The China Petroleum and Chemical Corporation (Sinopec) and Ecuadorian company Dygoil have bought bidding rules to participate in the tender that Ecuador's state oil company Petroecuador is holding to boost production on its four main fields, Petroecuador said in a statement.
Sinopec and Dygoil both bought bid rules for the Culebra-Yulebra and Auca blocks. The two blocks together have estimated reserves of 272 million barrels (mb) of oil.
The other two blocks on offer are Lago Agrio and Shushufindi, with combined reserves of 631mb.
Petroecuador recently delayed the deadline to receive bids on the blocks to March 23 from January 23 to allow more companies to participate in the tender, the statement said.
Russian energy company Acces-Wilca, Chinese oil company CNCP, and the Sipetrol international subsidiary of Chile's state oil company Enap have bought the Culebra-Yulebra rules.
Brazil's federal energy company Petrobras and Spain's Repsol YPF have bought bidding rules for all four blocks, while Argentina's Tecpetrol and the Ecuadorian subsidiary of UK oil company Perenco have bought bidding rules for the Auca and Culebra-Yulebra fields.