Saline Aquifers Unlocking Brazilian Carbon Storage Pathways

Abstract This study provides an overview of Brazil's efforts in CCS, focusing on three selected options based on Brazil's characteristics, and presents a case study for each: Case one concerns Enhanced Oil Recovery; Case two covers the hard-to-abate sector using a Hub System, and Case three focuses on bioenergy with geological storage. The goal is to provide insights into Brazil's potential to store CO2 in saline aquifers based on real projects, primarily using Hub systems. The first case describes the world's largest operating CO2-EOR project, the Tupi oil field, located in ultradeep water, southeast of Brazil. To manage the highly concentrated CO2 levels in the oil, specialized skills, materials, and technology were developed and now can be applied to other CCS projects, including those without hydrocarbon. This paper presents concerns about the pre-salt oil field, including the controversy surrounding carbon capture, precisely the geological type as opposed to the anthropogenic type. The second case focused on the saline aquifers, characterized by the sandstone reservoir of the São Tomé Member, located in the north Campos sedimentary basin, continental shelf, in front of Rio de Janeiro State. The maps show the generous size and thickness of the geological site, providing ample pore space for CO2 injection, but it is not a conventional trap. The third case presented Brazil's most advanced BECCS project, in Mato Grosso State, which includes recently acquired geological and geophysical data. This article proposes that an outstanding model to unlock the country's geological storage of CO2 pathways is based on the saline aquifer reservoir, in a Hub system connecting different hard-to-abate sources or a cluster of sources on a BECCS example. This study reanalyzed old seismic data previously used to search for hydrocarbons in areas where exploration had failed, as confirmed by wells. The data was reinterpreted to map geological reservoirs, particularly saline aquifers, to store CO2, presenting a new geological interpretation for this updated objective. A significant occurrence was the approval of Law N°. 14,993 in October 2024, establishing the legal framework for carbon dioxide capture and geological storage while defining the Agency responsible for building the regulatory framework.