UPDATE 7-Lukoil closes on deal on Repsol buy-source

* La Caixa in talks with Lukoil on Repsol stake sale

* Lukoil buy of Repsol may depend on Sacyr, financing

* Lukoil reported close to deal with Sacyr at 28 euros/shr (Adds quotes from source saying deal close, issues pending)

By Carlos Ruano and Dmitry Zhdannikov

MADRID/MOSCOW, Nov 21 (Reuters) - Russia's Lukoil (LKOH.MM) is close to a deal with shareholders of Repsol (REP.MC), including Spanish builder Sacyr Vallehermoso (SVO.MC), to buy a 30 percent stake in the oil company, but still needs to find financing for the deal, a source close to the talks said on Friday.

Lukoil could pay Sacyr 28 euros a share for its 20 percent stake in Repsol -- double Friday's closing price of 13.91 euros -- said the source.

"Much of the deal has been secured. The price Lukoil would pay (for Repsol shares) is agreed on at 28 euros per share," the source said.

The Russian company would buy another 10 percent stake in Repsol from Spanish savings bank La Caixa, insurance company Mutua Madrilena, and Repinves, which is partly owned by La Caixa, the source said.

But Lukoil still has to find financing for the deal, the source said.

"How Lukoil would finance the deal has not been arranged, and I don't think it will be over the next few hours," they said.

At 28 euros per share, 30 percent of Repsol is worth 10.7 billion euros ($13.40 billion).

Sacyr paid 26.7 euros per share for its stake in 2006.

Another hurdle that must be overcome, according to the source, is that the buy must not interfere with a planned merger between Spanish utilities Gas Natural (GAS.MC), in which Repsol has a 30 percent stake, and Union Fenosa (UNF.MC).

"The issue of how a potential Lukoil stake in Repsol could affect Gas Natural's bid for Fenosa is an important one," the source said.

Gas Natural plans to partly fund its 16.7 billion euro bid for Fenosa with a share issue to which Repsol has pledged to subscribe 1.6 billion euros.

Lukoil declined to comment on reports of a deal, while Sacyr Vallehermoso referred to previous statements where the company has said no deal has been reached over its planned asset sales.