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Techmaster Milling Tools Techmaster milling tools carries a large inventory of the standard and special milling tools which covers a wide range of milling requirements.

Main Categories:

• Taper Mill

• Econo Mill

• Pilot Mill

• String Watermelon Mill

• Deep Throat Mill

• Piranha Mill

• Diamond Point mill

• Junk Mill

Taper Mill

Designed for milling through various types of downhole obstructions, and for reaming out liners and whipstock windows. It is designed specifically for milling through tight spots in tubular. Custom design taper mills are utilized to clean the casing without cutting it, and to penetrate very gradually. The upper part of the taper mill is long enough to allow the addition of stabilizing blades while still remaining easy to fish. The three most used configurations are the 60 degree mill (30 degrees per side), The 30 degree mill (15 degrees per side) and the 15 degree mill (7 1/2 degrees per side.)

Econo Mill Is a low-cost mill for light-duty milling jobs, dressed with tungsten carbide. It is an effective tool for milling packers, bridge plugs, cement retainers and tubular equipments. Made with a standard rock-bit connection, it can be easily adapted to drill stem stabilizers or used inside a skirt to mill fish heads. No additional subs are required, circulation is directed junk slots along each cutting blade and through the center of the head for proper cutting removal and cooling.

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Econo Mill

Econo Mill Technical Specification

Dressed Diameter (in)

Top Pin Conn. API Reg. (in)

Length (in.)

Recommended Torque (Ft.Lbs)

3 1/4 - 4 3/8 2 3/8 7 5/8 3,000 - 3,500

4 1/2 - 5 3/8 2 7/8 8 5/8 6,000 - 7,000

5 1/2 - 7 3/8 3 1/2 9 7,000 - 9,000

7 1/2 - 8 3/4 4 1/2 11 1/2 12,000 - 16,000

10 1/4 - 12 1/4 6 5/8 16 1/2 28,000 - 32,000

13 - 16 7 5/8 18 45,000 - 60,000

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Pilot Mill Is best used for milling stuck tubular, such as Packers, liner hangers, rotary shoes or drill pipe and is ideal for cleaning a casing head before running casing patch, and suppressing the damaged parts of a casing.

String Watermelon Mill

Designed and dressed in such a way that it can mill up or down and allowing reaming from both directions. It is also designed to grind up casing into a fine metal powder instead of metal shavings.

Deep Throat Mill

Designed to drill cement, especially where small amounts exist. the three blades design gives a better cutting speed on cement.

Piranha Mill

Built to mill large amounts of junk like cemented drill pipe and packers.

Diamond Point

Made to bevel off liner tops for smoother entries, it may also be used for washing through packed sand fill with either a spud or rotating action.

Pilot Mills

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Junk Mill Junk Mills are the most commonly used milling tools designed to mill up or dress off a wide variety of junks such as squeeze tools, packers, tubing, bridge plugs, it also works well where there is a combination of junk and cement. The Junk Mill, dressed with Tungsten Carbide, chews its way through the toughest drilling materials. Junk Mills are applied for milling away of metal parts in a hole (subs, bits, pipes, etc.).

Techmaster junk mills are produced from high strength heat treated alloy. All Mills are available as bit type or with optional fishing neck and hard surface wear pads. Large circulation ports and ample fluid channels provide cooling and efficient removal of cuttings. This will makes milling jobs easy even when cutting the toughest fish such as alloy-steel packers, squeeze tools, perforating guns, drill pipe, tool joints, reamers, reamer blades, and rock bits.

Each type of junk mill is appropriate for a particular application, depending upon several factors:

• Hole shape.

• Shape of metal parts subject to destruction.

Junk Mill

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Application

Use Junk Mills to mill almost anything in the hole, including:

• Bailers

• Cement Packers

• Subs

• Bit Cones

• Drill Collars

• Reamers (short length)

• Testers

• Drill Pipes

• Setting Tools

• Washpipes

• Hangers

• Slips

• String shots

• Whipstocks

• Casing (collapsed)

Types

Available in standard designs covering a wide range of milling applications:

• Conventional Junk Mill

• Flat Bottom Junk Mill

• Conebuster/Concave Junk Mill

• Integral Bladed Junk Mill

• Super Junk Mill

• Offset Junk Mill

Junk Mills

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Conventional Junk Mill

Designed for cement, general junk, tubing, milling or packer removal.

Conventional Junk Mills

Flat Bottom Junk Mill

Used for dressing the top of the fish to make retrieving process easier. It can be supplied with more hard facing for longer tool time at bottom.

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Flat Bottom Junk Mills

Conebuster Junk Mill

An ideal solution for milling bit cones. The concaved shape causes the bit cones to be concentrated below the mill.

Conebuster Junk Mills

Integral Bladed Junk Mill

Dressed with high-quality tungsten carbide to ensure optimal performance in all applications, suitable for all types of general junk milling, as well as for removing packers, retainers, and squeeze tools. Tool integrity is ensured by integral blades machined out of the body, which can be fitted with cutting inserts for improved ROP.

Integral Bladed Junk Mills

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Junk Mill Technical Specification

Dressed OD Top Pin Conn.

API Reg. Overall Length

Fishing Neck Weight

(lbs) Length OD

3 1/2 - 4 1/2" 2 3/8" 20" 12" 3 1/8" 45

4 1/2 - 5 1/2" 2 7/8" 21" 12" 3 3/4" 62

5 1/2 - 5 5/8" 3 1/2" 23" 12" 4 1/4" 95

5 3/4 - 7 1/2" 3 1/2" 23" 12" 4 3/4" 105

7 1/2 - 9" 4 1/2" 27" 12" 5 3/4" 180

9 1/2 - 12 1/4" 6 5/8" 29" 12" 7 3/4" 350

13 - 15" 6 5/8", 7 5/8" 30" 12" 7 3/4", 9 1/2" 500

17 - 17 1/2" 7 5/8" 33" 12" 8 3/4", 9 1/2" 625

18 1/2 - 26" 7 5/8", 7 5/8" 37" 18" 9 3/4", 9 1/2" 1200

Custom sizes available on request

Components

1) Body 2) Hard-alloy Inserts 3) Tungsten Carbide Hard Face 4) Circulating Ports

Junk mill with guide consists of a body, cutting-and-wearing dressing with plain shape and tungsten-carbide powder. There is a connecting thread at the top, holes and special grooves for cooling and intensive washing out of chips at the bottom. A guide is screwed on the body to take a pipe aside of the production casing wall and holding while milling.

All mills feature integral AISI 4145HM body and can be used in both cased and open hole, available in a variety of standard and custom sizes, with or without stabilizing blades.

Techmaster junk mills are available with concave, convex, or flat bottoms in various combinations of fishing necks and stabilizers. Any specific length neck, stabilizer, or combination of both may also be ordered.

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Junk Milling Procedures 1) Tag the bottom of well, spud the junk, kick in the pumps, as in normal

drilling conditions.

2) Start rotation at 60-80 RPM.

3) Reduce weight on Mill.

4) If there is an indication junk may be turning, spud two or three times.

5) After milling one or two feet, pick up the Kelly fifteen to twenty feet off the bottom and reduce pump pressure or shut off pumps (depending on hole conditions). This action will let the loose junk settle to the bottom.

6) Once again feel for the bottom and spud. Begin rotation at 80-100 RPM using normal pump pressure, and weight at 4,000-6,000 lbs.

7) Repeat steps 3 and 4 every few feet, procedures from here onwards

will be governed by feel.

NOTE: In hard formation it will take fewer feet of hole to mill up the junk than in softer formation. This difference is due to junk more readily penetrating the softer formation.

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Recommendations for Milling Junk

Loose Junk in Open Hole

• Use a junk mill with an O.D. of 1/8" less than hole diameter.

• Use at least 10,000 lbs. of drill collars.

• Run a junk sub directly above the mill. (Please note: junk subs for 4-3/4" and smaller drill collars are not strong enough for repeated spud.)

JUNK MILLING

Frequent spud improves milling efficiency on loose junk. To spud the junk and force it down, proceed as follows:

1) Settle the neutral on zero point, mark the Kelly at the top of the Kelly bushing.

2) Pick up the Kelly four to six feet (four feet in deeper holes, six feet in shallower holes.)

3) Drop the Kelly and catch it (not slow down, but catch it) with the

brake about eighteen to twenty inches above the zero mark. (Example: Pick up 10' and drop it 8-1/2). This action causes the drill string to stretch & spud the junk on bottom with great force while the string is still in a state of tension. This prevents damaging the string which might be expected if the string is in compression at the moment of impact.

4) Spud the junk three or four times, turning the mill a quarter each time

between drops.

NOTE: In hard formation it will take fewer feet of hole to mill up the junk than in softer formation. This difference is due to junk more readily penetrating the softer formation.

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Stationary Junk in Open Hole

• Use a Junk mill with an O.D. of 1/8" less than the hole diameter.

• Mill with 4,000 to 10,000 lbs. of weight, depending upon the strength of the fish being milled.

• After each three to five feet of junk milled, pick up the mill ten to fifteen feet and ream hole down to the fish.

• After reaming the hole down, always set down on the fish while turning and increase milling weight without delay.

• Never apply weight first and then start rotating.

• Never set down on the fish with a light weight and spin, if you want to stop milling for any reason, always pick up the mill.

Loose and Stationary Junk inside the Casing

Procedure of running Junk Mill inside casing is the same except:

• Run a stabilizer directly above the mill which has the same O.D. as the mill.

• The mill head O.D. should be the same as the drift diameter of the casing.

• Wear pads with the same O.D. of the mill head are provided on the junk mill. These recommended items will eliminate possible damage to the casing.

Factors affecting milling rates

• The type of fish

• The stability of fish (Cemented or not)

• Weight on the mill

• Running speed on the mill

• Carbide dressing on the mill

• Stiffness and vibration of the drill collars.

• The hardness of the fish or cement

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Rotary Speed A high Surface Feet Per Minute (SFPM) speed can burn or damage tungsten carbide mills.

Weight for Milling

Excessive weight on the mill can damage the tungsten carbide that mills steel.

Typical Challenges Remedied by Adjustment of Milling Rate:

• Cemented Casing: Increase mill rotation and weight on the mill to improve the rate of penetration (ROP).

• Uncemented Casing: Mill at slower RPMs, with less weight on the mill.

• Severely Corroded Casing: Increase speed and decrease weight on the mill to prevent tearing or splintering of the casing.

• Rubber In The Hole: When milling rates drop, decrease the pump strokes or turn off the pumps, pick up the work string and spud the mill.

• Unstable Mill: Run a stabilizer above the mill, if possible, the OD of stabilizer should not exceed the dressed OD of the mill.

• Bouncing Or Rough Operation: Reduce speed and weight on the mill until the milling operation becomes smoother. After an hour, slowly increase the speed and weight.

• Older Model Liner Hanger, Centralizers, Scratchers: Most liner hangers mill easily, but some old types have slips and rotating parts, when these types are encountered, pick up the work string and spud the mill frequently to reposition and break up the hanger parts for effective milling.