MechanicalCementationProducts

The Weatherford Technique

That's the Weatherford technique.

For the last half century, the industry has depended onWeatherford to provide quality equipment for its primarycementing needs. Weatherford now offers the world'slargest and most complete line of cementing products -not just a partial solution. As the recognized specialistsin the field, Weatherford provides the broadest productoffering, innovative tool designs, the latest inmanufacturing technology, combined with the backing ofexperienced engineers to analyze the well and makedetailed recommendations for satisfying yourcementation objectives. From the beginning of thecementing job to its conclusion, Weatherford providescomplete assistance to make sure that job runs properly.Weatherford strives to provide customers with the lowestcementing costs possible.

CONTENTS

Welded Centralizers 2 (inside cover)Non-Weld Centralizers 3 (inside cover)SpiraGlider Centralizers 4Centralizers (non-weld) 5Centralizers (welded) 9Flow Enhancement Tools 14Roller Centralizers 15Stop Collars 16Specialty Tools 17Installation Patterns 19

CentraPro Plus™ Software Program

CentraPro Plus

The mechanical cementing products installationpattern, as part of the total cementing program,should be based on individual wellconditions and operating objectives. Toassist in developing the mosteffective program for a well,Weatherford has developed the

program, asophisticated lateral load softwareprogram designed to provide optimumdeployment of cementation products in the well.This innovative program utilizes three dimensionalanalysis to calculate the lateral forces as well ashookload calculations.

After job completion, Weatherford engineersevaluate the performance data of the well and, bycomparing it with other similar cementations, canhelp customers prepare for future cementing jobs.

Weatherford technicians regularly performdestructive tests to assure that Weatherfordproducts continue to meet the highest standards,exceeding even those of the American PetroleumInstitute. Weatherford commitment to the industryinvolves providing efficient products to meet realwell conditions.

Weatherford's main manufacturing plants arelicensed to use the API monogram.

Product Testing

Weatherford's specially-designed test proceduresmonitor products under abnormal conditions.

Weatherford's cementing engineers atthe wellsite.

EngineeringWeatherford's experienced cementing engineers areavailable worldwide to help ensure the correct

implementation of thecemention programand the properinstallation of eachpiece of equipment.The on-site engineerscontinually monitor thewell and can quicklyadapt the program tounforeseen conditions.

1

API SPECIFICATION

RIGID QUALITYCONTROL TESTS

ROLL-FORMED RIDGE

centralizers are manufac-tured for all commoncasing/hole size combina-tions... assurance thatWeatherford centralizersare of a consistently highquality.

are performed on everycentralizer to verify sizeand fit.

around end collarsprovide extra rigidity,minimizes out-of-rounddistortion in shipping orstorage, and makes astreamlined leading edge toprevent hanging up.

WELDED CENTRALIZERS

INTEGRAL HINGES

PREMIUM BOWSPRINGS

HINGE PINS

SUPER-STRONG WELDS

have eight sections and sevenshear points for maximumload capacity. Hinges wrap tothe inside, against the casing,for optimum design strength.

of high quality spring steelundergo special heat treat-ment to achieve maximumcentering power and mini-mum running resistance.

embody aself-locking design that willnot work loose, yet they tapeasily into place.

and maximum weld lengthare the product ofWeatherford’s patentedautomatic welding equip-ment. Assuring ultimatestrength and uniformity inevery weld.

For Excellent Performance Under Tensile Stress

Weatherford welded centralizers have been providingexcellent service for over 50 years. They are the result of highquality materials, coupled with the most advanced manufac-turing processes, including proprietary robotics technologyand automatic centralizer welding. Consistency is foremost inWeatherford’s goal of assuring performance excellence at thewellsite. Special high strength steel springs are made todesign specifications. End collars are uniquely designed withintegral hinges and self-locking hinge pins. The centralizerribs are engineered to maintain rigidity while providing astreamlined profile in the wellbore.

Testing centralizers for stress confirms that they will rununder demanding conditions without distortion or destruction.

2

NON-WELD CENTRALIZERS

More than 50 years experience has gone into thedesign, manufacture and continual improvement of theWeatherford non-weld centralizers. Weatherford’snewest generation of products reflects that experience.They are built for use in the most demandingconditions. Starting with the uniformity of the bowhardness to the heavy gauge end collars, they provide aruggedness for just about any application. Thesepremium products exceed the requirements for APISpecification 10D.

Testing centralizers for compression assures that thecentralizers can withstand very high forces whenrunning casing. The test, illustrated at left, shows that adamaged centralizer will still remain intact undersevere conditions.

EXCEEDS THEREQUIREMENTS OFAPI SPECIFICATION10D

CHOICE OF BOWS

HINGES

LOCKING TAB

With exceptional startingand restoring performance.

Weatherford offers five basicdesigns with additionalconfigurations available.The bows can be made instainless steel and in sizes tomatch any well profile.

Turned inward formaximum strength.

Each bow locks in placesecurely with patented tab.*

EXTENDED PROFILE

HIGH QUALITY BOWS

FIELD ASSEMBLY

END COLLARS

SELF LOCKINGHINGE PIN

Prevents bows from hittingagainst casing collar.

Uniform bow hardness.

All bow combinations canbe field assembled to reduceshipping costs.

Non-weld models featureheavy gauge steel withextra strong hinges.

For easy and sureinstallation.

For Excellent Performance While Under Compression

*U.S. Patent Number 4,077,470

3

SPIRAGLIDER™Highly Deviated AndHorizontal WellCentralizer System*

SpiraGliderSTEEL CONSTRUCTION

SMOOTH SURFACE

The system ismade of steel, giving it atoughness advantage overother materials and alloys.

Both spiral and straightfin designs minimize dragforces while running pipe.The fins glide smoothlyon the low side ofhorizontal boreholes.

Wide symmetrical fins aresmoothly beveled on bothends to have lower coeffi-cient of friction and to easecasing movement in eitherdirection.

SHAPED TO MINIMIZERUNNING RESISTANCE

OPTIMIZED HYDRODY-NAMICS AND FLOW-BYAREA

PRE-DEFINED FIN LOADRESISTANCE

UNIQUE STOP COLLARS

Hydrodynamic shape ofspiral fins allows optimalmud displacement andminimal pressure dropacross centralizer. Inducedvortex flows enable superiormud removal.

fin designresists high sideloads,yet are engineered tointentionally yield atpredetermined sideforceunder stuck-pipe conditions.

Provide protection forthe centralizer’s leadingedge and performs as apositioning device.

SpiraGlider

Typical AverageCoefficient of Friction**

n Zinc Steeln

0.12

0.10

0.08

0.06

0.04

0.02

0.00

**Valid for water/ben-tonite, water/chalk and oilbase mud, accord-ing to astudy by the Institute ofTribology, TechnicalUniversity of Clausthal,Germany

The Weatherford centralizers are the newestinnovations in a broad offering of cementation products. Theywere designed specifically for highly deviated or horizontalwells and are ideal for use with liner hangers. Thesystem consists of a STEEL centralizer and twoasymmetrically-beveled stop collars.Thecentralizer’s unique design features allow them to run inrestricted holes while yielding reduced wear and a lowcoefficient of friction for minimal drag. They promote optimalmud displacement during cementation, utilizing fins that createa vortex motion for superior mud removal. Theconstruction is tough and gives maximum standoff and wearresistance.

SpiraGlider

SpiraGlider

SpiraGlider

SpiraGlider

*patents pending

4

STRAIGHT BOW CENTRALIZERS

Weatherford’s non-weld straight centralizers are theresult of more than 50 years of field experience andlaboratory testing. This newest design has featuresmaking them ideal for both tubing and casingapplications.

Non-weld design eliminates weak spots.Choice of standard bow heights assures optimumstarting/restoring force criteria.Patented locking tabs hold bows in the collars.High-quality, spring-steel bows and speciallydesigned collar hinges provide reliable downholeperformance.Available in stainless steel.

Weatherford markets straight centralizer bows inseveral standard sizes and provides a variety of bowconfigurations for special applications. If your wellplan requires a special design, contact your localWeatherford representative.

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•

Non-Weld Straight Centralizers

STA 0 STA 1 STA 3 STA 3 STA 4

Non-Weld Centralizer Standard Bow HeightsStraight Centralizer Bow Configurations

In. 0.965 1.161 1.437 2.303 3.051

mm 24.5 29.5 36.5 58.5 77.5

STA0 STA1 STA2 STA3 STA4

ST A0 6.186 157.1 4.965 126.1ST A1 6.579 167.1 5.201 132.1

4" ST A2 7.131 181.1 5.201 132.1ST A3 8.902 226.1 5.201 132.1ST A4 10.398 264.1 5.201 132.1

ST A0 6.691 169.9 5.470 138.9ST A1 7.084 179.9 5.706 144.9

4 1/2" ST A2 7.636 193.9 5.706 144.9ST A3 9.407 238.9 5.706 144.9ST A4 10.903 276.9 5.706 144.9

ST A0 7.196 182.8 5.975 151.8ST A1 7.589 192.8 6.211 157.8

5" ST A2 8.141 206.8 6.211 157.8ST A3 9.912 251.8 6.211 157.8ST A4 11.408 289.8 6.211 157.8

ST A0 7.701 195.6 6.480 164.6ST A1 8.094 205.6 6.716 170.6

5 1/2" ST A2 8.646 219.6 6.716 170.6ST A3 10.417 264.6 6.716 170.6ST A4 11.913 302.6 6.716 170.6

ST A0 8.837 224.5 7.616 193.ST A1 9.231 234.5 7.853 199.

6 5/8" ST A2 9.782 248.5 7.853 199.ST A3 11.553 293.5 7.853 199.5ST A4 13.050 331.5 7.853 199.5

ST A0 9.216 234.1 7.995 203.1ST A1 9.609 244.1 8.231 209.1

7" ST A2 10.161 258.1 8.231 209.1ST A3 11.932 303.1 8.231 209.1ST A4 13.428 341.1 8.231 209.1

ST A0 9.847 250.1 8.626 219.1ST A1 10.241 260.1 8.863 225.1

7 5/8" ST A2 10.792 274.1 8.863 225.1ST A3 12.563 319.1 8.863 225.1ST A4 14.060 357.1 8.863 225.1

ST A0 10.857 275.8 9.636 244.8ST A1 11.251 285.8 9.873 250.8

8 5/8" ST A2 11.802 299.8 9.873 250.8ST A3 13.573 344.8 9.873 250.8ST A4 15.070 382.8 9.873 250.8

ST A0 11.867 301.4 10.646 270.4ST A1 12.261 311.4 10.883 276.4

9 5/8" ST A2 12.812 325.4 10.883 276.4ST A3 14.583 370.4 10.883 276.4ST A4 16.080 408.4 10.883 276.4

Casing Bow Type Maximum O.D. Min Compressed O.D.Size (in.) in. mm in. mm

ST A0 13.010 330.5 11.790 299.5ST A1 13.404 340.5 12.026 305.5

10 3/4" ST A2 13.955 354.5 12.026 305.5ST A3 15.727 399.5 12.026 305.5ST A4 17.223 437.5 12.026 305.5

ST A0 14.023 356.2 12.802 352.2ST A1 14.417 366.2 13.039 331.2

11 3/4" ST A2 14.968 380.2 13.039 331.2ST A3 16.739 425.2 13.039 331.2ST A4 18.235 463.2 13.039 331.2

ST A0 15.668 398.0 14.448 367.0ST A1 16.062 408.0 14.684 373.0

13 3/8" ST A2 16.613 422.0 14.684 373.0ST A3 18.385 467.0 14.684 373.0ST A4 19.881 505.0 14.684 373.0

ST A0 18.326 465.5 17.106 434.5ST A1 18.720 475.5 17.342 440.5

16" ST A2 19.271 489.5 17.342 440.5ST A3 21.043 534.5 17.342 440.5ST A4 22.539 572.5 17.342 440.5

ST A0 20.984 533.0 19.763 502.0ST A1 21.377 543.0 20.000 508.0

18 5/8" ST A2 21.929 557.0 20.000 508.0ST A3 23.700 602.0 20.000 508.0ST A4 25.196 640.0 20.000 508.0

ST A0 22.376 568.4 21.156 537.4ST A1 22.770 578.4 21.392 543.4

20" ST A2 23.321 592.4 21.392 543.4ST A3 25.093 637.4 21.392 543.4ST A4 26.589 675.4 21.392 543.4

ST A0 26.426 671.2 25.206 640.2ST A1 26.820 681.2 25.442 646.2

24" ST A2 27.371 695.2 25.442 646.2ST A3 29.143 740.2 25.442 646.2ST A4 30.639 778.2 25.442 646.2

ST A0 28.451 722.7 27.231 691.7ST A1 28.845 732.7 27.467 697.7

26" ST A2 29.396 746.7 27.467 697.7ST A3 31.168 791.7 27.467 697.7ST A4 32.664 829.7 27.467 697.7

ST A0 32.501 825.5 31.281 794.5ST A1 32.895 835.5 31.517 800.5

30" ST A2 33.446 849.5 31.517 800.5ST A3 35.218 894.5 31.517 800.5ST A4 36.714 932.5 31.517 800.5

Casing Bow Type Maximum O.D. Min Compressed O.D.Size (in.) in. mm in. mm

Non-Weld Straight Centralizer Bow Heights

NON-WELD CENTRALIZERS

5

TANDEM RISE™ BOW CENTRALIZERS

• Reduced wall sticking for easier pipe movement

This special design increases the ratio of restoringforce to moving force. It has the ability to withstandhigh lateral loads encountered in horizontal holes. Thenon-weld design increases its ability to withstandcompressive loading while running in the wellbore. It isavailable for close tolerance applications and can beinstalled over casing couplings and stop collars..Benefits include:

Better standoff for increased mud removalReduced drag while running pipe

Complete mud removal while cementing

••

•

• Increased contact area for less bow penetration intothe formation

Tandem Rise Bow Profiles

TR1 .171 4.35 .800 20.32 14 1/8* 358.8*

TR2 .171 4.35 1.171 29.74 14 1/8" 358.8

TR3 .171 4.35 1.421 36.09 14 1/8" 358.8

TR4 .171 4.35 2.171 55.14 14 1/8" 358.8

Bow Spring "X" “X" “Z"Number Bow Thickness Bow Height Max. Coupling Length

Based on Coupling 1"

Above Casing Size

mm mm mmin. in. in.

*Based on 5/8" clearance for coupling

1) All bows 1 ½" (38.1 mm) wideNOTE:

Non-weld Straight Centralizers – Tubing

Tubing centralizers can be effective in tubinglesscompletions, for guiding and stabbing tubing intodownhole equipment or in reducing frictional drag indeviated holes. They can also be used to center wirelinetools, to protect control lines and cables, or to prevent wearon tubing and casing due to thermal expansion andcontraction. For optimum tubing concentricity,Weatherford recommends the use of positive tubingcentralizers inside casing.

TR 1

TR 2

TR 3

TR 4

STTI 5 1/8” 130 3 3/8” 86

2 3/8" STTII 5 1/2” 140 3 1/2” 89

STTIII 7 1/4” 184 3 1/2” 89

STTIV 8 1/2” 216 3 1/2” 89

STTI 5 5/8” 143 3 7/8” 98

2 7/8" STTII 6 153 4 102

STTIII 7 3/4” 197 4 102

STTIV 9 229 4 102

STTI 6 1/4” 159 4 1/2” 114

3 1/2" STTII 6 5/8” 169 4 5/8” 117

STTIII 8 3/8” 213 4 5/8” 117

STTIV 9 5/8” 245 4 5/8” 117

* When bows are completely compressed, these figures represent thecentralizer’s largest rigid diameter presented by the bow, the hinge orany other part.NOTE: STI AND STII centralizers should not be installed over any casingcollar or stop collar.

(in. mm) (in. mm)

MinimumMaximum CompressedBow OD Bow ODSize Bow Type

(in.)

Non-weld Straight Centralizers – Tubing

NON-WELD CENTRALIZERS

6

Non-WeldPositive Centralizer

Size Bow Type/Maximum Box OD”

(In) PO1 PO2 PO3 PO4 PO5 PO6 PO7 PO8 PO9 PO10 PO11

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

4 5 1/8 130.2 5 1/2 139.7 5 7/8 149.2 6 1/8 155.6 6 1/8 165.1 6 7/8 174.6 7 1/4 184.2 7 5/8 183.7 8 7/8 225.4 10 3/8 263.5 5 7/8 149.2

4 1/2 5 5/8 142.9 6 152.4 6 3/8 161.9 6 5/8 168.3 7 203.2 7 3/8 187.3 7 3/4 196.9 8 1/8 206.4 9 3/8 238.1 10 7/8 276.2 6 3/8 161.9

5 6 1/8 155.6 6 1/2 165.1 6 7/8 174.6 7 1/8 181.0 7 1/2 190.5 7 7/8 200.0 81/4 209.6 8 5/8 219.1 9 7/8 250.8 11 3/8 288.9 6 7/8 174.6

5 1/2 6 5/8 168.3 7 177.8 7 3/8 187.3 7 5/8 193.7 8 228.6 8 3/8 212.7 8 3/4 222.3 9 1/8 231.6 10 3/8 263.5 11 7/8 301.6 7 3/8 187.9

6 5/8 7 3/4 196.9 8 1/8 206.4 8 1/2 215.9 8 3/4 222.3 9 1/8 231.8 9 1/2 241.3 9 7/8 250.8 10 1/4 260.4 11 1/2 292.1 13 355.6 8 1/2 215.9

7 8 1/8 206.4 8 1/2 215.9 8 7/8 225.4 9 1/8 231.8 9 1/2 241.3 9 7/8 250.8 10 1/4 260.4 10 5/8 269.9 11 7/8 301.6 13 3/8 339.7 8 7/8 225.4

7 5/8 8 3/4 222.3 9 1/8 231.8 9 1/2 241.3 9 3/4 247.7 10 1/8 257.2 10 1/2 266.7 10 7/8 276.2 11 1/4 285.8 12 1/2 317.5 14 381.0 9 1/2 241.3

8 5/8 9 3/4 247.7 10 1/8 257.2 10 1/2 266.7 10 3/4 273.1 11 1/8 282.6 11 1/2 292.1 11 7/8 301.6 12 1/4 311.2 13 1/2 342.9 15 406.4 10 1/2 266.7

9 5/8 10 3/4 273.1 11 1/8 282.6 11 1/2 292.1 11 3/4 298.5 12 1/8 308.0 12 1/2 317.5 12 7/8 327.0 13 1/4 338.6 14 1/2 368.3 16 431.8 11 1/2 292.1

10 3/4 11 7/8 301.6 12 1/4 311.2 12 5/8 320.7 12 7/8 327.0 13 1/4 336.6 13 5/8 346.1 14 381.0 14 3/8 365.1 15 1/2 393.7 17 1/8 435.0 12 5/8 320.7

11 3/4 12 7/8 327.0 13 1/4 336.6 13 5/8 346.1 13 7/8 352.4 14 1/4 362.0 14 5/8 371.5 15 406.4 15 3/8 390.5 16 1/2 419.1 18 1/8 460.4 13 5/8 346.1

13 3/8 14 1/2 368.3 14 7/8 377.8 15 1/4 387.4 15 1/2 393.7 15 7/8 403.2 16 1/4 412.8 18 5/8 422.3 17 457.2 18 1/4 463.6 19 3/4 501.7 15 1/4 387.4

16 17 1/8 435.0 17 1/2 444.5 17 7/8 454.0 18 1/8 460.4 18 1/2 469.9 18 7/8 479.4 19 1/4 489.0 19 5/8 496.6 20 7/8 530.2 22 3/8 568.3 17 7/8 454.0

18 5/8 19 3/4 501.7 20 1/8 511.2 20 1/2 520.7 20 3/4 527.1 21 1/8 538.8 21 1/2 546.1 21 7/8 555.6 22 3/8 568.3 23 1/2 596.9 25 1/8 638.2 20 1/2 520.7

20 21 1/8 536.6 21 1/2 546.1 21 7/8 555.6 22 1/8 562.0 22 1/2 571.5 22 7/8 581.0 23 1/4 590.6 23 3/4 603.3 24 7/8 631.8 26 1/2 673.1 21 7/8 555.6

24 25 1/8 638.2 25 1/2 647.7 25 7/8 657.2 26 1/8 663.6 26 1/2 673.1 27 711.2 27 3/8 695.3 27 3/4 704.9 28 7/8 733.4 30 1/2 774.7 25 7/8 657.2

Non-Weld Positive Centralizers – Casing

The Bow Spring Centralizer Sub meets the demandsof ultra-tight clearance casing strings. Where specialdrilling requirements demand that casing be run inprevious casing or open hole with close tolerances, thistool allows passing very tight restrictions, followed byexpansion into an under reamed hole. The Bow SpringCentralizer Sub offers numerous advantages,including:

• Combines slim hole capabilities with provenWeatherford welded centralizer

• Runs inside ultra-tight clearances• Centralizer bows recess completely into tool body

then expands for casing centering in open or underreamed sections

• Allows maximum fluid bypass area to minimize theimpact on circulating pressure

NON-WELD CENTRALIZERS

Casing* Previous Casing Open Hole Number ofSize Min. Drift ID Size Bow Springs

4.500 5.000 5 —9 45.000” 5.500” 6 —10 45.500 6.000 6 —10 47.000 7.500 7 —12 47.625 8.125 8 —12 68.625 9.125 9 —13 69.625 10.125 10 —14 610.750 11.250 12 —15 611.750 12.250 13 —16 613.375 14.000 14 —17 8

” ” 3/4” 7/8”

” 5/8”” ” 1/2” 5/8”” ” 7/8” 1/4” ” 1/2” 1/4”” ” 5/8” 1/2”” ” 1/2” 3/4”

” ” 1/4 1/2”” ” 1/2” ”” ” 3/4” 1/2”

Weatherford’s non-weld positive centralizers are available for both tubing and casing applications. Theysignificantly reduce frictional drag when used in deviated holes, and can provide nearly 100 percent standoff(concentricity) when run inside a cased hole.

Concentric casing strings facilitate liner and packer positioning, stage cementing, surface cementing,slip and packoff installation, and well-abandonment. Weatherford’s non-weld positive centralizers offer thefollowing features:

Non-weld design eliminates weak (brittle) spots

Patented locking tabs hold bows in the collars

•

•

•••

•

U-profile bow design permits maximum fluidpassage. Available with solid bows.

Can be transported unassembled to reduceLarge selection of bow sizes. shipping costs.

U.S. Patent No. 5,575,333

*Special Tools Available 16” - 24”

BOW SPRING CENTRALIZERSBOW SPRING CENTRALIZER SUB

POSITIVE CENTRALIZERS

Bow Spring Centralizer SUB*

7

NON-WELD CENTRALIZERS

CENTRALIZER SELECTIONTo select the right product for application, basic

considerations need to be examined.To help achieve the proper balance between starting

force and restoring force, Weatherford offers centralizerswith a wide range of bow heights and shapes as well asone piece aluminum rigid centralizers for deviated andhorizontal wells.

Centralizers for other casing and hole combinations available upon request.-Chart does not apply to BowSpring Centralizers Subs

The restoring force is the force exerted by a centralizeragainst the casing to keep it away from the bore holewall. Current API Specification 10D states that "67%may or may not be sufficient for a good cementation."Practical experience has shown that standoff values of 75to 90% are adequate, even in horizontal wells.

Restoring Force TestAccording to API SPEC 10D

Restoring Force

Test Positions

Starting Force and Moving(= Running) Force Testaccording to API SPEC 10D

F = Measured Starting andRunning ( = Moving) Force

W = Weight of 40 feetmedium weight casing

The starting force is the maximum force required tostart a centralizer into previously run casing. It shouldbe less than the weight of 40 feet (12.2 meters) ofmedium weight casing.

BOW SPRING SELECTION GUIDENON-WELD CENTRALIZERS

Casing Bow Preferred Casing Bow PreferredSize Type Hole Size Size Type Hole Size(In.) Combination (in.) Combination

(in.) (In.)4” ST A0 — 103/4” ST AO 121/4”

ST A1 — ST A1 121/4”ST A2 65/8” ST A2 125/8”ST A3 — ST A3 131/2”ST A4 — ST A4 143/4” 151/2”

41/2” ST A0 6” 61/8” 61/4” 113/4” ST AO —ST A1 61/2” 63/4” ST A1 —ST A2 — ST A2 131/2”ST A3 81/2” 83/4” ST A3 143/4” 151/2”ST A4 97/8” 105/8” ST A4 171/2”

5” ST A0 61/4” 61/2” 133/8” ST AO —ST A1 63/4” ST A1 143/4”ST A2 — ST A2 151/2”ST A3 81/2” 83/4” ST A3 16”ST A4 105/8” 11” ST A4 171/2”

51/2” ST A0 16” ST AO 171/2”ST A1 — ST A1 —ST A2 71/8” ST A2 181/2”ST A3 83/8” 81/2” ST A3 181/2”

83/4” 97/8”ST A4 105/8” 11” ST A4 20” 22”

61/2” ST A0 77/8” 185/8” ST AO —ST A1 81/2” 85/8” ST A1 —ST A2 85/8” 83/4” ST A2 —ST A3 105/8” 11” ST A3 22”ST A4 121/4” ST A4 24”

7” ST A0 83/8” 81/2” 20” ST AO —ST A1 ST A1 —ST A2 ST A2 22”ST A3 105/8” 11” ST A3 —ST A4 121/4” ST A4 24” 26”

75/8” ST A0 — 24” ST AO —ST A1 91/2” ST A1 —ST A2 97/8” ST A2 26”ST A3 121/4” ST A3 —ST A4 131/2” ST A4 28”

85/8” ST A0 93/4” 97/8” 26” ST AO —ST A1 105/8” ST A1 —ST A2 — ST A2 —ST A3 121/4” ST A3 —ST A4 131/2” ST A4 30” 32”

95/8” ST A0 — 30” ST AO —ST A1 11” ST A1 —ST A2 113/8” ST A2 —ST A3 113/4” 121/4” ST A3 32”

121/2” 125/8” ST A4 34” 36”ST A4 143/4” 151/2”

65/8” 61/2” 63/4”

81/2” 85/8” 83/4”81/2” 85/8” 83/4”

F <

8

WELDED CENTRALIZERS

The Weatherford S-Series centralizer is the standard weldedcentralizer for casing-hole size combinations and is a highquality welded product that meets or exceeds API Specification10D requirements. It offers a choice of six different bowheights, available for any casing/open hole configuration. Theend collars are available as latch-on or slip-on. The S-Seriesfeatures:

Rigid Design - End bands are equipped with ribs to providerigidity to the bands. Bow springs are of high quality heat-treated spring steel.Integral Hinge - Folded to the inside of the endbands so that,once installed, it won't unfold even under extremeconditions.Self-Locking Hinge Pins - Equipped with a positive safetylocking device.Clearance - Since bow springs are attached to the O.D. of theend collars, the centralizers may be installed over stop collarsor casing collars.

Some hole conditions do not require the same superiorperformance characteristics of the S-Series. In these instances,the B-Series centralizers offer an economical alternative. Theyare manufactured in a broad range of hole sizes and may beinstalled over the casing collars or stop collars.

These centralizers are specifically designed for closetolerance applications where running drag must be minimal, yetthe centering strength as high as possible. The uniquely-shapedbows accomplish this most effectively, making these centralizersthe optimum solution.

Available in stylesAvailable as latch-on or slip-onNotched or lap-welded versions availableFurnished with integral set screwsCan be installed without set screws, between stopcollars, for casing rotation.

•

•

•

•

•••••

Product Number: S110 _ _ Latch-On.Available bow springs: 25, 30, 36, 46, 57 and 85.

Product Number: B110 _ _ Latch-OnAvailable bow springs: 25, 36 and 46.

Product Numbers: 11216 Latch-on with lap-welded bows.: 12212 Latch-on with notched-bows: 12312 Slip-on with notched-in bows

Turbolizer

S-SERIES CENTRALIZERS

B-SERIES CENTRALIZERS

SINGLE LINER CENTRALIZERS

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WELDED CENTRALIZERS

Weatherford centralizers have all of thecharacteristics of regular centralizers as far as startingand restoring forces are concerned. The main differenceis that the centralizers have a built-in stopcollar and deflector blades. These blades, or fins, deflectthe fluid flow in a turbulent and outward directed spiral.

Lower starting forceAvailable with integral stops

Turbolizer

Turbolizer

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Choice of bow spring and deflector fin sizesEquipped with right or left handed finsHave integral set screwsMeet API Specification 10D requirements in mostcasing and hole combinationsFins are heat treated spring steelHave built-in stop collar on leading edge*

Greater centering efficiency360º wall coverage for increased load bearing area

fins on only one end so they can beinstalled over stop collars

Rotating centralizers were developed in response toindustry requirements for centralizers that could be usedwith a rotating liner in highly deviated conditions.These centralizers offer the following features:

High restoring force for optimum standoffLow moving force to minimize dragAllow free rotation of the pipe for maximumdisplacement efficiencyOver stop collar design minimizes moving forceswhile reciprocatingMeet or exceed API Specification 10D requirements

*Note: Single straight centralizers shouldnever be installed over stop collars, any upsetconnections or over a casing collars.

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Turbolizer

Turbolizer

The centralizer's fluid motion causes:Break up of cement and drilling fluids channelingDeflection of mud and cement toward washed-outsections of the well boreImproved filter cake removalSelf-cleaning action which prevents the turbolizersfrom "balling-up”

Turbolizer••

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TURBOLIZER™ CENTRALIZERS

SINGLE STRAIGHT CENTRALIZERS(TURBOLIZER)

DOUBLE REVERSE BOWTURBOLIZER CENTRALIZERS

ROTATING CENTRALIZERS (MODEL STT-1SL)

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WELDED CENTRALIZERS

These centralizers provide positive standoff and centering, andcan be used in both cased or open hole applications. In casedhole situations, they can be installed below casing hangingequipment and under liner hangers to facilitate proper setting.They offer:• Single bar or double bar — Single bar versions are

recommended for cased hole applications; double barfor open hole.

• Available in various configurations — Available in latch-onor slip-on versions and also in latch-on with integral stops.

These centralizers are custom built to suit severe serviceapplications such as in subsea conditions and in large boredeviated holes where extreme axial and radial loads may beencountered. Either a T-bar or flat bar may be used to provide alarge bearing surface to virtually eliminate well boregouging. Options may include:

• Extra heavy-duty end collars• Double rows of set screws• Flat bar or T-bar staves• Bronze cladding on stave ends to protect wellhead

equipment

Thermal stabilizers are used to insulate steam injection linesfrom the casing. The rigid stabilizers, with replaceable non-asbestos-compound insulation pads affixed to the bows, greatlyreduce heat loss.

These centralizers are designed for use with multiple tubingstrings (dual, triple, etc., or tubingless completions) run in onehole. The centralizers may be installed over close tolerance stopcollars.

SPRIAL-TYPE MT CENTRALIZERS

THERMAL STABILIZERS (NOT SHOWN)

RIGID T-BAR CENTRALIZERS

RIGID CENTRALIZERS, LATCH-ON

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WELDED CENTRALIZERS

These centralizers are designed to give a minimal amountof drag resistance when passing through the previous casing orwellhead and then spring out to fit underreamed sections andwashouts.• Useful in sections where gravel packing is being

implemented• Used for oversized holes• Available with special clearance collars designed to go

through restrictions

Weatherford Depth Orientation Markers are patented*devices which exert a focused magnetic field inside the casingso that they will affect the casing collar locator tool andprovide a downhole reference point.• Used on flush joint pipe where connections are hard to

detect• Used with non-magnetic tubulars in corrosive service• Provide a permanent benchmark on wells for future

production• Made to match specific casing weights• Offered in standard and close tolerance versions• Will sometimes save a gamma ray run

Weatherford micro-annulus seals are used to block offpossible gas or fluid migration along the casing-cementinterface. This product offers the following features:• Reduce interzonal communications• Prevent gas pressure on the annulus• Deter leakage of stimulation media up the annulus• Minimize gas storage well leakage• Decrease loss of injection media in injection wells• Standard model is rated to 275°F (135°C)• High temperature model rated to 400°F (204°C)

*U.S. Patent number 4,244,424

GRAVEL PACK CENTRALIZERS

DEPTH ORIENTATION MARKERS (DOM)™

MICRO-ANNULUS SEALS(CEMENT SEAL UNITS)

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WELDED CENTRALIZERS

WELDED CENTRALIZER SPECIFICATIONS

Notes:*1. Close Tolerance — Integral Stop-Collar*2. Where two bow spring sizes are indicated, the lower should be used for smaller hole sizes or with light weight casing and 2 centraliers per joint installations.*3. Type 12 and 16 bow springs are identical, 12 is for notched-in, 16 for lap-welded Close Tolerance Centralizer

Hole 2 2 3 4 5 5 6 7 7 8 9 10 11 13 16 18 20Size (in.)

3/8 7/8 1/2 1/2 1/2 5/8 5/8 5/8 5/8 3/4 3/4 3/8 5/8

Casing Size (in inches)

BOW SPRING SELECTION GUIDE — WELDED CENTRALIZERS

4 1/2-4 3/4 30 *16 *12 — — — — — — — — — — — — — —

5 3/4-6 36 30 25 *12/16 *12 — — — — — — — — — — — —

6 1/8-6 3/8 46 30/36 30 *16 *12/16 — — — — — — — — — — — —

6 1/2-6 3/4 46 46 36 25 *16 *12 — — — — — — — — — — —

7 3/8-7 7/8 57 46 46 36 30/36 25 *12 — — — — — — — — — —

8 -8 57 57 46 36/46 36 30/36 *16/25 *16 *12 — — — — — — — —

8 3/4-9 85 57 57 46 46 36 25 25 *12 — — — — — — — —

9 1/2-10 85 85 85 57 46/57 46 36 36 25/30 — — — — — — — —

10 -11 — 85 85 57/85 57 57 46 46 36 25/30 *12/16 — — — — — —

12-12 — — 85 85 85 85 57 57 57 46 36 25 — — — — —

14-15 — — — — 85 85 85 85 85 57/85 46/57 46 36/46 — — — —

17-18 — — — — — — — — — 85 85 85 57 46 25/36 — —

19 -20 — — — — — — — — — — — — — — 57 — —

22-23 — — — — — — — — — — — — — — 85 46/57 46

24 — — — — — — — — — — — — — — — 57 46/57

26 — — — — — — — — — — — — — — — 85 57/85

3/8 5/8

1/2 1/2

5/8

1/4

1/2

5/8

12 Bow 16 Bow 25 Bow 30 Bow 36 Bow 46 Bow 57 Bow 85 BowCasingSizeIn.

Max. Min. Max. Min. Max. Min. Max. Min. Max. Min. Max. Min. Max. Min. Max. MinBow Comp. Bow Comp. Bow Comp. Bow Comp. Bow Comp. Bow Comp. Bow Comp. Bow Comp.O.D. O.D. O.D. O.D. O.D. O.D. O.D. O.D. O.D. O.D. O.D. O.D. O.D. O.D. O.D. O.D.In. in. in. in. in. in. in. in. in. in. in. in. in. in. in. in.

4 6.000 5.500 6.250 5.500 7.250 5.500 7.550 5.500 8.500 5.500 9.250 5.500 11.500 5.500 14.500 5.500

5 6.500 6.000 6.750 6.000 7.875 6.000 8.250 6.000 8.750 6.000 9.750 6.000 12.000 6.000 15.000 6.000

5 7.000 6.500 7.250 6.500 8.375 6.500 8.750 6.500 9.125 6.500 10.250 6.500 12.500 6.500 15.500 6.500

6 8.125 7.625 8.375 7.625 9.500 7.625 9.875 7.625 10.375 7.625 11.375 7.625 13.625 7.625 16.625 7.625

7 8.500 8.000 8.750 8.000 9.875 8.000 10.250 8.000 10.750 8.000 11.750 8.000 14.000 8.000 17.000 8.000

7 9.125 8.625 9.375 8.625 10.500 8.625 11.000 8.625 11.500 8.625 12.375 8.625 14.625 8.625 17.625 8.625

8 10.250 9.625 10.500 9.625 11.500 9.625 12.000 9.625 12.500 9.625 13.875 9.625 15.625 9.625 18.625 9.625

9 11.250 10.750 11.500 10.750 12.500 10.750 13.000 10.750 13.500 10.750 14.875 10.750 16.625 10.750 19.625 10.750

10 12.375 11.875 12.625 11.875 13.625 11.875 14.125 11.875 14.625 11.875 15.875 11.875 17.750 11.875 20.875 11.875

11 13.375 12.875 13.625 12.875 14.625 12.875 15.125 12.875 15.625 12.875 16.875 12.875 18.750 12.875 21.875 12.875

13 15.000 14.500 15.250 14.500 16.250 14.500 16.750 14.500 17.250 14.500 18.750 14.500 20.375 14.500 23.500 14.500

16 17.625 17.125 17.875 17.125 18.875 17.125 19.375 17.125 19.875 17.125 21.375 17.125 23.000 17.125 26.125 17.125

18 20.250 19.750 20.500 19.750 21.500 19.750 22.000 19.750 22.500 19.750 24.000 19.750 25.625 19.750 28.750 19.750

20 21.625 21.125 21.875 21.125 22.875 21.125 23.375 21.125 23.875 21.125 25.375 21.125 27.000 21.125 30.125 21.125

1/2

1/25/8

5/85/85/8

3/43/43/8

5/8

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The centralizer is also a mechanical friction-reduction system that performs independently of drilling orcompletion mud film strength or lubricity. The small contactarea of the rollers with the casing or borehole wall functionsexceptionally well in underpressured conditions, where risk ofdifferential sticking is high.

LoDRAG

tools have been used primarily to run casing andsand-control screens into unconsolidated sandstone reservoirs.Using tools in these reservoirs can reduce axial dragby up to 60 percent. The tool can reduce axialfriction in cased holes by similar percentages.

LoDRAG

LoDRAGLoDRAG

ROLLER CENTRALIZERS

• Rollers help to avoid plowing that can create majordrag problems

• Precision machined inside diameter providesexcellent rotational performance in mud

• Small roller contact area reduces differential sticking• Rollers provide exceptional wear resistance• Torque-reducing performance improves the cement

sheath• The roller/axle relationship ensures that axle shear

stresses remain within elastic limits• High quality construction materials improve high-

pressure / high-temperature capabilities

LoDRAG™ CENTRALIZER

The majority of LoTORQ tools have been used in extended-reach wells to run and rotate long, heavy-wall liners whererotation provides an optimum cement sheath.

Weatherford developed a mechanical friction (torque anddrag) reduction system that performs independently fromdrilling/completion fluids. Analysis has shown that the smallcontact area of the rollers function exceptionally well inunder-pressured conditions where the risk of differentialsticking is high. The centralizers offers operatorsthe same benefits as the centralizer but also serveswell when long and/or heavy cemented liners are beingrotated.

LoTORQLoDRAG

The features of the centralizer include:LoDRAG

LoTORQ™ CENTRALIZERS

LoDRAG™

LoTORQ™

The tools achieve optimum performance when:

• Casing, liner, and screens are being run into horizontaland extended-reach wells

• Centralizer wear may compromise the cement job• Where HSE requirements ban the use of oil-based and

pseudo-oilbased mud• Underpressured formations may cause differential sticking

LoDRAG

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FLOW ENHANCEMENT TOOLS

Weatherford's broad offering of flow enhancementtools perform well in highly deviated and horizontalwells. They are designed in many sizes, materials andconfigurations to meet customer requirements, evenunder severe conditions.

The rigid centralizers are generally constructed in onepiece to add greater strength and are held in place byhigh load stop collars or set screws. The tools aredesigned to improve cement flow while promotingmaximum standoff from the bore hole.

• Blades overlap the entire 360º open holecircumference

• Reduced flow area between the spiral providesa vortex motion for increased fluid velocity

• Extra length gives maximum centralization• Spiral design provides optimum flow area• Made of high strength, corrosion-resistant cast

aluminum• Used with corrosion-resistant alloys (CRA) to

negate ionic transfer

• Spiral blades increase annular turbulence• Blades are set at an average of 45º for maximum

fluid swirl• Blades and collar made of abrasion-resistant mild steel• Continuous welds secure blades to collars• Available with or without set screws

• Designed specifically for highly deviated andhorizontal wells

• Ideal for use with liner hangers• Steel construction provides superior toughness

over other materials and alloys• Fin design provides low coefficient of friction to

reduce drag forces while running pipe• Fins create vortex flow to optimize mud displacement

and minimize pressure drop across the centralizer• construction gives maximum standoff• Fin design resists high sideloads• Spiral blades yield to allow passage through

unexpected undergauge open hole

SpiraGlider

Now Available in a Heavy Duty Version

RIGID CENTRALIZERS

SPIRAL RIGID CENTRALIZERS

SHORT SPIRAL RIGID CENTRALIZERS

SPIRAGLIDER™ CENTRALIZERS

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J10H STOP COLLARS

J10S STOP COLLARS

This stop collar is for use on casing up to 30 inchesin diameter. A single row of set screws offers goodgripping force and cost effectiveness.

gives excellentgripping force, and used where high axial loads areexpected

Superb solid collar set-screw device

Weatherford stop collars limit the movement ofmechanical cementing products on the pipe and aremanufactured to withstand high axial forces. Fourstandard designs are available.

This hinged stop collar has an internal groove intowhich a spiral locking pin is driven, firmly wedging thecollar into position around the casing. The JSH StopCollar is used on both upset and non-upset casing andprovides maximum annular clearance.

The J5H Stop Collar has a cross-bolt design thatmakes installation quick and easy. This economicalcollar can be used where annular tolerances are notcritical.

JSH STOP COLLARS

J5H STOP COLLARS

Model J5H Stop Collar(60500

Model J10H Stop Collar(60200)

Model J10S Stop Collar(60300)

Stop Collars

Size Collar Type/Maximum OD (in. mm)

(in.) JSH J5H J4H J10H/J10S

2 3/8 3 3/8 86

2 7/8 3 7/8 98

3 1/2 4 3/4 121 4 1/2 114

4 1/2 5 5/8 143 5 3/4 146 5 5/8 143

5 6 1/2 156 6 1/4 159 6 1/8 156

5 1/2 6 5/8 168 6 3/4 171 6 5/8 168

6 5/8 7 3/4 197 7 7/8 200 7 3/4 197

7 8 1/4 209 8 1/4 210 8 1/4 209

7 5/8 8 7/8 225 8 7/8 225 8 7/8 225

8 5/8 9 7/8 251 9 7/8 251 9 7/8 251

9 5/8 10 7/8 276 10 7/8 276 10 7/8 276

10 3/4 12 305 12 305 12 305

11 3/4 13 330 13 330 13 330

13 3/8 14 5/8 371 14 5/8 371 14 5/8 371

16 17 1/2 445 17 1/2 445

18 5/8 20 1/8 511

20 21 1/2 546 21 1/2 546

24 25 1/2 648

26 27 5/8 701

30 31 7/8 810

*Other sizes are available.

STOP COLLARS

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Model JSH Stop Collar(60900)

Rotating wellbore wipers can be used when wellconditions do not permit reciprocation of the casingstring, but do permit rotation. The 60-inch long stripsare clamped tightly to the casing at intervals along thelength of the wiper.

Note: Stop collars must be used with rotating wellbore wipers.

Reciprocating Wellbore Wiper

Wellbore Wipers

W i l d c a t ( 5 1 0 0 7 )

Weatherford’s ™ scratchers removeexcessive wall cake and improve the cement bondbetween the casing and porous formations whilereinforcing the cement column. Their hinged designmakes them easy to install.

For running in the hole, a series of scratchers ismounted on the casing string. The inclined externalbristles abrade the wellbore during running andreciprocation. The scratchers feature large fluid-bypassslots and coiled bristles for bending durability.

Wildcat

Product Casing Loop O.D. Compressed O.D.Number Size in. mm. in. Mm

5360041 4 ½” 11 1/8” 283 5 5/8” 143

5360051 5 ½” 12 1/8” 308 6 5/8” 168

5360070 7” 13 5/8” 346 8 1/8” 206

5360075 7 5/8” 14 1/4” 362 8 3/4” 222

5360085 8 5/8” 15 1/4” 387 10 3/4” 248

5360095 9 5/8” 16 1/4” 413 9 3/4” 273

5360010 10 3/4” 17 3/8” 441 11 7/8” 302

5360013 13 3/8” 20” 508 14 ½” 368

Other sizes upon request.

These wipers remove excess wall cake to improvecement-to-formation bonding by producing a wiping actionduring running and reciprocation. A continuous,interlocking and overlapping loop of tempered-steel wirecable is laced into the hinged collars. A bolt holds thewipers in position and eliminates the need for stop collars.A hinged version is also available.

SPECIALTY TOOLS

WILDCAT™ SCRATCHER

RECIPROCATING WELLBORE WIPERS

ROTATING WELLBORE WIPERS (MODEL 54850)

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SPECIALTY TOOLS

PLUG-BACK STINGERSWeatherford offers for rent or sale full length joints of

6.5 lb/ft. 2 / " EUE 8rd N-80 tubing fully dressed withappropriate centralizers and cable scratchers. Thisconfiguration is effective with rotation and/orreciprocation, depending on hole conditions and rigcapabilities. The centralizing and abrading action that the"Plug-Back Stingers" provide greatly improves the muddisplacement efficiency of the cement slurry. The smalldiameter stinger minimizes the possibility of mudcontamination in the slurry as it is withdrawn from theplugged interval and provides a "weak" point in the drillstring should problems cause the pipe to be cemented in.

Weatherford has been renting 2 / " tubing dressed toset cement for over 20 years on the Gulf Coast. Thisservice is now available from your local Weatherfordrepresentative. Tubing will come pre-dressed with hingedrotating centralizers and scratchers. The entire stringusually consisting of 10, 20, or 30 joints is racked andsafely stored in baskets. Additional components that areavailable include the drill pipe wiper darts, up-jetteddiverter sub, and handling tools. Handling tools caninclude a TS100 Spider, base plate and elevators.Crossovers and extensions are available as needed.

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7

8

8

“Plug-Back Stingers" provide greatly improves the muddisplacement efficiency of the cement slurry.

Weatherford cement baskets protect weak formationsfrom excessive hydrostatic pressure exerted by the weightof the cementing column. They are normally installed onthe casing string above the weak formations, but they arealso used in stage-cementing or in cementing the annulusfrom the surface. Each basket’s overlapping metal finsprovide maximum flexibility and fluid passage whilemaintaining optimum support characteristics.

Weatherford’s hinged baskets can be installed on upsetpipe and can be disassembled for shipping and spaceeconomy. Special sizes upon request.

CEMENT BASKETS (SOLID OR HINGED)

Cement baskets should be installed overstop collars to facilitate pipereciprocation.

STANDARD CEMENT BASKET SPECIFICATIONSCSG./ Latch-on No. of Slip-On No. of Total Basket Min.TBG. Type Bows Type Bows Length O.D. HoleSize. Size

3 ½" — — 1835731 10 24 ½" 11 ½"" 5"

4 ½" — — 1835741 10 24 ½" 12 ½" 6"

5 ½" 1825751 12 1835751 12 24 ½" 13 ½"" 7 1/4"

7" 1825770 14 1835770 14 24 ½" 15" 8 3/4"

7 5/8" 1825775 14 1835775 15 24 ½" 15 5/8" 9 ½"

8 5/8" 1825785 16 1835785 16 24 ½" 16 5/8" 10 5/8"

9 5/8" 1825795 18 1835795 18 24 ½" 17 5/8" 11 5/8"

10 3/4" 1825710 18 1835710 19 24 ½" 18 3/4" 12 3/4"

11 3/4" 1825711 20 1835711 21 24 ½" 19 3/4" 13 3/4"

13 3/8" 1825713 24 1835713 24 24 ½" 21 3/8" 15 ½"

16" 1825716 28 1835716 28 24 ½" 24 18"

18 5/8" 1825718 34 1835718 34 24 ½" 26 5/8" 20 5/8”

20" 1825720 34 1825720 34 24 ½” 28" 22"

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515 Post Oak Blvd., Suite 600, Houston, Texas 77027-9496Phone: 713-693-4000Fax: 713-621-0994www.weatherford.com

© 2001, Weatherford. All rights reserved. Brochure # 71.01

Weatherford, Hydro-Bonder, LoDRAG & LoTROQCentrPro, Tandem Rise Turbolizer, DOM, and Wildcat areregistered Trademarks of Weatherford International, Inc.

Weatherford products and services are subject toWeatherford’s standard terms and conditions. For moreinformation concerning the full line of Weatherfordproducts and services, please contact your authorizesWeatherford representative. Unless noted otherwise,trademarks and service marks noted herein are the propertyof Weatherford.

Case I:Over stopcollars

Case II:Betweenstop collars

Case III:Between couplingsand stop collars

Case IV:Over couplings

Choosing proper installation pattern for mechanical cementingproducts is essential to achieving desired results.

Weatherford

For example, centralizers should be installed between stopcollars in close-tolerance situations to avoid drag caused byincreased starting forces. So contact your Weatherford representa-tive for assistance in planning your cementation program.

will ensure that the products and the installationpattern will meet your operating requirements. This investmentwill pay dividends over the life of the well.

For optimal centering, centralizers are installed over stop collars.Installation on racks eliminates lost time. This pattern is notrecommended in close tolerance conditions.

For optimum centering in close-tolerance pattern, centralizersare positioned between stop-collars. STA0 or STA1 bows arerecommended. This pattern can be installed on racks. Closetolerance welded centralizers, with integral stop collars, areavailable alternatives.

In this alternate close-tolerance pattern, centralizers are installedbetween a stop collar and the casing coupling. This patternallows limited centralizer travel and uses only one stop collar percentralizer. Installation should not be performed on racks.

Installation of centralizers over casing coupling reduces annularflow area, concentrates lateral loads at the coupling, and requiresextra rig time. Weatherford does not recommend this pattern forclose-tolerance conditions where STA0 bows would be used.

RECOMMENDED INSTALLATION PATTERNS

CASE I

CASE II

CASE III

CASE IV

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