UPDATE 2-Russia's Putin offers surprise deal to Shell

* Shell accepts Putin's invite to work on Sakhalin 3 and 4

* Russia needs foreign help to develop its energy wealth

(Adds quotes, details, background)

By Simon Shuster

MOSCOW, June 27 (Reuters) - Russian Prime Minister Vladimir Putin moved again to ease his government's clasp over the energy sector on Saturday, capping off a week of foreign energy deals with a surprise offer for Royal Dutch Shell (RDSa.L).

Weaker oil prices, now half of what they were a year ago, have persuaded Russia to scale back its resource nationalism. Moscow now looks to be balancing the dogged protection of its energy wealth with the need to have foreigners invest in it.

The offer to Shell, which comes days after Russia struck major deals with France's Total (TOTF.PA) [ID:nLO221477], is emblematic of the renewed openness, because Shell was the victim of Russia's most aggressive drive to re-take control of its natural resources.

In 2006, under intense government pressure, it ceded control of the vast Sakhalin-2 project to Russia's Gazprom (GAZP.MM). But on Saturday, Putin invited Shell to help develop the giant Sakhalin-3 and Sakhalin-4 projects off Russia's Pacific coast.

"These require offshore production in difficult deep sea areas where your experience will be very valuable," Putin told Shell Chief Executive Jeroen van der Veer at a meeting in his summer residence outside of Moscow.