So, here we are. Brent crashed 5.5% overnight to be trading in my $40 target range, a new post-GFC low:

There was no news beyond the realisation that OPEC is broken, from Reuters:
It used to be said of OPEC that it was like a teabag – it only worked in hot water. If that is so, conditions on world oil markets could hardly be more difficult as prices languish at almost seven-year lows near $40 a barrel.