2. Well control
Well-control means methods used to minimize the
potential for the well to flow or kick and to maintain control
of the well in the event of flow or a kick. Well-control
applies to drilling, well-completion, well-workover.
IWCF
International Well Control Forum
3. Kick and
blowout
A kick is defined as any undesirable flow of
formation fluids from the reservoir to the wellbore,
which occurs as a result of a negative pressure
differential across the formation face . Its called
(influx_gain_flow)
a blowout is the uncontrolled release of the fluid or
gas, gained through the kick
Among the most likely and recurring
are:
Low Density Drilling Fluid
Abnormal Reservoir Pressure
Swabbing
Not Keeping the Hole Full on Trips
Lost Circulation
4. 1. Hydrostatic Pressure
All vertical columns of fluid exert hydrostatic
pressure.
HP = MW x 0.052 x TVD
2. Formation pressure
is the pressure contained inside the rock pore
spaces.
3. Fracture pressure
is the amount of borehole pressure that it takes to
split
or fail a formation and it can find it by (leak off test)
5. Bottomhole Pressure
Bottomhole pressure is equal to the sum of all pressures acting
in a well.
BHP= HP + SP + APL
o Bottomhole pressure at static (Pump off )
BHP=HP
o Bottomhole pressure at dynamic (Pump on)
BHP=HP+APL
Equivalent Circulating Density (ECD)
ECD=
𝑨𝑷𝑳
𝟎.𝟎𝟓𝟐∗𝑻𝑽𝑫
+MW
6. Swab and Surge Pressures
Swab pressure is the
temporary reduction in the
bottomhole pressure that
results from the upward
movement of pipe in the hole.
Surge pressure is the opposite
effect,
whereby wellbore pressure is
temporarily increased as pipe
is run into the well.
7. Warning signs of kicks
1. Flow rate increase
2 . Pit volume increase
3. Flowing well with pumps off
4. Pump pressure decrease and pump stroke
increase
5 . Improper hole fill - up on trips
6 . String weight change
7. Drilling break
8. Cut mud weight
9.Increased penetration rate
8. Flow check procedure
At the first indication of a kick
1. Stop drilling
2. Raise the bit off the bottom of the well ( to shut in the well )
3. Stop the pumps and check to see if there is a flow from the well
4. If the well does flow , close the BOP and shut in the well
5. Readings are taken to stabilize shut in drill pipe and casing
pressures
6. Calculation are made to determine the density of the mud that
will be used to kill the well
7. Calculations are also made to determine the kick out , and to fill
the hole with new mud
9. If well flow confirmed , the well should be
closed in quickly after a kick has been
detected in order to : Or reasons for
shutting in the well .
a . Minimize the size of the influx into the wellbore
.
b . Minimize the SICP .
c . Minimize the casing shoe pressure
d . Minimize chances of losses
10. The difference between the formation
pressure at the bottom of the well and the
hydrostatic pressure in the drillpipe.
Recorded when a well is shut in on a kick.
From the SIDPP, one can calculate the
increase in mud weight needed to kill the well.
1-Shut-in drillpipe pressure (SIDPP)
Shut-in pipe pressure
2-The shut-in casing pressure
(SICP)
is a measure of the difference between the
formation pressure and the HSP in the
annulus when a kick occurs.
12. Type of shut in well
1-Soft shut in mathod:
the choke line valves are opened to allow the well to flow
through the surface choke. After the preventers are sealed,
the choke is then closed to stop the flow. The ‘soft shut-in’
procedure gives the well additional time to flow before shut-in
2-hard shut in mathod:the choke line valves on the
drilling spool are in the closed position while drilling and
remain closed until after the preventer is sealed and well shut-
in.
13. 1. Shut-in Procedure while
Drilling
SPACE OUT Pick up drill string and spot tool
joint.
SHUT DOWN Stop the mud pumps.
SHUT IN Close the annular preventer or
uppermost
pipe ram preventer. Confirm that the well is shut
in
and flow has stopped. Open HCR valve.
2. Shut-In Procedure while
Tripping
Stab valve Install Full-Open Safety Valve (open
position)
in drill string.Close Safety Valve.
space out Spot tool joint.
shut-in Close the annular preventer or uppermost
pipe
ram preventer. Confirm that the well is shut-in and
flow has
stopped. Open HCR valve.
14. Kill Weight Mud or Kill Drilling Fluid Density is the mud weight required
to balance formation pressure. The kill weight mud may be pumped into
the well at different time depending on kill methods (Driller’s method,
Wait and Weight)
Kill Weight Mud (KWM) = Current Mud Weight + (
SIDPP
0.052∗TVD
)
Kill mud
15. Driller’s mathod
FIRST CIRCULATION
1. taken slow circulating rate pressure then calculate the pressure required on the
Drill Pipe for the first circulation of the well. (ICP = SCR + SIDPP)
2. Open the choke about one quarter, start the pump and break circulation; then
bring the pump up to the KILL RATE.
3. While the Driller is bringing the mud pump up to the KILL RATE, the choke
operator should operate the choke so as to keep the casing pressure at or near
the SICP reading.
4. Once the pump is up to the KILL RATE, the choke operator should transfer his
attention to the Drill Pipe pressure gauge and adjust the choke to maintain the
ICP on the drill pipe pressure gauge.
5. The last step on well control driller’s method is helding the the ICP constant on
the Drill Pipe pressure gauge by adjusting the choke throughout the whole of the
first circulation, until all of the Kick fluid has been circulated out of the well. The
pump rate must also be held constant at the KILL RATE throughout this period.
6. Once the Kick is out of the hole, Shut the well in and mix up the kill mud weight
required.
Second Circulation
7. Once the Kill mud is ready, open the choke about one quarter, start the pump and
break circulation. Then bring the pump up to the Kill rate.
8. While the Driller is bringing the pump up to the Kill rate, the choke operator
should operate the choke so as to keep the casing pressure steady at the same
pressure as when closed in.
9. While the Drill Pipe is being filled with heavy mud there are two options for
