By Christopher Bjork

MADRID--Repsol SA said Tuesday it has reached an agreement with the board of directors of Talisman Energy Inc. to acquire the Canadian oil company for US$8.3 billion, in a deal that will almost double the Spanish company's oil output right away and boost its potential for further expansion.

The deal has been unanimously approved and recommended by the two boards, Madrid-based Repsol said early Monday. Calgary-based Talisman separately confirmed the planned all-cash purchase.

Repsol is offering $8, or 9.33 Canadian dollars, for each Talisman share, a 60% premium to the average price over the past month, Talisman said.

Taking on Talisman's 2,809 employees would nearly double Repsol's exploration and production staff. While the Spanish company has a market value five times as big as Talisman's, it remains a tiny competitor in oil production and for more than a year has been shopping for an acquisition that would bolster its production capacity.

The addition of Talisman will increase Repsol's output by 76%, to 680,000 barrels of oil equivalent per day, and boost reserves by 55% to more than 2.3 billion barrels of oil equivalent, Repsol said.

The purchase of Talisman is expected to close by mid-2015, the Spanish company added

Write to Christopher Bjork at christopher.bjork@wsj.com

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