And all spare capacity is heavy man... sorry...

It effectively cannot be used to fill the gap because refining capacity does not exist for it... We could well see rising inventories with rising prices and the lead time on new refining capacity is in years...

Well, let's see.  Declining gas production is going to leave a lot of GTL plants with nothing to do.  If syngas-sweetening systems aren't too slow or expensive to add, maybe that heavy crude could be turned straight into diesel fuel by gasifying it, scrubbing the nasties and liquefying via F-T.

Unfortunately, that process appears to be only about 63% efficient (see page 37).  We'd need a lot more heavy crude than light to do the job; about 1/3 more for gasoline, almost 1/2 more for diesel.