LISBON, April 13 (Reuters) - Portugal's Galp Energia : ** Said in a statement on Monday that its oil output rose 42.5 percent in the first quarter from a year earlier to 38,400 barrels of per day. ** Oil and gas working interest output up 47.7 percent to 41,500 barrels of oil equivalent per day. ** Galp processed 34 percent more crude and gas, with 26.19 million barrels refined. ** Sales of refined products rose nearly 20 percent to 4.4 million tonnes. ** Total natural gas sales rose 5.6 percent to about 2.2 billion cubic metres. ** Due to post fourth-quarter earnings on April 27.