Denmark's AP Moller Maersk A/S (MAERSK-B.KO) said Tuesday its Maersk Oil unit has agreed to buy stakes in Mexican Gulf oil fields from Devon Energy Production Company, L.P. for a total cash payment of $1.3 billion.

The transaction comprises a 50% participating interest in the Cascade field and a 25% participating interest in each of the Jack and St. Malo fields, it said.

Maersk Oil estimates additional investments of $1.3 billion-1.8 billion ahead of on-stream production, going up to around $4 billion over time.

The Petrobras (PZE) operated Cascade field is expected to commence production in 2010 and the Chevron (CVX) operated Jack and St. Malo fields are expected to commence production in 2014, it said.

Maersk Oil's estimated share of recoverable resources from the three fields combined is more than 200 million barrels of oil equivalent.

At 1338 GMT, shares in AP Moller Maersk were up 0.3% at DKK35,400, against a flat overall market in Copenhagen.