UPDATE 1-Mexico's Pemex to tender Ayatsil bids later in 2009

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VERACRUZ, Mexico, June 11 (Reuters) - Mexico's Pemex will tender bids for the construction of platforms at the Ayatsil heavy oil fields later this year and the company expects to begin production there by the middle of 2011, a engineer from the company said on Thursday.

The field is expected to reach a peak of 65,000 barrels per day by 2015, said the engineer, who declined to be named because he is not authorized to speak to the press.

"This is the first phase of our exploitation plan of extra heavy crude that is an important part of the future of Pemex," the engineer said.

Ayatsil, found last year, is expected to help extend the life of Ku Maloob Zaap, which overtook the Cantarell field as Mexico's most productive oil field this spring.

Hector Salgado, another Pemex engineer, said on Thursday the Ku Maloob Zaap oil field is currently producing at a peak 830,000 bpd and will continue to produce at that level for the next seven years.

Pemex said earlier this year that the production at the Ku Maloob Zaap field could begin to decline as early as next year. (Reporting by Robert Campbell; Editing by Christian Wiessner)