PROBLEM$-2[5$ Marks$]$:

$($CLO$4$:SO$1)$

The surface casing with an OD of $13\mathrm{.}37$ inches set at a depth of $3000ft.$ The fracture gradient was found to be $0\mathrm{.}68\frac{}{f}t.$ The mud gradient is $0\mathrm{.}6\frac{}{f}t.$ The total depth of the well was $12000$ ft $,$ and the internal yield was $2500$ psi. Determine the maximum permissible surface pressure on the annulus. Assume that the casing burst is limited to $85\%$ of the design specification.