Coiled Tubing emergency
Procedures
Typical stack up
• Blind/shear • Pipe • Slip • Stuffing box • Quick connectorEmergency BOP Operation
• Stop tubing, set SLIP rams, PIPE RAMS• Stop pumping
• Cut coil with SHEARS
• Pull above blinds (stay in stuffing box !) • Close blinds
• Kill well down coil & / or kill line • Fish coil out of well
BLINDS SHEARS
PIPES SLIPS
CT Leak At Surface
• Clear area (esp. around reel & injector)
MINOR LEAK (pinhole)
• Pull slowly on to reel while displacing to
water (minimize reel pressure)
MAJOR LEAK (large or hazardous material)
• Set SLIP & PIPE rams then check set • Cut pipe, pull up to close BLIND rams • Purge reel , remove failure, fish CT in
CT Leak Below Surface
• Loss of pump pressure or string weight• Hole or parted CT may come thru stuffing box • Clear area and displace to water
• Pull out at max. 20 ft/min, pumping slowly • Evaluate leak when exits stuffing box
MINOR
• Pull on to reel carefully (may break)
MAJOR (or parted coil)
Stuffing Box Leak
• Stop coil and close SLIP & PIPE rams to
isolate annulus. Set manual locks.
• Place injector in neutral & engage brake. • Bleed off pressure above pipe rams.
• Bleed off stuffing box hydraulic pressure and
replace elements. Pressurize.
• Pressure test stuffing box through kill line
(avoid collapsing CT)
• Equalize pressure across BOP rams and
release manual locks.
Surface Equipment Leaks
Rotating Joint
• Close reel isolation valve inside work reel. • Repair or replace joint and test.
Surface Equipment Leaks
Leak Below BOP
• Clear area & evaluate
• Ensure coil sufficiently off bottom so it will
fall BELOW the MASTER VALVE when cut.
• Close shear/seal rams to cut and drop coil. • Pull up coil and close blind rams.
• Close swab valve & master valve.
• Repair leak, pressure test, plan fishing
Coiled tubing injector head
• Inside tension • Outside tension
Tubing Run Away (into well)
Coil is pulled into the well under its own weight due to insufficient chain grip.
• Speed up injector to match the descending
coil.
• Increase inside chain tension to increase
friction on coil.
• Increase stuffing box pressure to increase
Tubing Run Away (into well)
• If run away is hydraulic (not traction) reduceinjector hydraulic pressure to zero to set injector brake.
• If close to TD, may let fall to bottom then repair
equipment and recover coil. Some may be kinked.
LAST RESORT (if insufficient coil to reach TD)
• Apply all other measures to slow the coil then close
the SLIP rams to physically grab the coiled tubing.
Tubing Run Away (out of well)
Upthrust due to wellbore pressure exceeds coil weight and injector chain to coil friction.
• Speed up injector to match the coil speed. • Increase inside chain tension to increase
friction on coil.
• Increase stuffing box pressure to increase
Tubing Run Away (out of well)
• Increase reel pressure to keep up with coilcoming out of the well.
• Prepare to close master valve if coil comes out
of stuffing box.
• If coil does not stop, close the SLIP rams. Both
Tubing Pulls Out of Stuffing Box
If BHA is lost there is no external upset to tag on the stuffing box brass inserts.
• Stop the injector to keep the coil in the chains. • Close the blind rams to isolate the well.
Tubing Collapse At Surface
Wellbore fluids escape from stuffing box as strippers cannot seal around collapsed coil.
Collapsed pipe may not pull through the stuffing box brass bushings.
Tubing Collapse At Surface
WELL CONTROL
• Run back in until stuffing box seals around
coil.
• Reduce wellhead pressure by flowing the
well or stop reverse circulation.
• If seal cannot be obtained with stuffing
box, close PIPE rams to reduce leak.
Tubing Collapse At Surface
(well killed)
• Clamp coil above injector head.
• Bleed off stuffing box and open pipe rams.
• Back off inside chain tension and pull the tubing
through the injector with the rig or a crane.
• Re-clamp the coil above the injector and cut off the
coil in sections.
• Repeat until good condition coil is pulled through the
injector.
• Set slip and pipe rams, energize stripper, and make
Cutting and recovering coil
Close slip rams Close pipe rams
Cutting and recovering coil
Cutting and recovering coil
Open blind shear rams Spear fish (difficult)
or Pull test
Cutting and recovering coil
Raise BOPs and coil
Set tubing clamp
Cutting and recovering coil
Lower BOPs to expose cut coil Fit double end connector
Lower injector and make up double end connector
Pull test
Cutting and recovering coil
Lower stack and make up POOH
Tubing Breaks On Surface
Coiled tubing breaks into two sections at surface.
• Stop the injector and set the SLIP rams.
• Stop pumping operations and clear the area.
• Secure the coil to the reel and attempt to spool slack
back onto the reel.
• Remove the damaged section of pipe and reconnect the
coil with a dual roll-on connector.
Tubing Breaks On Surface
• If the remaining coil cannot be spooled onto the
work reel and no spare reel is available, it will be necessary to hang off the coil in the well until a reel is available or the well is killed.
• Close SLIP and PIPE rams then cut the coil. • Pull up and close the blind rams.
• Once spare reel capacity is available, fish coil
CT Reel Drive Fails
• Stop the injector.• Ensure coil held by injector and close and lock
SLIP and TUBING rams.
• Apply reel brake if fitted.
• Repair drive and inspect coil for damage. • If damaged, follow Leak Procedures.
• If coil is good, run in as deep as necessary to fix
the wrap on the reel. Do Not Run Kinked Tubing Into the Well !
• If spool cannot be fixed, follow cut and fish
Coiled Tubing Stuck In Hole
Three possible scenarios:
1. The coiled tubing itself is stuck somewhere between the BHA and the stuffing box.
2. The BHA is stuck.
3. Stuck in the stuffing box due to ballooned coil or excess stuffing box pressure.
Coil is considered stuck if it cannot be pulled free at the lesser of 80% of the weak link rating or 80% of the minimum yield rating of the coiled tubing.
Coiled Tubing Stuck In Hole
Three factors to consider:
1. Type of well: flowing oil or gas well, water injection well.
2. Type of BHA on the coiled tubing. 3. Type of operation carried out when stuck.
Coiled Tubing Stuck In Hole
• Continue Pumping• Determine stuck point and reason why. • Pull to 80% of CT yield and hold for 10
minutes.
• Observe the trend on the weight indicator
and measure the stretch in the tubing to calculate freepoint:
Free Point Calculation
L = S( As x E)
F x 12
L = length free (ft) S = stretch (in)
As = metal X-section area (in) E = modulus of elasticity
(30,000,000 psi for steel) F = pull force (lbs)
Stuck In Hole Options
• Flow the well at maximum rates to remove any
debris trapping the coil downhole.
• Displace the coil to N2 to increase buoyancy. • Underbalance the well if differentially stuck. • Circulate acid down to remove any soluble
material holding the coil.
• Cool the well if coil is helically stuck in
corkscrewed production tubing.
• Pump down the annulus to force obstruction
downhole.
Stuck In Hole Issues
• DO NOT work the coil violently across the coil
with frequent reversals.
• Log the number of cycles while trying to pull
free. Do not exceed fatigue limit !
• If coil cannot be freed, hang off the coil in the
SLIP rams and close the PIPE rams.
• Kill the well then cut at free point and fish the
Chemical / Explosive Cutters
• Determine free point and ENSURE well is dead. • Pull coil into tension so it is as straight as possible. • Close SLIP and PIPE rams, increase stuffing boxand chain pressure, and set the reel brake.
• Monitor pressure across pipe rams for leak.
• Bleed off the coil and monitor pressure to ensure
downhole check valve and coil integrity.
Chemical / Explosive Cutters
• Lay down gooseneck and cut the coil 5 feet abovethe injector. Secure remaining coil at the reel.
• Straighten the coil to run wireline inside.
• Connect 2 valves, pumping “T” and wireline
lubricator and BOP to the coil to run the cutters inside.
• Run cutter and freepoint tool to the correct depth
and cut the coil.
• COILED TUBING IS NOW OPEN TO
Chemical / Explosive Cutters
• With the well and coil killed, remove thewireline equipment.
• Dress the end of the coil for a double roll-on
connector
• Open the BOP rams and pull the coil out of the
hole, spooling back on to the work reel.
• NOTE: chemical or explosive cuts may need to
Power Pack Failure
• If the hydraulic power unit fails, injector head
motor brakes will automatically be applied.
• If in doubt, close SLIP rams and manually lock. • Close PIPE rams and manually lock.
• Chain reel incase reel brake fails.
• Maintain circulation if required to prevent coil from
becoming stuck in the hole.
• Repair or replace powerpack, ensure BOP
accumulators are fully charged.
Replacement Of Injector
• Close SLIP and PIPE rams, bleed off coil.• Ensure slips are holding coil, check valves hold. • Secure coil on either side of cut, clamp at injector. • Cut coil above injector and secure to reel.
• Bleed off pressure above tubing rams. • Back off inside chain tension.
• Break the union below the injector and walk up coil
Replacement Of Injector
• Back off chain tension and walk new injector
down to safety clamp on BOP
• Clamp above, remove clamp below.
• Make up union and pressure up inside chain
tension.
• Pull test before opening SLIP rams.
• If coil is run inside small ID tubing and BOP,
kink will be between stuffing box and chains.
• Coil run in large diameter completion will kink
at a diameter change or at the largest ID.
Tubing Kinked - Surface
• Stop injector immediately.• Close SLIP and PIPE rams and lock.
• Bleed off coil and ensure downhole check valves
holding.
• Cut coil at top of stuffing box to lift off injector. • Remove injector and dress coil for connector. • Run fresh coil through stuffing box and connect
with inline connector (dual roll on).
• Walk injector down to make up to BOP.
Tubing Kinked - Downhole
Rapid weight loss in large ID may lead to kinks.
• Increase in pump pressure due to kink restriction • Decrease in pump pressure as BHA may be broken
off
• Loss of string weight due to parted coil
Tubing Kinked - Downhole
Increase in pump pressure or string weight
• Stop pumping
• Pull out at 10 to 20 ft/min until kink tags stuffing
box
• Attempt to close SLIP and PIPE rams
• If kink cannot be pulled above the BOP, run in
to good pipe then hang off and cut coil in BOP
Tubing Kinked - Downhole
Decrease in pump pressure or loss of weight - String parted down hole.
• Calculate remaining coil from weight • Stop pumping
• Pull out slowly until coil comes out of stuffing box • Close blind rams then secure wellhead