Q$1)(25$ pts$)$ A well is producing $\backslash (3200\backslash$mathrm$\{$bb$\}/\backslash )$ day from a well. The thickness of the formation is $20$ ft $.$ Reservoir pressure at the outer boundary at $400$ ft is $2600$ psia. The wellbore pressure is $1700$ psia and the wellbore radius is $0\mathrm{.}5$ ft $.$ The fluid viscosity is measured as $1\mathrm{.}6$ cP $.$ It is known that there is a damage zone of $2$ ft around the wellbore. The permeability drops to $150$ mD in that damaged zone. Calculate the permeability of the formation?