The Fracture Gradient of an open hole formation at 3690 ft i

The Fracture Gradient of an open hole formation at 3,690 ft. is 0.618 psi/ft. The drilling mud currently in use is 9.8 ppg. Approximately how much Surface Pressure can be applied to the well before this formation breaks down?

Solution

Solution:-

Given:-

Current mud = 9.8 ppg

Depth (h) = 3690 ft

Fracture gradient = 0.618 psi/feet

Pressure at bottom due to mud = 0.052 *9.8 * 3690

= 1880.424 psi

Fracture pressure (P ) = fracture gradient * depth

= 0.618 * 3690

= 2280.42   psi

Surface pressure = Fracture pressure - pressure due to mud

= 2280.42 -   1880.424

Surface pressure = 400 psi       Answer