QUESTION $4(40$ pts$)$

A drill string is composed of drill pipes and is totally immersed in the hole $($you have the

same mud inside & outside the drill string$).$

Drill string length is $10,000ft$

Openhole diameter is $9$ in $($constant$)$

Drillpipe outside diameter $($OD$)$ is $5$ in

Drillpipe inside diameter $($ID$)$ is $4$ in

Flow rate is $600$ gpm

Compute:

a$)$ Annular capacity factor in: $f\frac{t^3}{f}t$; gal$/$ft; bbl$/$ft

b$)$ Total drill string displacement $($in bbl$)$ with bit on bottom

c$)$ The time required $($in min$)$ to pump mud from surface to bit.

d$)$ The time required $($in min$)$ to pump mud from bit to surface.