By Adriana Barrera and Ana Isabel Martinez

MEXICO CITY, Feb 6 (Reuters) - Mexican state company Pemex has awarded a contract for a crude oil and natural gas field to a company controlled by Carlos Slim, three sources with knowledge of the matter said, as the tycoon further strengthens his presence in the energy sector.

The so-called "mixed contract" for the onshore Macavil field in southern Mexico follows five contracts of the same model the state company awarded back in mid-December.

Under this new partnership model, Pemex retains at least a 40% stake. Pemex had planned to award 11 such contracts last year but interest has so far been muted and failed to draw big international players.

Reuters was unable to determine the name of the Slim-owned company that would receive the contract and its value. One of the sources said the contract was signed last week. Pemex and a spokesperson for Slim did not respond to requests for comment.

The contract for Macavil is billionaire Slim's latest foray into the energy sector as he adds to his vast business empire, which already includes telecommunications, infrastructure and consumer goods.

Macavil has proven reserves of 7 million barrels of condensate and 73 billion cubic feet (bcf) of gas and possible reserves of 34 million barrels of condensate and 409 bcf of gas.

The goal of the joint venture contract is to produce a total of 27.5 million barrels of oil and 393 bcf of gas by 2045, according to a project document seen by Reuters.

Pemex's strategic business plan for the next five years, presented a few months ago, projects peak crude production of 14,000 barrels per day at the field in 2028.

Slim, one of the world's richest people, has managed to cultivate close business relationships with Mexican governments of different ideological leanings over the years and is becoming increasingly close to the highly indebted state company.

In September, Slim's Grupo Carso GCARSOA1.MX agreed to finance the drilling of up to 32 wells in the Pemex-operated Ixachi onshore field, the country's most important known gas deposit.

Through Talos Mexico, a subsidiary of Talos Energy TALO.N, Slim's companies have also partnered with Pemex and Harbour Energy HBR.L in the Zama offshore oil field.

In 2024, Carso signed an agreement to partner with Pemex on the development of the Lakach deepwater gas project, seeking to revive a plan already abandoned twice before due to high costs. However, in October the company said it was reviewing the project's viability.

Slim is also expanding his reach in Mexican energy beyond deals with Pemex. In mid-January, Carso announced the purchase of a Lukoil subsidiary to gain full control of the Ichalkil and Pokoch fields.

(Reporting by Adriana Barrera and Ana Isabel Martínez; Editing by Stefanie Eschenbacher and Jamie Freed)

((adriana.barrera@thomsonreuters.com))