleur Sound and concluded that the ideal storage intervals include the Upper Miocene in the southern area, the upper part of Middle Miocene, and a massive channel system near the top of Upper Miocene which is likely to be a deposit from the paleo Tennessee River. Well log correlation was used to identify seven reservoir zones. Detailed reservoir properties were defined for these zones. The thickest net sand interval within the Chandeleur Sound area is found in the center. Static and dynamic storage capacity calculations estimate a total storage capacity of 306 to 2,000 million metric tons. of CO₂, depending on boundary condition. The value of 306 Mt is the most realistic and is used for source-sink matching. Chandeleur Sound is close to Louisiana Chemical Corridor (LCC) and has plenty of point sources for CO₂ supply. The costs associated with carbon capture, transport and storage and were considered. Pipeline is the only transport scenario considered for large volumes that must be transported on land and then into shallow marine settings. CO₂ pipeline regulations include both federal and state level jurisdiction. Pipeline costs estimation using FECM/NETL CO₂ Transport Cost Model and Terrain-based approach concluded that a 20 inches pipeline from the carbon gathering hub to the injection site would have a construction cost from $140 million to $1.16 billion in 2023’s dollars.