Geo.: Gas Production in Offshore Reservoirs in Brazil’s Pre-salt Region

Abstract

This study is focused on the natural gas production in the pre-salt area, in Brazil, where much of the expansion of the Brazilian oil industry is projected to occur. The oil production is based on a previous study, which indicates that in 2050 the pre-salt oil production can reach up to 3,160,000 bpd, and the total Brazilian oil production can be up to 3,765,000 bpd. Simulations were made to try to estimate the natural gas production for the period between 2015 and 2050. One great challenge of the petroleum production in this area is to deal with the large amount of CO2 present in these fields. This study considered Carbon Capture and Storage (CCS) as a mitigating option for the CO2 that would be emitted during the petroleum extraction. Carbon capture and storage (CCS) is recognised as a technology capable of reducing the large-scale emissions of carbon dioxide (CO2), which is an important part of the portfolio of alternatives necessary to achieve significant reductions in the global emissions of greenhouse gases (GHG). This study identified that the most suitable carbon capture method for the platforms (Floating Production, Storage, and Offloading (FPSOs)) that will operate in Brazil’s pre-salt fields is the use of membranes. Based on this capture method (membranes), the UOP Separex™ module system is selected as the standard to be tested. It is a compact module that can be installed on FPSOs. Because there remains considerable uncertainty over the precise amount of CO2 present in the natural gas from the pre-salt fields, a wide range, between 10 and 45 %mol of CO2 content was considered. The membrane area for each module was considered to be equal for both 10 %mol and for 45 %mol of CO2. The results show that in 2050, the gas production in the pre-salt region can be around 35,000 Mm3 per year, considering that the amount of CO2 in the natural gas is 10 %mol. However, it can be up to 20,000 Mm3 when considering that the amount of CO2 present in the natural gas is around 45 % mol.