RE: 600 psi NORMAL formation pressure is created from the weight of fluids within the pores of the formation rock from any depth and to surface, and is variable with the density of the fluid between fresh water and water with dissolved solids in it, salt being one common example. Using a safety factor with the idea of heavier mineral laden water in this well, formation pressure should be at about 2620 psi at 5600 feet of true vertical depth and will take a mud weight of 9.0 ppg (pounds per gallon) to balance normal formation pressure. If the company reports an overpressure of 600 psi while drilling then this tells me that they took a kick from drilling into the formation in an underbalanced state in the wellbore and the well had to be shut in. They were overcome by the overpressured formation. The 600psi value had to have come from the SIDPP or stabilized shut in drill pipe pressure recorded after the kick and the well shut in. We have to assume that they drilled into the formation with a mud weight greater than 9.0ppg to be overbalance to the formation pressure (I guess it was about 9.5ppg) so now formation pressure should be equal to the 2620psi from normal pressure gradient plus the 600psi SIDPP *PLUS* the differential presure between formation pressure and the overbalanced hydrostatic pressure of the original mud weight, prior to drilling into the overpressure.........add 150psi or so to that, possibly more. So, formation pressure should be in the neighborhood of 2620+ 600+ 150 = 3370psi and where a drilling mud density of 9.0 should control a normally pressured formation we see an abnormally pressured formation or overpressured formation and now it should take a mud weight of about 11.6ppg to balance the formation pressures in this well. For a safety factor, drilling ahead probably had them drilling with well control and with a mud density at or over 12.1ppg. Situations like this are delicate and attention to detail is necessary on several levels. These pressures show about 29% higher over normal pressure so I'd call that significant. In other pieces of news reported by the company, there are indications of high permeability and this makes the well highly valuable for reservoir volume and production flow properties. There is no doubt in my mind that they have a winner here but I am anxious to hear that it gets safely drilled to TD and effectively logged, cased and cemented.
Now I'm very curious to know how accurate this post is............lol.