Integration of a Typical Brazilian Pre-Salt Benchmark to a Topside Base Case to Consider Energy Demand and Carbon Dioxide Emissions in Reservoir Development and Management Studies

Abstract

Abstract. The transition to sustainable energy and the goal of net-zero carbon dioxide (CO2) emissions by 2050 highlight the need to optimize energy use and reduce emissions in the oil and gas industry. Offshore platforms, especially in Brazil's pre-salt fields, rely on energy-intensive processes that contribute significantly to CO2 emissions. This study integrates a representative pre-salt reservoir with a topside energy model to evaluate energy demand and emissions under different reservoir management strategies. A proxy embedded within the reservoir model dynamically allocates gas between reinjection and fuel consumption, while key separation stages ensure consistency with topside processes. Two production optimizations were compared: full gas recycling and partial recycling, where part of the produced gas supplies platform energy. In the partial recycle case, the final solution achieved a net present value only 0.2% lower than full recycling, while reducing energy demand and CO2 emissions by 9.3%. This approach is more representative of industry practice and becomes increasingly advantageous when costs are assigned to fuel use and emissions. The strategies also led to distinct well placement configurations and management outcomes: in the full recycle case, 70% of injectors operated with water-alternating-gas cycles of 366 days or less, whereas in partial recycling, 80% had cycles of 548 days or more. These results underscore the importance of incorporating topside gas allocation into reservoir optimization and highlight the value of integrating energy and environmental considerations to support more sustainable decision-making.