bowen overshot quotation

LT Overshot is one of the fishing tools which is fishing the pipes externally. It can catch drill collar, drill pipe, tubing, subs and other pipes. Because of the seals, the fluid can circulate with the high pump pressure after catching the fish. The top of the fish will be milled by under mill shoe. It can also work with jars to catch the stuck fishes. If the catched fish can"t be release from stucking, we should release the overshot and lifting the drill string.

You are viewing Bowen or Logan Overshots for sale by Pickett Oilfield, LLC. We have an extensive range of good used or rebuilt Overshots along with the accessories. Call us for your fishing tool needs. For more information contact us by phone at sales@pickettoilfield.com.

PickettOilfield.com offers prospective buyers an extensive selection of quality new, used, and refurbished Oilfield Equipment at competitive prices, including Overshots.

Overshots are a tool used on the downhole process during the fishing operations. It engages the tube or tool on the outside surface. A Grapple or other piece of equipment that is similar attaches onto the overshot and grabs the fish.

General Description ................................................ 3Use .......................................................................... 4Construction ............................................................ 4Gripping and Releasing Mechanism ................... 4Pack-off Mechanism ............................................. 5Operation ................................................................ 6Precautions ............................................................. 6Undersize Parts ....................................................... 7Spiral Parts .............................................................. 7Basket Parts ............................................................ 7Overshot Accessories ............................................. 7Subsea Sheared Pipe Retrieval Method ................. 9Specifications and Replacement Parts ......... 12 19Overshot Accessories Tables ........................ 20 22Calculated Strength Tables ........................... 23 24Illustrations .............. 3, 5, 7, 8, 9, 10, 17, 19, 20 22

The Bowen Series 150 Releasingand Circulating Overshot provides thestrongest tool available to externallyengage, pack-off, and pull a fish. Thebasic simplicity and rugged constructionwith which it is designed have madeit the standard of all external catchfishing tools.

The Bowen Series 150 Releasing andCirculating Overshot has gained worldwide acceptance for fishing by meansof external engagement of a fish. EachOvershot is a carefully engineered unit.In service, it takes a positive grip over alarge area of fish and is therefore capable of withstanding extremely heavy pulling, torsional and jarring strains withoutdamage or distortion to either the toolor the fish.

Bowen Overshots are continually developed to new standards of strength andefficiency and are expertly constructedof the highest quality material.Each Bowen Series 150 Releasing andCirculating Overshot is a compact unitdesigned to engage, pack off and pull aspecific size of tubing, pipe, coupling,tool joint, drill collar or smooth O.D. tool.Through the installation of proper undersize parts, they may be adapted toengage and pack off any smaller size.

Bowen course thread Overshots aredesigned for easier assembly andmaintenance. The Bowen CT Overshothas a course ACME thread on the upperend of the Bowl where the Top Sub isattached and at lower end where theGuide is attached. See SupplementalInstruction Manual 1150A for list.The course thread allows much easierfield assembly and will stand moreabuse than the fine series currentlyoffered. The internal parts are completelyinterchangeable with existing BowenOvershots.Cross over bushings can be providedfrom fine thread series to course threadseries, allowing full use of Bowls, TopSubs, and Guides currently in stock.All sizes of Bowen Series 150 Releasingand Circulating Overshot are available inFull Strength or Slim Hole Types. Despitethe extremely small outside diametersof Full Strength Type Overshots, theyare engineered to withstand the pulling,torsional and jarring strains, which mustbe exerted by modern machinery, torelease and retrieve a lost fish.The Slim Hole Type Overshots havereduced outside diameters, as compared to the Full Strength. They are usedto perform pulling jobs in tight holeswhere no other outside catch, releasingfishing tool can be run.Use

A Bowen Series 150 Releasing andCirculating Overshot is used to engage,pack off and retrieve twisted-off or losttubing, drill pipe, coupling, tool joint,casing or other similar fish.

The Bowen Series 150 Releasing andCirculating Overshot is composed ofthree outside parts: the Top Sub, Bowl,and Guide. The Basic Overshot may bedressed with either of two sets of internalparts, depending on whether the fish tobe caught is near maximum catch sizefor the particular overshot.If the fish diameter is near the maximumcatch of the Overshot, a Spiral Grapple,Spiral Grapple Control and Type APacker are used. If the fish is a tubingcollar, a Type D Collar Packoff Assembly will replace the Type A Packer.If the fish diameter is considerably belowmaximum catch size (usually 12"), aBasket Grapple and a Mill Control Packeris used.Gripping andReleasing Mechanism

The Bowl of the Overshot is designedwith helically tapered spiral section in itsinside diameter. The gripping member(Spiral Grapple or Basket Grapple), isfitted into this section. When an upwardpull is exerted against a fish, an expansion strain is spread evenly over a longsection of the fish. No damage or distortion results to either the fish or the Overshot. This design permits a far strongertool with a smaller outside diameter thanis possible with an overshot that employsa single tapered section which supportsslips.A Spiral Grapple is formed as a left-handhelix with a tapered exterior to conformwith the helically tapered section in theBowl. Its interior is wickered for engagement with the fish.A Basket Grapple is an expansible cylinder with a tapered exterior to conform tothe helically tapered section in the Bowl.Its interior is wickered for engagementwith the fish.

Three types of Basket Grapples areavailable to meet the need for catchingvarious types of fish:The Plain Basket Grapple is standard,and will always be furnished unlessanother type is specified. It is wickeredfor its entire interior length. It is used tocatch any plain single diameter fish.The Basket Grapple with Long CatchStop has an internal shoulder located atthe upper end, to stop the fish in bestcatch position. It is designed to stop andcatch an upset, or box section of a tooljoint, with sufficient length left below theGrapple to allow the joint or upset to bepacked off with a Basket Mill ControlPacker.The Basket Grapple with Short CatchStop has a double set of wickers, of twodifferent internal diameters. It is used tostop and catch a coupling with aruptured piece of pipe engaged in itsupper end. The upper set of wickers willcatch the ruptured pipe, and act as astop against the coupling, while thelower set of wickers will catch the coupling. The coupling will be stopped in bestposition to be packed off by the MillControl Packer.Grapple Controls are of two types: SpiralGrapple Controls are used with SpiralGrapples; Mill Control Packers are usedwith Basket Grapples.Grapple Controls are used as a specialkey, to allow the Grapple to move up anddown during operation while simultaneously transmitting full torque from theGrapple to the Bowl.Spiral Grapple Controls and BasketGrapple Controls are plain. Mill ControlPackers include a packoff. See Pack-offMechanism for a complete explanation.In operation, the Overshot functions inthe same manner, whether dressed withSpiral Grapple parts or Basket Grappleparts

During the engaging operation, as theOvershot is rotated to the right andlowered, the Grapple will expand whenthe fish is engaged, allowing the fish toenter the Grapple. Thereafter with rotation ceased and upward pull exerted,the Grapple is contracted by the tapersin the Bowl and its deep wickers grip thefish firmly.

During the releasing operation, a sharpdownward bump places the larger portion of the Bowl tapers opposite theGrapple smaller tapered portion, breaking the hold. Thereafter, when the Overshot is rotated to the right, and slowlyelevated, the wickers will screw theGrapple off the fish, effecting release.The fact that Bowen Releasing and Circulating Overshots require right handrotation only, both during engaging andreleasing operation, is extremely important. This feature eliminates the dangersthat are present when it is necessary torotate the string to the left.

The type of Pack-off used depends onhow the Overshot is dressed, and theoperators choice.When the Overshot is dressed with aSpiral Grapple, a Type A Packer is used.The Type A Packer is a sleeve type. Itseats at its O.D. against the inside of theBowl. It has an internal lip which sealsaround the fish. Each type A Packer isdesigned to pack off a specific size. A

Type A Packer should be ordered foreach catch size Spiral Grapple.A Mill Control Packer is used when theOvershot is dressed with a Basket Grapple. The Type R Mill Control Packer isused when a packoff is required. Theunique double lip seal of the Mill ControlPacker provides a positive seal of thefish. The Packer is self energized and isretained within the Mill Control by a lowersecond sealing lip and requires no adhesive for retaining the Packer. The TypeR is most commonly used. It has areplaceable inner seal and a replaceableouter seal. The inner seal and the outerseal may both be replaced in the fieldwhen required. The Type R Mill Control(with mill teeth) is available. Mill ControlPackers are designed to remove smallburrs and rough breaks only. Replacement inner and outer seals are listedon page 20. Also see the special HighPressure Pack-off accessories on page19.All Mill Control Packers are manufacturedto pack off a specific size. One should

Type D Packer assemblies are available to pack off tubing collars in tubingsize Series 150 Overshots. The Type DPacker assembly consists of a Packer,a Spring and an O-Ring. It is assembledin the Bowl above the Grapple. Its upperend is sealed in a counter-bore in theTop Sub, by the O-Ring. In operation,its lower end stops the collar in propercatch position, while the integral moldedseal enters and packs off the collarthreads at the top of the collar. ThesePackers are listed on page 16.The Type D Collar Packer is designedto be used with a Spiral Grapple, in placeof a Type A Packer, where the collarbeing fished is too short to allow effectivecatch and pack off length.

First determine that the Overshot isproperly assembled, is dressed with theproper size Grapple and that all its partsare in good working condition. Refer toSpecifications beginning on page 11.

Bump down; then simultaneously rotateto the right and slowly elevate the fishingstring until the Overshot is clear of thefish; combined rotating and elevating isimportant.

If the hole size is so much greater thanthe fish size that it is possible for theOvershot to pass alongside the fish,install either a Wallhook Guide or anOversize Guide in place of the StandardGuide. (see page 18)If the top of the fish is a heavily burredtool joint, replace the Standard Guidewith the proper Milling Guide, Type A orC. (see page 19)If the fish has an unengageable upperend, install an Extension between theTop Sub and the Bowl (see illustration onpage 7).Using the Top Sub, connect the Overshotto the fishing string and run it in the hole.To Engage and Pull the Fish

As the top of the fish is reached, slowlyrotate the fishing string to the right andgradually lower the Overshot over thefish; combined rotating and lowering isimportant.Allow the right-hand twist to slack out ofthe fishing string and then pull on the fishby elevating the fishing string.If the fish does not come, turn on thecirculating pumps and maintain anupward strain while circulation is forcedthrough the fish.

Unless an upward strain is maintained,never rotate the fishing string to the leftwhile the Overshot is engaged with thefish.Always bump the full weight of the fishingstring before starting releasing operations.Always shut off the circulating pumpsbefore lowering the Overshot over thefish.Function of the Overshotin Engaging the Fish

After the Overshot has reached the topof the fish, combined rotation andlowering results in the following:1. The guide will direct the fish into theOvershot.2. The Grapple will expand and the fishwill pass through it.3. The fish will pass through the Packoff Rubber and will be halted when itcontacts the pin end of the Top Sub.In the case where an external upsetsection is being engaged by a Basket Grapple, the fish will be haltedby the solid steel stop in the upperend of the Basket Grapple.

5. Likewise, once the fish is in thisposition, the circulation will sealthe Packoff Rubber around the fishand prevent fluid passage downthe outside. Thus, by building uppressure with the pumps, the fluidcan be forced down through the fish.Function of the Overshotwhen Releasing

The sharp downward bump places thelargest portion of the Bowl tapers opposite the Grapple and breaks the hold.Right-hand rotation expands the Grappleand by maintaining right-hand rotation,the Overshot may be withdrawn from thefish.Function of the Grapple

The mechanical conditions which causedthe Grapple to expand and contract are:1. The Grapple is a left-hand helix.2. The lower end of the Grapple isanchored in the Overshot Bowl.3. The inside diameter of the Grappleis smaller than the outside diameterof the fish.As the Overshot is rotated to the rightand lowered over the fish, the drag ofthe fish against the grapple causes theGrapple to unwind and expand sufficiently to allow the fish to enter.As the Overshot is rotated to the rightand withdrawn from the fish, the dragof the fish against the Grapple causesthe Grapple to unwind and expandsufficiently to allow the Overshot to bewithdrawn.

4. The fish is now properly located inthe Overshot and thereafter whenupward pull is exerted, the Grappleis contracted by the tapers in theBowl and the hold will be secure.

Undersize Spiral parts: Spiral Grappleand Type A Packer are used to catchsizes from Maximum Catch SpiralGrapple, down to Maximum CatchBasket Grapple, as specified in thespecifications tables on pages 11 thru15 inclusive.These Spiral Grapples and Type APacker should be changed for eachdifferent size fish. They will effectivelycatch and pack off worn fish as much as332" maximum undersize. The over-rangeof each grapple is approximately 132".There are exceptions, particularly in theSlim Hole type Overshots. Some of thesewill effectively catch undersize oroversize fish by no more than 116"maximum.Basket Parts

Bowen Lock Rings provide a positiveand releasable means for lockingstraight-threaded shouldered joints sothey will not back off.Type SS Top Sub(Short with Shoulder)

Top Subs are available for BowenOvershots in two types: SS, Short Subwith shoulder; and LS, Elevator Sub withshoulder. Type SS Top Subs are furnished as part of the assembly, unlessotherwise specified.Lock Rings

Bowen Lock Rings are available asoptional equipment to prevent the TopSub and Bowl of Bowen Series 150Releasing and Circulating Overshotsfrom unthreading during backing-offoperations. Use of Bowen Lock Ringseliminates the weakening practice ofdrilling and tapping the Bowl to installa set screw for securing the Bowl to the

If a twist-off has left a fishwhose upper end is unengageable, an ExtensionSub should be installedbetween the Top Sub andthe Bowl of the Overshot.This will permit lowering ofthe Overshot over the fishfar enough to insure engagement and a perfectpack off in the fishingoperation. Extension Subsare listed on page 21.Extension Sub

Basket Grapples will effectively catch fishworn as much as 332" maximum undersize. The over range of each grapple isapproximately 132".There are exceptions, particularly in theSlim Hole type Overshots. Some of thesewill effectively catch undersize fish bymore than 132" maximum.

Bowen Lock Rings are used in pairsconsisting of two identical rings. Therings have cam-teeth on one face, knurlson the other, and two breakout grooveson the edges. They are precision madefrom alloy steel, stress relieved, and heattreated.Assembly

When the Overshot is dressed with aspiral grapple and type A Packer, aSpacer is required between the Packerand Top Sub. Please refer to Lock RingTable on page 21. The purpose of theSpacer is to fill the space produced bythe extra standoff of the Top Sub whenused with the Lock Rings. No Spacer isrequired when A Packer is not used.

Itcoloy Mill Extensions are used to millaway flared or jagged metal from the topof the fish so that the fish will pass easilyinto the Overshot Bowl. For ordinarywork, they are installed between the Bowland the standard, oversize or wall hookguides.The Itcoloy Mill Extension is also usedin the Bowen Subsea Sheared PipeRetrieval Method (see page 9). In thiscase it is installed between the OvershotBowl and the special guides. They maybe ordered by giving the Overshotnumber and specifying Itcoloy MillExtension Type and fish size. Pricesavailable on request.

When unthreading is desired, a specialBowen Lock Ring Breakout Clamp isrequired. Slight right-hand torque mayhave to be applied for lining-up the Ringbreakout grooves to receive the Clamp.Lower Key Seat

Itcoloy Mill Guides are used to millaway jagged metal form the top of thefish so that the fish will pass easily intothe Overshot Bowl.They may be ordered, using the standard Guide number, and specifying,Itcoloy Mill Guide Type C and fish size.Subsea ShearedPipe Retrieval

The BOP being used must have at leasttwo sets of rams: lower pipe rams andshear rams above them. Before shearing, it is necessary to land the nearesttool joint on the pipe rams and closethem to suspend and pack off the string.The shearing then produces flattenedflare-ends with protruding ears.When the rig returns, the string must beretrieved, the end brought to the surfaceand the sheared piece removed. In thepast, sheared pipe retrieval has been difficult, costly and time-consuming. Oftenlarge parts of the BOP stack must bebrought to the surface to effect retrieval.The Bowen method of sheared piperetrieval can be achieved in a simple,time-saving and economical manner.It requires only two easy steps usingthe Series 150 Circulating and ReleasingOvershot equipped with a few specialaccessories

If the hole size is so much greater thanthe fish size that it is possible for theOvershot to pass alongside the fish, anOversize Guide or a Wallhook Guidemust be installed in place of the Standard Guide to insure alignment of thefish with the Overshot. These are listedon page 18.

Twist-offs in tool joints are not alwaysimmediately revealed at the surface andas a result drilling is not halted at once.In such cases the top of the fish is usually a badly burred tool joint, or drill pipe,and a Type A Mill Guide must be installedon the Overshot to trim the burr off thefish so that it can enter the Overshot.Itcoloy Mill Guides perform the sameservice on undersize tool joints and arealso used when the top of the fish is anunusually jagged section of pipe. Moreinformation on these is shown on page19.

The standard guide, grapple and packerhave been removed from a BowenOvershot and it is then dressed with aMill Extension and special flat-bottomLong Guide, and installed on the drillstring. The Mill Extension has taperedmilling ribs of Bowen Itcoloy (sinteredtungsten carbide) facing on its I.D. TheOvershot is lowered into the BOP andover the end of the drill pipe, and thenrotation takes place to mill down theflared ears of the sheared pipe. The endof the Long Guide is faced with softmetal so that if inadvertently it contactsthe BOP pipe rams, it does not damagethem. The Guide is also of a lengthwhich prevents the Mill Extension fromcontacting and damaging the tool joint inthe BOP. This is important because thisjoint O.D. is where engagement of thestring will take place.

After the milling step is completed, theBowen Overshot is brought back to thesurface, dressed with a special flatbottom Short Guide, Extension Sub anda Basket Grapple and Mill Control Packersized to engage the joint. (The ShortGuide also has a soft metal end toprevent ram damage.) The Overshot islowered again and as it enters the BOP,the milled-down flare-end passesthrough the Grapple and Mill ControlPacker, and is housed in the ExtensionSub while the Grapple engages andpacks off the tool joint. A pull is exertedon the Overshot to make certain ofengagement and then the BOP piperams are retracted, and the string israised to the rig floor where the severedjoint is removed and replaced, allowingnormal operations to resume.

The lists of assemblies and accessoriesin this Instruction manual have beenreduced to the most popular Overshotsand parts worldwide. This has been doneto make it easier for the customer toquickly find the information they requireand also for the ease of transmitting theelectronic version of the file.The Bowen Series 150 Overshot productline consists of many different sizes andtypes of assemblies and items. A listof over 225 of these is in SupplementalInstruction Manual 1150A. If a locallypopular assembly is not listed in Manual1150 it will most probably be listed inManual 1150A. However, this is still nota complete list. There are additionalassemblies not listed.The standard Series 150 Overshot is aright-hand operation tool with right-handthreads. But there are many specialsoffered. Some of the other tools madeare right-hand tools with left-handthreads, left-hand tools with left-handthreads, left-hand tools with right-handthreads, tools for H2S service, toolsfor CO2 service, tools for H2S and CO2service, very high strength tools, verythin wall tools, and with sizes rangingfrom 25/16" OD to above 32" OD.Even with all the possible combinations,National Oilwell continues to design newassemblies to add to aproduct line thatwas started almost 60 years ago!

If the hole size is so much greater than the fish size that it is possible for the Overshot to pass alongside the fish,an Oversize Guide or a Wallhook Guide must be installed to insure alignment of the fish with the Overshot.

In cases where the top of the fish is a badly burred tool joint or drill pipe, a Type A MillingGuide should be installedon the Overshot to trim the burr of the fish so that it can enter theOvershot. Type C Milling Guides perform the same service on undersize tool joints; theyare also used when the top of the fish is an unusually jagged section of pipe. Type C Guidesare available as carbonized, fluted guides or Itcoloy Guides.

The High Pressure Pack-off Assembly is a special assembly for use in areas of extreme pressure. It consistsof a Bushing and four packing elements. It is normally installed between the Bowl and the Guide of the Overshot.

ADHESIVE: Bowen has developed an adhesive which is particularlysuited to bonding Type R Inner Seals to Mill Control Packers. It is composed of two compounds, an epoxy resin with strengtheningmaterial and a catalyst, which are mixed prior to using. Bowen Adhesive Compound No. 1 (Resin) Part No. 41241-1 and Bowen Adhesive Compound No. 2 (Catalyst) Part No. 41241-2. One-pint cans.NOTE: Use the Same Outer Seal for Type R and Type E Mill Control Packer

If a twist-off has left a fish whose upper end is unengageable, an Extension Sub is installedbetween Top Sub and the Bowl of the Overshot. This will permit lowering of the Overshot overthe fish far enough to insure a secure engagement and a perfect packoff.Extension Sub SpecificationsSizes

Lock Rings prevent the Top Sub and Bowl of a Bowen Overshot from unthreading when reverserotation, such as backing-off, occurs. They provide a positive means of locking straight-threaded,shouldered joints without excessive torque or pins. Knurled surfaces on the rings dig into theshoulder when the joint is made-up. Cam teeth between the rings have pitches greater than thethread pitch and these cams produce the locking action.Lock Ring SpecificationsBowl No.

Series 150 Overshots General Description ................................................. 3 Use ............................................................................ 4 Construction ............................................................. 4 Gripping and Releasing Mechanism .................... 4 Pack-off Mechanism .............................................. 5 Operation .................................................................. 6 Precautions ............................................................... 6 Undersize Parts ........................................................ 7 Spiral Parts ................................................................ 7 Basket Parts .............................................................. 7I N D E X

Overshot Accessories .............................................. 7 Subsea Sheared Pipe Retrieval Method .................. 9 Specifications and Replacement Parts .......... 12 – 19 Overshot Accessories Tables ......................... 20 – 22 Calculated Strength Tables ............................ 23 – 24 Illustrations ............... 3, 5, 7, 8, 9, 10, 17, 19, 20 – 22

Series 150 Releasing and Circulating Overshot Series 150 Releasing and Circulating Overshot Dressed with Spiral Grapple and Parts Dressed with Basket Grapple and Parts

General DescriptionThe Bowen Series 150 Releasing The Bowen Series 150 Releasing and Bowen Overshots are continually devel-and Circulating Overshot provides the Circulating Overshot has gained world- oped to new standards of strength andstrongest tool available to externally wide acceptance for fishing by means efficiency and are expertly constructedengage, pack-off, and pull a fish. The of external engagement of a fish. Each of the highest quality material.basic simplicity and rugged construction Overshot is a carefully engineered unit. Each Bowen Series 150 Releasing andwith which it is designed have made In service, it takes a positive grip over a Circulating Overshot is a compact unitit the standard of all external catch large area of fish and is therefore capa- designed to engage, pack off and pull afishing tools. ble of withstanding extremely heavy pull- specific size of tubing, pipe, coupling, ing, torsional and jarring strains without tool joint, drill collar or smooth O.D. tool. damage or distortion to either the tool Through the installation of proper under- or the fish. size parts, they may be adapted to engage and pack off any smaller size.

3Bowen course thread Overshots are Construction Three types of Basket Grapples aredesigned for easier assembly and The Bowen Series 150 Releasing and available to meet the need for catchingmaintenance. The Bowen “CT” Overshot Circulating Overshot is composed of various types of fish:has a course ACME thread on the upper three outside parts: the Top Sub, Bowl, and Guide. The Basic Overshot may be The Plain Basket Grapple is standard,end of the Bowl where the Top Sub is dressed with either of two sets of internal and will always be furnished unlessattached and at lower end where the parts, depending on whether the fish to another type is specified. It is wickeredGuide is attached. See Supplemental be caught is near maximum catch size for its entire interior length. It is used toInstruction Manual 1150A for list. for the particular overshot. catch any plain single diameter fish.The course thread allows much easier If the fish diameter is near the maximum The Basket Grapple with Long Catchfield assembly and will stand more catch of the Overshot, a Spiral Grapple, Stop has an internal shoulder located atabuse than the fine series currently Spiral Grapple Control and Type “A” the upper end, to stop the fish in bestoffered. The internal parts are completely Packer are used. If the fish is a tubing catch position. It is designed to stop andinterchangeable with existing Bowen collar, a Type “D” Collar Packoff Assem- catch an upset, or box section of a toolOvershots. bly will replace the Type “A” Packer. joint, with sufficient length left below theCross over bushings can be provided Grapple to allow the joint or upset to befrom fine thread series to course thread If the fish diameter is considerably below packed off with a Basket Mill Controlseries, allowing full use of Bowls, Top maximum catch size (usually 1¦2"), a Packer.Subs, and Guides currently in stock. Basket Grapple and a Mill Control Packer is used. The Basket Grapple with Short CatchAll sizes of Bowen Series 150 Releasing Stop has a double set of wickers, of twoand Circulating Overshot are available in Gripping and different internal diameters. It is used toFull Strength or Slim Hole Types. Despite Releasing Mechanism stop and catch a coupling with athe extremely small outside diameters The Bowl of the Overshot is designed ruptured piece of pipe engaged in itsof Full Strength Type Overshots, they with helically tapered spiral section in its upper end. The upper set of wickers willare engineered to withstand the pulling, inside diameter. The gripping member catch the ruptured pipe, and act as atorsional and jarring strains, which must (Spiral Grapple or Basket Grapple), is stop against the coupling, while thebe exerted by modern machinery, to fitted into this section. When an upward lower set of wickers will catch the coup-release and retrieve a lost fish. pull is exerted against a fish, an expan- ling. The coupling will be stopped in best sion strain is spread evenly over a long position to be packed off by the MillThe Slim Hole Type Overshots have section of the fish. No damage or distor- Control Packer.reduced outside diameters, as com- tion results to either the fish or the Over-pared to the Full Strength. They are used shot. This design permits a far stronger Grapple Controls are of two types: Spiralto perform pulling jobs in tight holes tool with a smaller outside diameter than Grapple Controls are used with Spiralwhere no other outside catch, releasing is possible with an overshot that employs Grapples; Mill Control Packers are usedfishing tool can be run. a single tapered section which supports with Basket Grapples. slips. Grapple Controls are used as a specialUseA Bowen Series 150 Releasing and A Spiral Grapple is formed as a left-hand key, to allow the Grapple to move up andCirculating Overshot is used to engage, helix with a tapered exterior to conform down during operation while simulta-pack off and retrieve twisted-off or lost with the helically tapered section in the neously transmitting full torque from thetubing, drill pipe, coupling, tool joint, Bowl. Its interior is wickered for engage- Grapple to the Bowl.casing or other similar fish. ment with the fish. Spiral Grapple Controls and Basket A Basket Grapple is an expansible cylin- Grapple Controls are plain. Mill Control der with a tapered exterior to conform to Packers include a packoff. See Pack-off the helically tapered section in the Bowl. Mechanism for a complete explanation. Its interior is wickered for engagement with the fish. In operation, the Overshot functions in the same manner, whether dressed with Spiral Grapple parts or Basket Grapple parts

4 be ordered to match each size BasketDuring the engaging operation, as the Grapple. Mill Control Packers whenOvershot is rotated to the right and used, replace a Plain Basket Control.lowered, the Grapple will expand when The Plain Basket Control is used withthe fish is engaged, allowing the fish to Type A Packer a Basket Grapple when no pack-off ofenter the Grapple. Thereafter with rota- the fish is required.tion ceased and upward pull exerted,the Grapple is contracted by the tapers Type “D” Packer assemblies are avail-in the Bowl and its deep wickers grip the Inner Seal able to pack off tubing collars in tubingfish firmly. size Series 150 Overshots. The Type “D” Packer assembly consists of a Packer,During the releasing operation, a sharp a Spring and an O-Ring. It is assembleddownward bump places the larger por- in the Bowl above the Grapple. Its uppertion of the Bowl tapers opposite the Mill Control end is sealed in a counter-bore in theGrapple smaller tapered portion, break- Packer Top Sub, by the O-Ring. In operation,ing the hold. Thereafter, when the Over- its lower end stops the collar in propershot is rotated to the right, and slowly catch position, while the integral moldedelevated, the wickers will screw the Outer Seal seal enters and packs off the collarGrapple off the fish, effecting release. threads at the top of the collar. TheseThe fact that Bowen Releasing and Cir- Type R Mill Control Packer Packers are listed on page 16.culating Overshots require right hand The Type “D” Collar Packer is designedrotation only, both during engaging and Type “A” Packer should be ordered for to be used with a Spiral Grapple, in placereleasing operation, is extremely impor- each catch size Spiral Grapple. of a Type “A” Packer, where the collartant. This feature eliminates the dangers being fished is too short to allow effectivethat are present when it is necessary to A Mill Control Packer is used when the catch and pack off length.rotate the string to the left. Overshot is dressed with a Basket Grap- ple. The Type “R” Mill Control Packer is used when a packoff is required. The unique double lip seal of the Mill Control Packer provides a positive seal of the fish. The Packer is self energized and is retained within the Mill Control by a lower second sealing lip and requires no ad- hesive for retaining the Packer. The Type Basket Grapple Basket Grapple “R” is most commonly used. It has a with Short Catch Stop with Long Catch Stop replaceable inner seal and a replaceable outer seal. The inner seal and the outerPack-off Mechanism seal may both be replaced in the fieldThe type of Pack-off used depends on when required. The Type “R” Mill Controlhow the Overshot is dressed, and the (with mill teeth) is available. Mill Controloperator’s choice. Packers are designed to remove small burrs and rough breaks only. Replace-When the Overshot is dressed with a ment inner and outer seals are listedSpiral Grapple, a Type “A” Packer is used. on page 20. Also see the special HighThe Type “A” Packer is a sleeve type. It Pressure Pack-off accessories on pageseats at its O.D. against the inside of the 19. Series 150 Overshot Type DBowl. It has an internal lip which seals with Type D Packer Packer Assemblyaround the fish. Each type “A” Packer is All Mill Control Packers are manufactured in Packed Off Positiondesigned to pack off a specific size. A to pack off a specific size. One should

5Operation To Release from the Fish 5. Likewise, once the fish is in thisFirst determine that the Overshot is Bump down; then simultaneously rotate position, the circulation will sealproperly assembled, is dressed with the to the right and slowly elevate the fishing the Packoff Rubber around the fishproper size Grapple and that all its parts string until the Overshot is clear of the and prevent fluid passage downare in good working condition. Refer to fish; combined rotating and elevating is the outside. Thus, by building upSpecifications beginning on page 11. important. pressure with the pumps, the fluid To release from a recovered fish, follow can be forced down through the fish.Obviously, if the fish is smaller than themaximum outside diameter that the the same procedure while holding the Function of the OvershotOvershot was designed to engage, fish below the Overshot. when Releasinginstall undersize parts. The sharp downward bump places the Precautions largest portion of the Bowl tapers oppo-If the hole size is so much greater than Unless an upward strain is maintained, site the Grapple and breaks the hold.the fish size that it is possible for the never rotate the fishing string to the left Right-hand rotation expands the GrappleOvershot to pass alongside the fish, while the Overshot is engaged with the and by maintaining right-hand rotation,install either a Wallhook Guide or an fish. the Overshot may be withdrawn from theOversize Guide in place of the Standard Always bump the full weight of the fishing fish.Guide. (see page 18) string before starting releasing opera-If the top of the fish is a heavily burred Function of the Grapple tions.tool joint, replace the Standard Guide The mechanical conditions which causedwith the proper Milling Guide, Type A or Always shut off the circulating pumps the Grapple to expand and contract are:C. (see page 19) before lowering the Overshot over the 1. The Grapple is a left-hand helix. fish.If the fish has an unengageable upper 2. The lower end of the Grapple isend, install an Extension between the Function of the Overshot anchored in the Overshot Bowl.Top Sub and the Bowl (see illustration on in Engaging the Fish

page 7). After the Overshot has reached the top 3. The inside diameter of the Grapple of the fish, combined rotation and is smaller than the outside diameterUsing the Top Sub, connect the Overshot lowering results in the following: of the fish.to the fishing string and run it in the hole. 1. The guide will direct the fish into the As the Overshot is rotated to the rightTo Engage and Pull the Fish Overshot. and lowered over the fish, the drag ofAs the top of the fish is reached, slowly the fish against the grapple causes the 2. The Grapple will expand and the fishrotate the fishing string to the right and Grapple to unwind and expand suffi- will pass through it.gradually lower the Overshot over the ciently to allow the fish to enter.fish; combined rotating and lowering is 3. The fish will pass through the Pack- As the Overshot is rotated to the rightimportant. off Rubber and will be halted when it and withdrawn from the fish, the drag contacts the pin end of the Top Sub.Allow the right-hand twist to slack out of of the fish against the Grapple causes In the case where an external upsetthe fishing string and then pull on the fish the Grapple to unwind and expand section is being engaged by a Bas-by elevating the fishing string. sufficiently to allow the Overshot to be ket Grapple, the fish will be halted withdrawn.If the fish does not come, turn on the by the solid steel stop in the uppercirculating pumps and maintain an end of the Basket Grapple.upward strain while circulation is forced 4. The fish is now properly located inthrough the fish. the Overshot and thereafter when upward pull is exerted, the Grapple is contracted by the tapers in the Bowl and the hold will be secure.

6Undersize Parts weakening and hazardous practice ofUndersize parts are used when the fish to welding a steel strap across the Bowl andbe caught is smaller than the maximum Sub joint to hold them in place. Usingcatch size of the Overshot. excessive torque when making-up these joints is also no longer necessarySpiral Parts if the rings are used.Undersize Spiral parts: Spiral Grapple andType “A” Packer are used to catch sizes Bowen Lock Rings provide a positive andfrom “Maximum Catch Spiral Grapple”, releasable means for locking straight-down to “Maximum Catch-Basket threaded shouldered joints so they will notGrapple,” as specified in the specifications back off.tables on pages 11 thru Type SS Top Sub Type LS Top Sub Extension Subs15 inclusive. (Short with Shoulder) (Elevator Type If a twist-off has left a fish whose upperThese Spiral Grapples and Type “A” Packer with Shoulder) end is unen-gageable, anshould be changed for each different size Extension Sub should be Top Subsfish. They will effectively catch and pack off installed between the Topworn fish as much as 3¦32" maximum Top Subs are available for Bowen Sub and the Bowl of the Overshots in two types: SS, Short Subundersize. The over-range of each grapple Overshot. This will permit with shoulder; and LS, Elevator Sub withis approximately 1¦32". lowering of the Overshot shoulder. Type SS Top Subs are furnished over the fish far enough toThere are exceptions, particularly in the as part of the assembly, unless otherwise insure en-gagement and aSlim Hole type Overshots. Some of these specified. perfect pack off in thewill effectively catch undersize or oversize Lock Rings fishing operation. Exten-fish by no more than 1¦16" maximum. Bowen Lock Rings are available as sion Subs are listed onBasket Parts optional equipment to prevent the Top Sub page 21.Undersize Basket parts are used to catch and Bowl of Bowen Series 150 Releasingsizes from “Maximum Catch-Basket and Circulating Overshots fromGrapple” as specified in the specification unthreading during backing-off opera- Extension Subtables of pages 11 thru 15 inclusive, down tions. Use of Bowen Lock Rings eliminatesto any smaller size. the weakening practice of drilling and tapping the Bowl to installBasket Grapples should be changed for a set screw for securing the Bowl to theeach size fish to be caught. Top Sub. The Rings also eliminate theMill Control Packers should be changedfor each size fish.

There are exceptions, particularly in theSlim Hole type Overshots. Some of thesewill effectively catch undersize fish by Knurlsmore than 1¦32" maximum.Overshot Accessories Lock Rings

7Construction The Breakout Clamp consists of two screw handle is then tightened whichBowen Lock Rings are used in pairs keys that fit into the Lock Ring grooves, a forces the slightly tapered keys into theconsisting of two identical rings. The lower key seat, and an extended pin flat Lock ring breakout grooves, holds therings have cam-teeth on one face, knurls link chain attached at one end to a cam-teeth together, and permits theon the other, and two breakout grooves bracket which has a guide for another shoulders to back away from the knurledon the edges. They are precision made (movable) key seat attached to a screw faces when the joint is broken. Lockfrom alloy steel, stress relieved, and heat handle. Rings are listed of page 21.treated. To position the Breakout Clamp, theAssembly screw handle is backed-up as far as itOne Lock Ring is inverted and placed on will to, the other end of the chain is putthe other so the cam-teeth intermesh through a hole in the lower key seat, andand the breakout grooves are aligned, the keys are placed in the ring groovesand then they are placed on the Top Sub. opposite each other. The chain is thenThe Bowl is threaded on, and as the joint pulled around the rings so that all slackis made-up, the knurled faces opposite is removed and the nearest pin is slippedto the cam-teeth dig in and grip the into the pin slot on the bracket. Theshoulders. The pitch on the cam-teeth isgreater than the thread pitch, so ifreverse rotation is applied, the cam-teethbegin to ride up on each other. Thisproduces a wedging action which Itcoloy Mill Extensioneffectively locks the Top Sub to the Bowl. Screw Handle BracketThe joints are properly made up when Itcoloy Mill Extension with Guidereverse torque has been applied and a Itcoloy Mill Extensions are used to millslight separation in the cam-teeth Movable Key Seat away flared or jagged metal from the topshoulders is observed. Heavy make-up of the fish so that the fish will pass easily Pintorque is not required. Slot into the Overshot Bowl. For ordinaryWhen the Overshot is dressed with a work, they are installed between the Bowlspiral grapple and type “A” Packer, a and the standard, oversize or wall hookSpacer is required between the Packer guides.and Top Sub. Please refer to Lock RingTable on page 21. The purpose of the The Itcoloy Mill Extension is also usedSpacer is to fill the space produced by in the Bowen Subsea Sheared Pipethe extra standoff of the Top Sub when Retrieval Method (see page 9). In this Keysused with the Lock Rings. No Spacer is case it is installed between the Overshotrequired when “A” Packer is not used. Bowl and the special guides. They may be ordered by giving the OvershotDisassembly number and specifying “Itcoloy MillWhen unthreading is desired, a special Extension Type” and fish size. PricesBowen Lock Ring Breakout Clamp is available on request.required. Slight right-hand torque mayhave to be applied for lining-up the Ringbreakout grooves to receive the Clamp. Lower Key Seat Chain

8 Itcoloy Mill Guide The BOP being used must have at least Itcoloy Mill Guides are used to mill two sets of rams: lower pipe rams and away jagged metal form the top of the shear rams above them. Before shear- fish so that the fish will pass easily into ing, it is necessary to land the nearest the Overshot Bowl. tool joint on the pipe rams and close them to suspend and pack off the string. They may be ordered, using the stan- The shearing then produces flattened dard Guide number, and specifying, flare-ends with protruding ears. “Itcoloy Mill Guide Type C” and fish size. When the rig returns, the string must be Subsea Sheared retrieved, the end brought to the surface Pipe Retrieval and the sheared piece removed. In the During operations from a floating rig, past, sheared pipe retrieval has been dif- there is often many hundred feet of drill- ficult, costly and time-consuming. Often ing sting string extending from the rig to large parts of the BOP stack must be the sea floor, through the wellhead blow- brought to the surface to effect retrieval. out preventer (BOP) stack, and down into the well. If occurrences like a blow- The Bowen method of sheared pipe out, a loss of anchor and the rig drifts, retrieval can be achieved in a simple, a dangerous storm is approaching, etc., time-saving and economical manner. it is sometimes necessary for the rig to It requires only two easy steps using hurriedly move from the well-site. This the Series 150 Circulating and Releasing is done by temporarily severing the drill Overshot equipped with a few special sting inside the BOP and only tripping- accessories Oversize Guide Wallhook Guide out the upper end.GuidesIf the hole size is so much greater than Blowout Preventer Stackthe fish size that it is possible for theOvershot to pass alongside the fish, anOversize Guide or a Wallhook Guidemust be installed in place of the Stan-dard Guide to insure alignment of thefish with the Overshot. These are listed Type A Mill Guideon page 18.

Twist-offs in tool joints are not alwaysimmediately revealed at the surface andas a result drilling is not halted at once.In such cases the top of the fish is usu-ally a badly burred tool joint, or drill pipe, Shear Ramsand a Type A Mill Guide must be installedon the Overshot to trim the burr off thefish so that it can enter the Overshot.Itcoloy Mill Guides perform the sameservice on undersize tool joints and arealso used when the top of the fish is an Pipe Ramsunusually jagged section of pipe. Moreinformation on these is shown on page19. Itcoloy Mill Guide

Step 1: Flare Mill-Down Step 2: Engage and Pull Bowen sheared Pipe Retrieval OvershotThe standard guide, grapple and packer After the milling step is completed, the assemblies are available for all sizes ofhave been removed from a Bowen Bowen Overshot is brought back to the drill pipe and BOPs. Prices will beOvershot and it is then dressed with a surface, dressed with a special flat- quoted on request.Mill Extension and special flat-bottom bottom Short Guide, Extension Sub andLong Guide, and installed on the drill a Basket Grapple and Mill Control Packer How to Orderstring. The Mill Extension has tapered sized to engage the joint. (The Short Specify:milling ribs of Bowen Itcoloy (sintered Guide also has a soft metal end to (1) Make and working bore sizetungsten carbide) facing on its I.D. The prevent ram damage.) The Overshot is of BOPOvershot is lowered into the BOP and lowered again and as it enters the BOP, (2) The distance between the counterover the end of the drill pipe, and then the milled-down flare-end passes lines of the BOP pipe rams androtation takes place to mill down the through the Grapple and Mill Control shear ramsflared ears of the sheared pipe. The end Packer, and is housed in