That's right LWR, but I think that oil in the mud does not flow to the surface - a term used more to say that the oil flowed under its own pressure - but rather is brought up with the mud as the mud is circulated through the hole. If the oil had 'flowed to the surface' I think we would be a much happier mob than we are now!!!
But a TU from me again as the quality of your posts is excellent.
