UPDATE 2-Weatherford to buy TNK-BP's services unit

* Deal valued at $480 mln

* Weatherford shares rise 1.3 percent (Adds byline, analyst comment, background)

By Anna Driver

HOUSTON, May 29 (Reuters) - Weatherford International Ltd (WFT.N: Quote, Profile, Research) said on Friday it would buy the oilfield services unit of No. 3 Russian oil producer TNK-BP for $480 million in stock.

Under the terms of the deal, which must be approved by Russia's Federal Anti-monopoly Service, Weatherford will exchange 24.3 million shares for the unit, which had revenue of $650 million in 2008.

"This investment in Russia's oil industry and its future growth strengthens Weatherford's position in one of the most important global oilfield service markets," Bernard Duroc- Danner, chief executive officer of Switzerland-based Weatherford, said in a statement.

TNK-BP's services business comprises six operating companies owning and operating more than 75 drilling rigs, 180 workover units, 150 cementation and pumping units and more than 10 operating bases.

"From a replacement value alone, we think they are getting a pretty good deal, even if you want to risk it for Russian risk," said Bill Herbert, an analyst with energy research firm Simmons & Co Intl, noting that Weatherford is also getting a preferential relationship with TNK-BP.

Oilfield services companies, including Weatherford's larger rival Schlumberger Ltd (SLB.N: Quote, Profile, Research), have targeted Russia as a growth market for their services, but it can be a tricky place to operate for non-Russian companies.