Weatherford Fishing Tools

7/23/2019 Weatherford Fishing Tools

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Guidelines for Effective Milling

™F e at u ri n g Cu s to m Cu t i n s er t s— b ec a us e e ac h j ob i s d if fe r en t

Fishing Services

SM

M il l Sm ar t Te ch no lo gy



Contents

ContentsIntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

SMMi llSmart Technol ogy—An Engineered Approach to Mill ing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Custom Mi ll s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

General Operational Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Optimi zi ng Mill ing Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Opti mi zi ng Cutti ng Returns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Junk M i lli ng O perati ons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

General Recommendati ons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Junk Mil ls and Accessori es . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Pilot Milling Operations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

General Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Application-Specific Recommendations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Pilot Mills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Taper Milling Operations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23


Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Taper Mills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Watermelon/String Milling Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Watermelon/String Mills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Section Milling Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31


Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Section Mills. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Rotary-Shoe Washover Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42


Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

R o t a ry S h o e s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

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Guidelines for Effective Milling 1st ed. May 2006



2© 2 0 0 6 We a th e rfo rd . All rig h ts re s e rv e d .Gu id e lin e s fo r Effe c tiv e Millin g 1 s t e d . Ma y 2 0 0 6

List of Tables1 — Ty p i c a l C h a l l en g e s R e m ed i e d b y A d j u st m e n t o f M i l l i n g R a te . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2—Formula for SFPM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

3—Formulas for Determining Weight on the Mill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

4—Formulas for Determining Weight on the Rotary Shoe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

5—Recommended Drilling Mud Yield Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

6—Differences among Junk Milling Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

7 — S p ec i f i c at i o n s f o r B l a d e d J u n k M i l l s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

8—Specifications for Flat-Bottom (Cone-Buster) Mills. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

9—Specifications for Type P Junk Mill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

10—Specifications for Screw-on-Skirt Boot Basket. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

16

11—Specifications for the CustomCut™ Pilot Mill (Diamond Point) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

12—Selection Guide for CustomCut Inserts (Diamond-Point Pilot Mill) . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

1 3 — S pe c i f i ca t i o ns f o r t h e CustomCut Pilot Mill (Lower-Connection Type). . . . . . . . . . . . . . . . . . . . . . . . . 22

14—Selection Guide for CustomCut Inserts (Lower-Connection Type Pilot Mill) . . . . . . . . . . . . . . . . . . . . 22

15—Specifications for Taper Mills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

16—Specifications for Watermelon/String Mills . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

17—Causes of Difficulty in Cutting Out and Their Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

18—Specifications for the A-1 Section Mill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34®

1 9 — Sp e c i f ic a t i o ns f o r t he E l i m in a t o r S e c t io n M i l l . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

20—API Casing and Section Mill Correlation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

2 1 — Sp e c i f ic a t i o ns f o r t h e R e v e r se - F l o w S e c ti o n M i l l . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

22—Cut-Out and Milling Ranges for the Reverse-Flow Section Mill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

2 3 — Sp e c i f ic a t i o ns f o r t h e S l i mc o ™ S e c ti o n M i l l. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

2 4 — R ot a r y S h o e S e l e ct i o n G u i d e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Contents



Mill 1 ) t o g r i n d u p or p u l v er i z e; 2 ) a f i s h in g t o o l o r s ho e ( j u nk m i l l ) w it h

d i a mo n d o r t u ng s t e n- c a r bi d e c u t ti n g e d ge s u s e d t o g ri n d a w ay a f i s h s u ch a s s t u c k t oo ls o r pi pe i n a w el l. A m il l c an al so b e u se d a ) t o d re ss t he t op o f a f is h to b ecaught by another fishing tool, b) to ream out collapsed casing, c) to ream tubularsw i t h s c a le , d ) t o r e m ov e a s e c ti o n of c a si n g f o r s id e t r ac k i ng o r de v i at i n g awell, or e) to remove cement plugs.

— Excerpt f rom t he Dict ionary of Pet roleum Explorat ion, Drilling & Product ionNorman J. Hyne, Ph. D.

IntroductionWeatherford provides fishing services worldwide. Our highly experienced teams of fishing tool supervisors andoperators are ready to meet any challenge, and we offer the world's most advanced and comprehensive line of f i s h i ng t o o l s f o r a n y a p p l i ca t i o n :

Junk mills for removing stuck pipe, tubing, bridge plugs, packers, and cement or other debris obstructing thewellbore

Pilot mills for effectively milling casing, liners, rotary shoes, wash pipe, or large-ID tubing

Taper mills for reaming out restrictions, collapsed casing, and liner sections

Watermelon/string mills for milling collapsed areas in casing and liners, eliminating key seats and doglegs, andextending whipstock windows

Section mills for cutting sections of casing or for setting whipstocks

Rotary shoes for freeing tubulars that have become sand stuck, mud stuck, or mechanically stuck and for milling over packers, retainers, and bridge plugs

Weatherford has these and many other milling tools plus everything from jars to boot baskets, cutters toovershots, casing scrapers to underreamers, and knuckle joints to fishing magnets. And we serve your needsq u i c k l y w i t h l oc a t i o ns w o r l dw i d e —a l l w i t h a wi d e a r ra y o f f is h i n g t oo l s i n s t o ck a n d r ea d y t o g o .

M i l l i n g s u cc e s s d e p e n ds o n g o o d m i l l d e s i g n a n d e f fi c i e n t j o b e x e cu t i o n . T hi s h a n d b o ok , c o n c e rn e d w i t h j o bexecution, represents a distillation of valuable best practices, gleaned from decades of operational experience, toh e l p i m p ro v e t h e e f fi c i e n c y a n d o u t c om e s o f y o u r m il l i n g o p e ra t i o n s. W e h o p e y o u w i l l f i n d t h i s b o o k t o b e avaluable reference.

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Introduction



Introduction

Weatherford CustomCut milling- or cutting-grade inserts are available inv a r i o us c o n f i g u r at i o n s a n d g e o m e tr i e s . O u r a d v a nc e d m i l l e n g i n ee r i n g a n dcertified welders ensure a consistent and durable cutting structure on everym i l l a n d r o t a ry s h o e w e p r o d uc e .

CustomCut inserts feature a proprietary negative rake and chip breaker designthat effectively breaks up the cuttings. This provides smaller, thinner and lighter cuttings that are quickly and easily circulated and flowed to the surface for better holecleaning efficiency and faster penetration rates.

MillSmart t e ch n ol o g y a n d CustomCut carbide inserts are a major leap forward in performance, using materials

and designs that contribute to a complete system process approach. Focused research and engineering effortsand extensive field experience and case studies have generated a family of special-application carbide millingproducts—the CustomCut 100, 200 and 300 series.

CustomCut inserts can be teamed with our revolutionary new PowerStroke™ milling system, which features au n i q u e r e c i pr o c a ti n g , h i g h l y f l e x ib l e b r o a c h m i l l i ng d e s i g n t h a t r e d u c e s t o o l s t r es s a n d m a i n t a i n s c o m mu n i c a ti o nbetween shifted sections to prevent sidetracking. In its first field trial, the PowerStroke system remediated twos e v e r e d og l e g s i n o n e w e ll i n a s i n g l e t r i p .

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Custom Mills

S MM i l lS m a rt Te c hnol ogy —A n Engi ne ere d A pproac h t o Mi l l i ng

While the definition of the word is quite straightforward, there's much more to successful milling than peoplemight realize. To plan an effective milling operation, a number of things must be considered.

Weatherford's MillSmart milling technology is an engineered approach to milling that encompasses a widerange of proven products, services and technical resources, developed and refined by the world's largestand most experienced provider of milling and fishing services. MillSmart technology is based on atremendous amount of milling data—gathered by Weatherford's worldwide Performance Tracking Systemand used to create best practices for almost every imaginable application.

MillSmart customized hydraulic modeling software for job planning gives you the most realistic previewpossible of a proposed milling operation. Our suite of HydraPro™, HydraForce™, Hydra-Cut™ andHydraBoost™ software focuses on extended-reach, deepwater, horizontal, high-angle, high-temperature/high-pressure and other high-profile well designs for which pre-job planning is crucial.

Milling and pipe cutting are required in a variety of situations, including offshore well abandonment, loose junk

retrieval, section milling, fish-top cleanup, washovers, and milling of major obstructions. Over the yearsWeatherford engineers have designed and manufactured thousands of mills, both standard and custom. Needa c u s t o m m i l l f o r a u n i q u e s i t u a t i on ? W e a t h er f o r d o p e ra t i o ns a n d e n g i n e e r i n g p e r so n n e l h a v e p r o b ab l y a l r e a dyaddressed something very similar. We can design and manufacture a custom tool to your specifications.

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Gu id e lin e s fo r Effe c tiv e Millin g 1 s t e d . M a y 2 0 0 6

Challenge Recommendation

C eme nt ed c as in g I nc re as e mi ll s pe ed a nd w eig ht o n t he mi ll to im pr ov e th e r at e o f p en et ra ti on ( RO P) .

Uncement ed casing Mill at slower speeds, wit h less weight on t he mill.

Severely corroded casing Increase speed and decrease weight on the mill to prevent tearing or splintering of the casing.

R ub be r i n t he h ol e W he n m il li ng r at es de cr ea se , d ec re as e t he pu mp s tr ok es , o r t ur n o ff t he p um ps . P ic k u pt he work st ring, and spud t he mill t o help engage and break up t he rubber.

Unst able mill Run a stabilizer above the mill, if possible. The OD of the s tabilizer s hould not exceed t hed r e s s ed O D o f t h e m il l .

B o u n ci n g o r r o u g h o p e r at i o n D e c r e as e t h e s p e e d a n d w ei g h t o n t h e m i l l u n t i l t h e mi l l i ng o p e ra t i o n b e c o me s s m oo t h e r. Af t er an hour, slowly increase t he speed and weight . I f t he ROP is accept able, cont inue att he same speed and weight ; if not , increase t he speed and weight unt il an accept able ROPis achieved. I f necessary, repeat t he procedure unt il milling can resume. A shock sub canbe run just above t he mill t o reduce vibrat ion.

O l d e r -m o d e l l i n e r h a n g e r s,cent ralizers, and scrat chers

Most liner hangers mill easily, but some old t ypes have slips and rot at ing part s. Whent hese t ypes are encount ered, pick up t he work st ring, and spud t he mill f requent ly t oreposit ion and break up t he hanger part s f or ef f ect ive milling. I n milling cent ralizers andscrat chers, use t he largest -OD mill t hat can be run int o t he wellbore t o ensure t he best

Ge n er a l Op e ra t i on a l Re c om m e nd a t io n s


G en er al O pe ra ti on al R ec om me nd at io nsEach type of milling operation presents its own set of challenges, for which we provide recommendations in thefollowing pages; however, certain recommendations for optimizing milling rates and cutting returns apply to allkinds of milling situations.

Optimizing Milling RatesMilling rates are affected by the type and stability of the fish (cemented or not); weight on the mill; running speedof the mill; carbide dressing of the mill; stiffness and vibration of the drill collars; and hardness of the fish or cement. Table 1 provides guidelines for optimizing milling rates in various situations.

Table 1—Typical Challenges Remedied by Adjustment of Milling Rate




Ta b l e 2 — F o rm u l a f o r S F P M

Formul a

OD RPM 0. 262 = SFPM

E x a mp l e f o r a n 8 5 / 8 - in . OD J un k Mi l l at 1 10 R PM

8. 625 110 RPM 0. 262 = 249 SFPM

Table 3—Formulas for Determining Weight on the Mill

Formul as E x a m pl e s f or a n 8 5 / 8- i n . OD J u n k Mi l l

2 OD 0.7854 500 (maximum crushed)= Recommended weight on mill

28. 625 0. 7854 500 (maximumcrushed) = 29, 213 lb on mill

2 OD 0. 7854 150 (minimum insert )= Recommended weight on mill

28. 625 0. 7854 150 (minimuminsert ) = 8, 764 lb on mill

2 OD 0. 7854 500 (maximum insert )= Recommended weight on mill

28. 625 0. 7854 500 (maximuminsert ) = 29, 213 lb on mill

Table 4—Formulas for Determining Weight on the Rotary S hoe

Formul asE x a m pl e s f o r a n 8 5 / 8 - in . OD x7 1 / 4 - i n. I D R o t a r y Sh o e

2 2 (OD – ID ) 0. 7854 500 (maximumcrushed) = Recommended weight onrot ary shoe

2 2 (OD – ID ) 0. 7854 100 (minimum

crushed) = Recommended weight onrot ary shoe

2 2 (OD – ID ) 0. 7854 150 (minimuminsert ) = Recommended weight onrot ary shoe

2 2 (OD – ID ) 0. 7854 500 (maximuminsert ) = Recommended weight onrot ary shoe

2 2( 8. 62 5 – 7 .2 50 ) 0. 7854 500

(maximum crushed) = 8, 522 lb on|rot ary shoe

2 2( 8. 62 5 – 7 .2 50 ) 0. 7854 100

(minimum crushed) = 1, 714 lb onrot ary shoe

2 2( 8. 62 5 – 7 .2 50 ) 0. 7854 150(minimum insert ) = 2, 571 lb on

rot ary shoe2 2

( 8. 62 5 – 7 .2 50 ) 0. 7854 500(maximum insert ) = 8, 572 lb onrot ary shoe

2 OD 0.7854 100 (minimum crushed)= Recommended weight on mill

28. 625 0. 7854 100 (minimumcrushed) = 5, 842 lb on mill


Rotary Speeds

Experienced operators often intuitively determine the rotary speed required for effective milling rates. Smallmills—up to 8-1/2 in. (216 mm) in diameter—can sometimes be run up to 150 RPM but usually are kept to about100 RPM to prevent the drillpipe from whipping around. If run at a high speed, a mill can stick momentarily,c a u s i ng t h e p i p e t o t w i s t u n t i l t h e m i l l r e l e a se s i t . T h e s t r i ng t h e n v i o l e n tl y u n t w i s ts , o f t e n b r e ak i n g t o o l j o i n tc o n n e ct i o n s o r t w i s t in g o f f t h e p i p e . T h e r e fo r e , f o r s m a l l m i l l s , t h e d r i l ls t r i n g a n d h o l e c o n d i ti o n s l i m i t r o t ar y s p e e d .Run ample drill-collar weight to provide the inertia required to keep the work string at a constant rotary speed.

A high surface-feet-per-minute (SFPM) speed can burn or damage tungsten carbide mills. Crushed tungstencarbide cuts steel best at 150 to 200 SFPM (45.7 to 61.0 surface-meters-per-minute [SMPM]). Weatherford'sCustomCut™ tungsten carbide inserts cut steel best at 150 to 350 SFPM (45.7 to 106.7 SMPM). Use the formula

and example in Table 2 to determine the minimum and maximum recommended speeds.

W e i gh t s f or M i l ls a n dRotary Shoes

E x c e ss i v e w e i gh t o n t h e m i l l a n d

rotary shoe can damage thet u n g s te n c a r b i d e t h at m i l l s s t e e l .Crushed tungsten carbide cutss t e e l b e s t a t 10 0 t o 5 0 0 P SI(689 to 3,447 kPa). Tungstenc a r b i de i n s e r t s c ut s t e e l b e s t a t150 to 500 PSI (1,034 to3,447 kPa).

Use the formulas and examples inTables 3 and 4 to determine therecommended minimum andm a xi m um w e i gh t s o n t h e m il l a n don the rotary shoe, respectively.





Operati onal

Obj ecti ve

Y i el d P oi nt

(l b/ 100 ft2

)

Drill 10 to 15

W ash over 15 to 20

M ill >30


Optimizing Cutting Returns

The ideal cutting is usually 3/32 to 1/4 in. (2.38 to 6.35 mm) thick and2 to 4 in. (50.80 to 101.60 mm) long.

If cuttings are thin or hair-like and ROPs are low, increase the weight onthe tool.

If fish-scale cuttings are returned during pilot or section milling (commonwhen milling H-40, J-55, and K-55 pipe), improve ROPs by decreasingthe weight and increasing the rotary table speed. When milling N-80 or P-110 pipe, finer cutting returns can be expected.

The following are guidelines for the optimal use of drilling mud tocirculate steel cuttings out of the wellbore.

Maintain a minimum annular velocity of 120 ft/min (36.6 m/min).

Follow Weatherford's drilling mud yield point recommendations, shownin Table 5.

Avoid oil-based mud whenever possible.

O r d i na r i l y n o d i f f i c ul t y i n r a i s i n g s t e e l c u t t in g s i s e n c o u n t e re d w i t hcommon drilling practices. Most difficulties are encountered when al i g h t r i g w it h a s m a l l m u d p u m p i s u s ed i n r e m e d i a l w o r k. I n t h e s ecases, add bentonite to the mud so that the effective viscositybecomes sufficient to raise the cuttings.

I f b i r d n es t i n g o c c ur s a r o u nd t h e d r i l l s t ri n g , p u l l u p t h e w o r k s t r i ng ,circulate, and work the pipe until the correct cutting return is achieved.During long milling jobs, repeat the procedure frequently to maintainthe ROP.

Reverse circulation is another way to remove cutting accumulation onthe fish. In some cases, boot baskets (junk subs and baskets), reversecirculating junk baskets, or bailers are used to remove or catch steelcuttings.

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Table 5—RecommendedDrilling Mud Y ield P oints





Table 6—Differences among Junk Milling P rocedures

OpenHol e

Loose Junk S tati onary Junk

CasedHol e

— U s e a j u n k m i ll t h a t i s d r e ss e dwit h crushed t ungst en carbide.

— U s e a j u n k m i ll t h a t i s d r e ss e d

wit h crushed t ungst en carbide.

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—

Use a junk mill wit h a rough OD t hat is 1/ 8 in. smaller than t he holesize.

Run a st abilizer, wit h an OD equal t o t he size of t he junk mill, direct lyabove t he junk mill.

—

—

—

U s e a j u n k m i ll w i t h a s m o ot h - O D h e a d o f t h e s am e s i z e a s t h e d r if tdiamet er of t he casing.

To reduce t he risk of damage t o t he casing, ensure t hat t he junk millh a s s t a bi l i z e r p ad s t h a t a r e o f t he s a m e O D a s t h e m i ll h e a d .

Run a st abilizer, wit h an OD equal t o t he size of t he junk mill, direct lyabove t he junk mill.

— U s e a j u n k m i l l t h a t i s d r es s e d w i t hCust omCut ™ carbide insert s.

— U s e a j u n k m i l l t h a t i s d r es s e d w i t h

Cust omCut carbide insert s.

Junk Milling Operations

Junk Milling OperationsJ u n k m i ll s a r e o f te n s a i d t o b e th e t r u e wo r k h or s e s o f d ow n h o le m i l l i n g. U s e j u n k m i l l s t o m i l l a l m o s t an y t h in g i nthe hole, including:

—

—

—

—

—

—

Bailers

Bit cones

Bits

Calipers

Cement

Collapsed casing

—

—

—

—

—

—

D r il l c o ll a rs

Drillpipe

Hangers

Jars

Packers

Reamers of short lengths

—

—

—

—

—

—

Setting tools

Slips

String shots

Subs

Testers

Wash pipe

W h e n t u b ul a r s a r e c e m en t e d i n s id e a n d o u t , t h e j u nk m i l l i s t h e o n l y e f f ec t i v e t o ol ; h o w e ve r, i f t h e t u b u l ar s a r e n o tc o l l a p se d a n d t h e ID i s o p e n , a p i lo t m i l l m i g h t b e a b et t e r o pt i o n . A s k i r te d j u n k m i ll a s s e mb l y o r a s k i rt e d p i l ot m i l la s s e mb l y o f t e n y i e l d s b e t t er r es u l t s.

General Recommendations

For optimal performance when milling loose junk, use a junk mill dressed with crushed tungsten carbide. Under some conditions, operations can be improved by spudding, which pounds the junk onto the bottom, breaks it intosmaller pieces, and positions it for more effective milling.

Do not allow a sliver of junk to lodge next to the mill—indicated by a noticeable increase in torque and pickupdrag. Force the sliver down by spudding the mill.

Pick up the mill and spud the work string periodically to decrease the likelihood of a deep wear pattern developing

on the face of the mill. Spudding forces a new wear pattern to develop so that the mill face wears evenly.

Procedures

The procedures for milling looseand stationary junk, in open or cased hole, are basically thes a m e. T he f e w d i ff e r en c e s a r eshown in Table 6.

I n o p e n ho l e t h e j u n k m i ll i su s u a l l y d re s s e d r ou g h O D s o t h a tit can cut formation in undersized

hole sections; however, in casedh o l e t h e ju n k mi l l i s d r es s eds m o o th O D t o m i n i mi z e d a m a geto the interior surface of thecasing.

M i l li n g i s u s ua l l y b y t o rq u e— n otby weight applied to the junk or fish.





M i l l in g J un k o r F i s h

1 . R u n a t l e a s t o ne b o o t b a s k et ( t w o b o ot b a s k e t s a re r e c o m me n d e d ) d ir e c t ly a b o v e t h e j u n k m il l . B o o t b a sk e t sfor 4 3/4-in. and smaller drill collars are not strong enough for repeated long periods of spudding.

2 . U s e s u ff i c i e nt d r i l l c o l l a r we i g h t fo r m i l l i ng w e i g h ts t o b e a p p l ie d a n d t o o ve r c o me p u m p - of f f o rc e s .

3 . T r ip i n t he h o l e t o w i th i n 3 0 ft ( 9 .1 m ) of t h e j u n k or f i s h.

4 . B r e a k c i r c u la t i o n , a n d t a ke t h e u p a n d d o wn w e i g ht s o f th e w o rk s t r i ng w i t h th e p u m ps o n a n d wi t h t h e pu m p soff.

5 . W h i l e c ir c u l a ti n g , s l ow l y l o we r t h e wo r k s t ri n g w i th o u t ro t a t i ng i t .

6 . Ta g t h e t o p o f t h e j u nk o r f i sh w i th 5 , 0 00 l b ( 2, 2 6 8 kg ) o f d o w n we i g h t .

7 . M a r k t h e pi p e o r k e l l y a t th e t op o f t h e ke l l y bu s h i n g o r r ot a r y t a b l e .

8 . P i c k u p t he w or k s t r i n g 5 t o 1 0 f t ( 1 . 5 t o 3 m ) a bo v e pi c k u p w e i g h t.

9 . W h il e r ot a ti n g th e wo r k s t ri n g, s l ow l y l o we r i t.

Important: Rotary speed is dependent on SFPM for the junk mill OD. Refer to Table 2 (Page 6).

1 0 . Ta g t h e t o p of t h e j u n k o r f i s h , an d b e g i n m il l i n g w i th w e i g h t on t h e m i l l a s s h o w n in Table 3 (Page 6). Setdown on the junk or fish while rotating the work string, and add milling weight to the junk or fish without delay.

11 . M i ll w i th w e ig h t on t h e mi l l a s s ho w n i n Table 3.

Important: Do not apply weight first and then rotate. This sequence can damage the cutting structure face of the junk mill. Do not set down on the fish or junk with a light weight and spin. Spinning in one spot on the junko r f i s h c a n c a us e t h e s t e e l t o w o r k- h a r de n ; a s a r e s u l t, r e s t a rt i n g t o m i l l j u n k o r f i s h c a n b e d i ff i c u l t.

12. After each 3 to 5 ft (0.9 to 1.5 m) of junk or fish milled, pick up the junk mill 10 to 15 ft (3.0 to 4.6 m), and reamthe hole back down to the junk or fish.

1 3 . To s t o p m i l l i ng , s i m p l y p i ck u p t h e j u n k m i l l o f f b o tt o m .





Spudding on Loose Junk

1 . D e t e rm i n e t he t o p o f t h e j u nk , a n d ma r k t he p i p e o r ke l l y a t th e t o p of t h e k el l y b u s h i ng o r r o ta r y t a b l e .

2 . P i ck u p t he w o rk s t ri n g 4 t o 6 ft ( 1 .2 t o 1 .8 m ) a bo v e th e p ic k up w e ig h t.

3 . D r o p t h e wo r k s t r in g , a n d c a t ch i t w i t h t h e b r a ke 1 8 t o 2 0 i n . ( 4 5 7 t o 5 0 8 m m ) a b ov e t h e t o p o f t h e j u nk a t t h emark on the pipe or the kelly. Do not slow down, but catch the string with a sudden stop. For example, pick upthe work string 10 ft (3 m), and drop it 8.5 ft (2.6 m). This step causes the string to stretch and spud the junkon bottom forcefully while the string is still in a state of tension, preventing damage to the string that could beexpected if the string were in compression at the moment of impact.

4 . S p u d t he j u n k t h re e o r f o u r ti m e s , ro t a t in g t h e j u n k mi l l o n e - qu a r t er t u r n e a ch t i m e b e tw e e n d ro p s o r r o ta t i n g

the work string while spudding on the junk.5 . W h i l e r ot a t i n g it s l o w l y, l o w e r th e w o r k st r i n g to t h e t o p o f th e j u n k . Co n t i nu e m i l l i n g on l o o s e j u n k by t o r q ue

r a t h er t h a n b y w e i g h t a p pl i e d t o j u n k .


Junk Mills and Accessories

Weatherford's junk mills, dressed with crushed tungsten carbide or CustomCut™ tungsten carbide inserts, millthrough the toughest drilling materials.

Ordering Information

To ensure delivery of the proper junk mill for your application, include the following information:

Type of mill (bladed, cone buster, or type P)

M il l O D

S m o ot h o r r ou g h m i ll O D

Mill dressed with crushed tungsten carbide or CustomCut tungsten carbide inserts

Size and weight of casing through which the mill is to be run, if available

Top pin connection

—

—

—

—

—

—




© 2 0 0 6 We a th e rfo rd . All rig h ts re s e rv e d .

11Gu id e lin e s fo r Effe c tiv e Millin g 1 s t e d . M a y 2 0 0 6

Bladed Junk Mills

Ap p lica tio n s

—

F e a t u re s , A d v an t a g es a n d B e n e f i t s

—

—

—

—

—

—

—

W e a th e r f or d o f f er s a f u l l l i n e o f s t a nd a r d i ze d b l a d e d j u nk m i l l s , d e s ig n e d t o m i l l a n ytype of junk or debris from the wellbore. These “workhorses” of downhole millingoperations can be dressed either with CustomCut™ tungsten carbide inserts, for stationary fish or junk, or with crushed tungsten carbide, for loose fish or junk. Largecirculation ports and watercourses improve fluids circulation for cooling and facilitatecuttings removal. Bladed junk mills can be ordered for any length and OD to meet thes p e c i fi c r e q u ir e m e nt s o f t h e j o b .

SMWeatherford's bladed junk mills are products of the company's MillSmarttechnology—an engineered approach to milling that encompasses a wide range of

p r o v e n p r o du c t s , s e rv i c e s , a n d t e c h ni c a l r e s o ur c e s , d e v el o p e d a n d r e f i n ed b y t h eworld's largest and most experienced provider of milling and fishing services.

Milling almost anything in the wellbore, including, but not limited to: bit cones, bits,cement, packers, squeeze tools, perforating guns, drillpipe, tool joints, reamers,and reamer blades

Rugged, durable construction extends milling time per trip for maximized millingefficiency.

Crushed tungsten carbide dressing, used for milling loose fish or junk, extends thelife of the mill.

CustomCut tungsten carbide inserts, used for milling stationary fish or junk,improve penetration rates and milling footage.

E x t ra - l o n g mi l l h e a d s m i n i mi z e r i s k o f ca s i n g d am a g e .

Large circulation ports and watercourses improve cooling during milling operationsa n d p r o v i d e b e t te r f l u i d s c i r c u la t i o n a n d c u t t i ng s r e m o v a l f o r o p t i m al m i l l i n gefficiency.

Mill-head design customization capability provides milling solutions for the fullrange of open hole, casing, and tubing sizes and weights.

S m o o th O D r e d u ce s r i s k o f c a si n g d a ma g e i n c as e d - h ol e w e l lb o r e s .





Leng th OD

(i n. /mm ) (in. ) (in. /mm ) (i n./mm ) (lb/kg )

3-1/ 2 t o 4-1/ 2

88. 9 t o 114. 3 2-3/ 8

12

305

3-1/ 8

79. 4

45

21

4-1/ 2 t o 5-1/ 2

114. 3 t o 139. 7 2-7/ 8

12

305

3-3/ 4

95. 3

62

28

5-1/ 2 t o 6

139. 7 t o 152. 43-1/ 2

12

305

4-1/ 4

108. 0

95

43

5-3/ 4 t o 7-1/ 2

146. 1 t o 190. 5 3-1/ 2

12

305

4-3/ 4

120. 7

105

48

7-1/ 2 t o 9

190. 5 t o 228. 6 4-1/ 2

12

305

5-3/ 4

146. 1

180

82

9-1/ 2 t o 12-1/ 4

241. 3 t o 311. 2 6-5/ 8

12

305

7-3/ 4

196. 9

350

159

13 t o 15

330. 2 t o 381. 0 6 - 5 / 8 o r 7 - 5 / 8

12

305

7 - 3 / 4 o r 9 - 1 / 2

241. 3 or 196. 9

500

227

17 t o 17-1/ 2

431. 8 t o 444. 5 6 - 5 / 8 o r 7 - 5 / 8

12

305

7 - 3 / 4 o r 9 - 1 / 2

241. 3 or 196. 9

625

283

18-1/ 2 t o 26

469. 9 t o 660. 46 - 5 / 8 o r 7 - 5 / 8

12

305

7 - 3 / 4 o r 9 - 1 / 2

241. 3 or 196. 9

1, 200

544

S tandard Fi shi ng Neck Approxi mate

Wei ght

S tandard Top P i n

Connecti on (AP I Reg. )

S tandard Junk

M i l l OD

Table 7—S pecifications for Bladed Junk Mills


Op tio n s

—

—

—

—

—

—

—

Concave, convex, and flat-bottom designs available

Dressed with CustomCut™ tungsten carbide inserts for stationary fish or junk

Dressed with crushed tungsten carbide for loose fish or junk

Various lengths of fishing necks, stabilizers, and combination stabilizer-fishing necks available

S m o o th O D f o r c a s e d -h o l e w e l l b or e s

R o u g h O D f o r o p e n ho l e w e l l b o re s

C a n b e o r d e r ed f o r a n y l e n g th a n d O D t o m e e t j o b - sp e c i f ic r e q u i r e me n t s





Table 8—S pecifications for Flat-Bottom (Cone-Buster) Mills

S tandard Top

P i n Connecti on

(API Reg.)

(i n. ) (mm) (i n.) (i n.) (mm) (i n. ) (mm) (l b) (kg)

3-1/ 2 t o 4-1/ 2 88. 90 t o 114. 30 2-3/8 3-1/ 8 79. 37 45 20. 4

4-1/ 2 t o 5-1/ 2 114. 30 t o 139. 70 2-7/8 3-3/ 4 95. 25 62 28. 1

5-1/ 2 t o 6 139. 70 t o 152. 4 4-1/ 4 107. 95 95 43. 1

5-3/ 4 t o 7-1/ 2 146. 05 t o 190. 50 4-3/ 4 120. 65 105 47. 6

7-1/ 2 t o 9 190. 50 t o 228. 60 4-1/2 5-3/ 4 146. 05 180 81. 7

9-1/ 2 t o 12-1/ 4 241. 30 t o 311. 15 6-5/8 7-3/ 4 196. 85 350 158. 8

13 t o 15 330. 20 t o 381. 00 500 226. 8

17 t o 17-1/ 2 431. 80 t o 444. 50 625 283. 5

18-1/ 2 t o 26 469. 90 t o 660. 40 1, 200 544. 3

S tandard

Fl at Bottom (Cone Buster)

M i l l OD

Approxi mate

Wei ght

S tandard

Fi shneck

Length

12 305

196. 85 or

241. 30

S tandard

Fi shneck

Di ameter

6-5/ 8 or 7-5/ 8

3-1/ 2

7-3/ 4

or 9-1/ 2


Flat-Bottom (Cone-Buster) Mills

Weatherford's cone-buster junk mills are designed for use in milling and spuddingoperations to clean up loose junk in wellbores. The spudding action pounds loose

junk onto the bottom of the wellbore, breaking the junk into smaller pieces andpositioning it for more effective milling. Cone-buster junk mills can be ordered for any OD to meet job-specific requirements.


!

!

!

!

Large circulation ports and watercourses enable improved fluid circulation andcutting removal, saving time.

Slightly concave mill-head bottom restricts fish to the center of the mill head for better access control.

M i l l s c a n b e d r e s s ed s m o o t h O D f o r c a s e d- h o l e w e l l bo r e s a n d r o u gh O D f o r openhole wellbores for greater versatility.

M i l l i n g s o lu t i o n s c o v e r t h e f u ll r a n g e o f c a s i ng a n d t u b i n g s i z e s a n d w e i gh t s .






Ty pe P J unk M i l l

W e a th e r f or d ' s t y p e P j u n k m i l l i s u s e d f o r m i l l i n g j u n k a n d d e br i s f r o m t h ewellbore; but its durability also gives it the longer life needed for millingcemented tubulars. An offset center prevents coring of the mill during millingo p e r a ti o n s . T h e s p e c i al d e e p - V d e s i g n m a xi m i z e s f l u i ds c i r c u l a ti o n t o p r o v i d eb e t t er c o o l in g a n d m o r e e f f ic i e n t r e m o va l o f c u tt i n g s . T h e t yp e P j u n k m i l l c a nbe ordered in any length and OD to meet job-specific requirements. The typeP j u n k m il l i s u s u a ll y d r e s se d w i t h c r u s he d t u n gs t e n c ar b i d e bu t u n d er special applications is dressed with CustomCut™ inserts.

SMW e a th e r f or d ' s t y p e P j u n k m i l l i s a p r o d uc t o f t h e co m p a ny ' s Mi l l S ma r t

technology—an engineered approach to milling that encompasses a widerange of proven products, services, and technical resources, developed andrefined by the world's largest and most experienced provider of milling andfishing services.

Milling junk, debris, and cemented tubulars

Offset center prevents coring of the mill during milling operations,extending mill life and saving equipment costs.

D e e p -V d e s i g n p r o v i de s a l a r ge r c i rc u l a ti n g t o ta l f l o w a r e a fo r b e tt e r c oo l i n gof the carbide cutting structure and more efficient cuttings removal.

The mill can be dressed for open or cased hole to suit job-specific requirements.

Ap p lica tio n s

—

Fe a tu re s, Ad va n ta g e s a n d Be n e fits

—

—

—





Length OD

(i n. /mm ) (lb/kg ) (i n./mm ) (in ./mm )

3-1/ 2 t o 4-1/ 2

88. 9 t o 114. 32 3/ 8-in. Reg

45

20

12

304. 8

3-1/ 8

79. 4

4-1/ 2 t o 5-1/ 2

114. 3 t o 139. 7 2 7/ 8-in. Reg

62

28

12

304. 8

3-3/ 4

95. 3

5-1/ 2 t o 6

139. 7 t o 152. 4

3 1/ 2-in. Reg95

43

12

304. 8

4-1/ 4

108. 0 5-3/ 4 t o 7-1/ 2

146. 1 t o 190. 5 3 1/ 2-in. Reg

105

48

12

304. 8

4-3/ 4

120. 7

7-1/ 2 t o 9

190. 5 t o 228. 6 4 1/ 2-in. Reg

180

82

12

304. 8

5-3/ 4

146. 1

9-1/ 2 t o 12-1/ 4

241. 3 t o 311. 2 6 5/ 8-in. Reg

350

159

12

304. 8

7-3/ 4

196. 9

13 t o 15

330. 2 t o 381. 0 6 5/ 8- or 7 5/ 8-in. Reg

500

227

12

304. 8

7 - 3 / 4 o r 9 - 1 / 2

241. 3 or 196. 9

17 t o 17-1/ 2

431. 8 t o 444. 5 6 5/ 8- or 7 5/ 8-in. Reg

625

284

12

304. 8

7 - 3 / 4 o r 9 - 1 / 2

241. 3 or 196. 9

18-1/ 2 t o 26

469. 9 t o 660. 46 5/ 8- or 7 5/ 8-in. Reg

1, 200

544

12

304. 8

7 - 3 / 4 o r 9 - 1 / 2

241. 3 or 196. 9

M i l l

S tandard Fi shi ng Neck

B od y O D S tandard Top P i n

Connecti on

Approxi mate

S hi ppi ng Wei ght

Ta b l e 9 — S pe c i f ic a t i on s f o r Ty p e P J u n k M i l l





(in .) (mm) (in .) (mm) (in .) (mm) (in .) (mm) (in .) (mm) (in .) (mm) (in .) (mm) (in .) (mm) (lb ) (kg)

4- 1/8 to 4- 1/2 104.8 to 114.3 3-11/16 93.7 2- 3/8 60.3 33 838 3- 1/8 79.4 2 50.8 1 25.4 10- 1/2 266.7 50 23

2- 3/8 60.3 33 838 3- 1/2 88.9 2 50.8 62 28 2- 7/8 73.0 37 940 4 101.6 2- 1/2 63.5 66 30

5 to 5- 3/4 127.0 to 146.0 4- 1/2 114.3 2- 7/8 73.0 37 940 4 101.6 2- 1/2 63.5 1 25.4 10- 1/2 266.7 91 41

5- 7/8 to 6- 3/8 149.2 to 161.9 5 127.0 4- 5/8 117.4 3- 1/4 82.5 120 54

6- 1/2 to 7- 3/8 165.1 to 187.3 5- 1/2 139.7 5 127.0 3- 1/4 82.5 144 65

6- 1/2 165.1 261 118

6- 5/8 168.3 270 122

6- 3/4 171.5 280 127

7 177.8 298 135

8- 1/2 215.9 438 199

8- 5/8 219.1 451 205

11-1/2 to 13 292.1 to 330.2 9- 5/8 244.5 8- 1/2 215.9 529 240

10- 3/4 273.1 9- 5/8 244.5 806 366

12- 3/4 323.9 11 279.4 1,065 483

1- 1/2 38.1 10- 1/2 266.7

1 25.4 10- 1/2 266.7

266.7

7- 1/2 190.5 2- 13/16 71.4 17 431.8 1,295

7- 1/2 190.5 5- 1/2

50.8 10- 1/2 266.7

168.3 50 1,270 139.7 3 76.2 10- 1/2

165.1 4- 1/4 107.9 2

6- 5/8

7- 5/8

88.9 38

114.3 48

193.7 5114 to 17- 1/2 355.6 to 444.5

244.5 to 288.9

4

8- 5/8 to 9- 5/8

7- 1/2 to 8- 1/2

4- 5/8 to 4- 7/8

9- 5/8 to 11- 3/8

Ap p ro xim ate

Weight

117.5 to 123.8

190.5 to 215.9

219.1 to 244.5

93.7

3- 1/2

4- 1/2

965

1,219 6- 1/2

Fishneck

Diam eter

Bo d y Diam eter

U nd er S le ev e B or e Di am et er S le ev e Le ng thRecommended Hole Size

Stan d ard Skirt

Diam eter

Top and Bottom

C o nn e ct i on s O v er a ll L e ng t h

Table 10—S pecifications for S crew-on-S kirt Boot Basket


Screw-on-Skirt Boot Basket

The Weatherford screw-on-skirt boot basket catches debris and junk that is too heavy tocirculate out of the wellbore. Designed for use in the drill collar string, just above a millingtool or drill bit, the boot basket consists of an oversized skirt screwed onto a steelmandrel with a left-hand thread. The screw-on skirt allows easy access to the mandrel for inspection of both skirt and mandrel.

Except in highly deviated holes, Weatherford recommends running two boot baskets intandem to decrease the likelihood of junk bypassing a single basket.

Fe a tu re s, Ad va n ta g e s a n d Be n e fits! Tandem operation of boot baskets increases junk-catching capacity for greater

o p e r at i o n a l e f f ic i e n c y.

Removable skirt enables quick and easy inspection of skirt and mandrel for moret h o r ou g h t o o l i n s p e ct i o n a n d m a i n te n a n c e.

Integral skirt support ribs eliminate the need for welding the skirt or the mandrel,enhancing basket reliability.

S t a n da r d b o x - do w n , p i n -u p c o n n e c ti o n s e n a b l e r u nn i n g a b o v e a m i l l o r d r i l l b i t .

Drain holes in the skirt enable the wellbore fluids to drain after the boot basket isbrought out of the hole to surface.

!

!

!

!





Pilot Milling Operations


Pilot Milling OperationsPilot mills have either a diamond point, with a pilot, or a lower connection below the milling blades. Use pilot millson the following:

—

—

Casing

D r i l l pi p e a n d d r il l c o l l a rs

— Liners, hangers, and adaptors

T h e p i l o t o f t h e m il l c a n b e d r e s se d t o m i l l a n y j u n k e n co u n t e re d i n s i d e t h e f is h .


S e l e c t a pi l o t m i l l w i t h a b l ad e O D t h a t i s 1 /4 i n . l a r g er t h a n t he O D o f t h e t oo l j o i n t o r co u p l i n g of t h e f i s h mi l l e d .

T h e p i l o t OD s h o u l d be t h e s a m e as t h e d r i ft I D o f t h e f i sh .

T h e o p t i ma l s p e e d a n d w ei g h t f o r r un n i n g a p i l o t m i ll w i l l v a r y f ro m j o b t o j o b , e v e n i n t h e s am e w e l l . D if f e re n tconditions may require different rotary speeds and weights. In the absence of experience, start with a speed of 80 to 100 RPM and a tool weight of 2,000 to 6,000 lb (907 to 2,722 kg). Adjust the speed and weight to obtain thebest results.

To mill a liner or casing that is perforated, damaged with a spear, or collapsed, use 60 RPM and 2,000 lb (907 kg)of weight or less.

A sudden drop in milling rate during the milling of swaged casing may be caused by a loose ring of steel formed ata joint or weld, which turns with the pilot mill. Gently spud the mill to break up the ring and help position it for milling.

If cutting stops during the milling of wash pipe, casing, or liner, without a noticeable increase in torque, the fish

could be turning. If so, pull the mill, and retrieve the fish with a spear.

Liners, Hangers and Adaptors

Liner hangers can be milled efficiently, eliminating the need for inside cuts and the running of spears or jars for recoveries. For most liner milling jobs, first use a pilot mill to mill the liner hanger or adaptor and then the liner;however, if the ID of the hanger or adaptor is smaller than the ID of the liner, use a junk mill, then mill the liner witha p i l o t m i l l . T he p i l o t m i l l i s p r e f er r e d i f h a r d c em e n t i s b e h in d t h e l i n e r o r i f t h e h a ng e r h a s n u m er o u s b o w s p r i ng sa n d s l i p s . S e l ec t a p i l o t m i l l w i t h b l a de s o f t h e c o r r e c t O D f o r t h e p i p e c o u p l in g s .

Wash Pipe

T h e p i l o t m i ll i s t h e m o s t e ff i c i e nt t o o l f o r m i l li n g s t u c k w as h p i p e ; h o we v e r, i f d r i l l p i pe o r d r i l l c o l l a rs a r e i n s i d e t hew a s h p i p e, f i r s t f i sh t h e m o u t o r m i l l t h e m w it h a j u n k m i l l o r s m a l l er p i l o t m i l l .

—

—

Tubing

Wash pipe

Application-Specific Recommendations





Drillpipe and Drill Collars

Drillpipe and drill collars are milled with pilot mills if the ID is open. If the pipe is cemented inside the casing,particularly in deviated holes, the pipe is probably lying to one side, eccentric to the casing. This position usuallymakes the job difficult with a pilot mill; but using a smaller-OD pilot will allow the pilot mill to move away from thecasing ID. Otherwise, a full-gauge junk mill is recommended. A pilot mill performs reasonably on collars if the cuttingsare removed as milling progresses. If the cuttings tend to fall into the ID and plug it, use a full-gauge junk mill.

Casing and Tubing

U s e a p i lo t m i l l t o m i l l c a s i n g a n d t u bi n g a s y ou w o u l d t o m i l l w a s h p ip e .

Procedure

To mill J-55 or K-55 , use a weight of 4,000 to 6,000 lb (1,814 to 2,722 kg) and a speed of 125 RPM., use a weight of 8,000 to 10,000 lb (3,629 to 4,536 kg)

If the is surrounded by hard cement, or if the openhole diameter is the same as or less than the blade ODof the mill, more weight may be needed to drill cement or the formation in addition to the fish.

1 . L o we r th e mi l l t o ab o ut 5 ft ( 1. 5 m) a bo v e t h e f i sh .

2 . S e t th e b r ak e , ro t at e , a nd b r e ak c i r cu l at i on .

3 . S l ow l y i n c re a se t h e r o ta t io n t o 12 5 RP M .

4 . Ta k e p a ra m e t er s o f u p a n d d o w n we i g h t s. T h i s s t e p te l l s y o u th e n e u tr a l w e i g h t o f t h e st r i n g an d e n a b le s y o u

to note the normal torque in the string. By noting the torque in the string when the pilot enters the fish, youcan determine whether the pilot entered correctly.

5 . S l o w ly l o w e r t h e s tr i n g u n ti l t h e m i ll i n g b l a de s c o n ta c t t h e t o p o f th e f i s h; t h e n be g i n m i ll i n g .

Important: When working below the casing shoe, ream the hole up and down after every 20 to 30 ft(6 to 9 m) of fish milled to clean out any cuttings accumulated at the shoe. Periodic reaming to ensure cuttingr e m o va l i s a l s o a g oo d p r a ct i c e i n ho l e s w it h d r i ft a n g l es o f 3 0 º o r m o re .

6 . C o n t in u e m i l l i ng a t a n e v e n r a t e , w it h o u t i n te r r u pt i o n . D o n ot r e w e i gh t h e s t r i n g a t s ho r t i n t e rv a l s , b u t k ee p a neven rate of string weight on the pilot mill while milling.

materialFor N-80 and P-110 material and a speed of 125 RPM.Refer to Tables 2 and 3 (Page 6) for calculation of surface feet per minute (SFPM) and weight on mill,respectively.

casing

Pilot Mills

Weatherford's pilot mills, dressed with CustomCut™ carbide inserts, are recommended for millingcasing, tubing, wash pipe, drillpipe, drill collars, crossover swages, liners, hangers, and adaptors.tungsten


Size and weight of casing to be milled

Top pin connection

O D a n d I D o f tu b ul a rs t o b e mi l l ed

To ensure delivery of the proper pilot mill for your application, include the following information:

Type of mill (diamond point or lower-connection type)—

—

—

—





T M

C us t om C ut P i l ot M i l l ( D i am ond P oi nt)

Weatherford's CustomCut d i a m o nd - p o i nt p i l ot m i ll c a n be u s e d t o mi l l a f u ll r a n g e o f tubular products. The mill consists of a leading stabilizer (the pilot), which is sized for theID of the tubular, and a major diameter section, sized at least 1/4 in. larger than thecoupling OD. The CustomCut diamond-point mill can be dressed with crushed carbide or w i t h o ne o f t h e f a m i l y o f CustomCut inserts, as appropriate for the application.

Weatherford's diamond point CustomCut p i l o t m i ll i s a p r o d u c t o f t he c o m p a ny ' sSM

M i l l S ma r t t e c h n ol o g y — an e n g i n ee r e d a pp r o a ch t o m i l li n g t h at e n c o mp a s s e s a w i d erange of proven products, services, and technical resources, developed and refined bythe world's largest and most experienced provider of milling and fishing services.

The CustomCut diamond-point pilot mill is used for milling tubing, casing, liner hangers,liners, drillpipe, drill collars, wash pipe, or perforated liners.

CustomCut inserts that are specifically tailored to the operation and to the capabilitiesof the surface equipment. For surface equipment or fluids with limited capabilities,CustomCut 100 series inserts produce small, lightweight cuttings. For premium fluidsand high-volume surface equipment, CustomCut 2 0 0 a n d 30 0 se r i e s i n s e r ts m a x i mi z em i l l i n g r at e s a n d t h e l i f e o f t he p i l o t m i l l .

Ap p lica tio n s


—

—

—

—

—

— Full OD ensures that collars are milled in the same operation, eliminating creation of junk in the wellbore and extending the life of the pilot mill.

Optimized alignment of CustomCut insert to proper cutting angle produces smaller cuttings for better wellbore cleaning and longer life of the mill.

Longer blades extend downhole cutting time and the life of the mill.

Insert selection capability optimizes the mill design to the composition of the tubular being milled and the capabilities of surface facilities, resulting in higher rates of penetration.





Casing Si ze App li catio ns Inserts

(in. ) (in. ) (mm) 100C

4-1/ 2 5.250 133. 350 101C

5 5.813 147. 650 200M

5-1/ 2 6.300 160. 020 201M

6 6.875 174. 625 202M

6-5/ 8 7.640 194. 056 203M7 7.916 201. 066 300M

7-5/ 8 8.750 222. 250 301M

8-5/ 8 9.875 250. 825 302M

9-5/ 8 10. 875 276. 225 303M

10-3/4 12. 000 304. 800 304M

11-3/4 13. 000 330. 200

13-3/8 14. 625 371. 475

Surf ace equipm ent or

f l u i d s w i t h l i m i t e d c a p a b i li t i e s

High-volum e surf ace

equipm ent and prem ium f luids

6 5/ 8-in.

Reg.

3 1/ 2-in.

Reg.

Top P i n

Connecti on

M i l l Bl ade OD

4 1/ 2-in.

Reg.

Table 11—S pecifications for the CustomCut P ilot Mill (Diamond P oint)

Table 12—S election Guide for CustomCut Inserts

(Diamond-P oint P ilot Mill)




21 © 2 0 0 6 We a th e rfo rd . All rig h ts re s e rv e d .


T M

C us tom C ut P i l ot Mi l l ( Low e r-C onnec t i on Ty pe )

Weatherford's CustomCut l o w e r- c o n n ec t i o n ty p e p i l o t mi l l c a n b e u s e d to m i l l afull range of tubular products. This versatile tool is run above a taper mill; but ano p t i on a l s t a b i li z e r c a n a l s o b e r un w i t h t h e t a p er m i l l a s t h e p i l o t, w h i c h i s s i z edf o r t he I D o f t h e tu b u l a r. I n a d di t i o n , d r i l l c o l l a rs c a n b e ru n b e l o w t h e m i ll f o r milling weight in shallow-well applications. The major diameter section of thelower-connection type pilot mill is sized at least 1/4 in. larger than the couplingOD, eliminating creation of junk in the wellbore and extending the life of the pilotmill. The CustomCut lower-connection type pilot mill is dressed with one of thefamily of CustomCut inserts, as appropriate for the application.

Weatherford's lower-connection type CustomCut p i l o t m il l i s a p r o d u ct o f t h eSM

c o m p an y ' s M i l l S ma r t t e c h no l o g y —a n e ng i n e e re d a pp r o a c h t o m il l i n g t h a tencompasses a wide range of proven products, services, and technicalresources, developed and refined by the world's largest and most experiencedprovider of milling and fishing services.

The CustomCut lower-connection type pilot mill is used for milling tubing,casing, liner hangers, liners, drillpipe, drill collars, wash pipe, or perforatedliners.

CustomCut inserts are specifically tailored to the operation and to thecapabilities of the surface equipment. For surface equipment or fluids with

limited capabilities, CustomCut 100 series inserts produce small, lightweightcuttings. For premium fluids and high-volume surface equipment, CustomCut 200 and 300 series inserts maximize milling rates and the life of the pilot mill.

Ap p lica tio n s

F e a t ur e s , A d v an t a g e s a n d B e n e f i t s

—

—

—

—

—

—

— F u l l O D e n s u re s t h a t c o ll a r s a r e mi l l e d i n t he s a m e o p er a t i o n, e l i m i na t i n gcreation of junk in the wellbore and extending the life of the pilot mill.

Optimized alignment of CustomCut insert to proper cutting angle producessmaller cuttings for better wellbore cleaning and longer life of the mill.

Longer blades extend downhole cutting time and the life of the mill.

Pin-down design facilitates the optimal, operation-specific bottomhole assembly

to increase pilot milling success.

Insert selection capability optimizes the mill design to the composition of thetubular being milled and the capabilities of surface facilities, resulting in higher rates of penetration.





Casi ng S iz e App li catio ns Inserts

(in. ) (in .) (mm) 100C

4-1/2 5. 250 133. 350 101C

5 5. 813 147. 650 200M

5-1/2 6. 300 160. 020 201M

6 6. 875 174. 625 202M

6-5/8 7. 640 194. 056 203M7 7. 916 201. 066 300M

7-5/8 8. 750 222. 250 301M

8-5/8 9. 875 250. 825 302M

9-5/8 10. 875 276. 225 303M

10-3/ 4 12. 000 304. 800 304M

11-3/ 4 13. 000 330. 200

13-3/ 8 14. 625 371. 475

Surf ace equipm ent or

f luids wit h lim it ed capabilit ies

High-volum e surf ace

equipm ent and prem ium f luids

6 5/ 8-in.

Reg.

3 1/ 2-in.

Reg.

Top Box

Connecti on

M i l l Bl ade OD

4 1/ 2-in.

Reg.

Table 14—S election Guide for CustomCut Inserts

(Lower-Connection Type P ilot Mill)

Table 13—S pecifications for the CustomCut P ilot Mill (Lower-Connection Type)





Taper Milling Operations


Taper Milling OperationsUse taper mills to eliminate restrictions or to mill through pinched, collapsed casing. The mills have either atapered or a short, blunt nose that serves as a guide. The type of restriction type dictates which type of taper millto use.

Weatherford's s t a n da r d ta p e r m i l l is designed for milling through restrictions. The spiral blades and pointednose, dressed with crushed tungsten carbide, make this mill ideal for reaming collapsed casing and liners,cleaning permanent whipstock windows, milling through jagged or split guide shoes, and enlarging restrictionsthrough retainers and adaptors.

The b l u n t- n o s e ta p e r m i l l is effective in rough conditions that can cause longer, tapered mills to break. Theb l u n t -n o s e m i l l g e n e ra t e s l e s s t o rq u e t h a n a c o n v e n ti o n a l t a p e r m i l l a s a r e s u l t o f i t s s h o r t er s e c t i o n . W i th t h elower torque, the blunt-nose mill can be run with more weight, when required, for operations such as milling plate

or solid junk.


The torque encountered governs milling speed. To overcome torque challenges, do not exceed 75 RPM.

Do not rotate a taper mill resting on a fish. Doing so can further damage the fish. Enter the fish with a rotaryspeed of 75 RPM or less.

Use less weight when running a taper mill than a junk or pilot mill. After entering the fish, slowly increase the toolweight to 1,000 to 2,000 lb (454 to 907 kg), and avoid torque increase.

Procedures

The procedure for using a taper mill varies, depending on the application.

Cleaning a Whipstock Window

U s e a t a p er m i l l o f t h e s am e d i a m et e r a s t he l a r g e st m i l l u s e d t o m il l t h e w i n do w o r s l i g ht l y l a r ge r t h a n th e b i tused.

1 . R u n th e t ap e r mi l l i n to t h e h o le t o wi t hi n 5 f t ( 1 .5 m ) of t h e w i nd o w t o p.

2 . S t a rt t h e r o ta r y t a bl e , a n d r ot a t e a t a pp r o x im a t e l y 40 R P M d o wn t o t h e w hi p s t o ck f a c e .

3 . K e e p t he w e i g h t un d e r 1 ,0 0 0 l b ( 4 5 4 kg ) . E x ce s s i ve w e i g h t ca n c a u s e th e t a p e r mi l l t o s l i p o u t of t h e w i nd o wprematurely.

4 . R o t a te s l o w l y wi t h a l i g h t we i g h t d o wn t h e f u l l l e n g t h of t h e w h ip s t o c k fa c e . D o n ot t r y t o ma k e h o l e w it h t h etool.

5 . To c l ea n a l l t h e ro u g h ed g e s , r e p e at S te p s 2 t h r o ug h 4 s e v e ra l t i m e s, u n ti l t h e mi l l r u n s s m o o th l y fo r t he f u lllength of the whipstock.




Reaming Collapsed Casing

1 . D e t e rm i n e t h e a p pr o x i ma t e d i a me t e r o f t h e c o ll a p s e d c as i n g b y p a s s in g a n i m p r e ss i o n b l o c k o r b i t th r o u g hthe collapsed interval. Do not use a taper mill if the collapsed interval has passed the center. (See Step 4.)

2 . U s e a t a p e r m i l l t h a t i s a b ou t 1 /4 i n . l a r g e r t h a n t h e mi n i m u m I D o f t he c o ll a p s e d s e c t io n , an d m il l t h ec o l l a p se d i n t er v a l b y s t a g e s. I f t he c o l l a ps e i s s i g ni f i c a nt , u s e m i l l s o f s e v e ra l d i f fe r e n t si z e s t o b r i ng t h e I D o f the pipe to the full gauge and minimize any sidetracking tendency.

Important: Use a string mill if any danger of sidetracking exists. The casing conditions govern the length anddiameter of the mill. If used, the tool only reams.

3 . M i l l a t a ta b l e s pe e d o f a p p r o xi m a t el y 5 0 RP M . T h e t or q u e en c o u n te r e d go v e r n s t h e mi l l i n g we i g h t —u s u a l ly

2,000 to 3,000 lb (907 to 1,361 kg).4 . I f t h e co l l a p se i s s i g ni f i c a nt , t h e lo w e r po r t i o n o f t h e co l l a p se d i n t e rv a l m a y a c t a s a wh i p s t oc k . Th e t a p er m i l l

may cut through the upper portion of the interval and be deflected into the formation by the lower section of the damaged casing. Run a stabilizer and rigid hookup with a junk mill. Use a light weight with a table speedof about 125 RPM to mill the collapsed portion and enter the undamaged casing below. Step 2 suggestsanother approach if an opening is large enough to admit tubing or a macaroni string through the collapsedinterval.

Enlarging Restrictions through Retainers and Adaptors

U s e a t a p e r m i ll w i t h a d i a me t e r e q u al t o t h e d e s i re d e n l a r ge m e n t, u s u a l l y t he d r i f t I D o f t h e s t r i ng .

1 . M i l l t h r o ug h t h e r e st r i c ti o n a t a p p ro x i m at e l y 7 0 R PM , w i th t h e w e i gh t f r o m 2, 0 0 0 t o 6 ,0 0 0 l b ( 9 0 7 to 2 , 7 2 2 k g) .

The torque governs the speed and weight. If the torque is high, reduce the speed and weight until the millturns freely.

2 . I n cr e as e t he s p ee d t o 8 0 t o 10 0 RP M . R o ta t e up a n d do w n th r ou g h th e i nt e rv a l s e ve r al t i me s u n ti l i t i s s m oo t hand free.

Reaming Guide Shoes

In some cases, the bull plug on the bottom of liners or casing may be jagged or split so that the drilling stringhangs as it is pulled out of the hole. This condition can usually be remedied by reaming through the guide shoewith a taper mill. Use the procedure in “Enlarging Restrictions through Retainers and Adaptors.”






Ta p er M i ll s

W e a th e r f or d ' s t a p e r m i l l s a r e a v ai l a b l e i n s t a n da r d s i ze s o r c an b e s p e ci a l o r d e re d t o a n y l e n g t h a n d O D t o m e et job-specific requirements.


To ensure delivery of the proper taper mill for your application, include the following information:

Type of taper mill (standard or blunt-nose)

Ta p e r m i l l O DSmooth or rough OD


Top pin connection

—

—

—

—

—





Ta p er M i ll s

Weatherford's taper mills are used to mill out restrictions in collapsed casing andliner sections, mill through jagged or split guide shoes, enlarge restrictionsthrough retainers and adaptors, and de-burr whipstock windows.

The lower taper section guides the mill into the collapsed section. Then theslightly spiraled blades, dressed with crushed tungsten carbide, mill away theu n d e rs i z e d s e ct i o n t o f u l l t a p e r m il l d i a m e te r. T h e f u l l -b o r e I D i m p r ov e s f l u i d scirculation for cooling and facilitates cuttings removal.

Taper mills are available in standard sizes or can be special ordered to anylength and OD to meet the specific requirements of the job.

SMWeatherford's taper mills are products of the company's MillSmarttechnology—an engineered approach to milling that encompasses a wide rangeof proven products, services, and technical resources, developed and refined bythe world's largest and most experienced provider of milling and fishing services.

C r u sh e d t u n g s te n c a r b i d e -d r e s se d b l a d e s m i l l t h e s e c t i on t o f u l l t a p e r m i l ldiameter. Full-bore ID improves better fluids circulation, cooling during milling,cuttings removal, and overall milling efficiency.

Design customization capability, including length, OD size, and smooth- or r o u g h- O D o p t i on , p r o v i d es s o l u t i o ns f o r t h e f u l l r a n g e o f c a s in g a n d t u b i n gsizes and weights.

Length and OD can be customized to suit job-specific requirements.

The mill can be dressed with a smooth or rough OD, as required.

Crushed tungsten carbide-dressed blades are standard. CustomCut™ insertscan be added to retain the gauge OD of the mill.

Ap p lica tio n s

—

—

—

F e a t ur e s , A d v an t a g e s a n d B e n e f i t s

—

—

Op tio n s

—

—

—

— M i l l i ng o u t r e s t r i ct i o n s i n c o l l a p s e d c a si n g a n d l i n e r s e c t io n s o f a n y s i z e a n dweight

Milling through jagged or split guide shoes

Enlarging restrictions through retainers and adaptors

D e - bu r r i n g w h i p s t o ck w i n d o ws





Len gth OD

(i n. /mm ) (in. ) (in. /mm ) (in. /mm ) (l b/kg )

3-1/ 2 t o 4-1/ 2

88. 9 t o 114. 32-3/ 8

12

304. 8

3-1/ 8

79. 4

45

20

4-1/ 2 t o 5-1/ 2

114. 3 t o 139. 7 2-7/ 8

12

304. 8

3-3/ 4

95. 3

62

28

5-1/ 2 t o 6

139. 7 t o 152. 43-1/ 2

12

304. 8

4-1/ 4

108. 0

95

43

5-3/ 4 t o 7-1/ 2146. 1 t o 190. 5

3-1/ 2 12304. 8

4-3/ 4120. 7

10548

7-1/ 2 t o 9

190. 5 t o 228. 6 4-1/ 2

12

304. 8

5-3/ 4

146. 1

180

82

9-1/ 2 t o 12-1/ 4

241. 3 t o 311. 2 6-5/ 8

12

304. 8

7-3/ 4

196. 9

350

159

13 t o 15

330. 2 t o 381. 0 6 - 5 / 8 o r 7 - 5 / 8

12

304. 8

7 - 3 / 4 o r 9 - 1 / 2

241. 3 or 196. 9

500

227

17 t o 17-1/ 2

431. 8 t o 444. 5 6 - 5 / 8 o r 7 - 5 / 8

12

304. 8

7 - 3 / 4 o r 9 - 1 / 2

241. 3 or 196. 9

625

283

18-1/ 2 t o 26

469. 9 t o 660. 46 - 5 / 8 o r 7 - 5 / 8

12

304. 8

7 - 3 / 4 o r 9 - 1 / 2

241. 3 or 196. 9

1, 200

544

S tandard Fi shi ng NeckS tandard Taper

M i l l OD

S tandard Top P i n


Approxi mate

Wei ght

Ta b l e 1 5 — S p e ci f i c at i o n s f o r Ta p e r M i l ls





Watermelon/String Milling Operations

Use watermelon/string mills to mill collapsed areas in casing and liners, eliminate key seats and doglegs, andextend whipstock windows. Multiple watermelon/string mills can be run throughout the drillstring, as required.


Watermelon/String Mills

W e a th e r f or d ' s w a t er m e l o n/ s t ri n g m i l l s a r e a v a i l ab l e i n s t a n d a rd s i z e s o r c a n b e s p e c i a l o r d e re d t o a n y l e n g t h a n dOD to meet job-specific requirements.


To ensure delivery of the proper watermelon/string mill for your application, include the following information:

Type of mill (watermelon or string)

M il l O D

Smooth or rough OD

Size and weight of casing to be run through, if available

Connection sizes

—

—

—

—

—




Watermelon/String Mills

Weatherford's watermelon/string mills are excellent for milling out collapsed areas incasing and liners, eliminating key seats and doglegs, and extending whipstock windows.Multiple watermelon/string mills can be run throughout the drillstring.

Slightly spiraled blades, dressed with crushed tungsten carbide, are held to close ODtolerances for maximum opening in the casing or key seat. The blades are tapered top tobottom to allow upward and downward reaming.

Watermelon/string mills are available in standard sizes and can be special ordered to anylength and OD to meet the specific requirements of the job.

SM

Weatherford's watermelon/string mills are products of the company's MillSmarttechnology—an engineered approach to milling that encompasses a wide range of proven products, services, and technical resources, developed and refined by the world'slargest and most experienced provider of milling and fishing services.

Slightly spiraled blades, dressed with crushed tungsten carbide, are held to close ODtolerances for maximum opening in the casing or key seat.

Top-to-bottom blade tapering allows both upward and downward reaming for increasedefficiency.

Design customization capability, including length, OD size, and smooth- or rough-ODo p t i o n, p r o v i de s s o l u t io n s f o r th e f u l l r a n g e o f ca s i n g a n d tu b i n g s i ze s a n d w e i gh t s .

Length and OD can be customized to suit job-specific requirements.

The mill can be dressed with a smooth or rough OD, as required.

Crushed tungsten carbide-dressed blades are standard. CustomCut™ inserts can beadded to retain the gauge OD of the mill.

Ap p lica tio n s

—

—

Fe a tu re s, Ad va n ta g e s a n d Be n e fits—

—

—

Op tio n s

—

—

—

— Milling out collapsed areas in casing and liners

E l i m i na t i n g k e y s e a t s a n d d og l e g s in o p e n h o l e

Extending whipstock windows





Len gth OD

(i n. /mm ) (in. ) (in. /mm ) (in. /mm ) (l b/kg )

3-1/ 2 t o 4-1/ 2

88. 9 t o 114. 32-3/ 8

12

304. 8

3-1/ 8

79. 4

45

20

4-1/ 2 t o 5-1/ 2

114. 3 t o 139. 7 2-7/ 8

12

304. 8

3-3/ 4

95. 3

62

28

5-1/ 2 t o 6

139. 7 t o 152. 43-1/ 2

12

304. 8

4-1/ 4

108. 0

95

43

5-3/ 4 t o 7-1/ 2146. 1 t o 190. 5

3-1/ 2 12304. 8

4-3/ 4120. 7

10548

7-1/ 2 t o 9

190. 5 t o 228. 6 4-1/ 2

12

304. 8

5-3/ 4

146. 1

180

82

9-1/ 2 t o 12-1/ 4

241. 3 t o 311. 2 6-5/ 8

12

304. 8

7-3/ 4

196. 9

350

159

13 t o 15

330. 2 t o 381. 0 6 - 5 / 8 o r 7 - 5 / 8

12

304. 8

7 - 3 / 4 o r 9 - 1 / 2

241. 3 or 196. 9

500

227

17 t o 17-1/ 2

431. 8 t o 444. 5 6 - 5 / 8 o r 7 - 5 / 8

12

304. 8

7 - 3 / 4 o r 9 - 1 / 2

241. 3 or 196. 9

625

283

18-1/ 2 t o 26

469. 9 t o 660. 46 - 5 / 8 o r 7 - 5 / 8

12

304. 8

7 - 3 / 4 o r 9 - 1 / 2

241. 3 or 196. 9

1, 200

544

S tandard Fi shi ng NeckS tandard Taper

M i l l OD

S tandard Top P i n


Approxi mate

Wei ght

Table 16—S pecifications for Watermelon/S tring Mills





Section Milling Operations

Section Milling OperationsUse section mills for cutting a single string of casing or for cutting sections of casing above and below storageformations, in perforated zones, for squeezing cement to plug old wells, to permit a sidetracking operation, or toallow cement-bonding between new, smaller casing and the formation. Some section mills are used as well to millinternal casing patches, screens, liners, and liner packers.

A variety of specialized features have been developed to enable selection of the optimal section mill for theapplication.


Use the lightest weights possible in section milling, consistent with acceptable ROPs, especially if you suspect

corroded casing. Take care to prevent splitting the casing during milling.

If the milling rate suddenly drops, a loose ring of steel formed at a joint or weld may be turning with the sectionmill, preventing if from operating correctly. Gently spud the mill to break up the ring and help position it for milling.

The mill must completely cut through the casing so that the blades can be firmly seated on the casing. Whenoperating a section mill without a flow indicator, prolong the cut-out to ensure complete cut-through.

S e v e ra l s i t u at i o n s c a n m a k e c u tt i n g o u t d i ff i c u l t. Table 17 p r e s en t s ty p i c a l c a u s e s o f d if f i cu l t y a n d We a t h e rf o r d 'srecommendations for overcoming them.

Table 17—Causes of Difficulty in Cutting Out and Their S olutions

Cause Recommendation

I ns uf fi ci en t p re ss ur e a t t he to ol T hi s s it ua ti on is th e m os t c om mo n c au se of di ff ic ul ti es in cu tt in g o ut , s uc h a snot achieving proper knif e t ip f orce. Maint ain a pressure drop of at least 350 t o750 PSI (2,413 t o 5, 171 kPa) at t he mill orif ice (depending on t he t ool size) t okeep t he cut t ing knives open and cut t he casing.

Excessive pump surging in t hedrillst ring wit h subsequent yo-yoing

This sit uat ion can cause t he mill blades t o t ry t o cut t he casing over aconsiderable int erval and may int errupt t he cut . Decrease t he pump rat e.

Blocked t ool orif ice Lost -circulat ion material, pieces of drillpipe rubbers, or ot her substances canblock t he orif ice of t he t ool, causing it t o malf unct ion or plug t he sect ion mill.Ensure t hat t he milling f luid is f ree of t hese mat erials.

Poor cutting ret urns A good cut ting return is essential, or difficulties, such as birdnest ing and plugging,may develop. Wat ch t he shaker f or cut t ings. To improve t he ret urn, increase t hef low and mud weight with addit ives as necessary.




Procedure

1 . M a k e up t h e t o o l s t r i ng , a n d r u n i n t h e ho l e t o t h e d ep t h o f t h e i nt e n d e d c u t o ut .

2 . R o ta t e at 6 0 to 8 0 RP M fo r th e c ut - ou t .

3 . S t a rt t h e p u m p s, a n d b u i l d t h e p u mp s t r o k es t o t h e o u t p u t (g a l l o n s o r l i te r s p e r m i n ut e ) r e q ui r e d t o g i v e t heminimum pressure drop across the piston nozzle of the tool, depending on its size. After the cut-out, thepressure drops 200 to 500 PSI (1,379 to 3,447 kPa), depending on the tool size.

4 . A f t er t h e c u t - ou t , ro t a t e 1 0 t o 15 m i n t o c l ea n t h e c u t .

5 . A p p l y we i g h t , an d i n c r ea s e t h e r ot a t i o na l s p e e d to 1 5 0 t o 3 5 0 S FP M ( 4 5. 7 t o 1 0 6 .7 S M P M) . T h e mo s t

efficient milling weight is usually 2,000 to 9,000 lb (907 to 4,082 kg).

6 . A f t er t h e s e c t i on i s m i l l e d o r w he n t h e k n i v e s a r e w or n o ut , c i rc u l a te u n t i l t h e h ol e i s c le a n .

7 . S t o p t he c i r c u l at i o n , a nd r o t a te f o r 5 t o 1 0 m i n fo r t h e c o rr e c t k ni f e c l o s ur e .

8 . P u ll t h e t o ol i n to t he s ho e , a n d tr i p ou t co n ve n ti o na l l y.

Section Mills

Weatherford offers a variety of section mills to meet job-specific requirements.

Ordering InformationTo ensure delivery of the proper section mill for your application, include the following information:

M il l O D


L e n g t h of w i n d o w t o b e m i l l ed

Top pin connection

—

—

—

—





A-1 Section Mill

Ap p lica tio n s

—

-

-

-

-

-

-

—


—

—

—

—

—

W e a th e r f or d ' s A - 1 s e c ti o n m i l l i s a n e x t r e m el y r e l i a b l e h y d ra u l i c a ll y a c t i v a te d t o o l f o r m i l l i n g a s ec t i o n o f ca s i n g o r tu b i n g . T h e m i l l i s s i m p l e i n de s i g n , i s ea s y t o o p e r at e , a n dhas an outstanding reputation for milling performance. Milling knives are dressed withWeatherford's CustomCut™ tungsten carbide inserts to provide extended milling footagew i t h m a x i mu m r a t e s o f p e n e t r at i o n .

The A-1 section mill is available in four different models: single-cylinder, high-flow single-cylinder, dual-cylinder, and high-flow dual-cylinder. The dual-cylinder section mills providegreater hydraulic power to the milling knives for milling depths greater than 10,000 ft(3,048 m). The high-flow section mills keep the cutting structure cool and create a

continuous flushing-and-cleaning action on the milling knives.SM

W e a th e r f or d ' s A - 1 se c t i o n m i l l i s a p ro d u c t o f t h e c o m p an y ' s Mi l l S m ar t t e c h no l o g y —a nengineered approach to milling that encompasses a wide range of proven products,services, and technical resources, developed and refined by the world's largest and mostexperienced provider of milling and fishing services.

Milling knives are dressed with Weatherford's CustomCut tungsten carbide inserts for longer life and the resulting cost savings.

M i l l i n g k n i ve s a r e a v a i l ab l e w i t h s i n g l e b l a de s , f o r e q u i p me n t a n d f l u i d s w i t h l i m i te dcapabilities, or with double blades, for premium equipment and fluids.

Various nozzle sizes can be predetermined, using Weatherford's HydraPro™ hydraulicssoftware, to achieve the most productive flow pattern and hole-cleaning capabilitieswhile milling.

H i g h -f l o w m i l l s k e e p t he c u t ti n g s t ru c t u re c o o l a n d c r ea t e a c on t i n u ou s f l u s h in g - a n d-cleaning action on the milling knives, increasing the life of the equipment andconserving equipment costs.

Dual-cylinder mills provide more hydraulic power to the milling knives, which allowsmore efficient penetration rates.

Milling of a section of casing

a b o v e a n d b e l o w s t o r ag e f o r m a ti o n s

in perforated zones

for squeezing cement to plug old wells

t o a l l o w a s i d e t r ac k i n g o p e ra t i o n

to ensure cement-bonding between new, smaller casing and the formation

for plug and abandonment

Cutting a single string of casing





B od y O D

Approxi mate

S hi ppi ng Wei ght

(i n. /mm ) (lb /kg ) (in .)

4-1/ 2

114. 30 2 7/ 8-in. API Reg

215

978 10364 5-1/ 2

5-1/ 2

139. 70 3 1/ 2-in. API Reg

529

240 10351 6-5/ 8 to 7

6-1/ 4158. 75

3 1/ 2-in. API Reg 565256

10841 7-5/ 8

7-1/ 4

184. 15 4 1/ 2-in. API Reg

595

270 10558 8-5/ 8

8

203. 20 4 1/ 2-in. API Reg

911

41310277 9-5/ 8

9

228. 60 4 1/ 2-in. API Reg

1, 070

485 10811 10-3/4

11-3/ 4

298. 45 6 5/ 8-in. API Reg

1, 405

637 10405 13-3/8

M i l l

Casi ng ODTop P i n

Connecti on

Assembly

Number

API regular pin connect ions are st andard; ot her connect ions are available on request .

When ordering or request ing quot at ions on A-1 sect ion m ills, st at e dept h of sect ion and sizeand weight of casing t o be m illed.

Table 18—S pecifications for the A-1 S ection Mill





®

E l im i na t or S e ct i on M i l l

Weatherford's Eliminator s e c t i on m i l l i s a h y d ra u l i c al l y a c ti v a t e d t o o l u s e d to m i l l s e c t io n so f c a s i n g o r t ub i n g . W ea t h e rf o r d d e si g n e d t h i s m i l l w i t h a n e m ph a s i s o n s i m p l ic i t y,robustness, ease of maintenance, and ease of operation. Milling knives are dressed withCustomCut™ tungsten carbide inserts to provide extended milling footage with maximumpenetration rates.

The most distinguishing feature of the Eliminator mill is the knife configuration. Unlike allother section mills, the Eliminator mill has knives that pivot from the bottom rather thanfrom the top. This feature provides for a full-sweep diameter greater than the diameter of the casing collar—for the entire knife length. When the knives are activated, the

Eliminator s e c t io n m i l l l o o k s v e r y s i mi l a r t o a p i l o t m i l l . T h e f l o w i n d i c a to r i n c o r p or a t e d i nt h e d e si g n o f th i s m i l l g i v e s a p o s i t iv e p r e ss u r e dr o p a t su r f a ce w h e n th e c u to u t i s m a d e ,which prevents “skimming” the ID of the casing.

As with other hydraulic tools with arms, circulation through a restriction in the Eliminator m i l l c r e a te s a p r e s s ur e d r o p a c ro s s a t u b e , w h ic h c a u s e s t he t u b e t o t r a ve l d o w n wa r dwith the tool body. The downward travel and a tapered surface on the lower end of thetube force the cutting knives outward. The outward knife movement provides the cuttingaction into the inner surface of the casing. When cutout through the casing wall isachieved, the knives are fully supported into their outermost position, and cuttingproceeds in a downward direction on the upper face of the casing, immediately below thecutout point.

SMWeatherford's Eliminator section mill is a product of the company's MillSmarttechnology—an engineered approach to milling that encompasses a wide range of

proven products, services, and technical resources, developed and refined by the world'slargest and most experienced provider of milling and fishing services.

Ap p lica tio n s

—

-

-

-

-

-

—



in perforated zones


to permit a sidetracking operation

to allow cement-bonding between new, smaller casing and the formation






Body

OD

Overal l

Length

Approxi mate

Shi ppin g W eight OD W eight

(i n. /mm ) (i n./m ) (l b/kg ) (in. ) (lb/ ft)

4-3/ 8

111. 1

59. 5

1. 5

230

1045-1/ 2 14 to 23

M il l Casin g Connectio ns

Top

P i n

Bottom

Box

2 7/ 8-in. Reg


—

—

—

—

—

—

Reverse-milling knife profile, similar to that of a pilot mill when opened, yields a true OD for the life of the knives,thereby decreasing the number of trips in the hole and providing quicker cutout.

Integral stabilizer requires fewer connections and is changeable from the rig floor, saving redress time.

Nozzles in the bodies of the pockets flush cutting and debris away from the milling knives, improving penetrationrates and extending the life of the knives.

O p t i mi z e d n o z z l e d e s i g n a l l o w s h i g h e r f l o w r a t e s, u s i n g W e a t h e r fo r d ' s H y d ra P r o ™ h y d r au l i c s s o f t wa r e , t oachieve the most productive flow pattern and hole-cleaning capabilities during milling.

Flow indicator provides positive indication of cutout, preventing “skimming” the ID of the casing.

Milling knives are dressed with CustomCut™ inserts to provide extended milling footage with maximumpenetration rates

Table 19—S pecifications for the Eliminator S ection Mill





Reverse-Flow Section Mill

W e a th e r f or d ' s r ev e r s e -f l o w s e c t io n m i l l i s a h y d ra u l i c a ll y a c t ua t e d to o l u s e d t o m i l l asection in casing or tubing. This section mill is simple in design, easy to operate, and,

SMw i t h W ea t h e rf o r d ’s M i l l Sm a r t t e c h n ol o g y, h a s a c q u i re d a n o u t s t an d i n g r e pu t a t io n f o r

™milling performance. The milling knives are dressed with Weatherford’s CustomCuttungsten carbide inserts to provide extended footage with maximum penetration rates.

T h e s e c ti o n m i l l i s r u n i n c o n ju n c t i on w i t h a t a pe r m i l l , wh i c h h a s an i n t e g ra l c a r b i denozzle threaded in the bottom end. Combined with the internal pack-off system, thisc o n f i gu r a t io n a l l o w s p o s i t iv e f l u i d c o n t ro l t o t h e s e c t i on m i l l k n i v e s. P o s i t i ve f l u i d c o n t r olcreates a continuous flushing and cleaning action on the knives of the section mill and

p r e v e nt s t h e c u t ti n g s f r o m b a ll i n g a r o u nd t h e m . P os i t i v e f lu i d c o n t ro l a l s o k e e ps t h ecutting structure cool, which helps to prolong the life of the knives and produces smaller,more controllable cuttings.

Positive fluid control keeps the cutting structure cool and creates a continuous flushingand cleaning action on the knives, increasing the life of the equipment and conservingcosts.

Milling knives are dressed with Weatherford’s CustomCut inserts for longer life and costsavings.

Flow indicator provides a positive indication of cutout, which eliminates skimming theinside of the pipe and ensures proper operation of the tool.

Various nozzle sizes can be predetermined, using Weatherford's HydraPro™ hydraulicssoftware, to achieve the most productive flow pattern and hole-cleaning capabilitieswhile milling.

Ap p lica tio n s—

-

-

-

-

-

—

—


—

—

—

—



i n p e r f or a t e d zo n e s i n o i l w e l l s

to squeeze cement to plug old wells



Milling of internal casing patches, screens, liners, and liner packersSingle-string casing cutting operations





(in .) (mm) (in .) (mm) (in .) (mm) (in .) (mm) (in .) (mm)

17.0 6.538 166.06 6.413 162.9 6-1/4 158.7 9-1/16 230.2 6-3/8 169.9

20.0 6.456 163.98 6.331 160.8 6-1/8 155.6 8-15/16 227.0 6-1/4 158.7

23.0 6.366 161.70 6.241 158.5

26.0 6.276 159.41 6.151 156.2

29.0 6.184 157.07 6.059 153.9 5-7/8 149.2 8-11/16 220.7 6 152.4

32.0 6.094 154.79 5.969 177.0 35.0 6.004 152.50 5.879 174.7

38.0 5.920 150.37 5.795 172.6 5-5/8 142.9 8-7/16 214.3 5-3/4 146.0

20.0 7.125 180.97 7.000 177.8 6-7/8 174.6 9-11/16 246.0 7 177.8

24.0 7.025 178.43 6.900 175.2 6-3/4 171.4 9-9/16 242.9 6-7/8 174.6

26.4 6.969 177.01 6.844 173.8

29.7 6.875 174.62 6.750 171.4

33.7 6.765 171.83 6.640 168.6 6-1/2 165.1 9-5/16 236.5 6-5/8 168.2

39.0 6.625 168.27 6.500 165.1 6-3/8 161.9 9-3/16 233.3 6-1/2 165.1

29.3 9.063 230.20 8.907 226.2 8-3/4 222.2 12-5/8 320.7 8-7/8 225.4

32.3 9.001 228.62 8.845 224.7

36.0 8.921 226.59 8.765 222.6

40.0 8.835 224.41 8.679 220.4 8-1/2 215.9 12-5/16 312.7 8-5/8 219.1

43.5 8.755 222.38 8.599 218.4

47.0 8.681 220.50 8.525 216.5

53.5 8.535 216.79 8.379 212.8 8-1/4 209.5 12-1/16 306.4 8-3/8 212.7

48.0 12.715 322.96 12.559 319.0 12-3/8 314.3 17-11/16 449.2 12-1/2 317.5

54.5 12.615 320.42 12.459 316.4 12-1/4 311.1 17-9/16 446.1 12-3/8 314.3

61.0 12.515 317.88 12.359 313.9

68.0 12.415 315.34 12.259 311.4

72.0 12.347 313.61 12.191 309.6 12 304.8 17-5/16 439.7 12-1/8 308.0

Dressed Sto p

Stab iliz er

Sectio n MillCasin g

Drift ID

Kn ife

Co llap se

Diameter

Kn ife Maximu m

Op en Diameter Co u p lin g

OD

(in ./mm )

Weig h t

with

Co u p lin g

(lb /ft)

Bo d y

OD

(in ./mm )

11-1/2

292.0

8-1/4

209.5

6-1/8

155.6

5-1/2

139.7

6

5-3/4

6-5/8

8-5/8

8-3/8

12-1/8 308.0

212.7

219.1

168.2

146.0

152.4 8-13/16 223.8

8-9/16 217.5

9-7/16 239.7

12-7/16 315.9

12-3/16 309.6

442.917-7/16 12-1/4 311.1

8-1/2 215.9

8-3/4 222.2

6-3/4 171.4

5-7/8 149.2

6-1/8 155.6

9-5/8

244.5

13-3/8

339.7

14.375

365.1

Casin g ID

10.625

260.7

7

177.8

7.656

194.5

8.500

215.9

7-5/8

193.7

Casing

Siz e

(in ./mm )

Table 20—AP I Casing and S ection Mill Correlation





S ecti on M i l l

B od y O D

(i n. /mm )

Range Requi red Duri ng

Cut-Out Usi ng 10-P P G Fl ui d

(GP M /LPM)

Range Requi red Duri ng M i l l i ng

Usi ng 10-P P G Fl ui d

(GP M /LPM)

5-1/ 2

139. 7

100 t o 135

378. 5 t o 511. 0

200 t o 350

757. 1 t o 1, 324. 9

6-1/ 8

155. 6 8-1/ 4

209. 5

11-1/ 2

292. 0

600 t o 700

2, 271. 2 t o 2, 649. 8

1, 000 t o 1, 100

3, 785. 4 t o 4, 164. 0

130 t o 150492. 1 t o 567. 8

500 t o 7001, 892. 7 t o 2, 649. 8

S ecti on M i l l

B od y O D

(i n. /mm )

Casi ng

S i zes

(i n. )

Overal l

Length

(i n. /m )

Top P i n

Connecti on*

Approxi mate

S hi ppi ng Wei ght

(l b/kg )

5-1/ 2

139. 7 6-5/8 and 7 3 1/2-in. Reg.

450

204. 1

6-1/ 8

155. 6 7-5/8 4 1/2-in. Reg.

568

257. 6

8-1/ 4

209. 5 9-5/ 8

87

2. 216 5/ 8-in. Reg.

1, 050

476. 0

11-1/ 2

292. 0 13-3/ 8

90

2. 297 5/ 8-in. Reg.

1, 725

782. 4

74

1. 88

Table 21—S pecifications for the Reverse-Flow S ection Mill

Table 22—Cut-Out and Milling Ranges for theReverse-Flow S ection Mill

* API regular pin connect ions are st andard; ot her connect ions are available on request .





T M

S li mc o S ec ti on Mi ll

Weatherford's Slimco s e c t io n m i l l i s a h y d r a u li c a l l y a c ti v a t ed t o o l d e s i g ne d f o r section milling operations within small-diameter casing. The mill is simple androbust in design, is easy to operate and maintain and has an outstandingreputation for performance. Milling knives are dressed with Weatherford'sCustomCut™ tungsten carbide inserts to provide extended footage withmaximum penetration rates.

The Slimco s e c t io n m i l l h a s a n i nt e g r al f l o w i n d i c at o r, w h i c h g i v e s a po s i t i vepressure drop at surface when the cutout is made, preventing “skimming” of thecasing ID. Nozzles in the body pockets create a continuous flushing-and-cleaning

action on the knives of the mill, preventing cuttings from balling around them.This feature also keeps the cutting structure cool, which helps to prolong the lifeof the knives and produces smaller, more controllable cuttings.

SMWeatherford's Slimco section mill is a product of the company's MillSmarttechnology—an engineered approach to milling that encompasses a wide rangeof proven products, services, and technical resources, developed and refined bythe world's largest and most experienced provider of milling and fishing services.

Positive fluid control keeps the cutting structure cool and creates a continuousflushing-and-cleaning action on the knives, increasing the life of the equipmentand thus conserving costs.

Milling knives are dressed with CustomCut inserts for longer life and theresulting cost savings.

Flow indicator provides a positive indication of cutout, which eliminates“skimming” the inside of the pipe and ensures proper operation of the tool.

Various nozzle sizes can be predetermined, using Weatherford's HydraPro™hydraulics software, to achieve the most efficient flow pattern and hole-cleaningc a p a b i li t i e s w h i l e m i ll i n g .

Ap p lica tio n s

—

-

-

-

-

-

—

—


—

—

—

—



in perforated zones




Milling internal casing patches, screens, liners, and liner packers






(i n. ) (mm )

3-3/ 4 95. 3 2 3/8-in. Reg 4-1/ 2

4 101. 6 2 3/8-in. Reg 5

4-1/ 2 114. 3 2 7/8i-n. Reg 5-1/ 2

M i l l

B od y O D Top P i n

Connecti on

Casi ng

OD

(i n. )

Table 23—S pecifications for theS limco™ S ection Mill





Rotary-Shoe Washover Operations

Rotary-Shoe Washover OperationsRotary shoes (also known as washover shoes) are used in the demanding jobs of milling away formation or toolobstructions, such as stabilizer blades, reamer cutters, expanded packers, and bit bodies, that can hold thedrillstring in the hole. Using joints of wash pipe, the rotary shoe can be worked over the string and lowered to thestuck point.

Use rotary shoes to free and wash over:

—

—

—

—

Back-off tools

D r il l d o ll a rs

Drillpipe

Jars

—

—

—

—

Keyseat cutters

Packers

Reamers

Rock bits

—

—

—

—

Stabilizers

Subs

Tubing

Wireline and cable

Rotary shoes can also be used to mill fishing necks to a sufficient annular clearance so that an overshot can berun for fish recovery. Designs are available for heavy- and thin-walled shoes, for openhole and cased-holeapplications.


D u r i ng r u n n i n g o f r ot a r y s h o e s, t h e R O P c a n b e h i g h , c a us i n g d i ff i c u l ti e s w i t h c u tt i n g s r e m o va l . P a y a t t e nt i o n t ocorrect mud conditioning. Ensure that cuttings are removed as milled. If you encounter difficulties achieving theoptimal cutting returns, decrease the rotary table speed and the weight on the tool.

Because of the high temperature required for crushed tungsten carbide and CustomCut™ tungsten carbide insertapplications, maintain a minimum 3/8-in. wall thickness in the dressed area of the shoe. This thickness eliminatesthe possibility of steel cracking; it is also critical because of the area needed for effective carbide coverage.

For correct circulation and reduced torque, provide adequate clearance to the ID and OD of the shoe.Weatherford recommends that the ID of the dressed shoe be at least 1/16 in. less than the wash-pipe ID. Theclearance enables the shoe to mill the outside of the fish so that it passes into the pipe without interference. Dressthe OD of the shoe at least 1/16 in. larger than the pipe OD. The outer dressing of the shoe provides a circulationa n n u l us f o r c u t t i n gs r e m o v a l . I f c o nd i t i o ns a l l o w a n d i f t h e m i n i m u m 3 /8 - i n . w a l l t h i c k ne s s o f t h e s h o e i smaintained, the clearances are enlarged.

Procedure

1 . B a c k o f f th e s t u ck s t r i ng 3 0 t o 6 0 f t ( 9 to 1 8 m ) ab o v e t he s t u c k p o i n t of t h e p i pe t o e n ab l e r u nn i n g a m in i m u mnumber of wash-pipe joints. This measure is especially important in an unstable formation. The back-off also

frees pipe above the stuck point so that working the wash pipe over the fish is easier.

2 . B e g i n m i ll i n g a t 5 0 t o 1 0 0 R P M, a n d g r a d ua l l y i n c r ea s e t o 1 2 5 t o 1 5 0 R PM . S l o w ly i n c r e a se t h e w e i g h t fr o m2,000 to 6,000 lb (907 to 2,722 kg). Light weight and low speed reduce the likelihood of splitting or flaring theshoe. If torque is encountered, reduce the speed and the weight.




Rotary Shoes

Weatherford's durable, high-performance rotary shoes are dressed with specially selected crushed tungstencarbide or CustomCut™ tungsten carbide inserts to provide continuous sharp cutting edges for long washover intervals.

The tooth rotary shoe i s b e s t su i t e d fo r c u tt i n g f or m a t io n a n d c em e n t wh e n m i ni m a l m e t a l o b s t ru c t i o ns a r eencountered in the washover interval. The tool is effective for washing over stuck collars or drillpipe and tubingsanded in place.

The scalloped-bottom (wavy bottom), flat-bottom, drag-tooth, and cripple-tooth d e s i g ns o f r o ta r y s h oe sSM

e n a b l e t he s h o e w a l l t o b e d r e s se d w i t h e i t he r o f W e a th e r f or d ' s M i l lS m a rt t e c h n ol o g i e s— c r u sh e d t u n g st e n

carbide or CustomCut tungsten carbide inserts. With the use of inserts, the ID, the OD, and the entire face of theshoe self-sharpen. Each design eliminates the common difficulty of the carbide face wearing off, exposing a steelring where the carbide is most needed.


Weatherford applies dressing anywhere on the rotary shoes—bottom, inside, outside—and in any combinationnecessary. Depending on the job, wear pads can be provided on the OD to protect the casing. To ensuredelivery of the proper rotary shoes for your application, include the following information:

Type of head design (scalloped, flat, dragtooth, cripple tooth, or tooth)

Wash pipe size and weight

Dressed OD

Dressed ID

Smooth or rough OD

Connection size and type

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Rotary Shoes

Ap p lica tio n s


Weatherford's rotary shoes are used to wash over tubulars that have become sand stuck, mud stuck, or mechanically stuck and for milling over packers, retainers, and bridge plugs. Made of specially tempered steeland dressed with Weatherford’s CustomCut™ tungsten carbide inserts and/or crushed tungsten carbide, rotaryshoes provide the ultimate in strength, durability, cutting speed, and penetration rate. Rotary shoes are usually runon the bottom of one or more joints of washover pipe to cut clearance between the fish and the wall of thewellbore. Rotary shoe head designs are available in rough OD, for working in openhole wellbores, or smooth OD,for working in cased-hole wellbores. Rotary shoes can be ordered for any length, OD, and ID to meet job-specific

SMr e q u i re m e n ts , a n d al l c o m e wi t h W ea t h e rf o r d ’s M i l l Sm a r t t e c h on l o g y.

Milling over blades from stabilizers, cutters from roller-type reamers, and cones from bits

Washing over sand-stuck, mud-stuck, or mechanically stuck tubulars

Milling over packers, retainers, and bridge plugs

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Rugged construction provides optimal strength and durability for long equipment life.

Smooth OD for cased-hole wellbores reduces risk of casing damage.

Rough OD for openhole wellbores cuts clearance between the fish and the wall of the wellbore.

Size range from 3 1/2- to 16-in. OD and shoe head style customization capability for milling on the bottom, onthe OD, on the ID, or any combination of the three provide versatility for a variety of applications.

Increased cutting speed and milling efficiency offer both cost and time savings.





Type A

Used in open hole and inside casing. Drag-t oot h t ype shoe f or sof t f orm at ions or whenrunning a weak work st ring. I t cut s on t hebottom of the shoe only.

Type B

Used inside casing t o wash over and cuton t he bot t om only. Because t his t ype shoed o e s n ot c u t o n th e I D o r t h e O D o f t h eshoe, it will not dam age t he casing. I t cut son the bottom of the shoe only.

Type C

Used inside casing f or cut t ing met al on af ish wit hout dam aging t he casing. Does notcut on t he OD of t he shoe. I t cut s on thebot t om and the I D of t he shoe.

Type D

Used in open hole f or washing over andcut t ing m et al and cem ent wit h lim it ed insideclearance. Does not cut on t he I D of t heshoe. I t cut s on t he bott om and t he OD of t he shoe.

Type E

Used in open hole f or washing over andcutting metal, formation or cement. It cutso n t h e b ot t o m, t h e I D a n d t h e OD o f t h eshoe.

Type F

Used inside casing t o cut m et al on a f ish.Because t his t ype shoe does not cut on t heO D o f t h e sh o e , i t wi l l n o t d a ma g e t h ecasing. I t cut s on t he bot t om and t he I D of t he shoe.

Type G

Used in open hole wit h lim it ed out sideclearance, f or washing over a f ish andcut t ing m et al and a lim it ed am ount of cem ent . Because t his t ype shoe does notc u t o n t h e ID o f t h e s h oe , i t w i l l n o t d a ma g et he f ish. I t cut s on the bot t om and t he OD of t he shoe.

Type H

Used f or sizing and dressing of f t he t op of a f ish inside casing. M akes a t apered cuton t he f ish wit hout dam aging t he casing.Does not cut on t he OD of t he shoe. I t cut son t he bot t om and t he I D of t he shoe.

Type I

Used in open hole f or washing over andcut t ing t he f orm at ion, m et al, or cem ent wit hlim it ed inside clearance. I t cut s on t heb o t to m , t he I D a n d t h e OD o f t h e s ho e .

Table 24—Rotary S hoe S election Guide





Table 24—Rotary S hoe S election Guide (continued)

Type M

Type J Type K

Type L

Used inside casing f or cut t ing met al on t hef ish. Because t his t ype shoe does not cuton t he OD of t he shoe, it does not damaget he casing. I t cut s on t he bot t om and t he I Dof t he shoe.

Used in open hole f or washing over andcut t ing f orm at ion only. Does not cut on t heI D o f t h e s h oe . I t c u t s o n t h e b o tt o m a n dt h e O D o f t h e s ho e .

Used in open hole or inside casing f or washing over and/ or cut t ing f orm at ion only.D o e s no t c u t o n th e O D o r t h e I D o f t h eshoe. I t cut s on t he bot t om of t he shoe only.

Used inside casing f or washing over andcut t ing on t he bot t om only. Does not cut ont h e O D o r t h e I D o f t h e sh o e . I t c u t s o n th ebottom of the shoe only.




Guidelines for Effective Milling

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