(Adds EBITDA, average oil, gas output, background)
BOGOTA, April 30 (Reuters) - Colombia's state-owned oil company Ecopetrol said on Wednesday net profit fell 3.6 percent as crude oil production declined.
Consolidated net profit totaled 3.29 trillion pesos ($1.7 billion) in the first quarter versus 3.41 trillion pesos a year ago.
Non-consolidated crude oil production fell 3.8 percent from the same period last year to 504,400 barrels of oil equivalent per day (boepd) in the quarter, while gas output rose 4.5 percent to 107,300 boepd, Ecopetrol said.
Consolidated earnings before interest, taxes, depreciation and amortization, or cash flow, slipped 0.5 percent to 7.7 trillion pesos, good for a margin of 49 percent versus 52 percent a year before.
The company will hold a conference call at 1500 GMT to discuss the results with analysts.
The crude distillation unit of Ecopetrol's Cartagena refinery, one of two main refining plants in Colombia, has been shut down for upgrades since March while the same refinery's cracking unit was taken off line last year, prompting the company to boost fuel imports.
Colombia's oil sector has been hampered by an increase in bomb attacks on pipelines by the Andean nation's left-wing guerrillas. The attacks totaled 259 last year, the highest in a decade.
Oil companies usually manage to repair and restart the pipelines within a few days.
The company's Cano Limon-Covenas pipeline, which carries oil from the Cano Limon and Caricare fields operated by New York-listed Occidental Petroleum Corp, has been shut since a bomb attack by rebels on March 25. The company has been unable to get access to the site, which was being blockaded by an indigenous community living nearby. ($1 = 1934.0800 Colombian pesos) (Reporting by Peter Murphy; Editing by Jeffrey Benkoe)