1 Introduction

1.1   Scope

As the impact of a tie-in operation on the overall installation cost of a project grows with the water depth, a better understanding of available connection techniques, a judicious choice and an early integration of the tie-in method in the engineering studies are keys to successfully control the whole cost of a deepwater installation project.

Performing tie-in in deepwater involves using ‘diver-less’ and ‘guideline-less’ methods, with adapted subsea connectors, remotely operated tools and Remotely Operated Vehicles (ROV).

This document reviews the currently available tie-in methods for deepwater applications. It deals firstly with the interface requirements for a tie-in operation; knowing that tie-in methods and connector hardware are closely related.

The main connector systems are then described, prior to reviewing deepwater tie-in methods and their installation performance.

The interface requirements between the different subsea structures and installation means are described in Chapter 2, Interface requirement. Such interface engineering must address:

  • Subsea Production System design

  • Flowline End Termination (FLET)

  • Umbilical end termination

  • Operational conditions

  • Subsea field development plan and sequences

  • Installation vessels

  • Connection tools

  • and finally the ROV capabilities

In Chapter 3, Connector Technology and Manufacturers Review, the existing connector technologies are reviewed and the main manufacturers are listed in Appendix 01.

With the connector, special tie-in tools are required either ROV mounted tools or dedicated tools which are remotely operated from the surface tie-in vessel. These tie-in tool technologies are further investigated and presented in Chapter 4, Tie-in Tool Technology Review.

The key topics of tie-in methods are thereafter detailed in Chapter 5, Tie-in Methods in terms of operational procedures with its application limits and based on the selection of following deepwater applicable techniques:

  • Rigid steel jumpers

  • Flexible jumpers

  • Lay-down and pull-in

  • Direct pull-in

  • Deflect-to-connect

  • Vertical stab, hinge-over and lay-away

  • Surface tie-in, lay-away and lay-to

  • Vertical connection and triple flow-lines lay-away

  • Hybrid steel pipe and ‘flextail’

  • Vertical hard landing

  • Horizontal direct stabbing and stroking

In Chapter 6, Advantages & Disadvantages, the main advantages and disadvantages for each above tie-in methods are presented in a tabular form.

The Chapter 7, Hot-Tap Tie-in describes the hot-tap tie-in method, which, unlike the above deepwater connection methods, allows for a new pipeline to be tied-in into an existing flowline while keeping it in production.

The subsea metrology (Chapter 8, Subsea Metrology) is also an important topic, especially in the case of the rigid steel jumper fabrication and fitting.

Finally, in Section 8.7, “Hybrid technologies”, times estimated for deepwater tie-in operation are discussed.

[Tip]

Tip

Click these links below for access to 3D resources:

1.2   Codes, Standards, Specifications and Reference Documents

1.2.1   Codes & Standards

[1]
API_RP-1111
 

Recommended practice for design, construction, operation and maintenance of offshore hydrocarbon pipelines.

[2]
API_RP-17-A
 

Design and Operation of Subsea Production Systems-General Requirements and Recommendations

[3]
API_RP-17-G
 

Recommended Practice for Completion/Workover Risers

[4]
API_RP-17-N
 

Recommended Practice on Subsea Production System Reliability, Technical Risk, and Integrity Management

[5]
API_RP-17-P
 

Recommended Practice for Subsea Structures and Manifolds

[6]
API_RP-17-Q
 

Recommended Practice on Subsea Equipment Qualification.

[7]
API_RP-17-R
 

Recommended Practice for Flowline Connectors and Jumpers

[8]
API_RP-17-U
 

Recommended Practice for Wet and Dry Thermal Insulation of Subsea Flowlines and Equipment

[9]
API_SPEC-17-D
 

Design and Operation of Subsea Production Systems-Subsea Wellhead and Tree Equipment

[10]
API_SPEC-5L
 

Specification for Line Pipe

[11]
API_SPEC-6A
 

Specification for Wellhead and Christmas Tree Equipment.

[12]
API_TR-17-TR-13
 

General Overview of Subsea Production Systems

[13]
API_TR-17-TR-7
 

Technical report for Subsea Connector Qualification Procedures

[14]
API_TR-6-AF
 

Technical Report on Capabilities of API Flanges Under Combinations of Load

[15]
ASME_B16-5
 

Pipe Flanges and Flanged Fittings

[16]
ASME_B18-2-1
 

Square, Hex, Heavy Hex, and Askew Head Bolts and Hex, Heavy Hex, Hex Flange, Lobed Head, and Lag Screws (Inch Series)

[17]
ASME_B31-3
 

Process Piping

[18]
ASME_B31-4
 

Pipeline transportation systems for liquids and slurries

[19]
ASME_B31-8
 

Gas Transmission and Distribution Piping Systems.

[20]
ASME_B31-G
 

Manual for Determining the Remaining Strength of Corroded Pipelines

[21]
ASME_IX
 

Welding and Braising Qualifications, Article II Welding Procedure Qualifications and III Welding Performance Qualifications

[22]
ASME_V
 

Boiler and Pressure Vessel Code Section V - Non Destructive Examination

[23]
ASME_VIII
 

Boiler and Pressure Vessel Code Section VIII - Rules for Construction of Pressure Vessels - Division 1 & 2

[24]
AWS_D1.1-D1.1M
 

Structural Welding Code - Steel

[25]
DIN_EN-10204
 

Metallic products - Types of inspection documents

[26]
DNVGL-OS-C101
 

Design of offshore steel structures, general (LRFD method)

[27]
DNVGL-OS-C401
 

Fabrication and testing of offshore structures

[28]
DNVGL-RP-0002
 

Integrity management of subsea production systems

[29]
DNVGL-RP-0034
 

Steel forgings for subsea application

[30]
DNVGL-RP-A203
 

Technology qualification

[31]
DNVGL-RP-B401
 

Cathodic protection design

[32]
DNVGL-RP-F112
 

Design of Duplex Stainless Steel Equipment Exposed to Cathodic Protection

[33]
DNVGL-RP-F302
 

Offshore leak detection

[34]
DNVGL-RP-O501
 

Managing sand production and erosion

[35]
DNVGL-SE-0045
 

Certification of subsea equipment and components

[36]
DNVGL-SE-0478
 

Verification of subsea facilities

[37]
DNVGL-ST-E271
 

Offshore containers (replaced DNV 2.7-1)

[38]
DNVGL-ST-F101
 

Submarine Pipeline Systems

[39]
DNVGL-ST-F301
 

Subsea equipment and components

[40]
EN_10204
 

Metallic Products - Types of Inspection Documents

[41]
EN_1092-1
 

Flanges and their joints - Circular flanges for pipes, valves, fittings and accessories, PN designated - Part 1: Steel flanges

[42]
EN_13509
 

Cathodic Protection Measurement Techniques

[43]
IMCA_S_013
 

Deep water acoustic positioning

[44]
IMCA_S_019
 

Guidance on subsea metrology

[45]
IMCA_S_020
 

Guidelines on the management of survey and inspection data

[46]
IMCA_S_022
 

An introduction to inertial navigation systems

[47]
IMCA_S_023
 

Guidelines on the shared use of sensors for survey and positioning purposes

[48]
IMCA_S_025
 

Guidelines for the shared use of sensors for ROV and survey purposes

[49]
ISO_10423
 

Drilling and production equipment - Wellhead and christmas tree equipment (equivalent to API Spec. 6A)

[50]
ISO_12736
 

Wet thermal insulation coatings for pipelines, flow lines, equipment and subsea structures

[51]
ISO_13628-1
 

General Requirements And Recommendations.

[52]
ISO_13628-15
 

Subsea structures and manifolds

[53]
ISO_13628-2
 

Flexible Pipe Systems For Subsea And Marine Applications.

[54]
ISO_13628-4
 

Subsea Wellhead And Tree Equipment (identical to API Spec. 17 D).

[55]
ISO_13628-7
 

Completion / Workover Riser System (identical to API RP 17G)

[56]
ISO_14723
 

Pipeline transportation system – subsea pipeline valves

[57]
ISO_19900
 

General requirements for offshore structures

[58]
ISO_898
 

Part 1 Bolts, Screws And Nuts.

[59]
ISO_9001
 

Quality Systems: Model For Quality Assurance In Design/Development, Production, Installation And Servicing

[60]
NORSOK_L-005
 

Compact flanged connections

[61]
NORSOK_M-001
 

Materials selection

[62]
NORSOK_M-101
 

Structural steel fabrication

[63]
NORSOK_M-120
 

Material data sheets for structural steel

[64]
NORSOK_M-501
 

Surface preparation and protective coating

[65]
NORSOK_M-503
 

Cathodic protection

[66]
NORSOK_M-601
 

Welding and inspection of piping

[67]
NORSOK_M-630
 

Material data sheets and element data sheets for piping

[68]
NORSOK_M-650
 

Qualification of manufacturers of special materials

[69]
NORSOK_N-001
 

Integrity of offshore structures

[70]
NORSOK_N-004
 

Design of steel structures

[71]
NORSOK_U-001
 

Subsea production systems

[72]
NORSOK_U-009
 

Life extension for subsea systems

[73]
NORSOK_U-102
 

Remotely operated vehicle (ROV) services

[74]
NORSOK_Z-001
 

Documentation for operation (DFO)

[75]
NORSOK_Z-007
 

Mechanical completion and commissioning

[76]
NORSOK_Z-008
 

Risk based maintenance and consequence classification

[77]
OSPAR_Convention
 

The Convention for the Protection of the Marine Environment of the North-East Atlantic

[78]
SAE_AS4059C
 

Aerospace fluid power - cleanliness classification for hydraulic fluids

[79]
SAE_J343
 

Tests & Test Procedures for SAE 100R Series Hydraulic Hose and Hose assemblies

[80]
SAE_J517
 

Hydraulic Hoses

[81]
SI_1019
 

UK. Statutory Instrument 1976 No.1019 for Offshore Installations stating Operational Safety, Health and Welfare Regulations.

[82]
SI_289
 

UK. Statutory Instrument 1976 No.289 The Offshore Installations (Construction and Survey) Regulations 1974

[83]
SI_913
 

UK. Statutory Instrument 1976 No.913 Design and Construction Regulations

1.2.2   TOTAL Standards

[84]
GS-EP-PLR-100
 
[85]
GS-EP-PVV-145
 
[86]
GS-EP-PVV-172
 
[87]
GS-EP-SPS-001
 
[88]
GS-EP-SPS-002
 
[89]
GS-EP-SPS-007
 
[90]
GS-EP-SPS-008
 
[91]
GS-EP-SPS-009
 
[92]
GS-EP-SPS-010
 
[93]
GS-EP-SPS-011
 
[94]
GS-EP-SPS-012
 
[95]
GS-EP-SPS-021
 
[96]
GS-EP-SPS-023
 
[97]
GS-EP-SPS-029
 
[98]
GS-EP-SPS-033
 
[99]
GS-EP-SPS-034
 

1.2.3   Deepwater Reference Books

[100]
T084-EN001
 
[101]
T084-EN002
 
[102]
T084-EN003
 
[103]
T084-EN004
 
[104]
T084-EN005
 
[105]
T084-EN006
 
[106]
T084-EN007
 
[107]
T084-EN008
 
[108]
T084-EN009
 
[109]
T084-EN010
 
[110]
T084-EN011
 

1.3   References

This study is based on the following sources

  • Vendors / Manufacturer published technical data and documentation.

  • Industry published papers and documentation, e.g. OTC papers

  • In house technical data and past experience on subsea tie-in projects.

Reference is made to the documents "Pipeline Systems" Ref. [101], “Subsea Production Systems” Ref. [102] and "Umbilical" Ref. [103] part of the Offshore Reference Book documentation.

1.4   Acknowledgements

We wish to thank the manufacturers and subsea contractors for the provision with courtesy of technical information and photographs of their products.

1.5   Definitions & Abbreviations

1.5.1   Definitions

Connector: Connection hardware (hubs, seals, clamp, locking mechanism, etc.)

Deepwater: deeper than 1000 msw

Tie-in: Methodology, procedure for the subsea connection activity

WxBxH: Width x Beam x Height

Definitions below have been extracted from API RP 17R - Recommended Practice for Flowline Connectors and Jumpers.

Connector system: The actuated mechanical connector and related accessories required for its function.

[Note]

Note

This includes components such as the inboard hub with structure, outboard hub with connector, alignment guides, soft landing hydraulic cylinders, flowline connection structures at the flowline sleds, and/or tie-in manifolds, line pipe, metal-to-metal seal ring, secondary seal, and fluid coupling for actuation and connector function and seal pressure test.

[Note]

Note

The hydraulic actuators for connector make-up and/or soft landing may remain with the system, or may be recovered with a separate connector actuation tool.

Inboard hub: The hub attached to the subsea structure pipe.

Integral connector: A connector that contains a non-removable actuation mechanism utilized to lock and unlock the connector from the inboard hub.

Lock: The act or state of the connector being fully engaged on the inboard hub and having the full preload applied.

Multibore connector: Any connector that has more than a single bore for the transfer of fluids.

[Note]

Note

Bores may be concentric, symmetric, or non-symmetric; contained fluids may include produced and/or injected liquids or gases, hydraulic control fluids, corrosion inhibitors, and others.

Non-integral connector: A connector that utilizes an external actuation mechanism to lock and unlock the connector from the mating hub.

Outboard hub: The hub attached to the flowline jumper pipe.

Preload: The clamping force generated at the connection that is necessary to resist or counteract the separating forces caused by the internal pressure and/or externally applied forces and moments.

Definitions below have been extracted from API SPEC 17D - DESIGN AND OPERATION OF SUBSEA PRODUCTION SYSTEMS, PART 4: SUBSEA WELLHEAD AND TREE EQUIPMENT

Swivel flange: flange assembly consisting of a central hub and a separate flange rim that is free to rotate about the hub.

Rated working pressure: maximum internal pressure that equipment is designed to contain and/or control

[Note]

Note

Rated working pressure should not be confused with test pressure.

Flowline connector support frame: structural frame which receives and supports the flowline connector and transfers flowline loads back into the wellhead or seabed anchored structure.

1.5.2   Abbreviations

A&R

Abandonment & Recovery

API

American Petroleum Institute

BHGE

Baker Hugues, a GE Company

BOP

Blow Out Preventer

DFCS

Deflect and Connect System

DP

Dynamic Positioning

DP

Dual Port

EHF

Extremely High Frequency

FLET

Flowline End Termination

GI

Gas Injection

GOM

Gulf of Mexico

HCS

Horizontal Connection System

HCS-R

Horizontal Connection System Rigid

HCTU

Hot Tap Cutting Unit

ID

Internal Diameter

ID

IDentification

ILT

In-Line Tee

IMCA

International Marine Contractor Association

INS

Inertial Navigation System

ISU

Integrated Subsea Umbilical

LBL

Long Base Line

LRP

Lower Riser Package

MLF

MATIS Launch Frame

MPP

Multi-Phase Pump

MPSV

Multi-Purpose Support Vessel

MQC

Multi-Quick Connector

MSS

Manifold Support Structure

MtM

Metal to Metal

NCS

Norvegian Continental Shelf

OD

Outside Diameter

PGB

Permanent Guide Base

PICT

Pull In & Connection Tool

PIM

Pull In & Connection Module

PLEM

Pipeline End Manifold

PLT

Pull In and Lockdown Tool

PVXT

Production Vertical Xmas Tree

RIS

ROV Interface Skid

ROT

Remotely Operated Tool

ROV

Remotely Operated Vehicle

RTS

ROV-Operated Tie-in System

SIM

Stroke-In Module

SLED

SeaLine End Termination

SPS

Subsea Production System (i.e. subsea structures such as X-mas trees, manifolds, etc.)

STM

Seal Tooling Module

TCP

Thermoplastic Composite Pipe

TLP

Tension Leg Platform

UCON-H

Universal Connection system - Horizontal

UCON-V

Universal Connection system - Vertical

UCT

Universal Cleaning Tool

UKCS

United Kingdom Continental Shelf

UTIS

Universal Tie-In System

VCS

Vertical Connection System

WI

Water Injection

XT

Xmas Tree

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