Utilize the input text as a context reference, choose the right relationship between Petrobras and gas from the options. Options: product/material produced, manufacturer, distributed by, industry, position held, original broadcaster, owned by, founded by, distribution format, headquarters location, stock exchange, currency, parent organization, chief executive officer, director/manager, owner of, operator, member of, employer, chairperson, platform, subsidiary, legal form, publisher, developer, brand, business division, location of formation, creator.

By the end of 2012, Petrobras said, it would be producing 3.5 million barrels of oil and equivalent natural gas per day (boepd) worldwide, and by 2015 4.6 million boepd, making it one of the world's largest producers.
product_or_material_produced