Hard to say if that willl happen. The latest drop was a response to the IEA revising demand forecasts down, but the Saudis have cut production substantially and some analysts think they are going to try to defend the $100 mark. Of course they may or may not be able to do that. Have to wonder if Russia will cut back exports to sustain pricing, and if the Chinese will advance some credit vs future deliveries.
I still can't begin to figure out what index or benchmark you are using for "sour crude"... perhaps you'd care to make that clear?
Unfortunately I no longer have access to a Platts feed (and I'm not about to pay for it), but the most recent figures I see:
http://af.reuters.com/article/commod...BrandChannel=0
say that Urals (primary Russian export blend) was trading as of Sept 1 at dated Brent minus $.95. That spread varies of course, but I see no reason to expect that it will vary radically. Do you? If so, what are the reasons.
Again, "sour crude"
per se is not a traded entity. If you want to refer to price spreads between Brent (the usual reference benchmark) and Russian exports the figure you need to refer to is the spread between Brent and Urals Blend.
Russia does talk about a balanced budget at $114, but we all know that nations can go a long long time without a balanced budget. Sustained prices below $100 would give some pain, but it's in no way certain that it would cause any policy changes, especially since policy in the Ukraine would have no significant effect on oil prices. Even if Putin brought the troops home and became possessed by the spirit of Mother Teresa, that wouldn't change the global oil equation in the least.