In the context of the input sentence, determine the relationship between 'Petrobras' and 'gas'.
Options: product/material produced, legal form, developer, operator

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/material produced