The company this week acquired private Russian oil company Surgutneftegas's stake in a consortium managing the Junin-6 oil field in Venezuela. That consortium has a 40 percent stake in the field alongside state energy company Petroleos de Venezuela, or PDVSA.
Rosneft Chief Executive Officer Igor Sechin said his company plans to invest $10 billion on projects in Venezuela. This would support Rosneft's 15 million tons of annual oil production in the Latin American country, reports state-owned news agency RIA Novosti.
Russian energy company Gazprom Neft, a member of the consortium, said it expected Junin-6 would cost around $25 billion to develop and eventually reach a peak production level of around 450,000 barrels of oil per day.
Venezuela has some of the largest deposits of crude oil in the world. The Orinoco belt, which includes Junin-6, is considered one of the biggest reserve areas outside of the Middle East.
The health of Venezuelan President Hugo Chavez has raised concerns about the prospects of a struggling oil sector. Chavez is reportedly in Cuba for cancer treatment.