The onshore Caño Sur block spans 611,396ha in Colombia's Llanos basin. It is operated by state company Ecopetrol (100%) under a license granted by hydrocarbons regulator ANH in 2005. The 24-year license kicks in once the project's commercial viability is declared, with royalties ranging from 6.00% to 18.75%, depending on production levels. The project is divided along three geographical areas: east, central and west. The block's exploration phase started in 2008 and, by December 2013, more than 61 wells had been drilled, including exploratory, stratigraphic and delimiter wells. The commercial viability of Caño Sur's eastern area – 54,112ha, or 9% of the block's total surface area – was declared in December 2013. Ecopetrol plans to invest US$656mn and drill 135 holes in 2014-2018 to develop the eastern area, where production could increase to 25,000boe/d by mid-2016.