Starting in about 18 months, as a guess. Total and Schlumberger certainly know which side of the bread is buttered; they're not fools AT ALL.
If Putin isn’t dealing with the foreign companies that have the expertise honestly right now don’t expect any improvement in the future.
There will always be idiots. They will always advance money and be surprised when they get screwed, even though all their predecessors were screwed in the past.
Look at Cuba. Fidel consistently defaults on every loan made to him. It just a matter of when he will get around to it. The only major country that isn’t holding bad debts is the U.S., and that’s because we have a trade embargo.
If foreign companies want to get screwed, let them. No need for American shareholders to take the hit.