ISO 10427:1993
(Main)Petroleum and natural gas industries — Bow-spring casing centralizers — Specification
Petroleum and natural gas industries — Bow-spring casing centralizers — Specification
Specifies testing procedures to verify the manufacturer's design, the materials and process for the construction. Requirements are specified in the fourth edition of API Specification 10D (Spec 10D), Januar 1991, which is adopted as ISO 10427. For the purposes of international standardization, modifications have been made that are outlined.
Industries du pétrole et du gaz naturel — Centreurs de tubes de cuvelage — Spécifications
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Standards Content (Sample)
0 IS0
IS0 10427:1993(E]
Introduction
International Standard IS0 10427:1993 reproduces the content of
API Spec lOD, 4th edition, 1991. ISO, in endorsing this API document,
recognizes that in certain respects the latter does not comply with all
current IS0 rules on the presentation and content of an International
Standard. Therefore, the relevant technical body, within lSO/TC 67, will
review IS0 10427:1993 and reissue it, when practicable, in a form com-
plying with these rules.
This standard is not intended to obviate the need for sound engineering
judgement as to when and where this standard should be utilized and
users of this standard should be aware that additional or differing require-
ments may be needed to meet the needs for the particular service in-
tended.
Standards referenced herein may be replaced by other international or
national standards that can be shown to meet or exceed the requirements
of the referenced standards.
Appendix A to this document should not be considered as requirements.
It is included only as information.
. . .
III
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IS0 10427:1993(E)
INTERNATIONAL STANDARD 0 IS0
- Bow-spring
Petroleum and natural gas industries
casing centralizers - Specification
1 Scope
This International Standard specifies testing procedures to verify the manufacturer’s design, the materials and
process for the construction of bow-spring casing centralizers other than of the rigid or positive types.
2 Requirements
Requirements are specified in:
“API Specification 1OD (Spec lOD), Fourth Edition, January 1, 1991 - Specification for Bow-Spring Casing
Centralizers”,
which is adopted as IS0 10427.
For the purposes of international standardization, however, modifications shall apply to specific clauses and para-
graphs of publication API Spec 10D. These modifications are outlined below.
Page 6
Foreword, item d)
Throughout publication API Spec lOD, the conversion of English units shall be made in accordance with IS0 31.
In particular,
1 inch (in) = 25,4 mm (exactly)
LENGTH
= 304,8 mm or 0,3048 m (exactly)
1 foot (ft)
MASS 1 pound (lb) = 0,453 592 37 kg (exactly)
1 pound-force (Ibf) = 4,448222 N
FORCE
NOTE 1 kgf = 9,80665 N (exactly)
LINEIC MASS
LINEAR DENSITY 1 pound per inch (lb/in) = 17,857 967 kg/m
or 1 pound per foot (Ib/ft) = 1,488 163 9 kg/m
STRENGTH OR STRESS 1 pound-force per square inch (Ibf/in*) = 6,894,757 Pa
Page 7
Information given in the POLICY is relevant to the APl publication only.
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IS0 10427A993(E)
Page 11
Subclause 4.4, item a
Publication API Spec 5CT referenced therein is available under the following IS0 reference:
IS0 11960 (at present under study).
Page 15
Section 7, Marking
The specifications of section 7 may be used on a provisional basis. In the future edition of this International Stan-
dard, marking should comply with the provisions of annex E of the lSO/lEC Directives, part 2.
item d. Example
The NOTE is relevant to the API publication only.
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IS0 10427:1993(E)
Specification for Bow-Spring
Casing Centralizers
API SPECIFICATION IOD (SPEC IOD)
FOURTH EDITION, JANUARY 1, 1991
American Petroleum Institute
1220 L Street, Northwest
Washington, DC 20005
rT>
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IS0 10427:1993(E)
4
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IS0 10427:1993(E)
Issued by
AMERICAN PETROLEUM INSTITUTE
Production Department
FOR INFORMATION CONCERNING TECHNICAL CONTENTS OF
THIS PUBLICATION CONTACT THE API PRODUCTION DEPARTMENT,
2535 ONE MAIN PLACE, DALLAS, TX 75202-3904 - (214) 748-3841.
SEE BACK SIDE FOR INFORMATION CONCERNING HOW TO OBTAIN
ADDITIONAL COPIES OF THIS PUBLICATION.
Users of this publication should become familiar with its scope
and content, including any provisions it may have regarding marking
of manufactured products. This publication is intended to
supplement rather than replace individual engineering judgment.
REG. U.S. PATENT OFFICE
OFFICIAL PUBLICATION
Copyright @ 1990 American Petroleum Institute
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IS0 10427:1993(E)
2 American Petroleum Institute
TABLEOFCONTENTS
Page
Foreword . 2
Policy . 3
Sect. 1: Scope . 4
Sect. 2: General Information .
5
Sect. 3: Requirements .
6
Sect. 4: Testing Equipment .
7
Sect. 5: Procedure for Starting Force and Running Force Tests . 9
Sect. 6: Restoring Force Test . .10
Sect. 7: Marking. . .ll
Sect. 8: Recommended Methods for Estimating Restoring
Force Requirements in Deviated and Dogleg Holes . .12
Appendix A: Miscellaneous Information .
.15
mate. Note use of period instead of comma for decimal
Foreword
point in metric values, e.g. 25.4 mm. instead of Z5,4
a) This specification is under the jurisdiction of the
mm.
Committee on Standardization of Well Cements.
The factors used for conversion of U.S. Customary units
b) The purpose of this specification is to provide min-
to metric values in this specification are:
imum performance standards, test procedures and
marking requirements for bow-spring casing central-
1 inch (in) = 25.4 millimeters (mm)
izers.
1 foot (ft) = 0.3048 meter (m)
1 pound (lb) = 0.454 kilogram (kg)
c) The requirements contained herein are limited but
1 pound force (lbf) = 4.448222 Newton (N)
are deemed adequate for use in oilfield cementing
1 pound per foot (lb/ft) = 14.594 Newton per
operations.
meter (N/m)
d) Conversions of U.S. Customary units* to Interna-
tional System @.I.) metric units are provided through-
Attention Users: Portions of this publication have been
out the text of this specification in parentheses, e.g. 916
changed from the previous edition. The locations of
ft. (2’79 m.). S.I. Equivalents have also been included in
changes have been marked with a bar in the margin, as
all tables. U.S. Customary units are preferential and
shown to the left and right of these paragraphs. In some
shall be the standard in this specification. The metric
cases the changes are significant, while in other cases
equivalents of U.S. Customary units given in the body
the changes reflect minor editorial adjustments. The
of the standard and in the appendix may be approxi-
bar notations in the margins are provided as an aid to
users as to those parts of this publication that have been
Units based upon the foot and the
*U.S. Customary Units -
changed from the previous edition, but API makes no
pound commonly used in the United States of America and
defined by the National Bureau of Standards. warranty as to the accuracy of such bar notations.
Requests for permission to reprodwe or translate a11
Note
or any part of th‘e m.aterial published herein shodd hc
This edition supersedes the third edition, dated Feb-
addressed to the Director, Prod wt ion Dtycc 1-t wtjl t,
I ruary 17, 1986.
2535 One Main Place, Da,llas TX 75202-3904.
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IS0 10427:1993(E)
Spec 10D: Bow-Spring Casing Centralizers
3
POLICY
API PUBLICATIONS NECESSARILY ADDRESS THING CONTAINED IN THE PUBLICATION BE
PROBLEMS OF A GENERAL NATURE. WITH CONSTRUED AS INSURING ANYONE AGAINST
RESPECT TO PARTICULAR CIRCUMSTANCES, LIABILITY FOR INFRINGEMENT OF LETTERS
LOCAL, STATE AND FEDERAL LAWS AND REGU- PATENT.
LATIONS SHOULD BE REVIEWED.
GENERALLY, API STANDARDS ARE REVIEWED
AND REVISED, REAFFIRMED, OR WITHDRAWN
API IS NOT UNDERTAKING TO MEET DUTIES
AT LEAST EVERY FIVE YEARS. SOMETIMES A
OF EMPLOYERS, MANUFACTURERS, OR SUP-
ONE-TIME EXTENSION OF UP TO TWO YEARS
PLIERS TO WARN AND PROPERLY TRAIN AND
WILL BE ADDED TO THIS REVIEW CYCLE. THIS
EQUIP THEIR EMPLOYEES, AND OTHERS EX-
PUBLICATION WILL NO LONGER BE IN EFFECT
POSED, CONCERNING HEALTH AND SAFETY
FIVE YEARS AFTER ITS PUBLICATION DATE
RISKS AND PRECAUTIONS, NOR UNDERTAKING
AS AN OPERATIVE API STANDARD OR, WHERE
THEIR OBLIGATIONS UNDER LOCAL, STATE, OR
AN EXTENSION HAS BEEN GRANTED, UPON
FEDERAL LAWS.
REPUBLICATION. STATUS OF THE PUBLICA-
NOTHING CONTAINED IN ANY API PUBLICA-
TION CAN BE ASCERTAINED FROM THE API
TION IS TO BE CONSTRUED AS GRANTING ANY
PRODUCTION DEPARTMENT (TEL. 214-748-3841).
RIGHT, BY IMPLICATION OR OTHERWISE, FOR
A CATALOG OF API PUBLICATIONS AND MATE-
THE MANUFACTURE, SALE, OR USE OF ANY
RIALS IS PUBLISHED ANNUALLY AND UP-
METHOD, APPARATUS, OR PRODUCT COVERED
DATED QUARTERLY BY API, 1220 L ST., N.W.,
BY LETTERS PATENT. NEITHER SHOULD ANY-
WASHINGTON, D.C. 20005.
7
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IS0 10427:1993(E)
4 American Petroleum Institute
SECTION 1
SCOPE
1.1 Coverage. This specification covers performance cable to rigid or positive centralizers. Testing equip-
requirements for bow-spring centralizers under speci- ment as well as marking requirements are included. In
fied testing procedures. This testing serves (a) as verifi- addition, calulations for determining centralizer spac-
cation testing for manufacturer’s design, materials, and ing, based on centralizer performance and desired
process specifications; and (b) periodic testing confirms stand-off, in deviated and dogleg holes are presented.
the consistency of product performance. It is not appli-
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IS0 10427:1993(E)
Spec 10D: Bow-Spring Casing Centralizers
5
SECTION 2
GENERAL INFORMATION
2.1 Functions of a Centralizer: The purpose of a e. Flexed: A bow-spring is considered flexed when
three times the specified minimum restoring force
casing centralizer is to facilitate running casing to the
(*5%) has been applied.
desired depth, and to assist in centering the casing in
the bore hole. A centralizer can be constructed in var-
f.
Hole Size: The diameter of the borehole.
ious ways, using various types, shapes, and quantities of
bow-springs.
g. Restoring Force: The restoring force is the force
exerted by a centralizer against the casing to keep
2.2 Definitions
it away from the bore hole wall.
a. Annular Clearance for Perfectly Centered Cas-
h. Running Force: Running force is the maximum
ing. ID of borehole minus OD of casing divided by
force required to move a centralizer through the
two.
previously run casing.
b. Centralizer Permanent Set: Permanent set is the
change in centralizer bow height after repeated Note: Starting, restoring, and running force values
flexing. A centralizer is considered to have reached can vary based on installation methods.
permanent set after being flexed 12 times, for the
i. Standoff: The smallest distance between the OD
purposes of this specification.
of the casing and the ID of borehole.
c .
Deflection/Sag/Sag Point: Casing that is supported
j. Standoff Ratio: The standoff ratio is the ratio of
at two points will tend to sag between the support
standoff to annular clearance, expressed as a per-
points. This sag is called the casing sag or casing
centage. (Example calculation see Appendix A
deflection. The point where the deflection is at a
Section B).
maximum is called the sag point. (See Fig. 8.1)
d .
DLS: Dogleg Severity is a rate of change in devia- k. Starting Force: Starting force is the maximum
tion of the well bore and is measured in degrees force required to start a centralizer into the
per 100 feet (See equation Paragraph 8.6). casing.
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IS0 10427:1993(E)
6 American Petroleum Institute
SECTION 3
REQUIREMENTS
3.1 Starting Force:
3.3 Frequency of Testing:
The maximum starting force shall be less than the
a. Tests for design and process verification must be
weight of 40 ft. of medium weight casing as defined in
performed for a minimum of 6 prototype central-
~ Table 3.1. The maximum starting force is to be deter-
izers. All of the tested centralizers must conform
mined for a centralizer in new, fully assembled con- to the performance requirements of Table 3.1.
dition.
b. For confirmation of the consistency of product
performance, tests must be performed at least
annually for each centralizer size manufactured to
3.2 Restoring Force:
this specification in quantities greater than 500
The minimum restoring force, for 67% standoff ratio, per year. Corrective action must be implemented
shall not be less than the values shown in Table 3.1. See and documented for the centralizer size in ques-
Appendix A for the calculation of how the require- tion if the tested centralizer does not conform to
ments were derived. the performance requirements of Table 3.1.
TABLE: 3.1 SPECIFICATIONS: CASING CENTRALIZERS
1 2 3 4
Casing Size: Medium Wt. Casing Minimum Restoring Force Maximum Starting Force
At 67% Standoff Ratio
Inches mm. 1 b./ft. Lbf N. Lbf N.
k/m*
89 9.91* 14.8 396 396 1761
w* 1761
4’ 102 11.34 16.9 454 454 2019
2019
114 11.6 17.3 464 2064 464 2064
4%.
5 19.4 520 520 2313
127 13.0 2313
23.1 620 620 2758
5% 140 15.5 2758
24.0 35.7 960 960 4270
6% 168 4270
1040 4626
7 178 26.0 38.7 1040 4626
1056 1056 4697
194 26.4 39.3 4697
7%
53.6 1440 1440 6405
219 36.0 6405
8%
7117
244 40.0 59.6 1600 7117 1600
9%
2040 9074
273 51.0 76.0 1020 4537
10%
9608
298 54.0 80.4 1080 4804 2160
11%
10853
340 61.0 90.8 1220 5427 2440
13%
11565
16 406 65.0 96.8 1300 5783 2600
473 87.5 130.3 1750 7784 3500 15569
18%
20 508 94.0 140.0 1880 8363 3760 16725
*Liner sizes and Plain-end weights
10
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IS0 10427:1993(E)
Spec 10D: Bow-Spring Casing Centralizers
SECTION 4
TESTING EQUIPMENT
4.1 Test Stand: the flexed condition and the outer pipe (B). The
OD of the inner pipe A shall be within the toler-
Machinery that allows application of vertical loads and
ances as shown in Table 6.10 of API Specification
is capable of measuring these loads and vertical dis-
5CT for non upset pipe. Burrs or similar defects
placements.
shall be removed.
Examples of typical equipment are shown in Figs. 4.1
Surfaces on the ends of inner pipe A, outside the
and 4.2.
length to be covered by the centralizer and other
test components are exempted from above specifi-
4.2 Instrumentation:
cations.
a. Displacement: The test stand shall be instru-
b. Outer pipe (B, Figs. 4.1 and 4.2): The length of the
mented to allow reading of l/l6 inch (1.6 mm) or
outer pipe shall be greater than a Centralizer bow-
smaller.
spring in the flexed condition. The ID of the outer
4.3 Accuracy: pipe shall be the borehole diameter for which the
centralizer is designed. Tolerances shall be within
a. Load Measurements: Accuracy shall be within
J/& inch (0.8 mm). Burrs or
+j/8 inch (3.2 mm),
t5% of measured value.
similar defects shall be removed.
b. Displacement: Accuracy shall be within + &
The upper end of the outer pipe used for the Start-
inch (+ 0.8 mm) within the range of measure-
ing Force test may be beveled on the inside to a
ments.
maximum of 45 degrees with a maximum larger
pipe ID of +f/s inch (3.2 mm).
c. Calibration of all measuring equipment must be
performed at least annually.
The end of the outer pipe, (other than the upper
end used for Starting Force tests), beyond the
4.4 Test Pipe:
length covered by the centralizer when flexed dur-
a. Inner Pipe (A, Figs. 4.1 and 4.2): The length of the ing the Restoring Force test is exempted from
inner pipe shall be greater than a centralizer in above specifications.
FIG. 4.2
B
Example Casing Centralizer Restoring Force
Test Equipment
FIG. 4.1
Example Casing Centralize
...
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