ct emergency procedures
TRANSCRIPT
-
8/8/2019 CT Emergency Procedures
1/19
CoiledTubingEmergencyProcedure Page1/19
Coiled Tubing
Emergency Procedures
-
8/8/2019 CT Emergency Procedures
2/19
CoiledTubingEmergencyProcedure Page2/19
ListofContents
S# HazardScenarioRef# EmergencyProcedure Page
1 HazardScenario#2 CoiledTubingpartsabovetheInjector/Gooseneck 3
2 HazardScenario#3 CoiledTubingpartsbelowPCE 4
3 HazardScenario#4 CoiledTubingLeaks(Pinhole) 5
4 HazardScenario#5 PCELeakEitherAboveorBelowBlindRams 6
5 HazardScenario#6 FailureofCoiledTubingPowerPack 8
6 HazardScenario#7 PipedamagecausedbyInjectorHeadorGooseneck 9
7 HazardScenario#8 FailureofCTReelDrive 10
8 HazardScenario#9 Stuckpipe 11
9 HazardScenario#10 CoiledTubingRunAway 14
10 HazardScenario#11 LeakingBHACheckValves 16
11 HazardScenario#12 LeakinStripperPackOff 17
12 HazardScenario#13 CoiledTubingCollapse 19
-
8/8/2019 CT Emergency Procedures
3/19
CoiledTubingEmergencyProcedure Page3/19
Ref#2.CoiledTubingpartsabovetheInjector/Gooseneck.
a. HaltmovementofCTwithininjector.Setbrakesontheinjectorandtheservicereel.b. StoppumpingoperationsthroughCTworkstringandmonitorCTpressurec. Securewellasrequiredfortheoperationsd. Continuetomonitorwellheadpressuree. Assesssituationtodeterminecourseofaction
IfthereisnoflowthroughCTID, IfthereisslightflowandtheassessmentconcludesthattheCTworkstringcanbesafelymoved, If there is sustained flow and the assessment concludes that CT workstring movement is not
recommended,
f. Openaccumulatorcircuitpressureisolationvalveontheconsole. Closetheslipramsandthepiperams.g. Confirmclosureof theslipramsandpiperams(reportpositionof indicatorpins)andmanually lockthe
ramsassoonassafeworkingconditionspermit.
h. Release injectorbrakeandslackoffbuoyedworkstringweightontotheclosedsliprams. Reset injectorbrake.
i. CuttheCTworkstringusingtheshearrams. Opentheshearramsimmediatelyafterthecutiscompleted.j. PickupCTworkstringapproximatelyonefootwiththeinjectortolocatetheshearedendofCTabovethe
blindramposition.
k. Closethebindramsl. Confirmclosureoftheblindrams(reportpositionofindicatorpins)andmanuallylockwhensafeworking
conditionspermitaccesstotherams.
m. Ensure pressure is bled off above the blind rams. Make provisions to displace hazardous fluids in CTworkstringwithasafeliquidifneeded.
n. RuntheCTworkstring intothewelltopositionthe leakbelowthestripperassemblyandabovethepiperams.
o. Open the accumulator circuit pressure isolation valve on the console. Close the slip rams and the piperams.
p. Confirmclosureoftheslipramsandpiperams(reportpositionofindicatorpins)andmanuallylockramsassoonassafeworkingconditionspermit.
q. InitiatepumpingoperationsanddisplacehazardousfluidscontainedinCTworkstringwithasafeliquid.r. Monitorwellconditionsandwaitoninstructionsfromcompanyrepresentative.
-
8/8/2019 CT Emergency Procedures
4/19
CoiledTubingEmergencyProcedure Page4/19
Ref#3.CoiledTubingpartsbelowPCE
a. Ifa leakoccurs inthetubingbelowthestuffingboxduringdownholeoperations,(usually indicatedbyadrop in pump pressure or loss of string weight), suspend tubing operations and alert the company
representative.Itmustbeassumedthatthecoiledtubinghasaholesomewheredownholeatanunknown
depth.This
circumstance
will
mean
that
at
any
time
during
pull
out
of
the
hole,
the
tubing
could
be
pulled
openendedorleakingoutofthestuffingbox.
b. Clearallpersonnelfromthe immediateareaofthecoiledtubingaroundthe injectorheadandbetweentheinjectorheadandthecoiledtubingreel.
c. Displacethecoiledtubingtowaterandcommencetopulloutofholeatnotmorethan5meters/min(20feet/min).Ensureatalltimesthatallpersonnelareclearoftheimmediateareaasthepossibilityexistsof
pulling the tubing out of the stuffing box. Continue pumping water at a slow rate through the coiled
tubing.
d. Whentheleak inthecoiledtubingappearsabovethestuffingbox,stoptheinjectorandholdtheleakingsectionofcoiledtubingbetweenthechainsandthestuffingbox.
e. Inspecttheleak.Iftheleakisminor,continuetopulloutofhole,beingcarefulasthetubingisbeingbentoverthegooseneckandontothereelascatastrophicfailuremayoccur.
f. Iftheleakismajor,orthetubingisactuallyseveredorthewellborefluidsareescapingthroughthetubing,proceed,cutthetubingandshuttheblindrams.
-
8/8/2019 CT Emergency Procedures
5/19
CoiledTubingEmergencyProcedure Page5/19
Ref#4 CoiledTubingLeaks(Pinhole)
LeakinCoiledTubingAtSurface
Calllocalalert(siteandunitspecific)andensureallpersonnelareremovedfromtheoperational area. Inparticular
make
sure
all
personnel
remain
clear
of
the
area
between
the
injector
head
and
the
coiled
tubingreel.
Iftheleakissmallorapinholeleak,pulloutoftheholeslowlyandpositiontheleakonthelowerpartofthe coiled tubing reel as soon as possible. Be careful when area of the leak is bent onto the reel as
catastrophicfailuremayoccur. Makearrangementstohaveawaterhosepresenttowashawayanyfluid
from thereelwhichmaybehazardous. Makearrangementstostartpumpingwater throughthecoiled
tubing reel. Depressurize reel as much as conditions allow without exceeding collapse limitations of
tubing.
Notifythecompanyrepresentativeoftheproblemanddeterminethebestmethodtomaketheareasafe.Iftheleakisminorandwatercanbedisplacedtotheleak,continuetopulloutoftheholeandchangethe
reel.
Iftheleakisconsideredtobetooserioustodisplacetowaterandpulloutofhole,oruncontrolledleakageofhydrocarbonsorhazardousmaterialspreventsthis(i.e.checkvalvesnotholding),setthecoiledtubing
slipsandpiperamsandactivatethecutters.Pullthecoiledtubingstubpiececlearoftheblindrams,then
activatetheblindrams(manuallylockinplace).
Depressurizethecoiledtubingreelthroughtheriser. Ifhydrocarbonsarepresentinthereel,displacethereeltowaterandemptythecontentsviatherisertospecifiedsafedisposalarea.
CommencefishingthecoiledtubingheldintheBOPs. Seesectiononfishingoperations.LeakInCoiledTubingBelowSurface
Ifa leakoccurs inthetubingbelowthestuffingboxduringdownholeoperations,(usually indicatedbyadrop in pump pressure or loss of string weight), suspend tubing operations and alert the companyrepresentative. It must be assumed that the coiled tubing has a hole somewhere downhole at an
unknowndepth. Thiscircumstancewillmeanthatatanytimeduringpulloutofthehole,thetubingcould
bepulledopenendedorleakingoutofthestuffingbox.
Once thecompanyrepresentativehasbeenalerted,clearallpersonnel from the immediateareaofthecoiledtubingaroundtheinjectorheadandbetweentheinjectorheadandthecoiledtubingreel.
Displace the coiled tubing to water and commence to pull out of hole at not more than 15 ft/min (5meters/min). Ensureatalltimesthatallpersonnelareclearoftheimmediateareaasthepossibilityexists
ofpullingthetubingoutofthestuffingbox. Continuepumpingwaterataslowratethroughthecoiled
tubing.
Whentheleakinthecoiledtubingappearsabovethestuffingbox,stoptheinjectorandholdtheleakingsectionofcoiledtubingbetweenthechainsandthestuffingbox.
Inspecttheleak. Iftheleakisminor,continuetopulloutofhole,beingcarefulasthetubingisbeingbentoverthegooseneckandontothereelascatastrophicfailuremayoccur.
Iftheleakismajor,orthetubingisactuallyseveredorthewellborefluidsareescapingthroughthetubing,cutthetubingandshuttheblindrams.
-
8/8/2019 CT Emergency Procedures
6/19
CoiledTubingEmergencyProcedure Page6/19
Ref#5PCELeak
5.1RotatingJoint
Closethereelisolationvalveinsidethepowerreelandrepairorreplacetherotatingjointasrequired.Retest
andresume
operations.
5.2LeakBelowtheBlowOutPreventer
Iftheleakisminor,coiledtubingisintheholeandtheshear/sealramsarebelowtheleak:
Callalocalalertandnotifytheoilcompanyrepresentative. Clearallnonessentialpersonnelawayfromthearea. HookupthepumpertothekilllineoftheBOPandpumpfreshwaterslowlydowntheannulus.
Note:Avoidcollapsesituation.
Continuetopulloutoftheholeandmonitorthesituationclosely. Closetheswabvalveandblindramsoncethecoiledtubingisintheriserandrepairtheleak. Performareinstatement testonsurfaceequipmentaftertheleakhasbeenrepaired.Ifthecoiledtubingisinthewellandnoshear/sealramsbelowtheleak,ortheleakisconsideredserious:
Callalocalalertandnotifytheoilcompanyrepresentative. Ensurethatallpersonnelareremovedfromthearea. Ensurethatthecoiledtubing issufficientlyoffbottomsothatwhentheshearsealramsareactivatedthe
pipewilldropbelowtheXmastreemanualmastervalve. Ifatallpossible,thedecisiontocutthetubing
andactivatethesystemwillbetakenbytheoilcompanyrepresentative inchargeoftheoperation. This
may not always be possible. If the situation is extremely dangerous and requires a quick decision, the
coiledtubingsupervisorinchargeshouldmakethisdecision.
Closetheshear/sealrams inthesafetyheadtocutthepipeandallow ittodrop. (Iftheshear/sealramshaveseparateshearandblindrams,closetheshearramstocutthepipe,pullupthecoiledtubingandclose
theblindrams).
Close
the
swab
valve
on
the
Xmas
tree.
ClosethemastervalveontheXmastree. Repairtheleakandpressuretesttheriser. Planfishingoperations.5.3 LeakintheCoiledTubing(AbovetheStripper)
VeryhighcompressiveloadscanbeachievedwhenfirststartingtoRIHwithcoiledtubing,soextremecare
shouldbetakentopreventcrumplingthecoiledtubing.
a. Stopmovingthecoilandshutdownthepump.
b. Inspectthehole.Ifitisapinhole,orifthereisonlyminimalleakageorflow,continuetopulloutofthe
hole.Placingtheleakontothedrumwillhelpcontainthespill.
c. Iftheholeislargeandleakssignificantly,itmaynotbepossibletocontinuespoolingthecoiledtubing.If
thecheckvalvesholdpressure,thedamagedsectionofthecoiledtubingcanbecutandreconnectedto
continuespooling.Ifthecheckvalvesdonotholdoriftheyhavenotbeenused,pickupoffbottom,set
theslipsandcutthecoiledtubingwiththeshearrams(Note:Usethe lowerblind/shearramsifthere
aretwosetsinthewellcontrolstack).
d. Pickthecoiledtubingupabovetheupperblind/shearramandclosetherams.
-
8/8/2019 CT Emergency Procedures
7/19
CoiledTubingEmergencyProcedure Page7/19
e. Initiateakillprocedurethroughthekill line(downthecoiledtubing lefthanging intheslips)toeliminate
thesurfacepressure.
f. Whenthewellisdead,pulloutoftheholeandrepairorreplacethecoiledtubingstring,
Note:If
there
is
acid
in
the
coil,
it
should
be
displaced
to
the
wellbore
with
water
while
pulling
out
of
the
hole.
-
8/8/2019 CT Emergency Procedures
8/19
CoiledTubingEmergencyProcedure Page8/19
Ref#6.FailureofCoiledTubingPowerPack
Ifthehydraulicpowerunitbreaksdown,theinjectorheadwillceasetofunctioninafailsafecondition. Asthe
hydraulicpressurereducestozerothemotorbrakeswillcomeonandholdthetubing. Ifthissituationoccurs:
Ensure injector brakes are supporting the tubing. If for some reason there is some doubt as to theinjectorsabilitytodothiseitherduetoafaultybrakeoraleakinthe insidechaintensionsystem,closethetubingslipstoholdthecoiledtubing. Manuallylockwithhandwheel.
NOTE:theuseofthetubingslipswillcausesomelocalizeddamagetothetubingandforthisreasonthis
courseofactionshouldonlybetaken ifthere issignificantdoubtaboutthe injectorsabilitytoholdthe
string.
Closethepiperamsandmanuallylockinplace. Chainthetubingreeltopreventthetubingfromunspooling. Thisshouldonlybedoneintheeventthat
thereelbrakefailsorthereisleakageinthereelmotorsystem.
Maintain
circulation
if
required
Repairorreplacethepowerpack.NOTE: if replacing the power pack, ensure that the BOP accumulator on the replacement unit is fully
chargedbeforechangingover.
Equalizethepressureacrossthepiperamsandopentheslips. Iftheslipramswereactuated,pickupthecoiledtubingandinspecttheareaaroundwhichslipswereset.
Cleanandpolishthesurfacewithemerycloth. Ifthetubingisseriouslydamagedpulloutofthewelland
repairorreplacethestring.
-
8/8/2019 CT Emergency Procedures
9/19
CoiledTubingEmergencyProcedure Page9/19
Ref#7PipedamagecausedbyInjectorHeadorGooseneck
a. HaltmovementofCTwithininjector.Setbrakesontheinjectorandtheservicereel.b. StoppumpingoperationsthroughtheCTworkstringc. Securewellasrequiredfortheoperationd. Assesssituationtodeterminecourseofactione. Confirm the reduction in weight indicator reading and that the CT segment has fallen below the blind
rams.
f. When separated CT segment falls through stripper assembly and below the blind ram position, openaccumulatorcircuitpressureisolationvalveontheconsole. Closetheblindrams.
g. Confirmclosureoftheblindrams(reportpositionof indicatorpins)andmanually lockramsassoonassafeworkingconditionspermitaccesstotherams.
h. ClosecrownvalveonChristmastree.Countnumberofvalvehandleturnstoconfirmproperclosure.i. Monitorwellconditionsandwaitoninstructionsfromcompanyrepresentative.
-
8/8/2019 CT Emergency Procedures
10/19
CoiledTubingEmergencyProcedure Page10/19
Ref#8FailureofCTReelDrive
Ifthedriveislosttothecoiledtubingreel,itisnolongerpossibletomaintainbacktensiononthecoiledtubing
betweentheinjectorheadandthereel. Theeffectofthiswillbeforthereeltounspoolandforthetubingon
thereeltoattempttounravelandadoptacurvature largerthanthereeldiameter. Thepotentialdangerof
thissituation
is
that
any
personnel
in
the
vicinity
of
the
tubing
could
be
struck
by
the
unraveling
coiled
tubing.
Inthissituation:
j. Callanalert(siteandunitspecific).k. Immediatelystoptheinjector.l. Ensurethatthecoiledtubingissecurelyheldbytheinjectorandcloseandlockthetubingandsliprams.m. Applythetubingreelbrakeiffitted.n. Inspectthecoiledtubingreelandeffectrepair. Inspectthecoiledtubingfordamage.o. Ifthecoiledtubingisdamaged,proceedaspercoiledtubingleakonsurfaceSectionp. Oncethereeldrivemechanismisoperational,runthetubingintheholeasfaraspossibletoremovethe
unwrappedtubing
from
the
reel.
(applying
tension
will
not
re
tighten
the
tubing
beyond
the
top
wrap)
Do
notrunanykinkedtubingintothewell.
q. Onceall theunwrapped tubinghasbeenremoved from thereel,pulloutof theholespooling thepipecorrectly.
r. Ifitisnotpossibletorunthetubingfurtherintothewell,anditisnotpossibletospoolthetubinginthewell back onto the reel, (no surplus capacity on reel) then it will be necessary to cut the tubing and
continueasperLeak inCoiledTubingAtSurfacesectionAfterthisaction itwillbenecessarytofishthe
tubingandspoolitontoanotherreelwithsufficientcapacitytoholdthetubingstillinthewell.
-
8/8/2019 CT Emergency Procedures
11/19
CoiledTubingEmergencyProcedure Page11/19
Ref#9StuckPipe
Whenthepipe isunabletobemovedfreelywithaforceof80%ofthetensileyield,thepipe isstuckdueto
one of two reasons. Friction sticking is due to tortuous wellbore or buckled production tubing. Mechanical
stickingcanbetheresultofsolidsaccumulationaroundthecoiledtubingordownholetoolsbecominglodged
inthe
completion.
9.1.FrictionStuckCoiledTubing
Preventingfrictionstuckcoiledtubingbeginsinthejobplanningbyidentifyingwellborepathsthathaveareas
of dogleg severity (DLS) that can inhibit the free movement of pipe. Normally a relatively high DLS (10 15
deg/100)canbetoleratedif itexistsinan isolatedarea.However, iftheyarewidespreadinthecompletion,
even a moderate DLS can frictionally stick the coiled tubing. The drag weigh forces can be modeled to
determineiftherewillbeaproblem.Whileperformingtheoperation,frequentweightchecks(each500)will
helpidentifyaproblembeforeitbecomessevere.Thiscanalsobeaproblemindualortriplecompletionseven
ifthereisnoobviousDLSproblem.
a. Apply80%ofthetensileyieldtothepipeandmaintainthatforceforaminimumof30minutes.b. Ifpossible,continuetomaintaincirculationbypumpingatlowratepressuretominimizethecoiledtubing
pressure.
c. Pumpfrictionreducingadditivessuchaspolymergeldieselorbeadsdownthecoiledtubingordownthecoiledtubingproductiontubingannulus.IfpumpingdowntheCT/PTannulus,limitthepressurebelowthe
collapseratingofthecoiledtubing.
d. Displacethewelltoheavierfluidtoprovideincreasedbuoyancy.e. Additional buoyancy can be achieved by displacing the coiled tubing to nitrogen. Note that collapse
pressureconditionshaveincreasedwhenchangingthefluid/gasdisplacementofthewellboreandcoiled
tubing.
f. Mechanicalmovementcanbeinducedwithouttheuseofhydraulicjarsinthetoolstring.
9.2MechanicallyStuck
Iftheweight indicator loaddoesnotdecreaseafterapplyingatensile loadofupto80%ofpipetensileyield
rating,itislikelythatthecoiledtubingismechanicallystuck.Attempttolowerthecoiledtubingintothewell
todetermine if it isactuallystuckatthatpointor if it isunabletopassthrougharestrictionorupset inthe
completionpipe.
Ifthecoiledtubingcanbemoveddownward,thendeterminethefollowing:
a. Ifthepipe(ortools)couldhavebeenbentorbuckledbysettingdownexcessiveweightorrunningintoan
obstruction.
b. Review the well sketch for any obstructions or restrictions that may present problems for movement of
coiledtubingordownholetools.
c. Mechanicalmovementcanbeinducedwithouttheuseofhydraulicjarsinthetoolstring.
-
8/8/2019 CT Emergency Procedures
12/19
CoiledTubingEmergencyProcedure Page12/19
Thefollowingoptionsmayexisttoretrievethecoil:
a. Continuecirculationifpossible.
b. Workthecoilintheoppositedirectionfromthewayyouweregoing,whenitwasdiscoveredthecoilwas
stuck.If
afew
feet
of
progress
is
made
in
that
direction,
begin
working
the
coil
back
the
other
way.
Try
workingthecoildownafewfeet,andthentrytheupdirectionagain.Graduallyincreasetheoverpullorset
downweightineachcycleratherthangoingtomaximumsallatonce.
c. Often times coil circulation is lost to thesurface due to the solids buildup. If circulation canbe attained
acrossthesolidsbuildup,considerpumpingahighviscositysweeptohelpstringthesolidsout.Thegoalis
tostringoutthesolidstoreducethefrictionloadsothecoilcanbemoved.Asandarcharoundthecoil
hastremendousgrippingpower.
d. Avoidworkingthecoiloverthegooseneckwithhighcoilpressure,asthisdrasticallyreducesthenumberof
cycles that can be performed before suffering permanent coil fatigue (ballooned pipe). Check the coil
history to get an idea how much the coil, which is currently across the gooseneck, has been worked on
otherjobs.Takecarefulnoteofanypriorfishingjobsorstimulations wherethecoilhasbeenreciprocated
manytimes.
e. Try to increase the differential hydraulic pressure across the solid bridge by flowing the well harder,
increasinggasliftorsurgingthewellwhilecontinuingtoworkthecoil.
f. Iffluidcanbeinjected,considerpumpingingasornitrogendownthetubingcoiledtubingannulustoform
agascap.Thensurgethewelldownthewingvalvetoapplyahighupwarddifferentialpressureacrossthe
problemdebris,againwhileworkingthecoiledtubing.
g. Iffluidcanbeinjecteddownthecoiledtubingtubingannulus,thiscanbeusedinconjunctionwithworking
thepipe.Avoidpumpingatpressuresclosetothecollapseratingofthecoiledtubing.
h. Always keep track of coiled tubing cycles over the gooseneck. Do not work the pipe excessively if no
progress isbeingmade.Worktochangethedownholeconditionsto increasethechancesoffreeingthe
pipe.Then
resume
working
the
pipe
again.
i. Onceprogressismade,alwayscontinuecirculatingwhileworkingthepipebackuptheholeslowly.
j. Consideration can begiven to spottingacid across theproblem debris if you feel it is evenpartiallyacid
soluble.
k. A minor mechanical movement canbe achieved without the use ofjars by removing one of the three
pump suction valves from the triplex pump to induce hydraulicjacking through the coiled tubing. The
pulses created can contribute to solving both mechanical or friction stuck coiled tubing. However, this
option should be used with caution due to the inherent cycling effects imposed on the coiled tubing at
surface.
Ifthe
coil
cannot
be
retrieved:
l. If there is a tool string that can be released, pump a ball to release the hydraulic disconnect if it is
determinedthattheBHAisgettinghungup.
m.Killthewell,cutthecoiledtubingatthesurfaceandrunafreepointtooltodeterminethedepthtothe
stuckpoint.Follownormalfishingprocedurestoremovethecoiledtubing.
-
8/8/2019 CT Emergency Procedures
13/19
CoiledTubingEmergencyProcedure Page13/19
9.3 MechanicallyStuckwithoutCirculationa. Pump the kill weight fluid down the coiled tubing. If it is not possible to pump down the coiled tubing,
attempttopumpthekillweight fluiddown theannulus(atpressuresbelow thecollapsepressureofthe
coiledtubing).
b. Cutthecoiledtubingatsurfaceandrunafreepointtool.Follownormalfishingprocedures.
-
8/8/2019 CT Emergency Procedures
14/19
CoiledTubingEmergencyProcedure Page14/19
Ref#10CoiledTubingRunAway
10.1UncontrolledDescentofCoiledTubing
a. Applyadditionalpressuretothestripperassemblyandsimultaneously closethepiperams.
b. Increase the velocity of the chains (in the same direction as the pipe) to closer match the speed of the
coiled tubing Tailing into the well.This will help relieve the loss of friction between the chains and the
pipe.Attempttoincreasetheinjectorsinsidechainpressuretostoptheuncontrolledmovementofpipe.
c. Once the pipe has stopped falling through the chains, slowly reduce the chain speed and come to a
completestop.
d. Closetheslipramsandmanuallylockthem.
e. Oncethepipehasstopped,closethepiperamsandinspectfordamagetothechainsorpipe.
f. Observe pump pressures and circulation rate to determine if there is any damage to the bottom of the
coiledtubing,suchasacrimp,kinks,orbuckling.
g. Pumpthehydrauliccylindersopenontheinjectorchainskates.
h. Inspectthechainblocksandremoveanydebris.
i. Reset the inside (and outside) chain pressures to the proper settings. Verify the proper alignment and
spacing between the chains. If necessary, replace the chains or individual gripper blocks as necessary to
preventdamagetothecoiledtubingwhilepullingoutofthehole.Ifnoadditionalchainsorgripperblock
inserts are available, the chains can be material on site to facilitate better grip. (Use material such as
sodiumchloride,potassiumchloride,sand,etc.)
j. Ifthewellisundercontrolandtherearenomechanicalproblems,thenopenthepiperamsandsliprams.
Changethestripperelementifnecessary.
k.
Pull
out
of
the
hole
slowly
to
determine
if
the
end
of
the
coiled
tubing
can
be
pulled
inside
of
the
production tubing. Pull completely out of the hole to inspect the coiled tubing completely for external
damagethatmayhavebeencausedbytheslipsorchainsduringdescent.
-
8/8/2019 CT Emergency Procedures
15/19
CoiledTubingEmergencyProcedure Page15/19
10.2 UncontrolledAscentOutoftheWell
a. Applyadditionalpressuretothestripperassemblyandsimultaneously closethepiperams.
b. Increasethevelocityofthechains(inthesamedirectionasthepipe)toclosermatchthespeedofthe
coiledtubing
falling
into
the
well.
This
will
help
relieve
the
loss
of
friction
between
the
chains
and
thepipe.Attempttoincreasetheinjectorsinsidechainpressuretostoptheuncontrolledmovement
ofpipe.
c. Iftheseattemptsareunsuccessfulputtheinjectormotorsinneutralandclosethesliprms.
d. Oncethepipemotionishalted,closethepiperamsandslips,ifnotalreadyclosed.
e. Pumpthehydrauliccylindersopenontheinjectorchainskates.
f. Inspectthechainblocksandremoveanydebris.
g. Resettheinsideandoutsidechainpressurestothepropersettings.
h. Ifthewellisundercontrolandtherearenomechanicalproblems,thenopenthepiperamsandslip
rams.Changethestripperelementifnecessary.
i. Reduce the hydraulic pressure on the stripper element and pick up the coiled tubing enough to
inspecttheareasofpipeheldbytheslips.
j. Determine whether it will be necessary to repair/replace that section of coiled tubing prior to
resumingthepipeextraction.Beextremelycautiouswhilecheckingtheareaofpipeheldbytheslips
sincethepipemaybeweakenedandmayfailwithhighsurfacepressurepresent.
k. Continuetopulloutoftheholeandclosethemastervalve.Determinethecausefortheuncontrolled
movement of pipe prior to entering the well again. Replace or repair the coiled tubing string as
required
If thecoiled tubing isblownoutof thestripperassembly,close theblindramsandmastervalveas
quicklyaspossible.
-
8/8/2019 CT Emergency Procedures
16/19
CoiledTubingEmergencyProcedure Page16/19
Ref#11LeakingBHACheckValves
a. Ifaleakoccursinthetubingbelowthestuffingboxduringdownholeoperations,(usuallyindicatedbyadrop in pump pressure or loss of string weight), suspend tubing operations and alert the company
representative. It must be assumed that the coiled tubing has a hole somewhere downhole at an
unknowndepth.
This
circumstance
will
mean
that
at
any
time
during
pull
out
of
the
hole,
the
tubing
couldbepulledopenendedorleakingoutofthestuffingbox.
b. Oncethecompanyrepresentativehasbeenalerted,clearallpersonnelfromthe immediateareaofthecoiledtubingaroundtheinjectorheadandbetweentheinjectorheadandthecoiledtubingreel.
c. Displace the coiled tubing to water and commence to pull out of hole at not more than 15 ft/min (5meters/min). Ensure at all times that all personnel are clear of the immediate area as the possibility
existsofpullingthetubingoutofthestuffingbox. Continuepumpingwaterataslowratethroughthe
coiledtubing.
d. Whentheleakinthecoiledtubingappearsabovethestuffingbox,stoptheinjectorandholdtheleakingsectionofcoiledtubingbetweenthechainsandthestuffingbox.
e. Inspect the leak. If the leak is minor, continue to pull out of hole as in BOP emergency operationssection,beingcarefulasthe tubing isbeingbentoverthegooseneckandontothereelascatastrophic
failuremayoccur.
f. If the leak is major, or the tubing is actually severed or the wellbore fluids are escaping through thetubing,cutthetubingandshuttheblindrams.
-
8/8/2019 CT Emergency Procedures
17/19
CoiledTubingEmergencyProcedure Page17/19
Ref#12 LeakinStripperPackOff
Stripper leaks are a common occurrence and are affected by many factors such as stripper hardness, coil
smoothness, effectiveness of the coil lubrication system, and the stripper pressure that is used. Without
adequatelubrication,stripperscancompletelygripthecoilwhilegoinginthehole.Thiscancausecoilfailure
betweenthe
stripper
and
the
injector
head
chains.
The
standard
coil
lubrication
procedure
used
to
consist
of
lubricating the coil with diesel at the spool. To reduce the environmental impact of dripping diesel on the
ground,thestripperhousingcanbeandfittedwithasmalllubricationorifice,solubricationcanbedoneright
atthestripper.Thishastheadvantageofplacingthe lubricationwhere it isneededandthedisadvantageof
notbeingabletovisuallyverifyadequatelubrication.
12.1SmallStripperLeaks
Ifasmallleakdevelopsthestripperpressurecanbeincreaseduntilitstops.Donotallowevenasmallleakto
continue,becauseitwillcuttheelementsandbecomemoresevere.
If the leakcannotbestoppedbystripperhydraulicpressure,and thecoilcannotbepulledout, thestripper
shouldbechangedoutimmediately.
StripperReplacement
a. Notethecurrentstringweight,settheslipsonthecoil,andeitherslackoffcoilweightorpickup(depending
uponwhethercurrentweight ispositiveornegative)from30005000Ibstobesuretheslipsareholding.
Manuallylockintheslips.
b. Setthetubingramsandbesuretheramsareholdingbybleedingoffabovethem.Manuallylocktherams.
c. Bleedoffthepressureinthewellcontrolstackthroughthekillline.
d. Changeoutthestripperasperthemanufacturersprocedure.
e. Energize it to the proper pressure setting based on the wellhead pressure. The stripper can be pressure
testedby
pumping
through
the
kill
line.
f. Equalizethelubricatorpressurewiththewellheadpressure.
g. Unlock and open the tubing rams. Set the string weight to the previous value and unlock and open the
tubingslips.Proceedwithnormaloperations.
12.2 ORingLeaks
IfanOringorchevronsealbetweentheBOPstackandthestripperfails,alwaysclosethetubingramsfirst.
Thecoildepthandleakseverityshouldbeconsideredwhendeterminingthenextstep.
a. Stopthecoilandnotethecurrentstringweight,settheslipsonthecoil.
b. Setthetubingramsandmanuallylock.Bleedoffthelubricator.
c. BackoffthequickunionwheretheOringisleakingandwalktheinjectorheadupthetubing,byoperating
theinjectors ifrunningthecoil intheholeslowly,whileraisingthetrolleyhoist,tohelpsupportthetotal
injectorheadandguidearchweight.
d. Repair theOringwith astandard Oring patch kitor if aspareOring isalreadyon the lubricator,roll it
downintoplace.
-
8/8/2019 CT Emergency Procedures
18/19
CoiledTubingEmergencyProcedure Page18/19
e. Walktheinjectorheadbackdownandmakeupthequickunion.NewOringtoavaluecomparabletothe
currentwellheadpressure.
g. Setthestringweighttotheoriginalsetting.Unlockandopentheslips.
h.Equalize
across
the
tubing
rams
and
open
them.
Pull
out
of
the
hole
to
change
out
the
patched
O
ring.
If
aspareOringwasrolledintoplace,continuewithCTUwork.
-
8/8/2019 CT Emergency Procedures
19/19
CoiledTubingEmergencyProcedure Page19/19
Ref#13CoiledTubingCollapse
a.Killthewellifitisnotalreadydead.
b.Releasethestripperelementpressure,andremovethestripperelementsandretainingbushings.
c.Pickupthecoiledtubingslowlytodeterminethetopofthecollapsedpipe.
d. Run back into the hole with the coiled tubing until the undamaged portion of the pipe isacross thewell
controlstackcomponents.
e. Closethepipeandsliprams,andmanuallylock.
f. Relaxtheinjectorchainstoverifythattheslipramsareholding.
g. Cutthecoiledtubingabovetheinjector.
h. Opentheinjectorchains.Removetheinjectorfromthecoiledtubing,andsetitofftotheside.
i. Attachafulltubeclamptothecoiledtubingdirectlyabovethewellcontrolstack.
j. Connectthecraneortravelingblocktotheclampandopenthepipeandsliprams.
k.
Slowlypull
the
coiled
tubing
out
of
the
well
to
the
maximum
height
of
the
crane
or
block.
l. Attachacollapsedtubeclamptothecoiledtubingdirectlyabovethewellcontrolstack,andcutthetubing
abovethebottomclamp.Connectthecrane,andpullthecollapsedcoiledtubingoutofthewell.
m.Continuealternatingpulling,clamping,andcuttingthecoiled tubinguntilallofthecollapsedsectionhas
beenremovedfromthewellandthetransitionsectiontoundamagedpipeislocatedabovethewellcontrol
stack.Ensurethatthereisenoughcompetentpipeabovethewellcontrolstacktothreadthecoiledtubing
throughthestripperandinjector.
n. Closethesliprams,andremovetheclamp,
o. Install and secure the injector onto thecoiled tubing. Apply hydraulic pressure to the inside chains, and
switchtheinjectortotheextractionmodeOpenthesliprams.
p. Either connect the end of the coiled tubing to the other section of coiled tubing on the reel with a
connectoror
install
avalve
onto
the
end
of
the
coiled
tubing
and
begin
anew
wrap
on
the
reel.
q. Reinstallthestripperbushingsandelements.
r. Finishpullingoutofthehole,andreplacethereel.Determinethecauseofcollapsepriortoenteringthe
wellagain.