(Adds regulator quote, expected output)
By Adriana Barrera
MEXICO CITY, Feb 27 (Reuters) - Mexico has approved the auction terms for five shallow water areas containing around 355 million barrels of oil equivalent as part of its Round One tender opening up oil fields to foreign investors, the country's energy regulator said on Friday.
Round One includes several fields grouped by basin, with the first batch of 14 contracts approved in mid-December.
The terms of the newly-approved second tranche will be published later on Friday, the National Hydrocarbons Commission (CNH) said. The five shallow water areas comprise 9 oil fields, most of them with proven reserves.
Edgar Rangel, a CNH Commissioner, said he expected output from the fields to average 125,000 barrels per day (bpd), with the potential to rise to 150,000 bpd.
"It is a very good volume, it is good crude," Rangel said.
Round One covers areas including the Chicontepec basin and the Perdido area, including shallow and deep water fields, and the government expects to attract up to $50.5 billion in investments between 2015 and 2018.
Last month, however, the government said tenders for the exploration and production of shale and other more expensive oil and gas deposits could happen later than planned because of the slump in oil prices, which could also affect government spending in 2016.
State-run oil company Pemex has postponed some deep water exploration projects and will cut jobs because of the slump.
Pemex is struggling to reverse a decade-long slide in crude production and exports after the historic overhaul of the domestic energy sector was finalized last year, ending its long monopoly.
Mexico is the world's 10th largest crude producer and oil revenue makes up about a third of its budget. (With reporting by Ana Isabel Martinez, Christine Murray and Joanna Zuckerman Bernstein; Editing by Simon Gardner, Andre Grenon and Meredith Mazzilli)