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This paper revisits the intense using of energy in the world and the role of the fossil fuels with predominance of the oil in the global primary energy supply and their effects to climate change. It also presents a new reading on the thermodynamic conditions and characteristics of CO2 and CO2-EOR together with oil industry advancement in the world and Brazil. The interface with chemical EOR processes involving nanoparticles (NPs), their application inside the reservoirs for EOR and understanding of fines migration reducing, among other physical phenomena is also studied. Carbon capture and storage (CCS) is a worldwide strategy for mitigating climate change. CO2 geosequestration is also analyzed on the leakage of CO2 and brine from aquifers and their implication to the security of the storage and environment. Recent studies show that, globally, CO2-EOR can extract up to 375 billion of additional oil barrels and geological storage up to 360 Gt of CO2 in the next 50 years. Pre-salt is a complex of microbial carbonate reservoirs with stromatolite framework in ultra-deep waters (1500–3000) m depth, underneath by thick salt layer (2000–2500) m. Its reservoirs are in the depth up to (5500–6500) m TVDSS and approximately (200–300) km offshore. It presents light oils and high (GOR) ranging (200–400) Sm3/Sm3 and huge CO2 contamination (8–15)%. Due to the large CO2 content of oil, this work investigated CO2-EOR and CO2 geosequestration within the reservoirs. Pilot test demonstrated that miscible CO2-EOR with WAG is feasible and beneficial to this hydrocarbon Province. This study also calculated and validated the potential of CO2-EOR to the CCS. It concludes that Pre-salt can contribute to recovery factor (RF) increasing about 5.7 billion of additional oil barrels, and to CCS with about 266 Mt CO2 to be geological stored, for the next 20 years. In this context, this work also analyses the recent changes on the Brazilian oil and gas regulation to encourage new international Companies to enter in Brazil and Pre-salt for petroleum exploring. In Pre-salt, CO2-EOR also connects the petroleum energy system to CCS, transforming the oil reservoir in a carbon sink. These results represent a substantial role of Pre-salt to the energy efficiency of energy resources recovering from the biosphere and a high contribution to the climate change mitigation. [ABSTRACT FROM AUTHOR]

Enhanced weathering is a simple and scalable negative emissions technology with an estimated carbon dioxide removal potential of multiple gigatons per year. To date, the only life-cycle assessment of enhanced weathering was published by Lefebvre et al. (2019) in this journal. They estimated the carbon dioxide removal potential in Sao Paolo State in Brazil to be 1.3–2.4 Mt/y, examined the penalty from transportation greenhouse gas emissions, and pointed out that using life-cycle assessment can give more reliable estimates of climate change mitigation potential of enhanced weathering systems. In this letter, we discuss the limitations of life-cycle assessment of enhanced weathering, and then propose a more comprehensive life-cycle optimization approach, where the system configuration can be automatically synthesized to maximize environmental performance. This concept can be extended further to life-cycle sustainability optimization by including economic and social dimensions. • The first life cycle assessment of enhanced weathering was reported in 2019. • Life cycle optimization and life cycle sustainability assessment are also needed. • A combined life cycle sustainability optimization framework should be developed. • Hybrid models can be used to address future issues in enhanced weathering. [ABSTRACT FROM AUTHOR]