Given the pore pressure and fracture gradients of Table at different depths . do the following : A ) Plot the data , both the base curves and marginal curves ; B ) Perform a first pass design using the bottom - up reasoning . C ) Where appropriate , include the differential sticking limit , using 2,000 psi as a limit on acceptable differential pressure . D 2000 4000 ( Swab margin 0.4 ppg . Surge margin 0.3 ppg . Design factor 0.4 ppg . Differential sticking limit = 2400 psi )