SIST EN ISO 3421:2022
(Main)Petroleum and natural gas industries - Drilling and production equipment - Offshore conductor design, setting depth and installation (ISO 3421:2022)
Petroleum and natural gas industries - Drilling and production equipment - Offshore conductor design, setting depth and installation (ISO 3421:2022)
This document specifies the requirements and recommendations for the design, setting depth and installation of conductors for the offshore petroleum and natural gas industries. This document specifically addresses:
— design of the conductor, i.e. determination of the diameter, wall thickness, and steel grade;
— determination of the setting depth for three installation methods, namely, driving, drilling and cementing, and jetting;
— requirements for the three installation methods, including applicability, procedures, and documentation and quality control.
This document is applicable to:
— platform conductors: installed through a guide hole in the platform drill floor and then through guides attached to the jacket at intervals through the water column to support the conductor, withstand actions, and prevent excessive displacements;
— jack-up supported conductors: a temporary conductor used only during drilling operations, which is installed by a jack-up drilling rig. In some cases, the conductor is tensioned by tensioners attached to the drilling rig;
— free-standing conductors: a self-supporting conductor in cantilever mode installed in shallow water, typically water depths of about 10 m to 20 m. It provides sole support for the well and sometimes supports a small access deck and boat landing;
— subsea wellhead conductors: a fully submerged conductor extending only a few metres above the sea floor to which a BOP and drilling riser are attached. The drilling riser is connected to a floating drilling rig. The BOP, riser and rig are subject to wave and current actions while the riser can also be subject to VIV.
This document is not applicable to the design of drilling risers.
Erdöl- und Erdgasindustrie - Bohr- und Förderausrüstung - Offshore-Leiterauslegung, Setztiefe und Einbau (ISO 3421:2022)
Industries du pétrole et du gaz naturel - Équipements de forage et de production - Conception des tubes conducteurs en mer, profondeur de mise en place et installation (ISO 3421:2022)
Le présent document spécifie les exigences et les recommandations relatives à la conception, la profondeur de mise en place et l'installation des tubes conducteurs destinés aux industries du pétrole et du gaz naturel en mer. Le présent document couvre plus particulièrement les aspects suivants:
— conception du tube conducteur, c'est-à-dire détermination du diamètre, de l'épaisseur de paroi et de la nuance d'acier;
— détermination de la profondeur de mise en place pour trois méthodes d'installation, à savoir battage, forage et cimentation, et injection;
— exigences pour les trois méthodes d'installation, notamment l'applicabilité, les modes opératoires, la documentation et le contrôle qualité.
Le présent document est applicable:
— aux tubes conducteurs de plate-forme: installés à travers un trou de guidage dans le plancher de forage de la plate-forme, puis à travers les guides fixés à la jacket par intervalles à travers la colonne d'eau pour soutenir le tube conducteur, supporter les actions et empêcher les déplacements excessifs;
— aux tubes conducteurs soutenus par une plate-forme auto-élévatrice: un tube conducteur temporaire utilisé uniquement lors des opérations de forage, qui est installé par une plate-forme de forage auto-élévatrice. Dans certains cas, le tube conducteur est mis en tension par des dispositifs de mise en tension fixés à l'appareil de forage;
— aux tubes conducteurs auto-porteurs: un tube conducteur autoportant en porte-à-faux installé dans des eaux peu profondes, habituellement des profondeurs d'eau d'environ 10 m à 20 m. Il fournit le seul soutien au puits et soutient parfois un petit pont d'accès et débarcadère;
— aux tubes conducteurs de tête de puits sous-marins: un tube conducteur entièrement immergé s'étendant seulement de quelques mètres au-dessus du fond marin et auquel sont fixés un BOP et un riser de forage. Le riser de forage est relié à un appareil de forage flottant. Le BOP, le riser et l'appareil de forage sont soumis aux actions des vagues et des courants, tandis que le tube prolongateur peut également être soumis aux VIV.
Le présent document n'est pas applicable à la conception des risers de forage.
Industrija za predelavo nafte in zemeljskega plina - Vrtalna in proizvodna oprema - Načrtovanje plavajočih vodnikov, nastavitev globine in vgradnja (ISO 3421:2022)
Ta dokument podaja zahteve za načrtovanje, nastavitev globine in vgradnjo vodnikov, ki se uporabljajo v industriji za predelavo nafte in zemeljskega plina na odprtem morju. Ta dokument obravnava:
– načrtovanje vodnika, tj. določitev premera, debeline stene in vrste jekla;
– določanje nastavitve globine za tri načine vgradnje, in sicer vgradnjo z zabijanjem, vrtanjem/cementiranjem in vodnim curkom;
– zahteve glede vgradnje za metode vgradnje, tj. načela izbire, delovne postopke in parametre.
Ta dokument se uporablja za:
– ploščadne vodnike: vgradijo se skozi vodilno luknjo v odru vrtalne ploščadi in se nato z vodili, nameščenimi v ustreznih razmikih vzdolž vodnega stolpca pritrdijo na plašč tako, da omejujejo vpliv meteoroloških in oceanografskih dejavnikov na vodnike ter preprečujejo prevelike vzdolžne premike;
– vodnike, podprte z dvigalom: začasni vodniki, ki se uporabljajo samo med postopki vrtanja in jih vgradi dvižna vrtalna ploščad. V nekaterih primerih se vodnik napne z napenjali, ki so pritrjena na vrtalno ploščad;
– prosto stoječe vodnike: samonosilni kesoni v konzolnem načinu, vgrajeni v plitvih vodah, katerih globina običajno dosega približno od 10 do 20 m. Zagotavlja edino podporo za vrtino ter včasih podpira manjšo ploščad za dostop in privez čolnov;
– Podvodni vodniki v ustju vrtine: vodniki, ki so v celoti pod vodno gladino in se dvigajo le nekaj metrov nad morskim dnom.
Ta dokument se ne uporablja za dvižne cevi za vrtanje.
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-september-2022
Industrija za predelavo nafte in zemeljskega plina - Vrtalna in proizvodna oprema -
Načrtovanje plavajočih vodnikov, nastavitev globine in vgradnja (ISO 3421:2022)
Petroleum and natural gas industries - Drilling and production equipment - Offshore
conductor design, setting depth and installation (ISO 3421:2022)
Erdöl- und Erdgasindustrie - Bohr- und Förderausrüstung - Offshore-Leiterauslegung,
Setztiefe und Einbau (ISO 3421:2022)
Industries du pétrole et du gaz naturel - Équipements de forage et de production -
Conception des tubes conducteurs en mer, profondeur de mise en place et installation
(ISO 3421:2022)
Ta slovenski standard je istoveten z: EN ISO 3421:2022
ICS:
75.180.10 Oprema za raziskovanje, Exploratory, drilling and
vrtanje in odkopavanje extraction equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN ISO 3421
EUROPEAN STANDARD
NORME EUROPÉENNE
June 2022
EUROPÄISCHE NORM
ICS 75.180.10
English Version
Petroleum and natural gas industries - Drilling and
production equipment - Offshore conductor design, setting
depth and installation (ISO 3421:2022)
Industries du pétrole et du gaz naturel - Équipements Erdöl- und Erdgasindustrie - Bohr- und
de forage et de production - Conception des tubes Förderausrüstung - Offshore-Leiterauslegung, Setztiefe
conducteurs en mer, profondeur de mise en place et und Einbau (ISO 3421:2022)
installation (ISO 3421:2022)
This European Standard was approved by CEN on 27 May 2022.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 3421:2022 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
European foreword
This document (EN ISO 3421:2022) has been prepared by Technical Committee ISO/TC 67 "Materials,
equipment and offshore structures for petroleum, petrochemical and natural gas industries" in
collaboration with Technical Committee CEN/TC 12 “Materials, equipment and offshore structures for
petroleum, petrochemical and natural gas industries” the secretariat of which is held by NEN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by December 2022, and conflicting national standards
shall be withdrawn at the latest by December 2022.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 3421:2022 has been approved by CEN as EN ISO 3421:2022 without any modification.
INTERNATIONAL ISO
STANDARD 3421
First edition
2022-06
Petroleum and natural gas
industries — Drilling and production
equipment — Offshore conductor
design, setting depth and installation
Industries du pétrole et du gaz naturel — Équipements de forage
et de production — Conception des tubes conducteurs en mer,
profondeur de mise en place et installation
Reference number
ISO 3421:2022(E)
ISO 3421:2022(E)
© ISO 2022
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 3421:2022(E)
Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Symbols and abbreviated terms.3
4.1 Symbols . 3
4.1.1 Symbols for conductor design . 3
4.1.2 Symbols for setting depth . 5
4.2 Abbreviated terms . 7
5 General requirements . 7
5.1 General . 7
5.2 Limit states for conductor design . 7
5.3 Setting depth requirements. 8
5.4 Installation requirements . 8
5.5 Design situations . 8
6 Design parameters .8
6.1 General . 8
6.2 Metocean parameters . 8
6.3 Ice parameters . 9
6.4 Seismic parameters . 9
6.5 Soil parameters . 9
6.6 Engineering design parameters . 9
6.6.1 Platform parameters . 9
6.6.2 Well operations parameters . . 10
7 Conductor design .11
7.1 General . 11
7.2 Actions . 11
7.2.1 General . 11
7.2.2 Permanent actions (G) . 11
7.2.3 Variable actions (Q) .12
7.2.4 Deformation actions (D) .12
7.2.5 Accidental actions (A) .12
7.2.6 Environmental actions .12
7.3 Partial factors for actions . 13
7.4 Boundary restraints . 14
7.4.1 General . 14
7.4.2 Platform conductors . . 14
7.4.3 Jack-up supported conductors . . 15
7.4.4 Free-standing conductors . 15
7.4.5 Subsea wellhead conductors . 15
7.5 Strength and stability checks . 15
7.5.1 General .15
7.5.2 Design method.15
7.5.3 Axial compression .15
7.5.4 Bending . 17
7.5.5 Shear. 18
7.5.6 Combined stress. 18
7.6 Fatigue . 19
8 Setting depth .20
8.1 General . 20
iii
ISO 3421:2022(E)
8.2 Setting depth for fluid circulation channel . 20
8.3 Setting depth for wellbore structural foundation . 21
8.3.1 General . 21
8.3.2 Installation by driving, drilling and cementing. 21
8.3.3 Installation by jetting . 24
9 Installation .26
9.1 General . 26
9.2 Driving . 26
9.2.1 Applicability .26
9.2.2 Driveability analysis .26
9.2.3 Installation procedures . 26
9.2.4 Pile group conductor driving sequence . 27
9.2.5 Data documentation . 27
9.2.6 Quality . 27
9.3 Drilling and cementing .28
9.3.1 Applicability .28
9.3.2 Size match of bit and conductor .28
9.3.3 Wait on cement.28
9.3.4 Quality .28
9.4 Jetting .28
9.4.1 Applicability .28
9.4.2 Size match of bit and conductor .28
9.4.3 Jetting bottom hole assembly .29
9.4.4 Jetting procedure .29
9.4.5 Jetting operating parameters .29
9.4.6 Data recording .29
9.4.7 Quality . 30
Annex A (informative) Additional information and guidelines .31
Bibliography .35
iv
ISO 3421:2022(E)
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 documents 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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
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, Materials, equipment and offshore
structures for petroleum, petrochemical and natural gas industries, Subcommittee SC 4, Drilling
and production equipment, in collaboration with the European Committee for Standardization
(CEN) Technical Committee CEN/TC 12, Materials, equipment and offshore structures for petroleum,
petrochemical and natural gas industries, in accordance with the Agreement on technical cooperation
between ISO and CEN (Vienna Agreement).
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
ISO 3421:2022(E)
Introduction
This document provides requirements and guidance on the design, setting depth, and installation of
offshore conductors used by the petroleum and natural gas industries worldwide. Sound engineering
judgment is necessary in the use of this document.
Conductor design addresses actions and action combinations, strength and stability checks, and fatigue
checks. Setting depth provides calculation methodologies for different installation methods. Installation
identifies relevant methods and their applicability together with corresponding procedures as well as
documentation and quality control requirements.
Some background to and guidelines on the use of this document is provided in Annex A.
vi
INTERNATIONAL STANDARD ISO 3421:2022(E)
Petroleum and natural gas industries — Drilling and
production equipment — Offshore conductor design,
setting depth and installation
1 Scope
This document specifies the requirements and recommendations for the design, setting depth and
installation of conductors for the offshore petroleum and natural gas industries. This document
specifically addresses:
— design of the conductor, i.e. determination of the diameter, wall thickness, and steel grade;
— determination of the setting depth for three installation methods, namely, driving, drilling and
cementing, and jetting;
— requirements for the three installation methods, including applicability, procedures, and
documentation and quality control.
This document is applicable to:
— platform conductors: installed through a guide hole in the platform drill floor and then through
guides attached to the jacket at intervals through the water column to support the conductor,
withstand actions, and prevent excessive displacements;
— jack-up supported conductors: a temporary conductor used only during drilling operations, which
is installed by a jack-up drilling rig. In some cases, the conductor is tensioned by tensioners attached
to the drilling rig;
— free-standing conductors: a self-supporting conductor in cantilever mode installed in shallow water,
typically water depths of about 10 m to 20 m. It provides sole support for the well and sometimes
supports a small access deck and boat landing;
— subsea wellhead conductors: a fully submerged conductor extending only a few metres above the
sea floor to which a BOP and drilling riser are attached. The drilling riser is connected to a floating
drilling rig. The BOP, riser and rig are subject to wave and current actions while the riser can also
be subject to VIV.
This document is not applicable to the design of drilling risers.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes 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 19900, Petroleum and natural gas industries — General requirements for offshore structures
ISO 19901-4, Petroleum and natural gas industries — Specific requirements for offshore structures —
Part 4: Geotechnical and foundation design considerations
ISO 19901-8, Petroleum and natural gas industries — Specific requirements for offshore structures —
Part 8: Marine soil investigations
ISO 19902, Petroleum and natural gas industries — Fixed steel offshore structures
ISO 19906, Petroleum and natural gas industries — Arctic offshore structures
ISO 3421:2022(E)
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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
axial capacity
ability of conductor to resist vertical actions without soil failure
Note 1 to entry: The axial capacity of a conductor can change with time due to the soil disturbance and recovery.
3.2
conductor
tubular pipe set into the seabed (3.11) to provide the initial stable structural foundation for setting the
surface casing (3.13) and protecting the internal well string from metocean actions
3.3
conductor shoe
short conductor joint whose upper end is connected to a whole conductor while its lower end has an
internal chamfer to assist penetration
3.4
design situation
set of actions and combination of actions representing real conditions during a certain time interval, for
which the design demonstrates that relevant limit states are not exceeded
3.5
drilling and cementing
method for installing a conductor (3.2) where a borehole is drilled, the conductor is lowered into the
borehole and cement slurry placed in the annulus
3.6
driving
method for installing a conductor (3.2) where a vessel or rig is used to hammer the conductor into place
3.7
effective weight
weight in sea water or drilling fluid
3.8
jetting
method for installing a conductor (3.2) where the bottom hole assembly and conductor are combined,
the borehole is washed by hydraulic force and the conductor simultaneously lowered into the hole
3.9
metocean action
effect of wind, wave and current on a conductor (3.2)
Note 1 to entry: The determination of these effects can include the influence of tide, surge, vortex induced
vibrations and related processes.
3.10
sea floor
interface between the sea and the seabed (3.11) referring to the upper surface of all unconsolidated
material
[SOURCE: ISO 19901-1:2015, 3.30]
ISO 3421:2022(E)
3.11
seabed
materials below the sea in which the structure is founded, whether of soils such as sand, silt or clay,
cemented material or of rock
Note 1 to entry: The seabed can be considered as the half-space below the sea floor (3.10).
[SOURCE: ISO 29400:2020, 3.128]
3.12
setting depth
distance between the depth reference point, usually the sea floor (3.10) or sea level, and the conductor
shoe (3.3)
Note 1 to entry: A minimum setting depth is required to provide adequate axial capacity and formation integrity
at the conductor shoe during surface casing drilling and cementing.
3.13
surface casing
casing that is run inside the conductor (3.2) to contain pressure in conjunction with the wellhead and
blow-out preventer and to protect weak formations
3.14
undrained shear strength
maximum shear stress at yielding or at a specified maximum strain in an undrained condition
4 Symbols and abbreviated terms
4.1 Symbols
4.1.1 Symbols for conductor design
A accidental actions
A cross-sectional area
cs
C moment reduction factor
m
D
deformation actions
D outer diameter
od
D Palmgren-Miner's sum or damage ratio during a certain time interval
R
E
Young’s modulus of elasticity
E extreme quasi-static metocean actions due to wind, wave and current
e
E
metocean actions due to owner-specified operating wind, wave and current parameters
o
F design value of action
d
f representative bending strength
b
f representative axial compressive strength
c
f Euler buckling strength
e
f representative shear strength
v
ISO 3421:2022(E)
f representative yield strength
y
G
permanent actions
I
moment of inertia of conductor cross-section
K effective length factor
K local experience factor
LE
L
unbraced length
L calculated fatigue life
f
maximum bending moment on cross-section due to environmental actions and defor-
M
E
mation actions
maximum bending moment on cross-section due to eccentricities of inner strings not
M
I
being centralized
N number of cycles to failure under constant amplitude stress range
i
n number of cycles of stress range
i
Q
variable actions
r
conductor radius of gyration
T time period over which Palmgren-Miner’s sum is determined
t
wall thickness
U utilization of conductor
m
V shear due to factored actions
Z elastic section modulus
e
Z plastic section modulus
p
γ partial action factor for extreme metocean action
f,E
partial action factors applied to the total quasi-static metocean actions plus equivalent
quasi-static action representing dynamic response for operating and extreme metocean
γγ,
f,Ef,E
Oe
conditions, respectively, and for which different values can be applicable for different
design situations
γ fatigue damage design factor
FD
partial action factors for the various permanent, variable, deformation and accidental
γγ,,γγ,
GQ DA
actions
γ partial resistance factor for bending strength
R,b
γ partial resistance factor for axial compressive strength
R,c
γ partial resistance factor for shear strength
R,v
λ
column slenderness parameter
σ bending stress due to forces from factored actions
b
ISO 3421:2022(E)
axial compressive stress due to forces from factored external axial actions of wellhead,
σ
ce
BOP, christmas tree, emergency equipment and Workover equipment
axial compressive stress due to forces from factored internal axial actions of inner cas-
σ
ci
ings and tubing
τ
maximum shear stress due to forces from factored actions
b
4.1.2 Symbols for setting depth
A side surface area
s
D outer diameter
od
ρ fluid density
fluid
FF, partial safety factors
ss1 2
F axial force applied to the conductor during the BOP installation stage
xBOP
F axial force applied to the conductor in the extreme design situation
xcap
F axial force in conductor
xial
F axial force applied to the conductor during the subsequent casings installation stage
xsc
F axial force applied to the conductor during the surface casing installation stage
xsur
F axial force applied to the conductor during the christmas tree and tubing installation stage
xXt
fz unit skin friction
()
g
acceleration due to gravity
H jetted conductor setting depth in the seabed
h minimum setting depth of the conductor
min
K axial stiffness of the conductor
con
K coefficient of lateral earth pressure
K axial stiffness of the coupled foundation composed of the surface casing and the conductor
cs
K axial stiffness of the wellbore coupled system composed of all casings and the conductor
sys
L length of conductor above the sea floor
a
N axial force in conductor
load
P soil fracture pressure
f
P fluid circulation pressures
fluid
P annular pressure loss of fluid
l
Q conductor axial capacity immediately after jetting
Q skin friction resistance of conductor
f
Q axial capacity of conductor
r
ISO 3421:2022(E)
Q set-up axial capacity of jetted conductor
setup
Q
axial capacity of jetted conductor
t
R
design safety factor of conductor capacity
S WOB utilization
s soil undrained shear strength
u
s mean soil undrained shear strength within the setting depth range
u,ave
t
time after the completing of jetting
u
pore water pressure
W effective weight of jetting BHA
BHA
W effective weight of BOP
BOP
W effective weight of capping equipment
cap
W effective weight of conductor
con
W weight of cementing string in air
cs
W weight of the fluid inside the cementing string
fc
W
weight of the fluid displaced by the casing assembly
fdc
W weight of the fluid inside the surface casing
fs
W effective weight of surface casing during cementing
land
W effective weight of drill-ahead running tool
RT
W weight of surface casing in air
sc
W effective weight of subsequent casings after cementing
squ
maximum action applied to the conductor from the time the surface casing is landed until
W
sur
the cement is set
W effective weight of production tubing
tub
W effective weight of wellhead housing
WH
W last WOB recoded during jetting
WOB.last
W effective weight of christmas tree
XT
α distribution coefficient for the effective weight of the BOP
α distribution coefficient for the effective weight of the subsequent casings
Δα soil set-up factor
t
σ minimum principal stress at the calculated depth
'
effective horizontal stress
σ
h
ISO 3421:2022(E)
'
effective vertical stress, or overburden pressure
σ
v
αβ,
empirical coefficients of soil fracture pressure
4.2 Abbreviated terms
APB annular pressure build-up
BHA bottom hole assembly
BOP blow-out preventer
HFT hydraulic fracture test
LWD logging while drilling
OEM original equipment manufacturer
ROV remote operated vehicle
SCF stress concentration factors
VIV vortex induced vibrations
WOB weight on bit
5 General requirements
5.1 General
A conductor has the following main functions:
a) to stabilize and to protect the near-surface sediments from collapse and fracturing under fluid
pressures during surface casing drilling and cementing;
b) to resist the effective weight of the first casing string (surface casing), which is landed shortly after
installation of the conductor, or the first two casing strings if a liner is landed before the surface
casing;
c) as a composite system with the surface casing, to provide lateral stability for the well system and
the BOP against cyclic and tensile loading from direct metocean actions, vessel motions and riser
motions including VIV.
The exposure level of the well that a conductor supports shall be specified prior to the start of the
design or assessment in accordance with ISO 19900.
5.2 Limit states for conductor design
Conductor design shall determine conductor outer diameter, wall thickness, steel grade and choice
of connectors to satisfy design situations through all phases of the conductor’s design service life,
including the installation method.
The limit state approach shall be used for conductor design and assessment. ISO 19900 outlines the
limit state verification requirements. The pertinent limit states are:
a) ultimate limit states (ULS);
b) abnormal/accidental limit states (ALS);
ISO 3421:2022(E)
c) serviceability limit states (SLS);
d) fatigue limit states (FLS).
Additional information and guidance are given in Annex A.
5.3 Setting depth requirements
Conductor setting depth shall be determined to address the function requirements outlined in 5.1.
The setting depth shall be designed to resist the actions resulting from the conductor’s installation
method.
5.4 Installation requirements
The installation method can be affected by the demands of the well as well as related field conditions.
The following installation methods are considered in this document:
— driving;
— drilling and cementing;
— jetting.
In some cases, a combination of driving and drilling and cementing methods can be applied. Installation
requirements (see Clause 9) shall be consistent with the chosen installation method.
5.5 Design situations
Conductor design requirements should be determined based on the exposure level, site-specific soil
conditions, metocean and ice conditions, and installation method.
Conductor design should consist of the following:
— operational design situations;
— extreme design situations;
— abnormal design situations;
— accidental design situations;
— short duration design situations;
— serviceability design situations.
Design situations are described in ISO 19900.
6 Design parameters
6.1 General
Metocean, ice, soil and engineering design parameters should be collected.
6.2 Metocean parameters
The metocean parameters shall include:
a) water depth;
ISO 3421:2022(E)
b) tide and storm surge;
c) significant wave height and spectral peak period;
d) current velocity and profile;
e) wind velocity and profile.
Collection of metocean parameters should be in accordance with the requirements of ISO 19901-1 and
consistent with the requirements of ISO 19902. Guidance on wind, wave and current directions is given
in Annex A.
Metocean parameters are primarily used to determine actions on the conductor and to calculate
corresponding action effects. Action effects are used to check conductor strength, stability and fatigue.
6.3 Ice parameters
Ice parameters should include ice thickness and strength (see ISO 19906).
6.4 Seismic parameters
Seismic parameters should be determined by using either the simplified or the detailed seismic action
procedure, as specified in ISO 19901-2.
6.5 Soil parameters
Where site-specific geotechnical data are available or acquired specifically for conductor design, the
soil properties and corresponding geotechnical parameters should include:
a) soil profile with classification and index properties for each layer;
b) design profile of submerged unit weight of soil;
c) design profile of undrained shear strength of cohesive soil layers;
d) design profile of effective angle of internal friction of cohesionless soil layers.
Marine soil investigations shall be conducted in accordance with ISO 19901-8. Use of the soil parameters
in design and installation shall be in accordance with ISO 19901-4.
Where site-specific geotechnical data are not available, there exists a risk of conductor foundation
failure. Mitigation of this risk to acceptable levels may be achieved where there is extensive regional
experience, site geologic conditions are consistent with those of past successful installation sites, and
bounding values of regional of field geotechnical parameters are considered in the design of setting
depth.
6.6 Engineering design parameters
6.6.1 Platform parameters
For fixed platform, the conductor is an auxiliary structure. The parameters required shall include:
a) spacing between well slots;
b) guide hole size, elevation and constraint;
c) corrosion protection;
d) interfaces to facilities such as cellar deck and christmas tree flowlines.
ISO 3421:2022(E)
6.6.2 Well operations parameters
6.6.2.1 General
Well operations include drilling, completion, production and Workover phases. The action effects that
the conductor resists during design situations depend upon its configuration as described in 5.2 and
5.5. Some of the parameters referred to in 6.6.2.2, 6.6.2.3, 6.6.2.4 and 6.6.2.5 are used for conductor
design (see Clause 7) and some are used to determine setting depth (see Clause 8).
6.6.2.2 Platform conductors
For platform conductors, the following parameters shall be collected:
a) wellbore structure and casing configuration;
b) weight of BOP, wellhead, christmas tree and Workover equipment;
c) action effects to which the conductor is subjected during drilling, completion, production and
Workover phases;
d) actions due to thermal APB for surface casings that are not fully cemented or poor cemented, if any.
6.6.2.3 Jack-up supported conductors
The parameters for jack-up supported conductors are the same as those for platform conductors in
6.6.2.2. In addition, the following parameters shall be collected:
a) tension at the upper end of the conductor, if any;
b) misalignment between the jack-up platform and the conductor;
c) relative motion that can occur between the jack-up platform and the conductor.
6.6.2.4 Free-standing conductors
The parameters for free-standing conductors are the same as those for platform conductors in 6.6.2.2.
6.6.2.5 Subsea wellhead conductors
For subsea wellhead conductors, the followi
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