Ecopetrol holds a 50% interest in the Magdalena Middle Valley's Boranda-1 well, which is operated and 50% controlled by Canadian exploration company Parex.
CEO Juan Carlos Echeverry says "2016 was a year of enormous challenges for Ecopetrol," but he believes increased investment in 2017 will improve results in the coming years.
"Investment reductions are expected to affect its ability to replenish reserves in the long run above production levels," said Lucas Aristizabal of Fitch.