Oil majors including Chevron, Total, Shell, BP and Argentinian state energy firm YPF have been among the companies tipped to invest $5bn (£4bn) this year into the sprawling Vaca Muerta shale deposit in Neuquen Province, which is almost the size of Belgium.
This investment to undertake exploration and hydraulic fracturing, or fracking, at the site will rise to $15bn in subsequent years, the Financial Times reported.
As part of the agreement, Argentina will offer a subsidised price of $7.50 per million British thermal units of natural gas produced at new wells until 2020. In a statement, the government called the subsidised price "indispensable for attracting long-term investment".
Although Vaca Muerta (which translates as "dead cow") has drawn investment from US firms such as Chevron and Exxon Mobil, it is largely unexplored.
"This is a day that will open the energy future of our country," Argentinian President Mauricio Macri said in a televised address. "We have to give guarantees and provide certainty in order to attract investment."
Production from Vaca Muerta is about 50,000 barrels of oil a day, which is expected to double by 2018.
Argentina's recoverable shale oil reserves are estimated at 27bn barrels.
In November, Argentina's state-controlled energy company YPF announced an additional $192.5m joint investment to work on the site with Malaysian state firm Petronas. The two companies put nine wells into production in the Amarga Chica block, located in Vaca Muerta, between May 2015 and September last year with a $165m investment.
Local newspaper La Nacion reported on Sunday that Macri's government has decided to lift a 15-year-old export duty on oil and oil products.
Macri, who took office in December 2015, has been trying to spur energy investments to help bolster Argentina's economy, which is in recession.