that looks identical to the layer i had on my dubbel using wyeast trappist high gravity yeast. Took it like 3 weeks to start to fall out, even when i bottled some of it was still left on top but the beer turned out great. I would be willing to bet that your beer will turn out fine too.
Bottled: Janet's Brown, Session Dry Stout, Yellow Fly Cream Ale
Gallons Brewed In 2011-40