The strategy is being undertaken at three massive offshore oil fields located 230 kilometres (143 miles) off the coast of Rio de Janeiro. Petrobras separates CO2 from natural gas produced as a byproduct of oil extraction using specialised membranes. It then reintroduces the carbon into the reservoir.
The process raises subsurface pressure in reservoirs, making it easier to bring more oil to the surface and extending the field’s life. The removal of CO2 enables Petrobras to safely pipe the remaining natural gas to shore. Otherwise, leaks could occur because CO2 forms carbonic acid, which corrodes steel pipes, and Brazil’s offshore gas contains high levels of the pollutant.
“It’s driven by operational concerns. It has nothing to do with environmental consciousness. They shouldn’t take any credit for it.” said Cleveland Jones, a consultant and researcher at the National Institute of Oil and Gas in Rio de Janeiro.
However, Petrobras emphasizes in its most recent sustainability report how the carbon capture program reduces emissions intensity, or the amount of greenhouse gases emitted per barrel of production. Carbon capture is also listed as one of its main green technology achievements. Petrobras developed the technique in the late 2000s as the most viable means to transport petrol from the middle of the ocean to end consumers on land.
Carbon injection can have a net positive impact on the climate if the carbon is captured from the atmosphere or industrial sources as opposed to reinjecting CO2 that was in the ground to begin with. The latter, though, is what’s used widely throughout the oil industry to increase fossil fuel extraction.
Brazilian policies governing fossil fuel operations also forced Petrobras’s hand: Flaring or venting the CO2 separated from the natural gas would break Brazilian regulations. To bring the natural gas ashore and avoid corroding its pipelines, Petrobras had to find a technical solution.
In response to questions, Petrobras clarified that it isn’t including the carbon reinjection program — known as carbon capture, utilization and storage — as part of its net emissions reduction or as a potential source of carbon offset credits. Still, the company highlights how it plans to reinject an accumulated 80 million tons of CO2 from 2015 through 2025 as a major advance in its climate commitments.
“We have the largest offshore CO2 reinjection program in the world,” it said in its climate change report.
Petrobras has two pipelines which utilize carbon capture to clean natural gas from offshore reserves and plans to put a third pipeline into service next year. This could increase supplies by up to 21 million cubic metres per day and reduce Brazil’s reliance on costly liquefied natural gas imports from Bolivia, which has become an unreliable supplier of the power-plant fuel.
Petrobras produces oil that is comparatively low in carbon, both from the amount of energy used to produce the oil, and the chemical makeup of the oil itself. A single well in Brazil’s so-called pre-salt offshore region can produce more than 50,000 barrels a day, while it takes more than 5,000 wells to produce the same amount in Texas’s famed Permian Basin. This means it takes less energy and emissions in Brazil to produce the same amount of oil. That’s in part due to the company’s use of C02 to boost the efficiency of its wells.
Though many producers are making efforts to cut pollution on-site, the majority of a barrel of oil’s greenhouse gas emissions are produced when it’s burned by consumers for transportation or energy.
Petrobras also claims that its more than a decade of CO2 reinjection knowledge would enable it move into other types of carbon storage, such as gathering emissions from refineries and storing them in disused oil fields, which may be a source of carbon credits. To offset its emissions, the oil industry has been advancing carbon capture and storage initiatives. Occidental Petroleum Corp. is absorbing carbon from the atmosphere and injecting it into oil fields as part of a plan to eventually achieve net zero emissions from its petroleum.
Other oil companies have had trouble getting carbon capture to function. Chevron’s Gorgon CCS carbon capture and storage project in Australia is injecting barely a third of the carbon that it is expected to and faces years of effort to attain full capacity. The project was meant to capture and store 4 million tonnes of CO2 per year from a liquefied natural gas facility.
According to various lines of research, carbon capture will need to increase to reach net zero by 2050 if the globe is to prevent warming by more than 1.5 degrees Celsius. While more than $7 billion was invested in carbon capture projects between 2018 and 2021, BloombergNEF reported last year that more than 70% of all captured CO2 is used for enhanced oil recovery. The paper also stated that the usage of carbon capture for oil extraction by fossil fuel companies for more than 30 years has contributed to a lack of general acceptability of the technology.
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