By Jack Kimball BOGOTA, Aug 9 (Reuters) - Pacific Rubiales Energy Corp , the largest private oil producer in Colombia, said on Thursday it would raise output from its Rubiales field by 10.5 percent to 210,000 barrels of oil equivalent per day (boepd) in 2013 versus the end of 2012. Latin America's fourth-biggest oil producer, Colombia, has ramped up oil output over the last decade after a U.S.-backed military offensive made areas of the country safer for investors and helped reverse years of declining crude output in the 1990s. Thanks to an environmental license at its Rubiales oil field, it should increase production to 190,000 boepd by the end of 2012 and to 210,000 boepd in 2013, CEO Ronald Pantin told an investor call about the company's second quarter results. The Rubiales field currently produces 172,000 boepd. The field located in the heavy-oil-rich Llanos Basin is one of Colombia's signature success stories. Burnt to the ground by rebels more than a decade ago, better security and fiscal terms has turned Rubiales into Colombia's top producing field. A military crackdown over the last decade pushed Marxist guerrillas into remote hideouts, and foreign oil companies have flooded in, snapping up assets in a country once largely dismissed as a failing state. The FARC rebel group is weaker than it has been in decades, but still poses a threat and has stepped up attacks on the oil industry while the sector has also faced increased demands from local communities in oil-producing provinces. Colombia's national oil production has shot up to a record of around 950,000 bpd and the government hopes to hit 1 million bpd this year -- increased output at Pacific's fields are seen as key to reaching the goal.The company said it expected production at its Quifa field, also in the Llanos, to rise to 60,000 bpd by the end of this year from 44,500 bpd in the second quarter. It did not give an outlook for output in 2013 for Quifa. In the April-June period, Pacific sold 42 percent of its crude to the United States, 31 percent to Europe and 20 percent to Southeast Asia. Total production for Pacific -- which also has operations in Peru -- was around 250,000 bpd on Aug. 7, the company said. Net income in the second quarter fell 36 percent versus the same period last year to $224 million while gross revenue increased 8 percent to $1.04 billion in the same timeframe. "Overall, the financial results of the second quarter, 2012 evidenced the deterioration of margins due to higher costs and expenses, and confirmed our concerns regarding the lack of growth in production due to the delay in the approval of licenses," local brokerage InterBolsa said in a research note. "However, we expect a positive effect on the stock price, as we believe that the approval of the environmental license to expand production at the Rubiales field and the positive results of the exploration campaign in Quifa North and Sabanero should offset a slightly negative reading of the financial results." Pacific stock rose 4.2 percent on the Colombia's stock exchange on Thursday.