MEXICO CITY, June 18 (Reuters) - Spanish oil company Repsol and China's Sinopec are among the 16 energyfirms and consortia that have qualified for next month's auctionof six blocks in Mexico's Chicontepec basin, state-run oilmonopoly Pemex said on Tuesday.
The Chicontepec basin, discovered more than 80 years ago, islocated in the east-central states of Veracruz and Puebla and ishome to about 40 percent of Mexico's certified hydrocarbonreserves.
The six blocks up for auction - Pitepec, Amatitlan, Soledad,Miquetla, Humapa and Miahuapan - make up about 15 percent of thebasin's total reserves, or about 3.2 billion barrels of crudeequivalent (bce), according to Pemex data.
The July 11 auction will mark the third round of thecountry's fee-per-barrel private contracting scheme, fruit of a2008 reform aimed at revitalizing aging oil fields.
While Mexico's constitution mandates that only the state canown and extract oil and gas resources, President Enrique PenaNieto has promised a reform to attract new investments fromprivate oil companies aimed at boosting lagging production.
While details of the reform have yet to be revealed, a formalproposal is expected by September.
Repsol's Mexican unit is set to compete for all six blocks,while the local arm of Sinopec will bid on two, Miquetla andPitepec, Pemex said.
The Miquetla block holds the most proven, probable andpossible (3P) reserves among the blocks, or about 1 billion bce.
Both Schlumberger, the world's biggest oilfieldservices company, and Halliburton, the second biggest,will also compete for all six blocks up for grabs.
While international oil majors BP and Royal DutchShell both purchased project specifications, neitherultimately sought to qualify for the auction.
Last year, Chicontepec produced an average of 74,800 barrelsper day (bpd).
But despite heavy investment, Pemex has failed tomeet previous production forecasts at the geologicallycomplicated basin, where millions of barrels of oil arescattered across many small deposits, a feature that makesproduction costly and slow.
Mexico is the world's No. 7 oil producer but output hasstagnated in recent years, dropping by roughly a quarter sincehitting a peak of 3.4 million bpd in 2004.
