It's not uncommon to use air drilling in O&G holes. Less common than it used to be as fraccing and horizontal technology have developed which are generally better options for tight reservoirs except in certain mineralogies involving swelling clays when air can still be a good option. CTP used air drilling themselves at Ooraminna.
Air drilling can be cheaper as it's faster, but not if you are only intending to drill a few metres. They'd have had to case off the P1 and then switch to air from mud which more than cancels out any cost benefit. It makes no sense that they would switch if they were using it as a pilot hole. They would just have kept drilling with the mud system already set up and running.
Finally, if this was planned as you suggest, why do they have to wait for the equipment to arrive on site to conduct the sidetrack? If planned they would have the equipment on site to avoid having to perform another rig move and set up on WM27 again. Which is a significant additional cost.
It's clearly an unplanned sidetrack, and highly likely the reason they are drilling it is because the air drilling of the P3 didn't deliver the result they hoped.
CTP Price at posting:
11.5¢ Sentiment: None Disclosure: Held
