Total said the Tempa Rossa field in southern Italy could produce as much as 50,000 barrels of oil per day and more than 8 million cubic feet of natural gas when it comes on stream within the next four years.
The project represents a $1.9 billion investment for Total, which has a 75 percent stake in a partnership with Shell at the field.
Yves-Louis Darricarrere, president of Total's exploration division, said the field represents a "significant achievement" for his company.
"The field has significant potential and will make a strategic contribution to regional economic development," he said in a statement.
Italy this week placed a temporary ban on short selling on its stock exchange as it struggles to cope with the ongoing European sovereign debt crisis.
Total said it expects production will entail the use of eight wells in the onshore field, six of which have already been drilled. A production center associated with the field would store gas and process oil for later exports.