API 8 Round

API 8 Round Connections

Connections

Scope

Connection Specific Running Guidelines

These guidelines apply specifically to the use of API
8RD (STC, LTC, EUE, NUE) connections. This document
is based on API RP 5C1 which is the main document
applicable for this connection.

References
IDM Code GDL00389/3 / October 2019

.API RP 5C1: Recommended Practice for care and use of

.casing and tubing, latest edition.
API 5A3: Recommended practice on thread compounds

.for casing, tubing and line pipe.

ISO 13678: Petroleum and natural gas industries
-Evaluation and testing of thread compounds for use

.with casing, tubing, line pipe and drill stem elements.

API RP 5A5: Field inspection of new casing, tubing, and

.plain-end drill pipe.

API RP 5B1: Gauging and inspection of casing, tubing,

.and line pipe threads.

API 5B: Specification for Threading, Gauging and Thread

.Inspection of Casing, Tubing and Line Pipe Threads.

API TR5TP: Torque-Position Assembly Guidelines for API
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Casing and Tubing Connections.

Equipment, Material & Documents

1. Verify API modified thread compound is available.
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2. If other compound is to be used, ensure it provides

adequate lubrication and sealability. Refer to API RP
5A3 or ISO 13678 for further details. 1
 Pre-Running
API 8 Round Connections

1. If drifting the connections at the rig site it is

recommended to do so from box to pin end.

2. Ensure connections are cleaned and free of all debris

and / or contaminants.

3. Use high pressure water with detergent to clean

the connections, it is not advisable to use an oil based
Connection Specific Running Guidelines

solvent which may leave a residue on the threads.

4. Never move or handle pipe without the correct

thread protectors securely in place.

5. Visually inspect threads prior to running, ensuring no

damage is evident.

6. Verify compatibility of the API 8RD pipe with any

accessories such as pup joints.

7. Verify material grade of all accessories ensuring

compatibility with main string.

Inspection
1. Inspection criteria for all API connections is as
outlined in API RP 5A5.

2. Ensure the complete thread area has no tears,

gouges or raised metal.
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3. Black crested threads within the complete thread

length area must not exceed 25% of the circumference
of two (2) threads.

4. Complete thread length is indicated in API RP 5B1.

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5. Any gouge or tear which traverses from the coupling

OD to the face is cause for rejection.
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 Thread Compound Application

API 8 Round Connections

1. Apply a thin coating of thread compound on pin
and box connections, fully covering all threads.

2. The thread form should be fully visible.

Connection Specific Running Guidelines

IDM Code GDL00389/3 / October 2019

3. During make up an API 8RD connection has high

interference between flanks, leading to high friction.
Hence, it is very important to apply dope correctly
on both ends to avoid galling. Due to connection
configuration the thread crests and roots are not in
contact, there is a gap to be filled by the running
compound.
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 Thread Lock Application
API 8 Round Connections
Connection Specific Running Guidelines

1. Connections must be clean and dry when applying

thread lock.

2. Apply a thin coating of thread lock on 50% of the

pin threads furthest from the pipe body.

3. Do not apply thread compound to pin or box.

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 Make Up

API 8 Round Connections

Make up process and torque values are referenced
in API RP 5C1.

Make Up with Optimum Torque

To achieve correct make up, apply optimum torque.

After reaching this value, it is necessary to verify the box
face position reaches the vanish point of the pin, with a

Connection Specific Running Guidelines

tolerance of ± two threads from the box face.
IDM Code GDL00389/3 / October 2019

No visible
Vanish point threads

Make Up with Maximum Torque

If after applying optimum torque there are several

threads visible beyond the box face, apply 25% more
torque to reach an acceptable final position. If after
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applying the additional torque there is more than

three threads exposed, the joint must be rejected as
questionable.
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 Make Up with Minimum Torque
API 8 Round Connections

If the box face surpasses thread vanish point by more

than two (2) thread turns without attaining 75%
of optimum torque, the joint should be treated as
questionable and rejected.

MAXIMUM
Connection Specific Running Guidelines

MAKE-UP
ACCEPTABLE
OPTIMUM ZONE

MINIMUM
TORQUE

2 threads out 2 threads inside

Casing sizes (≥ 4 ½") will have a 3/8" (0.375") equilateral

triangle stamped at the pin end, this triangle is solely an
aid to establish the location of the thread vanish point
and is not a basis for make up acceptance / rejection.
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 Pulling

API 8 Round Connections

1. Automatic stabbing system or stabber is highly
recommended to maintain the pipe in a vertical position.

2. Apply the back up tong jaw on the lower part, over

the mill end of the coupling.

3. Apply power tong in low rpm (3-5 rpm) to break

out the connection, ensuring the pipe is stabilised

Connection Specific Running Guidelines

during the break and spin out process.

4. Visual inspection is recommended to classify the

thread condition. Any rejected connections should be
clearly marked and segregated for further investigation.

5. Apply clean, dry thread protectors after applying

IDM Code GDL00389/3 / October 2019

storage compound on clean, dry connections.

6. Storage / thread compound should always be

applied to connections post job, even rejects.

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API 8 Round Connections
Connection Specific Running Guidelines
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Tenaris has produced this manual for general information only. While every effort has been made to
ensure the accuracy of the information contained within this publication, Tenaris does not assume any
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responsibility or liability for any loss, damage, injury resulting from the use of information and data
herein. Tenaris products and services are only subject to the Company’s standard terms and Conditions
or otherwise to the terms resulting from the respective contracts of sale, services or license, as the case
may be. The information in this publication is subject to change or modification without notice. For more
complete information please contact a Tenaris’s representative or visit our website at www.tenaris.com.
This manual supersedes Version 03 / March 2018. ©Tenaris 2019. All rights reserved.