How do i calculate the time of circulation? Whilst drilling the $81/2"$ hole section of a well the mud pit level indicators indicate that the well is flowing. When the well is made safe the following information is collected:

Drillpipe pressure $=120$ psi

Casing pressure $=90$ psi

Pit gain $=9$ bbls

ATTACHMENT $1$

CASING$/$HOLE DATA

$103/4"($ID $10,050)53\mathrm{.}5$ lb$/$ft casing shoe $7500$ ft$.$

$85/8"$ hole $10000$ ft

DRILLSTRING DATA :

$5"($ID $4,25)19\mathrm{.}5$ lb$/$ft drillpipe in hole

BHA $-320$ ft of $6\mathrm{.}25"$ x $213/16"$ collars

PUMP DATA :

Type $-$ Triplex pump Output $=0\mathrm{.}1768$ bbls$/$stk

kill rate$/$circ$.$ press. $16$ spm @ $700$ psi circ. pressure

MUD DATA :

Mud in hole $10$ ppg

Leak of test pressure: $14\mathrm{.}8$ ppg

DEPTH OF KICK : $10000$ ft$.$