00025499

7/28/2019 00025499

1/16

4q

SooietyfPotrobumEn@wra

SPE 25499Fishing With Coiled TubingR.L,Hilts,Otis EngineeringCorp.; S*H.FowlerJr,, HalliburtonManufacturing&ServicesLtd.;and C.W.Pleasants, Otis EngineeringCorp,SPEMembere

*VW lW,SacW ofPctro!wmnglnwa, Inc.TIM iwwt w -W bf prwnlalbn q 1 - P rodwxon ~.1~ .: Syfmpos lumWM 10Ok lahoma C IW OK, U .S.A. , March 21-23 , 1SS3.TM p@or w Mxd8d tor pmmtmkm by an W% Pmsmm OunmMw tolbwl~ rwiw d lnlomwon wmalrmd in an abstrwl Wbmillti by lha wlhw(s). ComonW of the papof,*~. * ~ - ~ by ttw 80ckW of P@o@m Ewlneefa and m WbM M comwlbo by tha wtnor(s). Tiw matwlal, m pmn.nted, &me ml nesw.sarlly felledcJYY:&w 0! PohOwm EnJmu8! d# 0rtlc4m, m nwnbom. Paporopmwn lod a l8PE mnt lngo amwqul topub ll ca ll an w byEdl to tl al f kwnmll lws 01 lhaSwMy~mCOPYk-@WM~~*_ti**. Iiluatmlkmt rnw nelb..+hd, Th. *rWl [email protected]*n0Vdd9Mntc4@tom qndby wmm lhs w Isp rononM. Wrh@Llbw lsn, SPE , P .0 , Box 2S30S6, R ictwd ton , TX 7SOW2032, U.S.A. hhX, fd3246 SPEUT.

AB~TRAcl INTRODUCTIONImprovedcoiled tubing (CT) technok:y, developmentof An oilfield definition of fishing might be: an attempt tospeciallydesigned hydraulically-actuatedservicetools, and engage and retrieve unwanted, unserviceable,or oftenincreasedemphasis on cost efficiency have made coiled damagedequipmentfroma wellbore. The term fishingtubing a viable option for many fishing jobs. Beforetie is generally used when downhole equipment cannot beemergenceof coiled tubing fishing technology, traditional retrievedfrom the well usingthe tools or methoddesignedserviceproceduresincludeduseof wirelineto retrievefish to operateor retrieve that pieceof equipment, Generaily,fromoil andgas wells. If wirelinewasunsuccessful,a rig fish fall into two cmegories - some are simplyor hydraulic workover (snubbing)unit had to work over nuisances, causing decreased production or increasedthe well and remove the fish, operatingdifficultiesand costs, but somemustbe removedfor sitfetyor mechanicalreasons if the well is to continueThis paper addresses the successfuluse of CT in fishing production.operations. The capabilityof CT to circulate fluids at thefish and generate high downhole forces enakiies the In productionoperations, fish might include:retrievalof fish in situationsthat wouldnot be possibleorcost effectiveby other service options, Cf fishing canbe o Stuck, damaged, or inaccessiblesubsurfaceflowperformed under premre on live, highlydeviated or controls, plugsor subsurfacesafetyequipmentthathorizontal wells; the job can be compietd and the well cannot be pulledby wireline.returned to production within 1 to 3 days for only afriictionof the cost of a workover, q Lengthsof wirelineor logging (E-line)cable,The paper will describe the tools, their capabilities, and q Service tool strings.service techniques currently in use for CT fishingoperations as well as new equipment being developed, c Other foreign objects,Data from several case histories will be used to provideconsiderations,surface rig-up, andjob limitations, Pefore 1980, the qutdity of the CT, particulary the weldjoints, was relatively low, and tubing failures resulted inReferencesend illustrationsat end of pepcr. fishingjobs to removethedropped pipe, In spite of these

827

7/28/2019 00025499

2/16

.q

2 FISHING WITH COILED TUB:NQ SPE 25499problems, the benefits of CT could not be ignored,particularlysince falling oil prices during the 80s createdthe need for operators to seek cost-efficientalternativesinproduction operations, CT could offer the benefits ofmobility, relativelylow cost, andbriefjob timescombinedwith s?me of the advantage of jointed pipe, such ascirculation, utilization of pressure-activated tools, andcapabilityto work on live wells,As the quality and reliabilityof CT and related equipmentimproved, changa such as increased tensile strength,improvedwelds, and !argertubing S:zesfurther expandedthe range of jobs that could be performed with CT. CTcouldbe consideredfor services that used downholetoolssuch as inflatablepackers, downholedrilling motors, andservice tools on the end of the tubing string for installingand removingdownholeflow controls.he expandingnumber of horizontal and highlydeviatedwel)s haa increased the number of jobs fbr CT sincewirelineand electric-line servicm reiy on gravity for tooldeployment and, therefbre, are not effective in highly-deviatedwellbore configurations.lLarge diameter, more-reliableCT enabled tool designersto develop specialized heavyduty, coiled-tubingworkatrings to service downhole flow controls. Thesetoolstrings form the basis for fishing-with-coiled-tubingoperations. The availabilityof CT services and suitablefishing tools has expandedthe number of fish that can beretrievedfrom live wells, ofien eliminatingthe need for aworkoverwith a rig or hydraulicworkover unit,COMPARISONOFWIWLJNEv~RW!UXWirelinesemice is readily available and is the most cost-effective means of performing many well servicingoperations, In addition, numerous tools and techniqueshave been developed for wireline fishing operations, andwireline operators with invaluable experience in fishingproceduresare available. However,wireline is limitedbywall configurationsthatmust eitherbe straightor deviatedlessthan60 degreesfromvertical, Increasedwelldeviationlimits thembilityto jar effectivelyand cancreate problemswith tool transport.Sand and debris on top of a fish can prevent a wireline-conveyed service tool from effectively reaching and

latching the fish; in addition, there is a practical limit tothe amountof sand that bailers can remove since trips toemptythe bailer may allowmore debristo settleon top ofthe fishy If a CTunit is neededto circulatedebrisoffthefish, the unit shouldbe used for the fish retrievaloperationalsosincethese operationscanbe performedconcurrently.CT has three major advantagesover wireline for fishingoperations:

@ It has the capability to circulate various washfluids, including nitrogen and acid, at highpressures to wash, jet, or dissolve sand, mud,scale, and other debris off the top of the fish.. It has the capabilityto generatelarge axial forcesin straight or highlydeviated wells for jarringand/or pulling a fish that is too heavyfor wireline.q It can perform the above operations concurrently.

The breaking strength difference of wireline and CT isillustrated in Figure 1,CT AND -INF EWGY COMPARISONSOnemethodused to comparethe efficiencyof fishingwithCT to wireline is to approximate the availabie energy ineach system that can be utilized to deliver impactforcesdownhole. This can be done by applying the internalenergy and strain equations in the Appendix.Tables 1 and 2 list the appropriateinformationto comparethe internalstrain energyof CT and wirelineat depthsof500 ft. A graphical representationof the internalenergyis shown in Figure 2.Examinationof the tablesand bar graph of FigureZ showsthat the internal strain energy, U, of CT at 500 h is 8.32times that of wireline. Upon tklher review, time resultsare not surprising, ccmidering the hangoff weightof theCT at such a shallow depth is rather insignificantcomparedto the surface load applied, It should also benoted that the spring rate of the CT systemis 1,723 lb/in,This implies that the jarring force in the system willdecrease rapidly s the tubing contracts, but the initialforce or surface load is so large that the overall effectonthe internal strain energy is positive.

7/28/2019 00025499

3/16

.

SPE2S499 ROBERTL. HILTS, S, HAMPTON FOWLER, CHARLES W. PLEASANTS 3

Tables3 and 4 list the appropriate informationto comparethe internalstrain energyof CT and wirelineat a depth of10,000 ft. A graphical representation is also includedinFigure 2,The internalstrain energy, U, for CT is again impressive,but this time it is 2,20 times that of wireline. Why thelower energy ratio as comparedto both systemsat 500 ft?It should be noted that the hangoff weight of the CT isconsiderable, almost 12,000 lbs. The usable force is,ttwrefore, decreased cmsiderrbly but is balancedson>;whatby the greater amount of deflection, &,of thelonger lengthof tubing in the hole,When examining the data of the wireline system, thedeflection, 6, is enormous at 3@8 inch-. This, alongwith the extremely low mass and weight of the wire,explainsthe large increasein internalenergyof this systemas compared to the wireline system of 500 ft. l%is, inturn, also explains how the energy level of the wirelinesystemhas gainedon that of the CT systembut overall isstill ccmaidrrablyhas. With such a large deflection, thespringrate, k, wouldbe expectedto decreasesignificantly,and this is indeedthe case.This data is an indication of the maximum amount ofenergy available in a particular system; how this energytranslates into jarring force will dependupon such factorsas the jar stroke, stemweight, andwhether an acceleratoris introducedto the system. This data, however, alongwiththe benefitsof acwhoie circulationandabiiity to usethe tubing as a transportationmediumfor downhoietooisin highlydeviated and horizontal weils does heip supportthe fact that CT providea an exceiient option forperformance of fishing operations and deserves highcmsideration.

CT requires a specialized tooistring designed to takeadvantageof the tubings flow and pressure capabilities,Whiie wireiine reiiea on speed or wire strain to createimpact forces, CT can also utiiize iarge axial forcesbecauseof its high tensiie strength.The tooistring used for CT fishing may vary byapplication; however, a typical toolstring is shown in

829

Figure 3, and a discussion of the various componentsfoiiows.CT Connector - Thiscomponentis the crossoverbetweenthe CT and tooistring. The CT connector must bedesigned to withstand the working pressure and tensiieioading capahiiitieaof thu tubing string, A thread+nconnector,zpprop:iate for small diametertubing, is shownin Figv.s 4. New higher-strength siip-type connectordesigri are fiow avaii~~bieor 2-inch and larger O,D,~~bingthat eiiminate the need for threading of the CT.$This type of connector is also shown in Figure 4.Emergency Disconnect Sub - The emergencydisconnectsub is used in the event the tooistring becomesstuck and cannotbe reieased. A baii iscircuited throughthe tubing strin~ to the disconnect sub, and activates therelease mechanism. This feature may also be used toreiease a fish suspended in a biowout preventer (ROP) atthe surfacein order to rig down the CT injectorand rig upthe additional lubricator and wireiine fir recovery(Figure 5).Rack Pressure Valve - This is basicaiiy a check vaivethat aiiowsflow through the CT and intothe weilbut wilinot aiiow back flow into the tubing. In the event of asurface ieak in the tubingstring, this valvewili prevent theuncontrolledreleaseof weii fluidsat the surfaceabovetheBOP stack (Figure 6),Ported Knuckle Joint - Becauseof the curvature in theCT, the ported knuckie joint is needed to allow thetooistring to flex without the influence of side ioadings,This curvatureis especiallyprominent near the end of thetubing string, wherethere is insufficienthangingweighttostraighten the tubing string, When fishing in iargerdiameter weilbores, the ported knucklo joint wiii aisoenablethe fishing toois to foiiowthe low side of the holewhere the fish is most iikeiyto be iocated (Figure 7),Accelerators - Acceleratorsthat employ a heiicai springto store the energy necessaryto activatethe jars are usedto acceleratethe weightedstemto a high velocityto createimpact ioads at the fishing or service tooi, It is notuncommon for jar up and down accelerators to beinciuded in the CT fishing tooistrings, particularitywhenused in shaiiowdepth, highiydevjated or horizmmdapplications(Figure 8),

7/28/2019 00025499

4/16

4 FISHING WtTH COILEDTUBING SPE 25499

Weighted Stem - The weightedstem provides the massrequired to imparthigh impactloadsto the fish whenusedin conjunctionwith the jars and accelerators(Figure 9).Hydraulic Jars - The hydraulic jars are the timedelaydevices that allow the up or down acceleratorsto fillyextendor contractbefore releasing. The jars also containthe necessary stroke to allow the weighted stem toaccelerateto a high velocityto insure a high impact forceis transmittedto the fish, It is not uncommonfor upanddown jars to be made up into fishing toolstrings(Figure 10).Fishing c: Service Tools - The appropriatetool for thedesired operation is attachedbelow the jars. These toolscanbe overshots, tap=taps, spears,,wirelinepulling tools,junk baskets, and custom-designedhydraulically-actuatedrunning and pulling tools (Figures 11& 12).SERVICETocLS4J!J~FRDEVELOPMENTNewsystems are now :beingdevelopedthatwill allowthedeploymentof videoequipmenton CT. Downholevideotechnologyis not new to thepetroleum industryin electricline applications; however, restrictions posed by cabledeploymentpreventthe camerafrombeing transportedintohighlydeviated and horizontalwells. CTdeployed videoequipment will further facilitate fishing operations inapplicationswith deviatedwell configurations.,Another tool undergoing development is the downholeforce generator, This device takes advantage of theinternalpressure capabilitiesof CT to deliver large tensileand compressive forces downhole. These forces can beused to shift sleevesand to set and retrievedownholeflowcontrols. The downhole force generator will beparticularlyadvantageousinhighlydeviatedand horizontalapplicationswhere friction limits the amountof force thatcan be delivered to the end of the tubing string.

PRF-JOB PI ANNINGThe followingsteps shouldbe taken in pre-job planningtomaximize the economic benefits of CT in fishingoperations:

q

q

q

Qbta in an Accurate Descriotion and Historvgf the FishIt is important for the qerator to assess jobrequirements by thoroughly reviewing the joblogs, impressionblocks, matingparts, andsimilarequipment, Access to well schematics anddimensional data for a known fish can save timeon the well site; knowledge of conditions orreasons the fish remained in the wellborecan alsofacilitate planning, For example, if scaie in theproductiontubingcausedthe lossof wirelinetools,removal of the scaleprior to actual fishing wouldoptimizeoperational eftlciency.tain FoIIow-UDInformation Based on In. .ltl~

-Wireline drift runs and impression block runsprovideadditionalinformationnecessaryto finalizefishing strategy. Downhole video cameras canprovide an invaluable source of informationconcerninglocation, condition, and orientationofthe fish that can save days of fishing time on thewell site, 4Take Advantaae of the Benefits of WirelinQIn certain fishing jobs, wireline used inconjunction with CT ran shorten the overall jobtime. Wirelinesfast rig-upand trip speeds allowdrifts, impressionblocks, andwire retrieval toolsto be run quicklyand eftlciently. Wirelineruns tobait the fish (gripping the tish with a service toolthat can be purposely left in the well andsubsequenty engaged)can be accomplishedmorequickly than those done with CT. Wireline issensitive to small changes in weight indicatort~adings; thus, it is useful in locating the top ofwire, tight spots, or tubing leaks that cannot bedetectedwith CT.It ispreferableto considerCTunit personnelwithprior wireline and wireline fishing experienceforactual operation of these procedures as theirknowledgeof the tools and techniques in variousfishing situations can maximize the efficiencyofthe operation.

830

7/28/2019 00025499

5/16

.*

SPE 2S499 ROBERTL. HILTS, S. HAMPTON FOWLER, CHARLES W. PLEASANTS 5m

It is importantto plan for those situationsinwhichthe first fishing attempts are unsuccessfulor thefish separates, If possible, have a part similar tothe one being fished availableon location. Also,have adequate spare parts on hand for thedownholetools that will be utilized,and ifpossibleand practical, keepa backupset of tools available.q Jest Tool~ o We t IIEntry

The trial testing of speciti tools and/or operationson the surfaceprior to commencingthe job on thewell site is highly advised. CT generatessignificantly ttigher fbrces than many wirelinetoolsare capableof wkhstanding. Brokentoolsontop of the original fish can be harder to retrievethan the original fish,-

Safety is the primary concern in all oilfieldoperations, and CT fishing, as with any live wellintervention, must be performed with caution.gThe toolstring should include a hydraulicdisconnect and a minimum of one back pressurevalve, The CT BOP stack should be thoroughlyinspected, tested, and redressed as required priorto arriving on the well site. The in@ctormust beanchored securely to prevent movement orswayingduring thejarring operationas movementcan place undesirable bending loads on thewellhead equipment, It is advisableto flange ailsuffaceconnections.

SURFACE RIG UPTheprimary considerationsare safety and the removal ofthe fish (once ithas beenpulledto the surface)in planningthe surfacerig-upfor CT fishing, Aspreviouslystated, allwellheadconnectionsshould be flanged, and the injectormust be firmly anchoredwith guy wires,Surthceequipmentrig-upswill vary fromjob to job as willthe fish they are attempting to retrieve, Following is abrief description of a typical rigup that has been used

successfidlyfor removing long fish from the wellbore ofkeeping the rig-upheight at a minimum.A flangedwirelineBOP is connecteddirectly to the tree.This wireline BOP is used to hold the fish that has beenbrought to the surface if it is too long for the availableriser. Above the wirelineBOP is a four-foot flangedriserwith a gate valve. Above the gate valve is sufficientflanged lubricator to cover the fishing tool workstring,followedby the CT BOP stack, and injector (Figure 13).The advantage of this rig-up lies in how the fish isretrieved at the surface, A typical fish retrieval sequencewould be as follows:

q Hold the fish with the wireline BOPq UsetheCT hydraulicdisconnectto releasethe fishbelow the gate valveq Lift the CT and close the gate valveq Rig down CT, and rig-up wireline with alubricator long enoughto cover the entire fish

An alternative to using the above s~~ence uses aspecially-sized hanger sub below the CT hydraulicdisconnect sub, which can be held imd sealed by acombinationpipe and slip ram BOP, The fish can thenbelocated across the combination BOP, followed by theclosing of the pipe and slip rams; the pressure above theBOP is then bled off. Atler insuring that the rams havesealed, the hydraulic disconnect is used to release the CTfrom the fish, In the event that the fish cannot be fullysealed off, or if it is extremely long, the well must bekilledbefore the fish canbe removed.On someoffshore rig-ups, the distiincefrom the tree to theplatformdeck or rig floor will provide enoughdistancetocover the toolstring and fish with a riser as shown inFigure 14.

mMMLll@SAny pulling tool run on CT should be designedto releaseeasilyin the event the fish cannotbe retrieved, It may be

831

7/28/2019 00025499

6/16

6 FISHING WITH COILED TUBING SPE 25499

difficult to shear the pins in a down-to-releasepullingtool usingCT, particularlyif downtype acceleratorsandjars are not employed. However, there are seversi typesof pulling tools designedfor use on CT that can easilybereleasedby usingtheavailablepressure in the tubingstring(Figure 11)or by simply slackingoff the tubingweight.The pressure-release-type tools are disengaged bycirculating a bail to the tool via the tubing string or bypumping fluid at a high enough flow rate to create thenecessarypressuredifferentialto activatethe pullingtoolsreleasemechanism, Mechanicsi-typepullingtools, suchasovershots and spears, can be released by slacking offtubing weight, which activates the tools ratchetmechanism. This allowsthe pulling tool to cyclebetweenthe catch8nd releasemodes.GT F-Low-cycle fatigue can result from the CT passingrqwttedly over the injector tubing guide (gooseneck)during the jarring operations. The effects of low-cyclefat@ueare well known and area functionof the internaipressureof the tubing, the radiusof the tubing guide, andthe radiusof the pipeon the reel.io The higherthe intemaipressure of the tubing and the smailer the radius of thetubing guide or reel, the shorter the predicted life of theCT will be.Whenjarring fbr an extended period of time, it may benece$saryto increasethe bend radius to reduce the effectof low-cycle fatigue. The radius can be increased byopening the tubingguide, spoolingadditional tubing fromthe reel, setting the rest brake, and using a crane tosupport the free arch formedby the additionalCT.Depending upon the equipment and internal tubingpressure, attemptsto retrieve the fish are normallylimitedto 50 to 150 jarring cycles, If the fish has not beenrelemed, the CT should be removed from the wellbore,and severai hundred feet of tubing removed prior toresuming the fish retrievsi operation. The removai of asegmentof tubing limits the numberof jarring cyclesthatone sectionof CT receives; this, in turn, limits the fatigueof the tubing. If severe sweilingof the CT has occurred,the entire rest of tubing shouldbe replaced,

~ DebriSWhenthe top of Lie fish is expectedto havelarge debrissuch & metai cuttings, cement, or scale that cannot beeasily circulatedto surface, a junk basket may be run aspart of the bottomholeassembly. A junk basket has alsobeen effective in picking up segments of broken pullingtools,Pullina ~Pri tr to iatching the fish, circulation of a high-viscositypili may be rJsedto assist in ck.aning debris that couldhinderthe fishingoperation from the hole. When the holehas been swept clean, accurate pick-up and siack-offweightscanbe performedand recorded. Oncethe fishhasbeen engaged, overpull should be Iimit,edto 80% of thetubing yield strength. This limit should be downrated iffatigue of th( CT string is expectedbecauseof extensiveand repetitiveservice.In a fluid-filledwell, one method to increase the overpullavailable at the fish is to displace the CT with nitrogen,whichprovidesthemaximumbuoyancyeffects. However,displacing the tubing with nitrogen will aiso increasetheCT internalpressure at the surface, therebydecreasingthefatigue life of the tubing, Because of compressibilityofthenitrogen, this methodcanaiso causepotentisiproblemsat the surface in the event of a tubing failure above theBOPstack.

erehr-Stuck FIs~Malfunctionedlock mandrels, corrosion, sand, and finescan remit in stuck fish that can require nearlythe physicailimits of the CT string to release. In addition, repeatedjarring in one section of the coil weakens the tubing bycausinglow-cyclefatigueas it passesbackand focthacrossthe gooseneckof the injector,The development of 100,000 psi high-strength CTincreases the tensile force available for pulling and/orjarring. The cycle life of high-strengthCT is longerthanthat of typicai 70,000 psi CT and, accordingly, can beadvantageous in jarring operations.l The use of high-strengthtubing is aiso beneficialwhenfishing inwellsthatare deep, have long horizontal sections, or require high--pressurecirculation,

832

7/28/2019 00025499

7/16

SPE2S499 ROBERTL. HILTS, S, HAMPTON FOWLER, CHARLES W. PLEASANTS 7

ts and PIw in Horizontal WellsIn verticalwells, wirelineis oftenused to run a gaugeringandjunk basket belowthe production-packersettingdepthto insure the wellbore is to size and relativelyfree fromdebris. Wireline may also be used to set a plug in thetailpipe below the packer prior to landing the tubing forcirculatingthe packer fluid into the well, In applicationswhere the production packer is set in the highlydeviatedor horizontal sectionof the wellbore, CT can be used forrunning the gauge ring and junk basket or setting andretrieving plugs in the tailpipe.9~nhoie FISNM. .Retrieving fish that have been dropped into the openholecan be particularly difficult when consideringwashouts,doglegs,and fill that can make locating and latching thefish nearly impossiblein somecases. The skuationisaggravatedby thefactthatthe toolstring usuallymust passthroughsmallerID tubing above the openhole.Useof a downholevideocameracan facilitatepreplanningfor this type of job by determining the location andorientationof the fish as well as the ability of a wireli.~e-or CT-conveyedfishing tool to latch the fish.GA= HISTORl~The followingcasehistoriesprovidedata concerningusageof specific fishing techniques and how their usageaccomplishedsuccessfulretrieval in actual applications.

Id P~k in wins NioD\QThe operator neededto log a well below a wirelineplug,which had been stuck in the tailpipe landingnipple for 10years, Thewell wasproducingthroughperforationsin thetubing above the plug, The plug was covered with fill,and previous wireline attempts to retrieve the plug hadbeenUnSUCCeSSth!.CT washeddown to the plug and latched the equalizingprong, Repeatedheavy jarring did not successfullyfreethe prong, Acid was spotted on top of the plug, andcontinuedjarring resulted in damage to the pulling tool.The tool was replaced, and the CT was dkplaced withnitrogento increasethe jarring force availableat the fish,

Jarring cent ..ded,andthe prong wassuccessfullyreleasedand retrieved, The plug mandrel was also releasedandretrieved, thereby completingthe fishin~job,In this case, the success of this fishing job can beattributedto the ability of CT to washdebris and generatehigh impact loads.!2T ~ w~rell~e ut~llzed to., . . 13ecover Lost WireWhile attemptingto set a plug below the packer in the no-go nipple at 9,700 ft, the wireline operator lost jarringaction and parted the wire, resulting in NOO ft of .108inch wire being left in the well, It was determined thatiron oxide and iron sulfide, which were present in thewellbore, could have contributed to the loss of the wireand tools,T%e .108 wire was fished using 3/16 braided line towithin200 feetof the plugwherescale had settledout intoa solid bridge. CT was rigged up with a small C).D.bottomholeassemblyand a high pressurejetting nozzletowashdown past the top of the wire and remove the scalefill. On the first pass, 100 feetof progresswasmadepastthe lastknowntop of the wire, Wirelinewas subsequentlyable to recover the exposed wire.A second CT pass was made which cleaneddown to theplug, and the lastof the wirewas recoveredwith wireline.A pressure test determined that the plug was set andholding. A final cleaning trip was made to clear thetubing, and the well was turned over to operations.In this case, CTwas successfullyused in conjunctionwithwireline to recover lost wire.

Too1- With Brid_ and_Tool ~ck in Pr~tion TM

Abridgeplugwas being run below the packer on i+subseawell to perform a workover when the toolstring becamestuck in the 3 1/2 tubing at 10,000 R due to iron oxideand iron sulfide scale. Attemptsto free the plug resultedin the electric line being pulled out of the rope socket,Wirelinefishing attempt~wxensuccessful.CT and high pressure jetting techniques were used toremove the scale down to the top of the fish, A CT

833

7/28/2019 00025499

8/16

. .

8 FISHING WtTH COILED TUBING SPE2S499

fishing toolstring with an on-off overshot were run butcouldnot latch the fish. A wireline impressionblock wasutilized and showed a clean fishing neck. Wireline wasrerun and engagedthe fish but could not release the plug.The overshotwas modified for a larger catch and run onCT, which successfullylatchedthe fish, jarred it free, andtransportedit to the surface.In this case, CT jet cleaning removed the scale that keptwireline from locating the fish. The high impact andpullingcapabilitiesof CT were attributedwith the successof this job.Qrift ~ I.D. of a Wireline Retrievabl~Safetv VahQDuringwireline drifting of a well, a fluted drift bar, toolarge to pass through the I.D. of the wireline retrievablesubsurface safety valve, became stuck in the valve andlock mandrel. Wireline attempts using both wire and3/16 braided line to retrieve the drift bar wereunsuccessful.An overshotwas used to engagethe stuck drift bar, sincethe original fishi~gneck had been damaged@ previouswirelinejarring. Pullingtools, used to engagethe externalfishing neckon the top of the overshot, broke upon heavyjarring by the CT, An additionalovershot was modifiedto includean internalfishingneckon top, and was plantedon the fish using wirelinet A pulling tool was used tolatch the overshot, and sumequentheavy jarring by CTbroke the skirt on the overshot, A heavy wall skirt wasdesignedfor tlwovershot, whichwasrerun andlatchedthestuck drift bar. Repeatedheavy jarring pulled the stuckdrift free tfom the subsurface safety valve.Thisjob illustrates the need to have spare parts and toolsas well as alternative plans available if the primaryapproachshould fail.Five Wlrellne ToW and 300. Ft of wir~;~elwImproper assembly of wireline pulling tools would notallow the tools to release as designed, resulting in fivetmlstrings and 300 ft of wireline abandonedon top of asubsurfacesafety valve, The fish includedthe followingtoolstrings:

1,875 inch slickline running tool and toolstringstuck in the safety valve2-inch pulling tool and todstring latched to firstfish2-incii wiregrab and toolstring hooked into a ballof wire above the secondfish,Pulling tool and toolstring latched to the third fish2-inch pulling tool snd toolstring latched to thefourth tish -

The total job took five days of fishing with CT andwireline. Extensive CT jarring was employed until thepulling tool of toolstring number 4 parted. Wirelinewasused for drifting and to remove wire as necessary.Continuedjarring with CT and wire removal by slicklineresultedin all of the fish being removed fromthe wellandsubsequentinstallationof a new safety valve.This case history again demonstrates the advantagesofwirelineused in conjunctionwith CT to provide the mosteffectivemeans for a success!hlfishingoperation.Qrift Runs and Pl~lv Devw WeJ.!S. . -Using the CT workstring and a specially designedjunkbasket highlydeviated wells were drifted to the packersettingdepths, Thejunk basketwasdesignedwitha barrelsection and, therefore, can pass casing and cementingcollars, CT-conveyedplugs were set and retrievedusingthe hydraulically-actuatedsemice tools in well deviationsbetween60 and 85 degrees,YVirelineTo@ma Drm m the Rat~the pac~A twenty-foot long, 1-1/2-inch wireline toolstring wssdropped intothe cased ratholebelowthe packer, Withthefish in place, the well could not be logged below thepacker, The well was deviated 28 degrees at the fish,which was covered with till, Wireline was unable tolocatethe fish due to the fill,CT washeddown to the toolstring and latched the fish,After the latchingoperation, gel was pumpedthrough theCT to circulate the sand out of the bottom of the well,

834

7/28/2019 00025499

9/16

q

SPE25499

The fish was pulledSuccessfuly logged.

ROBERT1. HILTS, S. HAMPTON FOWLER, CHARLES W. PLEASANTS 9

to the surface, and the well was McNeillYof Otis En~ineerin~CorPoration and A. KarimHedjszi: Nazzeer M: (ltza~, and Amin H, Nasser ofSaudi-Aramcofor their valuable contributions to coiledl%e successof L$isjob canbe attributedto CTs ability towash and circulate, which allowed well cleanout to beperformed in conjunctionwith a fishing job.Wirel ne Plus Covered With DrillirvrMutjAfter a drilling rig successfuly set a productionpacker, aplugwas set in the tailpipeby wireline. While circulatingout the hole, diesel mud had settled out above the plug.Wirelineattempts to latch the plug and bail the mud wereunsuccessful, A CT unit was then brought on site andpositionedon the drilling rig. A specially-portedpullingtoolwasused to successfill} washaway themud, allowingthe plug to be releasedand retrieved.CTs fast rig-up and trip speed saved a considerableamount of drilling-rig time, which would have entailedpulling the production tubing, washing down to the plug,retrieving the plug by wireline, and re-running theproductiontubing,CONCLUSIONCT canbe used to effectivelyremove fish from live wellswhere wireline alone has failed. Previously, a workoverwouldhavebeenrequiredto cleanthe well andretrievetheGwmholetool, The use of preplanning,wireline, and CToperators that are experienced in fishing can reduce jobtime and increasethe chanceof successwhenutilizingCTforjarring and retrieving.Theuseof downholevideo cameras,high strengthtubing,anddownholeforcegeneratorswill enhancethe capabilitesof Cl systems when used in fishing operations,particularly in highly deviated and horizontal weliapplications. The development of new state-of-the-artservice too!?such as these wiii promote expansionof CTtechnologyand further enhanceits abiiity to support fieldservicene&

NO~The authors with to thank the management of OtisEngineeringCorporation for their permission to publishthis paper, The authors also wish to thank A, Keith

tubing fishing.REFERENCES1, Moore, S.D,: TheCoiledTubingboom, PetroleumEngineer International (April 1991) 16-20.2. Mullin, M.A., McCarty, S.H,, ana Plante, M,E,:FishingWith 1,5and 1,75 InchCoiiedTubing atWesternPrudhoeBay, Alaska, paper SPE 20679, presentedat theInternationalArctic TechnologyConference, Anchorage,AK, May 29-31, 1991,3. Fowler Jr., S.H., and Pleasants, C.W.: Operationand Utilization of Hydraulic-ActuatedService Tools forReeledTubing, paper SPE 20678 presented at the 199065th AnnualTechnical Conference& Exhibitionof SPE,NewOrleans, LA, September23-26,4. Walker, E.J., and Schmohr, D.R.: The Role ofCoiled Tubing in the Western Operating Area of thePrudhoe Bay Unit, paper SPE 22959, presented at L}eSPE Asia-PacificConference, Perth, Western Australia,November4-7, 1991.5, Robison, C,E,, and Cox, D.C,: AlternateMethodsfor Installing ESPs, paper OTC 7035, presented at the24th AnnualOffshore TechnologyConference,Houston,TX, May4-7, 1992,6, Cobb, C,C,, and Schuitz, P.K.: AReai-TimeFiberOptic Oownhole Vidtw System, paper OTC 7046,presented at the 199224th Annual Offshore TechnologyConference,Houston, TX, May 4-7, 1992,7, Radenwker, R,A,, Oiszewski, K,K,, Goiffon, J,J,,andMaddox,S.D.: ACoiled-Tubing-DepioyedDownholeVjdeo System, paper SPE 24794, presented at the 199267th AnnualTechnicaiConference& Exhibition of SPE,Washington,DC, October4-7,8, Kilgore, M.D.: New Muscle for Coiled Tubing,paper OTC 7034, presented at the 1992 24th AnnuaiOffshoreTechnologyConference,Houston,TX, May4-7,1992,

835

7/28/2019 00025499

10/16

q

10 FISHINGWITH COILED TUBING SPE254999. Sas-Jaworsky, Alexander IJ: Coiled Tubing:OperationsandServices,Part 2: WorkoverSafety,WorldOfl (December1991)71-78.10, Chitwood, G,B,, Lewis, P.C., Fowler, S,H,, andZemick, W.M.: High Strength Coiied Tubing ExpandsServiceCapabilities, paper OTC 7032, presented at the1992 24th Annual Offshore Twhnology Conference,Houston,TX, May 4-7, 1992.11. $higley, J,E,, and Mitchell, L.D,: MechanicalEngineeringD~ign, McGraw-Hill Inc., New York, NY(1983) 110, 111, 132-135.12, Blake, A,: Practical Stress Analysis in EngineeringDesign,MarcelDekker Inc., NewYork, NY(1982)52-58.~pPFNDIXINTERNALSTRAINENERGY, DEFLECTION, ANDSPRINGRATE EQUATIONSOneway to comparethe efficiencyof fishing withCoiledTubi~!gversus wireline is to approximatetheavailableenergy in each system. This can be done byinvestigatingthe internal strain energy equation,U, foran elastic memberof uniform cross section:i(1) U = F(V2Where: d is the axial deflectionof the memberF is the tensile load on the member

Deflection,6, of an eiastic memberof uniform crosssection is definedby the followingequation:11(2) 6 = FL/AEWhere: A is the cross sectionalareaE is the modulus of elasticityL is tie unloaded length of the elasticmember

Also of interest is the spring rate, k, of an elasticmemberof uniform cross sectionwhich is defined bythe followingequation:(z(3) k = F/Ii = AE/L

Equations (l)-(3) can be combined, which resultsin the following:titz(4) u = FL/2AE = F2/[2(AE/L)]= 1=/2k

836

7/28/2019 00025499

11/16

TABLE 11.25 IN O.D, X .095 IN W.1. CT -500 FTModulus of Elasticity: 30E06 psi Maximum Surface Load: 18,000 IbaTubing Weight: 586 Ibs Deflection, & 10,1 ininternal Enerov, U: 7,331 ft-lb SpringRate,k: 1,723 ~slln

TABLE 2.108 IN O.D, WIRELINE -500 FTModulus of Elasticity: I 30E06 psi I Maximum SurfaceLoad: I 1,000 Ibs1 1wireline Weight: I 15,6 Ibs I Deflection, & J 21,6 inIImernal EM* .+. U: I Eelit-is I Snrina Rata. k I 46.8 lbs/in

TABLE 31,26 IN 0,0. X 0095 IN W,T, CT - 10k FT

Modulus of Elasticity: 30E06 psi Max, Surface Load: 18,000 IbsTubing Weight: 11,720 Ibs Deflection, & 72,9 inInternal Energy, U: 19,068 ft4b Spring Rate, k: 86,2 Ibsfin

/TABLE 4.108 IN OD, WIRELINE . 10k FT

A

Modulus of Elasticity: 30E06 PSi Max,Surface Load: 1,000 IbsWireline Weight: 311.1 Ibs Deflection, & 300.8 inInternal Energv, U: 8,634 ft4b Spring Rate, k: 2.29 lbs/in -+

7/28/2019 00025499

12/16

TENSILE STRENGTH COMPARISONSWIRELINE AND COILED TUBING,092 IN WL

1,25 x .095 IN CT1.50x .1091?4CT5x012NcTmmMm@S10162O*3O354O45 5TENSILE STRENGTH, LUS

(Thousand.)FIGURE1 =TENSILESTRENGTHOFCOILEDTUBING& WIRELINE

INTERNAL ENERGY COMPARISONS1.25 X .095 INCH CT & .108 INCH WLL I

.108WL, S00 FT

1,25 CT, S00 FT

,108 WL, 10k FT

1,25 CT, 10k FT, , , v0240 bENERQV, FT-LBS(Thousands)

F!QURE2 q INTERNALENEROYCOMPARISONSOF COILEDTUBING& WIRELINE

7/28/2019 00025499

13/16

q SPE2Cj499

...

,,

1

rb

COILEDTUBING_ COILED TU61NG

CONNECTOR SUB

D MlCOILED TUBING BACK PRESSUREVALVECOILED TUBING- PORTED KNUCKLEJOINT

COILEI) TUBINGACCELERATOR

COILED TUBINCSTEM

_..- COILED TUBINGJARS

COILEi) TUBING-_ PULLING TOOLFOR FLOWCONTROLS

!.I.HREAD-ON SLIP-TYPETYPE

Figure 4CoiledTubingConnectors

Figuro6BackPressureValve

Figure5CoiledTubingEmergencyDisconnect

F

1

Figure7CoiledTUblngPortedKnuckleJointFlguro3 839

7/28/2019 00025499

14/16

SPE25499 q q

[

--

lllliliFigure8CoiledTubingAcmdorator Figuro()CoiledTubingStem Figure10ColladTUblngJars

840

7/28/2019 00025499

15/16

8q ~pE254y)

.

QQ

0

000e

0

Figure11 Figure12CoiledTubingPulling CoiledTWng RunningToolfor flow Controls Toolfor FlowControls341

7/28/2019 00025499

16/16

n(45=-=3r.TUBING INJECTOR

STRIPPER

BLIND RAMSSHEAR RAMSSLIP RAMSPIPE RAMS

k-+k- RISER AS REQUIREDTO COVER FISHINGTOOL STRING4$ GiATEVALVEM------ 4 FLANGED RISERT

. :~=j- WIRELINE BOP

4----- TREE CONNECTIONFig, 13LandWellColladTubingFishingJob RigUpConfiguration

TUBING INJECTOR

+ TRPPERBLIND RAMSSHEAR RAMSSLIP RAMSPIPE RAMS

p---f_

I RISER AS REQUIREDr AND FISH

TO COVER TOOLS1IIIJ.-l~~+- SHEAR/SEAL BOP

I.--ILII~ TREE CONNECTIONLJFig. 14OffshoreWeiiCoiiadTubingFishingJob Rig UpConfiguration

842