Mexican national oil company Pemex has begun signing contracts with oilfield service firms specifically invited to submit bids for a new batch of priority exploration and production projects, the state-owned company's chief executive said.

CEO Octavio Romero said on the sidelines of an energy event in Ciudad del Carmen, home to numerous Pemex installations in the southern Gulf Coast state of Campeche, that the closed bidding process offers Pemex cost savings.

"We invite the companies, who form consortia to carry out these comprehensive projects, from construction of the facilities, the drilling of wells, laying both marine and onshore pipelines ... and the consortium that offers the best price wins," Romero told reporters late on Thursday.

The CEO said he expects all the related contracting for this year's projects to be finalized by the middle of this year. Romero, a close confidant of President Andres Manuel Lopez Obrador, has previously said Pemex aims to discover and develop 20 new oil and gas fields each year, targets viewed as extremely optimistic by industry analysts.