Firms from a range of countries will invest $2.12 billion to develop oil fields in Ecuador's Amazon basin region, the government said Wednesday.

Oil companies from China, France, the United States, Argentina, Colombia and Ecuador will work to boost output on 17 fields considered mature, where there are reserves of some 277 million barrels.

"We are talking about $2.12 billion in private investment in the best area for oil production in Ecuador. It's great news," said Vice President Jorge Glas.

The companies involved are Franco-US Schlumberger; Argentine Tecpetrol and YPF; Colombia's Montecz and Edinpetrol; US firm Halliburton; China's Sinopec; and Ecuador's Sertecpet.

Ecuador, OPEC's smallest member, has total oil reserves estimated at 4.5 billion barrels. It produced 526,000 barrels per day in 2013 mostly through state oil concerns.