Refer to the input text as context and select the correct relationship between 'Petrobras' and 'gas' from the available options.
Options: chief executive officer, distributed by, product/material produced, distribution format

But now, after about $250 billion of investment and the discovery of some of the world's largest offshore oil and gas resources, Petrobras is producing 2.8 million boepd, 20 percent less than its estimate for 2012 output.
product/material produced