How To Avoid Stuck Pipe in Hard or Soft Cement

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CEMENT FAILURE
.
DEFINITION:
A cured (harden) cement job breaks apart and falls (caves) into the
wellbore.
CAUSE:
Long rathole section below the casing shoe allows the heavier
cement to settle and fill the rathole. After curing and drill-out, the mud-
contaminated cement sheath breaks apart and falls into the hole.
.
Wellbore stability problems can break the rathole out of gauge

Casing
Shoe & leaving the cement at and above the shoe unsupported.
.
Rat-Hole Squeeze
Plug Open hole squeeze plugs and kick-off plugs can break apart from:
poor cement recipes /mixing /placement; high formation stress at plug
depth; loss of support as the formation below the plug breaks out of
gauge; impact damage from fast trip speeds and BHA rotation at plug
depth.
.
Cement from closely spaced wells can break apart and fall into the
hole if the well paths are too close.
WARNING:
Pack-off /bridge can occur any time after drilling out of the shoe or open-
hole cement plug.
.
Increasing volume of hard cement detected over shaker 1+ days

after cementing the casing or setting an open hole cement plug.
.
Very erratic torque and drag. Hole fill after connections and trips.
.
Large volume of cement cavings at connection and trip bottoms-up.
FREEING:
String motion prior to sticking: Moving or Static.
.
Circulating pressure after sticking: Restricted (bridged) or Impossible

(pack-off).
.
Bleed off all trapped pump pressure.

.
(Top Drive) Torque-up the string to +/-80% of drillpipe make-up torque.

Carefully reciprocate to ensure torque limit is applied at stuck depth.
.
Apply low pressure (+/-200 psi). Maintain the pressure if circulation is

possible.
.
Jar down with maximum jar-trip load.

.
If possible, circulate Hi-Vis (<400) or Hi-Density (>400) sweeps at

maximum pump rate to remove cement fragments from the hole.
Kick-Off PREVENTION:
Plug Minimize casing rat-hole length. Allow sufficient cement curing time.
.
Reduce trip speed before the BHA enters the shoe, kick-off plug, open
hole plug depth.
.
Minimize rotating /circulating time with the BHA in the plug /shoe area.
Page 57
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FREEING, HOLE PACK-OFF /BRIDGE
INDICATIONS
The mechanism of pack-off or bridge is identified by the inability to circulate with total pack-off
or restricted circulating pressure with bridging (partial pack-off). String motion prior to sticking
may have been moving or static.
FIRST ACTION, TORQUE-UP & JAR DOWN TO RE-ESTABLISH CIRCULATION
Immediate action is recommended as additional packing off is likely from solids settling
and /or differential sticking may occur if the drillstring is not moved.
Hole Angle Less Than 600:
.
1. Bleed off all trapped pump pressure.

.
2. (Top Drive) Torque-up the string to +/- 80% of drillpipe tooljoint make-up
torque. Carefully reciprocate to ensure torque limit is applied at stuck depth.
.
3. Apply low pump pressure (+/-200 psi). Maintain the pressure if
restricted circulation is possible.
. Torque
4. Slack-off to maximum jar-trip load. Hold torque and set-down weight
until the jar trips or for +/- 10 minutes.
.
5. If pump pressure drops off, slowly increase pump speed to maintain the
applied pressure. Caution, pack-off may re-seal with increased fluid flow.
Circulation must be re-established to remove the pack-off and free the string.
.
6. Maintain torque, low drillstring pressure and continue jarring down while JAR
trying to re-establish circulation. Jarring for 10+ hours may be necessary to
establish circulation and free the string.
.
If hole angle is less than 400, attempt to break up the pack-off by bleeding off
all pressure and releasing string torque. Reciprocate with light overpulls and
heavy set-down weights and apply/release torque until some string
movement is possible or for +/-30 minutes. Repeat the procedure from step
#2.
.
Hole Angle Greater Than 600:
.
1. Bleed off all trapped pump pressure.

.
2. (Top Drive)Torque-up the string to +/- 80% of the drillpipe tooljoint make-
up torque. Carefully reciprocate the string to ensure torque limit is applied at
stuck depth.
.
3. Slack-off maximum jar-trip load, hold torque and set-down weight until
the jar trips or for +/- 10 minutes.
.
4. Work the pipe with light overpulls and heavy down-jarring until some pipe
movement is established.
.
5. Apply low pump pressure (+/-200 psi). Maintain the pressure if restricted
circulation is possible. If drillstring pressure drops off, slowly increase pump
speed. Caution, pack-off may re-seal with increased fluid flow.
.
6. If circulation cannot be established, repeat the procedure from step #4.
Repeating this procedure for 10+ hours may be necessary to establish
circulation and free the string.
Depending on the situation, other options may include: picking up a Heavy Down-Jarring Assembly
(see Differential Sticking section); washing over the fish; jarring up; or side tracking the well.
Page 60
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SOFT CEMENT
DEFINITION:
Sticking the drillstring in a cement application
(squeeze or kick-off plug) that is not yet
sufficiently cured (hard).
Soft
Cement CAUSE:
A joint or more of the drillstring is run into the
top of the soft cement before circulation is
started.
.
Just as circulation is started, the increased

annulus pressure drives out excess water
Hard causing the cement to flash set.
Cement
WARNING:
Over estimated % of hole enlargement.
.
Unknown or incorrectly estimated top of

cement.
.
Excess cement volume pumped.

.
Set-down weight indicated above the

calculated top of cement.
.
Relying on set-down weight to determine the

top of the cement.
.
Pack-off occurs just a circulation is started.

FREEING:
String motion prior to sticking: Static or Moving.
.
Circulating pressure after sticking: Impossible.

.
Bleed off trapped pressure.

.
Do not apply torque.

Flash Set .
Jar up with maximum jar-trip load.

.
Continue jarring up until the string jars free or

an alternative decision is made.
Excess PREVENTION:
Pump Water Always calculate the top of the cement.
Pressure .
Do not use the weight indicator to find the top

of the cement. Start washing and reaming at
least 2 stands above the top of the cement.
.
If set-down weight is observed above the

calculated top of the cement, DO NOT start
circulation. Pull up 1 to 2 stands before
starting washing and reaming operations.
Page 62
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FREEING, SOFT CEMENT
INDICATIONS
Hole pack-off caused by Soft Cement can occur with the string static or moving. Circulation is
impossible as the cement flash sets.
.
FIRST ACTION, JAR UP
Immediate action is recommended as additional cement curing will occur with time and/or
differential sticking can occur if the drillstring is in open hole and not moved.
1. Bleed all trapped pump pressure.

Jar .
2. DO NOT apply torque.

.
3. Jar Up with maximum jar-trip load. Maintain over-

pull until the jar trips or for +/-3 minutes.
Continue jarring up for +/-15 minutes.
.
4. If no progress is made, stop jarring and attempt to

break up the cement by applying /releasing torque
and working the pipe. Try to establish circulation.
.
5. If the pipe does not work free, continue jarring

up and working the pipe down.
.
6. Continue repeating steps 1 through 5 while

considering other options. Pick up an up-jarring
fishing assembly with an accelerator, washing
over the BHA or side tracking the well.
Page 65

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0 0 S 0 0 S

Wellbore stability problems can break the rathole out of gauge

Increasing volume of hard cement detected over shaker 1+ days

Circulating pressure after sticking: Restricted (bridged) or Impossible

Bleed off all trapped pump pressure.

(Top Drive) Torque-up the string to +/-80% of drillpipe make-up torque.

Apply low pressure (+/-200 psi). Maintain the pressure if circulation is

Jar down with maximum jar-trip load.

If possible, circulate Hi-Vis (<400) or Hi-Density (>400) sweeps at

1. Bleed off all trapped pump pressure.

1. Bleed off all trapped pump pressure.

Just as circulation is started, the increased

Unknown or incorrectly estimated top of

Excess cement volume pumped.

Set-down weight indicated above the

Relying on set-down weight to determine the

Pack-off occurs just a circulation is started.

Circulating pressure after sticking: Impossible.

Bleed off trapped pressure.

Do not apply torque.

Jar up with maximum jar-trip load.

Continue jarring up until the string jars free or

Do not use the weight indicator to find the top

If set-down weight is observed above the

1. Bleed all trapped pump pressure.

2. DO NOT apply torque.

3. Jar Up with maximum jar-trip load. Maintain over-

4. If no progress is made, stop jarring and attempt to

5. If the pipe does not work free, continue jarring

6. Continue repeating steps 1 through 5 while

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