(Refiles to clarify name is Det norske)
OSLO/LONDON, Nov 16 (Reuters) - Norway's Det norske oljeselskap has agreed to buy Premier Oil's Norwegian business in a $120 million cash deal that prompted gains in both companies' shares.
The deal is one of a flurry of transactions made in the Norwegian North Sea in the last month, showing buyers and sellers are finding more common ground on price expectations.
Last month, E.ON sold its Norwegian oil and gas business for $1.6 billion to Russian billionaire Mikhail Fridman's fund LetterOne and Det norske also acquired Svenska Petroleum's Norwegian assets for $75 million.
The transaction comprises Premier's 50 percent stakes in the Norwegian Vette development and the adjacent Mackerel and Herring discoveries, a 50 percent interest in the Froey field and seven exploration licences in the North Sea, the two companies said on Monday.
Shares in Det norske were up 3.6 percent by 1028 GMT, while Premier's shares were 6.25 percent higher, both outperforming the European oil and gas index which was up 1.8 percent.
Det Norske's Premier deal is worth around 9 percent of its market value but gives the asset-hungry company access to relatively cheap barrels of oil, analysts at Swedbank, who recommend buying the stock, said.
Det Norske said it would finance the deal with existing funds and undrawn debt facilities and that it would benefit from Premier's carry-forward tax losses, undepreciated tax balances and exploration tax refunds equalling approximately 1.0 billion Norwegian crowns ($114.98 million).
Premier will use the cash to pay down its mounting debt pile, a move that was also wecomed by analysts.
"(This) looks to be a good deal for Premier. The Vette project will still have struggled to reach sanction in this environment so we believe this is a sensible move to crystallise value and take pressure off the balance sheet," said BMO Capital Markets analyst David Round, who rates Premier's shares as 'underperform'.
Last week, Premier said it had cut capital expenditure and deferred some project development and exploration spending into 2016 partly to cope with lower oil prices.
The transaction is subject to government approval and is expected to complete by year-end, the companies said. ($1 = 8.6973 Norwegian crowns) (Reporting by Terje Solsvik in Oslo and Karolin Schaps in London; Additional reporting by Stine Jacobsen and Ole Petter Skonnord in Oslo; Editing by Jane Merriman)