BUENOS AIRES, Jan 16 (Reuters) - Combined shale oil and natural gas output from Argentina's vast Vaca Muerta formation was about 33,000 barrels of oil equivalent per day (boepd) at the end of September, with a trend toward growth, data from the formation's home province of Neuquen showed on Friday.
The information from the province's mining and energy department showed a sharp increase in unconventional oil and gas production when compared with Vaca Muerta output of 13,779 boepd in January 2014 and 4,775 boepd in January 2013.
"The upward trend continued in October, November and December but I cannot say by how much. Fourth-quarter production numbers are not available yet," said a source in the provincial government with knowledge of the situation but who asked not to be named due to being unauthorized to speak to the press.
State-run oil company YPF does not publish Vaca Muerta production data on an ongoing basis.
YPF says it wants to attract $200 billion in investments needed for Argentina to close its $7 billion per year energy deficit. YPF was nationalized in 2012 when the Argentine government seized 51 percent of the company from Spanish oil major Repsol.
The South American grains powerhouse began running energy deficits in 2011, a year before President Cristina Fernandez expropriated YPF. She said at the time that former parent company Repsol was under-investing in Argentina. (Reporting by Hugh Bronstein; Editing by James Dalgleish)