Germany's BASF and Russian gas giant Gazprom have completed an asset swap defining BASF unit Wintershall's rights to the Yuzhno-Russkoye gas field in Western Siberia, the companies said.
This is a further step to clarify ownership rights of Russian gas assets, which Gazprom and foreign partners have been working on for years.
Under the agreement, Wintershall takes 25% minus one share in Severneftegazprom (SNGP), the holder of the Yuzhno-Russkoye licence, the two companies said in a statement.
Wintershall will also be given a privileged share without voting rights in SNGP, which effectively would give it a share of 35% in its operating profits.
In return, Gazprom raised its share in a joint German gas trading outfit Wingas to 50% minus one share from 35%, completing a deal announced 18 months ago.
Another yet to be implemented part of the deal entails Gazprom obtaining a share in a Wintershall division that holds gas exploration rights in Lybia.
A BASF spokesman said this would be carried out in the near future.
A spokesman for E.ON Ruhrgas, which also aims to reach a final agreement about jointly producing gas with the two partners at Yuzhno-Russkoye, said today: "There are no new developments (on our side)."
E.ON has said it was considering giving Gazprom stakes in gas-to-power plants in the UK, among other ideas, as part of asset swaps under discussion.