Argentine oil company YPF, a unit of Spain's Repsol-YPF, said it found more than 150 million barrels of shale oil at the Loma La Lata field, located in the western province of Neuquen.

YPF CEO Sebastian Eskenazi made the announcement Tuesday at a ceremony in Neuquen in which he was joined by President Cristina Fernandez - via videoconference - and Planning Minister Julio de Vido.

"In an event last year with the president, we announced a (non-conventional) gas discovery (that was) one of our most significant. A lot of people criticized us, others told us it was small. But YPF is serious first and foremost: when we say things, we fulfill them and push ahead with them," Eskenazi said.

The new find was made in the Vaca Muerta formation, a source rock that covers 30,000 sq. kilometers (11,583 sq. miles) in the Neuquen basin, where YPF controls about 12,000 sq. kilometers (4,633 sq. miles).

"In Loma La Lata and Vaca Muerta, in an explored area of just 320 sq. kilometers (123 sq. miles), we have 150 million barrels of resources, (equivalent) to almost 35 percent of YPF's oil reserves (which creates) enormous expectations for the future," Eskenazi said.

Shale is a porous sedimentary rock that often holds petroleum or natural gas that must be extracted using hydraulic fracturing, or "fracking," which involves injecting a mixture of water and chemicals at high pressure to release the hydrocarbons trapped in the rock.

"What's important about this discovery is not just the volume. What's important is that it's something new. It's new energy with a new future and new expectations," Eskenazi said.

YPF, Argentina's largest hydrocarbon producer, will begin developing a pilot area covering 25 sq. kilometers (9.7 sq. miles) and expects to drill 17 new wells and fracture another 14 existing wells through year's end at a total investment cost of $270 million.