CIDADE ANGRA DOS REIS PLATFORM (Reuters) - Brazilian state oil company Petrobras will begin sequestering carbon dioxide in the offshore Lula oil field in the coming months to boost production and lower the environmental impact of its deep water crude exploration campaign.
Brazil’s offshore oil fields in the vast region known as the subsalt, which the country hopes will turn it into a major oil exporter, contain large quantities of CO2 that Petrobras does not want to release into the air because of the associated greenhouse effects.
“CO2 re-injection is common in the industry, but it is not common offshore and certainly not at this depth and pressure,” said Rivadavia Freitas, a Petrobras engineer who works on the offshore production platform Cidade Angra dos Reis.
The company expects to begin re-injecting the gas by March either back into the oil reservoirs, which would boost their productivity, or into sub-sea salt caverns to keep it from entering the atmosphere.
Some analysts have said the CO2 reinjection could lead to higher production costs in the subsalt region, but Brazilian environmental regulators have instructed Petrobras that the CO2 must not be released.
The platform is moored at the Lula field about 300 kilometers (186.4 miles) from the coast of Rio de Janeiro at a water depth of 2,150 meters (1.3 miles), with the oil lying some 5,000 meters (3.1 miles) below the ocean’s surface.
Equipment on board the platform will separate the carbon dioxide from the natural gas that is produced along with the oil. When the platform reaches full production, Petrobras could re-inject as much as 1 million cubic meters of C02 per day.
Controlling CO2 is crucial not only to limit climate impact but also to reduce corrosion of equipment and deep sea pipelines caused by the mixture of CO2 and water. The company is testing specialized materials that can resist those corrosive effects.
Norwegian oil company Statoil since 1996 has captured and sequestered carbon dioxide associated with natural gas produced in the offshore Sleipner West field, in part responding to a Norwegian carbon emissions tax that gave the company economic incentive to avoid releasing it into the environment.
Reporting by Brian Ellsworth; Editing by John Picinich