Assessing Reservoir and Containment Risks for Potential CCS Sites in Campos Basin, Offshore Brazil

Summary Deepwater fields in the Offshore Brazil Campos Basin, located about 260 km from the coast, contain high CO2 levels, with deeper reservoirs reaching 6,000 m. This study assesses Carbon Capture and Storage (CCS) options for two CO2 source fields, Field X and Field Y, to identify suitable storage sites and avoid emissions while producing. The screening focuses on two regions: R1 (30–80 km away), which offers potential storage in a saline aquifer, and R2 (100–200 km away), where major hydrocarbon fields are expected to be depleted and repurposed for CO2 storage. Saline aquifers provide large pore space and favorable geological conditions, while depleted reservoirs may offer cost advantages by utilizing existing wells and infrastructure. Subsurface studies recommend CO2 storage in low-risk reservoirs, specifically in post-salt Cretaceous sand in R1 and Quissama Carbonate in select R2 fields. Future depleted reservoirs in R2 are estimated to offer a storage capacity of 12.6 Tcf (∼640 million metric tons), assuming a 30% recovery factor. In the short term, an injection plan could be implemented in R1, utilizing 1.4 Tcf of storage capacity into saline aquifer. CO2 injection into depleted fields is generally more practical as it does not require de-watering to maintain pressure