ISO/PAS 16846:2025
(Main)Oil and gas industries including lower carbon energy — Thermoplastics lined tubing for wells
Oil and gas industries including lower carbon energy — Thermoplastics lined tubing for wells
This document specifies requirements for downhole thermoplastics lined tubing (TLT) used in the oil and gas industries, including configuration, materials, manufacturing, inspection and testing, documentation, marking, packaging, transportation, storage and use. This document is applicable to downhole thermoplastics lined tubing (TLT) used in contact with media related to oil and gas exploration and production (which involves multiphase flow, as well as water injection). This document is suitable for thermoplastics including but not limited to polyethylene (PE), polyethylene of raised temperature resistance (PE-RT), ultra-high molecular weight polyethylene (PE-UHMW), crosslinked polyethylene (PE-X), polypropylene (PP), unplasticized polyamide (PA-U), polyketone (PK), polyphenylene sulfide (PPS), polyvinylidene fluoride (PVDF), and polyetheretherketone (PEEK) which meet the requirements of relevant design specifications, standards or regulations.
Industries du pétrole et du gaz, y compris les énergies à faible teneur en carbone — Tubes à revêtement thermoplastique pour les puits
General Information
Standards Content (Sample)
Publicly
Available
Specification
ISO/PAS 16846
First edition
Oil and gas industries including
2025-07
lower carbon energy —
Thermoplastics lined tubing for wells
Industries du pétrole et du gaz, y compris les énergies à faible
teneur en carbone — Tubes à revêtement thermoplastique pour
les puits
Reference number
© ISO 2025
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ii
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, symbols and abbreviated terms . 2
3.1 Terms and definitions .2
3.2 Symbols and abbreviated terms .4
3.2.1 Symbols.4
3.2.2 Abbreviated terms .4
4 TLT configuration . 5
4.1 Configuration .5
4.2 Pipe ends .5
4.3 Connection type .5
5 Materials requirements . 7
5.1 Backing pipe .7
5.2 Liner .7
5.3 CB ring .7
5.4 Coated coupling.8
6 Manufacturing . 8
6.1 Selection of backing pipe .8
6.1.1 New tubing serves as the backing pipe .8
6.1.2 Used tubing serves as the backing pipe .8
6.2 Threading .8
6.3 Lining .8
6.3.1 Mechanical fit lining .8
6.3.2 Cement backed lining .9
6.4 Manufacture of CB ring and installation of couplings .9
6.4.1 Manufacture of CB ring.9
6.4.2 Installation of couplings .9
6.5 Traceability .9
6.6 Purchaser inspection .9
7 Inspection and testing .10
7.1 Inspection of backing pipe .10
7.2 Inspection of liner .10
7.2.1 Surface quality .10
7.2.2 Dimensions .10
7.2.3 Performance .10
7.3 Inspection of TLT .10
7.3.1 Length measurement .10
7.3.2 Thread gauging and inspection .11
7.3.3 Straightness evaluation.11
7.3.4 Drift test . 12
7.3.5 Hydrostatic test . 12
7.3.6 Bonding strength test . 12
7.3.7 Connection test . 12
7.3.8 Rapid decompression test . 13
7.3.9 Combined loading test . 13
7.4 CB ring test . 13
7.5 Inspection frequency and acceptance criteria . 13
7.5.1 Lot . 13
7.5.2 Inspection frequency . . 13
7.5.3 Batch release test .14
7.5.4 Type test .14
7.5.5 Acceptance criteria . 15
iii
8 Documentation .15
8.1 Documents provided by the purchaser . 15
8.2 Documents provided by the manufacturer . 15
9 Marking, packaging, transportation and storage .16
9.1 Marking .16
9.2 Packaging .16
9.3 Transportation .16
9.4 Storage .16
10 Use . 17
Annex A (informative) Maximum operating temperatures and characteristics of typical
thermoplastics .18
Annex B (informative) Test method for gas permeability of polymer materials .30
Annex C (informative) Test method for bonding strength of TLT .32
Annex D (informative) Use of TLT .34
Bibliography .35
iv
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 67, Oil and gas industries including lower carbon
energy, Subcommittee SC 5, Casing, tubing and drill pipe.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
v
Publicly Available Specification ISO/PAS 16846:2025(en)
Oil and gas industries including lower carbon energy —
Thermoplastics lined tubing for wells
1 Scope
This document specifies requirements for downhole thermoplastics lined tubing (TLT) used in the oil and
gas industries, including configuration, materials, manufacturing, inspection and testing, documentation,
marking, packaging, transportation, storage and use.
This document is applicable to downhole thermoplastics lined tubing (TLT) used in contact with media
related to oil and gas exploration and production (which involves multiphase flow, as well as water injection).
This document is suitable for thermoplastics including but not limited to polyethylene (PE), polyethylene of
raised temperature resistance (PE-RT), ultra-high molecular weight polyethylene (PE-UHMW), crosslinked
polyethylene (PE-X), polypropylene (PP), unplasticized polyamide (PA-U), polyketone (PK), polyphenylene
sulfide (PPS), polyvinylidene fluoride (PVDF), and polyetheretherketone (PEEK) which meet the
requirements of relevant design specifications, standards or regulations.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
the requirements of this document. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 472, Plastics — Vocabulary
ISO 2859-1, Sampling procedures for inspection by attributes — Part 1: Sampling schemes indexed by acceptance
quality limit (AQL) for lot-by-lot inspection
ISO 10405, Petroleum and natural gas industries — Care and use of casing and tubing
ISO 10893-3, Non-destructive testing of steel tubes — Part 3: Automated full peripheral flux leakage testing of
seamless and welded (except submerged arc-welded) ferromagnetic steel tubes for the detection of longitudinal
and/or transverse imperfections
ISO 11960, Petroleum and natural gas industries — Steel pipes for use as casing or tubing for wells
ISO 13678, Petroleum and natural gas industries — Evaluation and testing of thread compounds for use with
casing, tubing, line pipe and drill stem elements
ISO 13679, Petroleum and natural gas industries — Procedures for testing casing and tubing connections
ISO 15156-2, Petroleum and natural gas industries — Materials for use in H S-containing environments in oil
and gas production — Part 2: Cracking-resistant carbon and low-alloy steels, and the use of cast irons
ISO 15527, Plastics — Compression-moulded sheets of polyethylene (PE-UHMW, PE-HD) — Requirements and
test methods
ISO 23936-1, Petroleum, petrochemical and natural gas industries — Non-metallic materials in contact with
media related to oil and gas production — Part 1: Thermoplastics
API RP 5B1, Gauging and Inspection of Casing, Tubing and Line Pipe Threads
API Spec 5B, Threading, Gauging, and Inspection of Casing, Tubing, and Line Pipe Threads
API Spec 15S:2022, Spoolable Reinforced Plastic Line Pipe
API TR 17TR2, The Ageing of PA-11 in Flexible Pipes
ASTM A700, Standard Guide for Packaging, Marking, and Loading Methods for Steel Products for Shipment
3 Terms, definitions, symbols and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 472 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1.1
backing pipe
tubing before being lined with a thermoplastic liner (3.1.12)
[SOURCE: ISO/PAS 24565:2022, 3.1.1, modified — "ceramic liner" has been replaced by "a thermoplastic
liner".]
3.1.2
batch release test
BRT
test performed by or on behalf of the manufacturer on a batch of products, which must be satisfactorily
completed before the batch can be released
3.1.3
bonding strength
shear stress required to strip off the liner (3.1.12) from the backing pipe (3.1.1) along the axial direction
3.1.4
compatibility
degradation degree of material properties caused by physical or chemical reactions with produced or
injected fluids, as well as the stability of the materials in sunlight
3.1.5
CB ring
corrosion barrier ring
polymeric ring inserted between adjacent lengths of liner (3.1.12) in a tubing string to provide continuity of
corrosion protection
[SOURCE: ISO/PAS 24565:2022, 3.1.6, modified — The full form "corrosion barrier ring" has been changed
from a preferred term to an admitted term.]
3.1.6
coupling
internally threaded cylinder for joining two lengths of threaded pipe
[SOURCE: ISO 11960:2020, 3.1.8]
3.1.7
drift mandrel
device used to check the size of casing and tubing before it is run
Note 1 to entry: The drift mandrel is put through each joint of casing and tubing to make certain the inside diameters
are sizes specified for the particular job.
3.1.8
flare of the liner end
edge formed by turning the outer edge of the thermoplastic pipe (3.1.17) along the cross-section of the
backing pipe (3.1.1)
3.1.9
gas transmission rate
volume of gas passing through a plastic material, per unit area and unit time, under unit partial-pressure
difference between the two sides of the material
3 2
Note 1 to entry: It is expressed as volume value at standard temperature and pressure, in cm /(m ·d·Pa).
[SOURCE: ISO 15105-1:2007, 3.1, modified — The abbreviated term "GTR" has been removed; the original
note 1 to entry has been replaced by a new one.]
3.1.10
gas permeability
volume of gas passing through a plastic material of unit thickness, per unit area and unit time, under unit
partial-pressure difference between the two sides of the material
3 2
Note 1 to entry: It is expressed as volume value at standard temperature and pressure, in cm ·cm/(cm ·s·Pa).
[SOURCE: ISO 15105-1:2007, 3.2, modified — The admitted term "coefficient of gas permeability" and the
symbol "P" have been removed; the original notes to entry have been replaced by a new one.]
3.1.11
label 1
dimensionless designation for the size or specified outside diameter that can be used when ordering the pipe
Note 1 to entry: see Table 1.
[SOURCE: ISO 11960:2020, 3.1.24, modified — Note 1 to entry has been added.]
3.1.12
liner
thermoplastic pipe (3.1.17) lined onto the inner wall of the backing pipe (3.1.1)
Note 1 to entry: The liner is aimed at preventing corrosion and scaling, and improving wear resistance.
3.1.13
maximum operating temperature
maximum temperature to which a component is subjected, including deviations from normal operations,
such as start-up/shutdown
[SOURCE: ISO 23936-1:2022, 3.1.12]
3.1.14
premium connection
threads used in tubing and casing of which the structure and characteristics are different from those
specified in API standards
3.1.15
renovation
work incorporating all or part of the original fabric of the pipeline, by means of which its current performance
is improved
[SOURCE: ISO 11295:2022, 3.1.6]
3.1.16
thermoplastic, noun
plastic that is capable of being softened repeatedly by heating and hardened by cooling through a
temperature range characteristic of the plastic and, in the softened state, of being shaped by flow repeatedly
into articles by moulding, extrusion, or forming
Note 1 to entry: See ISO 472:2013, 2.1177 and 2.1178.
3.1.17
thermoplastic pipe
extruded pipe with thermoplastic (3.1.16) as the main raw material and no more than 5 % of other
components added
3.1.18
thermoplastics lined tubing
TLT
steel tubing with thermoplastic pipe (3.1.17) lined onto its inner wall by diameter-compression and/or
drawing processes
3.1.19
type test
TT
test performed to prove that the product is capable of conforming to the requirements given in the relevant
standard
Note 1 to entry: The type test results remain valid until there is a change in the product provided that the process
verification tests are done regularly.
3.2 Symbols and abbreviated terms
3.2.1 Symbols
t wall thickness of liner
3.2.2 Abbreviated terms
CB corrosion barrier
ID inner diameter of backing pipe
OD outer diameter of liner
PA-U polyamide, unplasticized (PA-U11, PA-U12)
PE polyethylene (PE-HD, PE-MD)
PE-RT polyethylene of raised temperature resistance
PE-UHMW ultra-high molecular weight polyethylene
PE-X polyethylene, crosslinked (PE-Xb)
PEEK polyetheretherketone
PK polyketone
PP polypropylene (PP-H, PP-B, PP-R, PP-RCP)
PPS polyphenylene sulfide
PTFE polytetrafluoroethylene
PVDF polyvinylidene fluoride
4 TLT configuration
4.1 Configuration
TLT consists of the backing pipe and the liner. The typical configuration of TLT body under mechanical fit
design is shown in Figure 1.
Other manufacturers may pump a holding layer of viscous material that hardens over time (grout) to fill the
annulus between the backing pipe nominal ID and the liner OD.
The purchasers shall select the appropriate design and performance requirements based on downhole
conditions, well type and other commercial considerations.
Key
1 liner
2 backing pipe
Figure 1 — Configuration of TLT body
4.2 Pipe ends
Unless otherwise specified in the order, backing pipes for TLT shall be supplied with API Spec 5B threads at
both ends and with corresponding couplings. If specified in the order, backing pipes shall be supplied with
threads at both ends and without couplings, or with other premium connections.
4.3 Connection type
Lengths of backing pipes shall be connected with each other with couplings. Example of the connection
type is shown in Figure 2. The minimum coupling length shall conform to the requirements specified
in Table 1. CB rings are usually equipped on the inner wall of the coupling to ensure liner continuity for
corrosion protection of exposed backing pipe and connection. The length of the CB ring shall conform to the
requirements specified in Table 2. Other forms of coupling protection, such as coatings, may be used, but the
coupling make-up torque shall not be affected.
The flare of the liner end shall extend over the whole end of the backing pipe and shall be in contact with
the CB ring in the coupling putting the CB ring in compression, thus ensuring the integrity of the whole
connecting structure. Other forms of coupling protection are acceptable.
The previously mentioned requirements are applicable for all manufacturers’ technologies including grout
backed lining.
Key
1 liner
2 backing pipe
3 flare of the liner end
4 CB ring (or coating)
5 coupling
6 threads
l CB ring length
L coupling length
Figure 2 — Example configuration of TLT connection
Table 1 — The minimum length of the coupling
Minimum length of coupling, L
mm
Label 1
non-upset tubing external upset tubing
2-3/8 124 140
2-7/8 151 158
3-1/2 166 171
4-1/2 182 186
Table 2 — Length range of CB ring
CB ring length, l
Label 1
mm
2-3/8 30 to 40
≥2-7/8 40 to 55
5 Materials requirements
5.1 Backing pipe
When using new tubing as the backing pipe, its dimensions and properties shall conform to the requirements
specified in ISO 11960. When used in a sour environment, the backing pipe shall conform to the requirements
of resistance to sulfide stress cracking specified in ISO 15156-2.
For renovation, previously-used tubing may also be used as the backing pipe. The technical requirements for
material, performance and testing of used tubing shall be agreed on by the purchaser and the manufacturer
based on the working environment. Tubing previously used in a sour environment shall not be used as the
backing pipe.
5.2 Liner
Thermoplastics used in manufacturing liner for oil and gas exploration and production include, but are not
limited to, PE, PE-RT, PE-UHMW, PE-X, PP, PA-U, PK, PPS, PEEK and PVDF, to which are added those additives
that are needed to facilitate the manufacture of pipes conforming to this document. This document can also
be applied as a reference when using other types of thermoplastics as the lining material.
NOTE 1 Maximum operating temperatures for typical thermoplastic materials are shown in Annex A.
If additives are used, they shall be uniformly dispersed. The additives shall not be used separately or
together in quantities sufficient to impair the chemical, physical or mechanical characteristics as specified
in this document.
The material characteristics of PE, PE-RT, PE-UHMW, PE-X, PP, PA-U, PK, PPS, PEEK and PVDF used for the
liner materials are shown in Annex A.
When the liner is used in a specific oil and gas field environment, the compatibility shall be determined
in accordance with ISO 23936-1, Level 3 – Material stability (accelerated) or for PA-U alternatively in
accordance with API TR 17TR2. When the liner is used in a specific environment containing sand, abrasion
property shall be determined in accordance with ISO 15527.
When the liner intends to be used in environments containing acidic gases (H S, CO , etc.), the gas
2 2
permeability of TLT should be evaluated in accordance with Annex B.
The colour of the liner can be natural. Other colours should be agreed upon between the purchaser and the
manufacturer.
The liner shall be made by virgin material. No more than 3 % (mass fraction) of clean, reprocessed material
generated from a manufacturer’s own production may be used if it is derived from the same virgin material
as used for the liner. The thermoplastic pipes shall be in accordance with this document.
External reprocessed material and recycled material shall not be used.
NOTE 2 External reprocessed material is produced from unused thermoplastic product, regardless of where they
are manufactured.
NOTE 3 Recycled material is produced from used thermoplastic products which have been cleaned and crushed
or ground.
5.3 CB ring
CB rings are typically made of polymer materials that meet the requirements of resistance to corrosion,
temperature and wear for the bore fluids, usually, elastomers, fibre-filled PTFE.
5.4 Coated coupling
Coated couplings are used as an integral part of the lined tubing system, when a CB ring is not utilized by the
manufacturer. Coating material shall follow the same requirements of resistance to corrosion, temperature
and wear for the bore fluid.
6 Manufacturing
6.1 Selection of backing pipe
6.1.1 New tubing serves as the backing pipe
When new tubing is used as the backing pipe, dimensions and properties shall conform to the requirements
specified in ISO 11960.
The inner wall of the backing pipe shall be clean before lining into the liner.
6.1.2 Used tubing serves as the backing pipe
6.1.2.1 Distinguishing of the used tubing
When used tubing is served as the backing pipe, the tubing shall be straight (free of any bends or deformation)
and free of fractures, cracks or ruptures.
The used tubing shall be inspected and conform to the requirements of ISO 10405. The minimum wall
thickness of the used tubing shall be not less than 87,5 % of the corresponding new backing pipe.
6.1.2.2 Cleaning of the used tubing
Physical, chemical and/or mechanical methods shall be used to remove grease, wax, sand, scale, rust and
any other organic residues and impurities in the used tubing.
6.1.2.3 Straightening of the used tubing
Straightness of the used tubing shall be in accordance with ISO 11960, otherwise it shall be straightened as
specified in 7.3.3.
6.1.2.4 Drifting of the used tubing
Each joint of the used tubing shall be drift-tested throughout its entire length, and accepted only if the drift
mandrel passes freely.
6.2 Threading
If necessary, machine the threads on pipe ends to the dimensions and tolerances specified in API Spec 5B or
as agreed on between the purchaser and the manufacturer.
6.3 Lining
6.3.1 Mechanical fit lining
TLT should be fabricated by inserting the liner into the backing pipe. The interference fit between the liner
and the backing pipe is realized by inserting the liner into the backing pipe via the diameter reduction or
drawing process, taking advantage of the memory effect of the thermoplastic material to allow it to expand
and fill. After inserting, the longitudinal stress induced by diameter reduction can be released by placing the
TLT at room temperature for a long time or standing at higher temperature for a short time, and then flare
of the liner end can be formed. It is necessary to strictly control the heating temperature and heating time
during flaring and ensure the matching between the flaring mould and the liner.
6.3.2 Cement backed lining
This process involves inserting the liner inside the backing pipe with enough annular space left to pump
grout, the grout is left to cure over time before the liner ends are flared for API connections or finished for
premium connections without flaring.
Other lining processes are also acceptable.
6.4 Manufacture of CB ring and installation of couplings
6.4.1 Manufacture of CB ring
The CB rings shall be moulded and/or machined to the exact dimensions to meet the requirement of specific
type steel couplings.
When the CB ring is made of polymer materials such as rubber or PTFE, the moulding conditions of the CB
rubber ring or PTFE billets shall be documented. When the polymer coating is used for CB ring, the coating
conditions shall be documented.
For premium connections, CB rings shall be moulded and/or machined to meet their dimensions
requirements.
6.4.2 Installation of couplings
The coupling for connection shall conform to the requirements specified in ISO 11960 and its length shall
conform to the requirements specified in Table 1. The CB ring should be inserted into the coupling and
match the end of the TLT, thus ensuring the integrity of the whole connecting structure between tubing and
coupling.
Before screwing, thread compound shall be evenly applied on the entire meshing surface between the
tubing and the coupling. The coupling shall be tightened mechanically, and the torque shall conform to the
requirement specified in ISO 10405.
Each joint of TLT supplied with the coupling shall be visually examined separately to see whether the
coupling is tight or not. The thread of the tubing shall not be exposed. The CB ring shall not be deformed,
warped, damaged or broken off.
6.5 Traceability
The manufacturer shall establish and follow procedures for maintaining and/or identifying the lot number
of the backing pipe even after the liner being inserted. The lot number shall be marked on the products as
required.
The manufacturer shall also establish and follow procedures for identifying the lot number of TLT (final
product) and mark the products as required.
6.6 Purchaser inspection
When an inspector representing the purchaser desires to inspect the tubing or witness quality control
tests, the inspector shall be reasonably notified of the start of the production as well as the time at which
the product will be available for witness or inspection. The manufacturer shall afford all reasonable and
safe facilities to meet the inspector's requirement for the product manufactured in accordance with this
document. All inspections shall be made at the place of manufacture before shipment unless otherwise
specified on the purchase agreement and shall be conducted so as not to interfere unnecessarily with
the operation of the production line. A written acceptance report from the purchaser's inspector shall be
available for each lot before shipment if thus specified in the purchase agreement.
7 Inspection and testing
7.1 Inspection of backing pipe
The wall thickness of backing pipe shall be inspected by automated full peripheral flux leakage testing in
accordance with ISO 10893-3. Other inspection items and corresponding methods for the backing pipe shall
be determined by the agreement between the purchaser and the manufacturer.
7.2 Inspection of liner
7.2.1 Surface quality
The inner and outer surfaces of thermoplastic liner shall be flat and smooth, free of dents, bubbles and other
surface defects which can affect its performance. The liner shall not contain visible impurities. The flare of
the liner end shall be cut flat and perpendicular to the axis.
7.2.2 Dimensions
The outer diameter of the liner shall conform to the supplier quality control dimension requirements, and its
wall thickness shall be not less than 3,0 mm. The wall thickness requirements of the commonly used liner
such as PE, PE-RT, PE-UHMW, PE-X and PP are shown in Table 3. The wall thickness requirements of other
liners shall meet the manufacturer liner design requirements applicable to the purchaser well conditions.
Different lining technologies such as cement-backed lining define the liner dimensions and share non-
proprietary details with the purchaser.
Table 3 — Wall thickness and tolerances of the liner
Wall thickness of liner, t Thickness tolerances of liner
Label 1
mm mm
2-3/8 3,0 0 to +0,3
2-7/8 3,5 0 to +0,3
3-1/2 4,0 0 to +0,3
4-1/2 4,5 0 to +0,3
7.2.3 Performance
The liner performance shall be inspected in accordance with the requirements specified in 5.2. The specific
inspection items and methods for liner shall be determined by the agreement between the purchaser and
the manufacturer.
7.3 Inspection of TLT
7.3.1 Length measurement
TLT shall be supplied in length conforming to the joint length requirements specified in Table 4. The length
of accessories, such as coupling stock and pup joints, shall be as specified in the agreement. The length
of each joint of finished product shall be measured to ensure meeting the requirements. Length shall be
measured in metres and be accurate to 0,01 m.
Table 4 — Range lengths of TLT
Range 1 Range 2 Range 3
m m m
a
TLT with threads at both ends and with corresponding couplings 6,10 to 7,32 8,53 to 9,75 11,58 to 12,80
negotiated by agreement between
Pup joints
the purchaser and the manufacturer
a
Length other than those listed may be furnished by agreement between the purchaser and the manufacturer.
7.3.2 Thread gauging and inspection
The API thread of TLT shall be inspected in accordance with API RP 5B1. Premium connections shall be
inspected according to the purchase agreement.
7.3.3 Straightness evaluation
Deviation from straight, or chord height, shall not exceed the following:
a) for Label 1: 4-1/2 or larger, 0,2 % of the total length of TLT measured from one end to the other, as
shown in Figure 3;
b) for Label 1: all the sizes, 3,18 mm (1/8 in) maximum drop within the 1,5 m (5,0 ft) length at each end, as
shown in Figure 4.
Key
1 taut string or wire
2 TLT
L total length of TLT
Figure 3 — Full-length straightness measurement
Key
1 straight line
2 TLT
a
Hooked end.
Figure 4 — End straightness measurement
7.3.4 Drift test
Each length of TLT shall be drift-tested throughout its entire length. Drift mandrel dimensions (length
and diameter) shall conform to Table 5 or be determined by agreement between the purchaser and the
manufacturer.
Table 5 — Standard drift mandrel size
Standard drift mandrel size
min.
Label 1
mm
Outer diameter Length
2-3/8 40,6 1 067
2-7/8 50,8 1 067
3-1/2 63,5 1 067
4-1/2 86,4 1 067
7.3.5 Hydrostatic test
The pressure tolerance of TLT shall not be lower than that of the backing pipe. The hydrostatic test shall be
carried out in accordance with ISO 11960 and held the test pressure for not less than 5 s without leakage.
7.3.6 Bonding strength test
The bonding strength between the liner and the backing pipe of TLT shall be not less than 0,1 MPa. The
bonding strength test should be carried out in accordance with Annex C.
7.3.7 Connection test
7.3.7.1 Make-up and break-out test
Make-up and break-out tests shall be carried out in accordance with ISO 13679. The actual make-up torques
should be recommended by the manufacturer for reference. The tubing connection shall withstand four
cycles of make-up and break-out operation without thread gluing damage. The flare of liner end and CB ring
shall not be damaged in the form of cracking, flattening, etc.
7.3.7.2 Evaluation of corrosion integrity
The manufacturer shall be responsible for the flare of the liner end and CB ring integrity of the coupling/
connection and shall be able to demonstrate this integrity for their particular designs of liner and connection
geometry. Typically, this should be done through a combination of hydrostatic pressure tests at elevated
temperatures and/or flow loop tests of TLT specimens in fluids representative of downhole corrosive
environments.
7.3.8 Rapid decompression test
Rapid decompression test shall be carried out in accordance with API Spec 15S:2022, Annex B. There shall
be no collapse or blistering of the liner or sustain other damage visible with the unaided eye. The test shall
result in no disbondment exceeding the manufacturer’s acceptance criterion.
For TLT not intending for gas or multiphase flow service, this subclause does not apply, and the tubing shall
be marked indicating that neither gas service nor multiphase flow service is permitted.
7.3.9 Combined loading test
The manufacturer shall verify that the TLT has suitable integrity under the mechanical and thermal loads
to be encountered during installation and use in any given service. When required by the purchaser, the
combined loading test should be carried out in accordance with ISO 13679. The TLT system shall not be
separated from the joint during the test and shall not fail, and there shall be no changes in appearance of
the joint under pressure conditions. When the tubing is used in a dynamic condition, for instance, used as a
wellhead string puller, fatigue tests shall be performed.
7.4 CB ring test
All polymeric materials used for manufacturing CB rings can be subject to physical and/or chemical
degradation when
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