2. 1
What is Fishing?
• The removal of any undesirable object from
the well bore.
• Recovery of an undesirable situation in the
well bore.
– A stuck or parted drill string or BHA.
– Completion, Casing (stuck, cemented, parted,
damaged etc.)
– Loose junk that may impede drilling, causing
damage to drilling equipment.
– Logging tools stuck or wireline parted during
logging operations.
3. Evaluate the Problem
– Identify the Fish & Obtain the dimensions, size, latch on characteristics
– What is in the hole?
– Is the drilling string stuck?
– What is the BHA (Bottom Hole Assembly)
– Where is the top of the fish, if the string is parted?
– Design & select appropriate fishing tool
– Use the selected tool to locate, latch & retrieve the Fish
– Be patient, trial & error and improvement is required
2
4. • Get accurate fish description and dimensions.
• Have background information such as:
– Formation type at fish top.
– Mud type and weight throughout system.
– Casing sizes, weights and depths.
– Operation at time of trouble.
• Be clear and precise, use written communication when possible.
• Insure that all concerned parties understand and agree on the procedures to
be used.
• Keep all concerned parties informed throughout execution of procedures.
3
5. Cardinal Rules of Fishing
– Know your dimensions
– Know where the top of the fish is
– Know all tensile and torsional
– Never rotate the fish out of the hole
– Fast trip time is not always the best
– Must be O. D. fishable
– Familiarize yourself with the fish
– Verify all pertinent information
4
6. Job Planning & Record Keeping
• Successful fishing jobs start with:
– Excellent job planning
– Meticulous record keeping
• Proper preparation ensures that:
– Most options are planned for and that equipment, personnel and other assets
are available when needed.
• Questions to Determine Tool Selection
– What is the condition of the top of the fish; burst, flared, amount of pipe above
tool joint?
– At what depth is the top of the fish?
– Is there a connection looking up?
– What is the OD and length of the fishing neck?
– Is the top of the fish in a washed out section?
– Is the Bit on or off bottom?
5
7. Steps
• Recovering the Fish
– Engaging the fish
– Jarring
– Washing over
– Milling
• The Preferred Method of Engaging a Fish is to screw it back together
– Features and Benefits:
– Maximum allowable circulation
– Maximum torque may be applied
– Cannot accidentally release
– Maximum strength for jarring
– No Internal Restrictions
6
8. Desired Features of Engaging Devices
– Releasable
– Full and positive circulation
– Full bore for wireline application
– High tensile and torsional strength
– Can transmit high tensile and torsional loads on fish
7
9. Drill Pipe
Accelerators
Oil Jar
Bumper Jar
Box
Tap
Taper
Tap
Spear
Assembly
Screw
in Sub
or Joint
Overshot
Drill Collars
• Screw-in Subs
• Overshots – External Catch
• Spears
• Taps – External & Internal Catch
Attachment Tools & Accessories
External
Catch Internal Catch
10. What Size Overshot?
• Determined by fish O.D. and hole I.D.
• Normally run largest O.S. that will go in hole.
• Rule of thumb: 1/8 less than casing I.D. or 1/2 less than hole size.
• In horizontal wells with a soft to medium formation, run as small an overshot as will
make the catch.
• In horizontal wells with a hard formation, ½” less than hole size as in vertical wells.
Grapples
• The spiral is stronger but the basket is more durable.
• Exact fish O.D. is important. Grapples are manufactured with small tolerances in catch
sizes.
• Tolerance for catch size of grapples is 3/32 undersize to 1/32 oversize.
• This applies only to FS type overshots.
• Basket grapple tolerances for slim holes overshots is 1/16 under size with no over
size tolerance.
• Tolerances for slim hole spiral grapples is 1/16 over/under.
11. Overshots
10
• 150 – Releasable, Circulation
• 70 - Short Catch Releasing
• 20 – Jar down, Short Catch Sucker Rod
• 10 – Releasing Sucker Rod
• Full Strength (F.S.) – Engineered to withstand all pulling
• Extra Strength (X.F.S.) – Engineered to extreme abuse
• Semi Full Strength (S.F.S.) – Engineered to withstand all pulling
• Slim Hole (S.H.) – Engineered to withstand heavy pulling strain only
• Extra Slim Hole (X.S.H.) – Engineered for a pick-up job only
Grapple
(Basket
/Spiral)
Control
(Mill
Tooth/P
lain)
Inner bowl is helically tapered
Outer Grapple taper matches bowl
Grapple moves up and expands as fish enters
With up-pull, grapple moves down and securely
engages the fish
Top Sub
Bowl
Guide
12. Bowen Releasing Spears
11
Used to catch and retrieve any size tubing, drill pipe and
casing.
May be run with cutters, spear pack-offs, etc. as required.
Operation:
– The spear is run in the well in the catch position.
If fish is not engaged, rotate one round to the left, at the
tool, to reset grapple.
To release, bump down sharply to break the hold, rotate
one full round to the right at the tool.
– The matching cams of the release ring and nut resist freezing
or jamming.
Spears are normally run on drill pipe with a bumper sub
to aid in their release.
Spear should be fully inserted into the fish until the stop
ring is encountered
Upward movement will cause the slip cone to expand
and engage the fish
Mandrel
Grapple
Release
Ring
“Bull Nose” Nut
13. What Is Jarring?
12
Jarring is the process of:
– Transferring stored energy (work string stretch) into kinetic
energy by releasing the detent (delay mechanism) in the Jar.
– Detent is a delaying mechanism to prevent the jar from firing
until the stretch is achieved in the string
14. 13
Hydraulic/Mechanical Jars & Bumper Subs
• The Hydraulic Fishing Jars:
– operated with a straight pull which employs the principles of hydraulics and
mechanics.
– the most commonly used jars.
– controlled by the over pull applied to the string before the jar trips.
• Mechanical Drilling Jars:
– utilize a detent provided by spring loaded jay slots and rollers.
– trip only after achieving preset pull load.
– be activated by over pull only.
• Fishing bumper subs:
– require stretch in the drill string to provide the impact.
– are governed by the law of inertia along with the elasticity of the drill string to
perform effectively.
– do not damage the work string because the tool joints are in tension when the
blow is delivered.
– require practice to achieve maximum results.
15. 14
Accelerators
Fishing Jars
Bumper Sub
Attachment
Tool
Drill Collars
Drill Collars
Drill Collars
Accelerators
Drill Collars
Attachment
Tool
Bumper Sub
Fishing Jars
Impact vs. Impulse?
Note: A light hammer or fewer
drill collars will deliver a fast
impact but will diminish quickly.
A heavy hammer or more drill
collars will deliver less impact
but will last longer.
• Impact is desirable when only
a slight movement will free
the fish, such as a stuck
packer.
– Use in all cases if the fish
does not move.
– Regulated by varying the
pull load prior to the jar
tripping.
• Impulse is desirable when
you are differentially stuck in
a long hole section.
– Force
16. Fishing for Junk
•What is the junk?
–size, weight, condition?
–Is it magnetic?
–Will junk fit into standard junk basket?
–Is the junk millable?
•The junk could be:
–Bit cones
–Float collar and wiper plug debris
–Rig tools
–Slip elements
–A joint of backed off casing or any number of things
•Ways to fish junk:
–Magnets
–Baskets
–Jet Systems
–Po-Boy baskets
19. Fishing Magnet
18
– All small objects with magnetic attraction
– Run on pipe; capability/rotate/ circulate
– Must wash fish; surface/ magnetic pole
– Run boot basket above for small junk
– Most, but not all tungsten carbide bit inserts
are non-magnetic
20. 19
Boot Basket
Cup
– The boot basket is used to recover small objects.
– It is usually run in conjunction with a bit or milling tool.
– The bit or mill will break up the junk into small pieces
which will be carried up the hole by fluid circulation.
– Turbulence in the annulus will cause the junk to drop
off in the cup of the boot basket.
– Boot baskets can be useful when drilling up bridge
plugs, retainer production packers, cement retainers or
other drillable material.
21. 20
Bowen Itco Type - Junk Basket
– Used in soft to medium formations to cut a core and retrieve junk
– Top sub, barrel, carbide shoe & two finger catchers
– Thrust ball-bearing assembly for free rotation of the barrel and
shoe around the catchers to minimize finger catcher breakage
– Mill O D: 1/4” less hole size
– Carbide I D of shoe: slightly less than ID of catchers
22. 21
Finger Catchers
– The fingers in the upper catcher extend only halfway to the center, it’s
function being to break the core when an upper strain is taken on the string.
– The lower catcher has alternately long and short fingers which extend almost
to the center, forming a close fitting basket which will retain the core or small
pieces of junk.
Junk Basket Lower Catcher Junk Basket Upper Catcher
23. 22
Reverse Circulation - Jet Junk Basket
• Bearing for free rotation of barrel and shoe around the
finger cages
• Close-fitting finger catchers hold smaller pieces of junk.
• Operations:
– Circulate capacity of string
– Check ID’s/ insure ball will pass
– Drop ball: shear pins: reverse
– Not necessary to cut core
– Hyd. power deflects junk/barrel
– Preferred tool for hard formation
24. 23
Venturi Jet - Junk Basket
– Nozzles are easily changed to adjust the
pressure drop at the tool
– True internal vacuum of barrel creates reverse
circulating effect enabling the recovery of larger
debris
– Uses conventional finger catchers, flapper valves
or mouse traps
– Filter screens can be used if required
26. 25
Poor Boy Basket
Used when fish is too large for conventional
baskets and can be of several types including:
– finger type
– peen type
– spring tine
– wire welded inside type
27. 26
Finger Type Shoe
– A finger type shoe may be run when
there is large but free junk lying on
the bottom of the hole.
– Made of mild steel for easy bending.
– While rotating and circulating, slight
weight is applied closing the fingers
in to secure the fish.
28. 27
Wire Catcher Shoe
– The wire catcher shoe has flexible wire welded
inside to catch the junk.
– Good for loose junk.
– Use care not to rotate too much or the wire
might break off.
– Might be good to catch a hammer, lead,
rubber, or a pipe wrench.
29. 28
Mills
• Junk mills are used to mill up almost anything that is accidentally dropped
into or becomes stuck in the hole
• Loose junk can be “spudded” on to break it into smaller pieces so that it can
be held in place and cut by the mill
• Mills are used to entirely mill away pipe that has been cemented up both
inside and outside and cannot be retrieved by any other method
31. 30
Cone Buster/Flat Bottom Mills
• In open hole a mill without stabilizer pads is used.
• The O.D. of the mill should be about ¼” inch less than the
hole diameter with a rough O.D. that will cut a small
amount of side clearance.
• The bottom configuration can be either flat or concave –
the flat bottom being used for loose junk such as bit cones,
slips or small hand tools, etc.
32. 31
Bladed Mill
• Rugged, durable construction
• Concave, convex, and flat-bottom designs available
• Tungsten carbide inserts for stationary fish or junk
• Crushed tungsten carbide for loose fish or junk
33. 32
Bladed Mills/Stabilizer Pads
• Optional-length fishing necks, stabilizers, and
combination stabilizer-fishing necks available with
extra-long mill heads for minimizing risk of casing
damage.
34. 33
Piranha Junk Mill
• A very aggressive Mill
• Dressed with Crushed Carbide
• Used for loose Junk, bit cones, slip dies
35. 34
Tapered Mills
• Crushed tungsten carbide-dressed reamer
blades
• Dressed smooth or rough OD
• Milling through jagged or split guide shoes
• De-burring whip stock windows
• To make gauge run prior to running internal
liners
• Mill out collapsed casing
37. 36
Factors Effecting General Milling Rates
• Stability of fish
• Type and hardness of fish
• Weight on mill
• Rotary speed
• Type of dressing
• Mud properties
38. 37
Pilot Mill/Diamond Point
• Full O.D. for ensuring that collars are milled
• Applicable to a range of tubular goods
• Optimized alignment of inserts to proper cutting angle and
cutting size.
• Extended blade length for extended down hole cutting time
• QUIK Cut Inserts
– For surface equipment or fluids with limited capabilities, the Quik
Cut insert produces small, lightweight cuttings
– For premium fluids and high-volume surface equipment, the Quik
Cut “dimpled” insert provides maximized milling rates and life of
Pilot Mill.
39. 38
Pilot Mill/Lower Connection Type
• Same features as the Pilot mill/diamond point type
• Pin-down design for optimal, operation-specific bottom hole
assembly
40. 39
Typical Milling BHA
IB Stabiliser
OD Of Blades - Same
OD as mill
Shock Sub
IB Stabiliser
OD Of Blades - Same
OD as mill
Weatherford Pilot mill
Blade OD - 1/4" Larger than the
coupling
IB Stabiliser c/w float
OD Of Blades - same as
casing drift
REMAINING BHA
Drill Collars
Drilling jars
Drill collars
Taper Mill
NOTES:
Stabilisation size below the mill will be altered as milling progresses in
order to counter the effects of eccentric casing.
All connections above the mill should be made up to minimum
recommended API value PLUS 10%
All connections below the mill should be made up, using minimum
dope application, to minimum recommended API value plus 15%
HWDP
DP to Surface
Cross Over Sub
Operating parameters:
WOM 5000 to 20,000lbs
RPM 120 to 200 RPM
Torque 3000 to 8000 ftlbs above FRT
Bit Sub
(bored for float)
41. 40
Sand Stuck Tubing
• Causes:
– Hole in casing or packer not holding
– Frozen packer
• Solutions:
– Perforating the tubing above the packer and
establishing circulation
– Jarring loose or milling over and retrieving
• If the tubing is plugged:
– It can be cleaned out on the inside with small
diameter drill pipe.
– Use coil tubing to clean out.
– Use inside-outside back-off collar.
42. 41
Internal/External Cutters
• Is designed to:
– mechanically/hydraulically operated to
cut tubing or drill pipe
externally/internally
– be fed by the knives entirely by
Rotation or pump pressure
– cut any where on the tube, doesn’t
have to be under a collar or coupling
Top Sub
Rubber Ring
Piston
Segments
Piston O-Ring
O-Ring
Feed Ring
Shear Pin
Guide Screw
Knife
Body
Guide
Knife Pin
43. 42
Washover Operations in Cased & Open Hole
A Washover assembly is used when jarring has failed to
free a fish.
The primary function of washpipe is to allow a large
section of fish to be swallowed, mill clearance
between fish and formation, mill away junk around the
fish, mill away a keyseat & stabilizer blades
The top sub acts as an X-over to the jarring BHA.
The Washover assembly includes the following:
– Washover shoe
– Washpipe
– Top sub
– Jar assembly
Washover
back-off
safety
joint
Length of
washover
pipe
Rotary shoe
44. Shoe Selection
43
– Short tooth or scallop shoes best for
medium to hard formation
– Medium tooth is faster for soft
formation
– Flat bottom or ocean wave; used to cut
packers, stabilizers, reamers, tool joints
– Select shoes carefully, they vary
– Quality & performance count
45. 44
Rotary Shoes
If you are milling on permanent packers:
– dress the I.D. with crushed carbide so that the mandrel
O.D. will be fishable after the burn over.
If you are milling over a retrievable or dual packer:
– dress the I.D. so as to mill the packer slips and rubber
elements just enough to effect release.
46. 45
Fishing Tools
• The other Fishing tools include, back off collar
• Wall hook guide
• Packer retrieving spear (top, bottom catch)
• Rope spear, Wire Prong, Wire Grab
• Whipstocks
• Casing scrapers, Swages, back off tools
47. • Unfortunately, we do not always get the problem solved in the first or second
attempt. Some fishing jobs are very difficult. Patience is needed on these
types of operations. Complex fishing jobs are like a puzzle, they must be
solved 1 step at a time.
• There comes a time in all fishing jobs, when the chance of success has to
be weighed against the cost. If the best choice is not working, what are the
alternatives? Is the hole valuable enough to keep fishing?
• Usually the Drilling Superintendent knows the cost limitations of the job, and
will be the person to make this decision.
• Use proven techniques.
• Don’t jump to conclusions that could lead you down the wrong path.
• Practice patience
46
