Question

1. Th e mud engineer of an Arabian oil company designed the mud weight of 10 lbm/gal for a formation that needed to be drilled where the pressure gradient was found 0.52 psi/ft. Th e surface casing was set at a depth of 2,500 ft. It was noticed that the fracture gradient below the surface casing was 0.73 psi/ft. Th e driller realized that he was passing a pressure transition zone while drilling at a depth of 10,000 ft. Th is new situation gave the impression that the designed mud weight might be less than pore pressure which results a kick. To avoid a kick, determine the maximum safe underbalance between mud weight and pore pressure if the well kicks from formation at a depth of 10,000 ft.

Answer 1