CARTAGENA, Colombia, May 15 (Reuters) - Attacks on Colombia's oil pipeline network by the country's leftist guerrillas have fallen by half so far this year, Mines and Energy Minister Amylkar Acosta said late on Wednesday, as surveillance has been stepped up.
Bombings are a persistent and costly nuisance for the Andean nation's oil sector, dominated by state-run Ecopetrol, shutting pipelines for days pending repairs with the run-off crude often polluting streams and rivers.
Acosta said there had been 39 attacks so far in 2014, half the 78 carried out this far into 2013. Seventy other attempted attacks were thwarted by the security forces this year, he said. He did not have a comparative year-ago figure.
"It's been shown that there is a better capacity of the armed forces to respond," Acosta told reporters, adding that the use of surveillance drones was also bolstering defenses.
Nonetheless, a string of bombings from March 25 on the Cano Limon-Covenas pipeline, which carries crude from the Cano Limon and Caricare oil fields, has had a bigger impact than usual and the line has been shut since then.
An indigenous community, the U'wa, who live near one of the damaged stretches, blocked attempted repairs for weeks, demanding the duct be routed away from their area. Acosta said the pipeline would re-open soon, but declined to be specific.
"We are finishing repairs on the various points of the pipeline," he said, estimating the shut-down had cut oil production by a total 3.1 million barrels so far, equating roughly to three days' nationwide crude production.
Colombia produces around 1 million barrels of oil per day and together with mining, the sector accounts for almost three- quarters of the country's exports. (Reporting by Peter Murphy; Editing by Dan Grebler)