The expansion is expected to cost US$3.8bn and will double the plant's capacity to 165,000b/d. Works are expected to be completed in the first half of 2013, the statement said.
The modernized plant will enable a high conversion rate, a recovery of valuable products rate greater than 95% and the production of fuels with low sulfur content, according to the statement.
In addition, the modernized refinery will allow integration with the petrochemical industry and will allow Reficar to offer a basket of competitive products in premium markets, meeting the highest national and international environmental standards.
Ecopetrol in May completed the purchase of a 51% stake held in the Reficar JV that had been set up to expand the Cartagena refinery from Switzerland's Glencore.
Ecopetrol now has a 100% stake in the expansion project. The Swiss firm had been unable to finance its share of the project.