(Adds official announcement)
BUENOS AIRES, July 14 (Reuters) - Pan American Energy LLC , a unit of BP, said on Thursday that it will invest $1.4 billion in exploring and producing Argentina's conventional and unconventional energy reserves.
Its plans include a $900 million investment in Golfo San Jorge, mostly in the province of Chubut where it operates the country's biggest oil field, and $300 million in the shale-gas-rich province of Neuquen, the company said in a statement.
Pan American started exploring for unconventional oil in Neuquen in 2011 and develops shale gas there.
The company has reported a 34 percent rise in its oil output in Argentina from 2001 and 2015, bringing it to 108,000 barrels per day. Its production of gas rose 67 percent to 19 million cubic meters per day in the same period. (Reporting By Eliana Raszewski, Additional Reporting by Nicolas Misculin, Writing by Mitra Taj; editing by Grant McCool)