Italian energy giant ENI has agreed to buy UK-based oil producer Burren Energy for £1.736bn ($3.58bn).
Burren Energy's operations include oil fields in Turkmenistan.
ENI agreed to pay £12.30 per share for the firm, which has operations in Turkmenistan, Congo, Egypt and Yemen.
The deal has been in the balance for several weeks, with ENI making offers of £10.50 and £12 a share, offers that Burren rejected.
Shares in Burren rose 101 pence, or 8.84%, to 1243 pence on news of the takeover.
Foothold in Turkmenistan
The deal increases ENI's output in Congo and gives it a presence in Turkmenistan, a country with "increasingly attractive" growth potential, it said.
The offer represents a premium of 50.6% to the average closing price of 817 pence per Burren share for the three months to 8 October, Burren said in a statement.
"The price achieved reflects the high quality and strategic nature of our business and assets," said Burren chairman Keith Henry.
Burren was founded in 1994 by Finian O'Sullivan, who still has a stake of about 4% in the firm.
Burren, which floated in 2003, has a minority stake in Indian firm Hindustan Oil Exploration and also has a small oil shipping business.
Record oil prices and demand for new sources of supply have added to interest in mergers and acquisitions in the oil sector.