In developing its Tupi oil field in the Santos Basin, Petrobras was looking for a CCUS solution to avoid the venting of associated natural gas that has a high carbon dioxide composition of 8%-40% in some wells. However, capture technologies had not been tested in a location 300 km off the coast and over 2 km below the ocean’s surface and it was unclear how best to handle the captured carbon dioxide.
It decided to test Water-Alternating-Gas injection technology in this remote environment, simultaneously reducing carbon dioxide emissions and optimizing oil recovery. Following a successful pilot project in 2011, Petrobras started commercial scale capture and carbon dioxide enhanced oil recovery two years later. There are now eight floating production, storage, and offloading units incorporating carbon dioxide separation and injection facilities moored in the area.
As of December 2019, Petrobras had reinjected 14.4 million tonnes of carbon dioxide into rock reservoirs. This technology is one of the enablers of Petrobras having reduced the upstream’s carbon intensity of its operations by more than 40% from 2009 to 2019. The Santos Basin programme is the third largest carbon capture, utilization and storage (CCUS) project in the world, accounting for around 12% of global capacity. As new production units come on stream, Petrobras aims to reach a total of 40 million tonnes of reinjected carbon dioxide by 2025.
Petrobras invested over US $115 million in CCUS research and development between 2006 and 2019, helping to tackle the challenge of not releasing carbon dioxide produced to the atmosphere in ultra-deep waters. In November 2020, it won the Firjan Sustainability Award for its innovative solution in combining carbon dioxide storage in rock reservoirs with optimizing oil extraction.
Image credit: André Motta / Banco de Imagens Petrobras