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Decommissioning & Abandonment Engineering
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Key Services
Subsea & Platform Well Abandonment • Strength, fatigue and
stability analysis of riser,
wellhead and conductor systems• Tensioning requirements of the
conductor and
casing during plugging and abandonment• Vertical well loading
assessment• Identification of maximum tubing pull loads•
Engineering criticality assessment• Corroded and displaced well
integrity assessment• Original well build simulation for in situ
loads• Definition of allowable pressures for abandonment • Vessel
drift-off limits and watch circle assessment• Jack-up rig
modelling• Jack-up barge cantilever assessment• Component analysis
of crossover tools and existing
connectors• Design of conductor strengthening systems
Lifting Analysis• Assessment of platforms, manifolds and
flowlines• Design and analysis of lifting members and tools•
Removal of concrete in piles• Procedure generation
Reverse Engineering• Reverse installation analysis of risers,
flowlines and
moorings • Riserless abandonment system design• Cutting
sequences• Selection of cutting tools• Operational procedures and
storyboards• Execution of turnkey platform removal
Planning & Supervision Services • Data gathering and review
of historic records • Cost comparisons and concept selection•
Vessel selection and feasibility studies• Scrap yard selection•
Offshore supervision
Other decommissioning services within the Acteon group include
casing cutting/retrieval, marine procedure management, lifting and
retrieval services, and design of abandonment programmes.
The end of an asset’s life can often present the most
challenging technical situations that demand the best engineering
solutions. 2H Offshore has engineering expertise and experience
with platform wells, subsea wells, and infrastructure, to help
solve your decommissioning challenges.
Uncertainties in asset data, changes in design approach and
compromised structural integrity are just a few of the problems to
be overcome. Our multi-disciplined team of experts will perform
accurate risk based assessments of your asset to help bridge this
gap and allow you to identify and mitigate potential concerns early
in the project cycle.
Working closely with you and your equipment vendors, 2H will
help solve decommissioning challenges such as the operation of
modern, high specification vessels on obsolete wellhead designs,
and loss of structural performance due to time-dependent
degradation.
Our engineers have a thorough understanding of the safety
philosophy of industry design codes and a practical knowledge of
decommissioning operations gained from projects in the Gulf of
Mexico, North Sea, Irish Sea and offshore Malaysia. This expertise
enables us to ensure your decommissioning operations are conducted
as safely and efficiently as possible.
Decommissioning & Abandonment Engineering
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PCPPOC – DANA Freestanding Conductor Platform AnalysisIn the
DANA field, offshore Malaysia in 46m water depth, a LWS (Light
Weight Structure) was connected to and laterally restrained by a
MOPU (Mobile Offshore Production Unit). During decommissioning, the
LWS was to be disconnected and left freestanding. 2H completed
fatigue analysis of the freestanding LWS to identify the reduction
in well loads required to allow the LWS to withstand environmental
loading for sufficient time in the disconnected configuration. This
allowed PCPPOC to plan abandonment operations in a way that avoided
costly temporary strengthening works.
Chevron – Alder Suspended Well Plug and Abandonment Fatigue
AnalysisThe Alder field is located in approximately 150m water
depth in the central North Sea. 2H was contracted to assess fatigue
accumulation in four previously suspended subsea wells. 2H worked
closely with equipment vendors to ensure the fatigue performance of
critical components was accurately captured and identified to
Chevron the wells for which further fatigue mitigation strategies
were required.
Project ExperiencePetrofac – Cendor MOPU Decommissioning &
Conductor PreparationThe Cendor field is located offshore
peninsular Malaysia in 63m of water. 2H was contracted to perform
detailed engineering of retrofit structures, a bridge link and hook
up arms on the platform topsides, to enable the well conductors to
free-stand without buckling. This allowed the MOPU to be
disconnected. 2H also provided installation engineering services to
resolve the interfaces between the MOPU, the heavy lift vessel and
the fixed platform.
Centrica Energy – F3-8 Well Plug and Abandonment from a
Jack-upCentrica Energy was planning to conduct plug and abandonment
operations on subsea vertical appraisal wells offshore Netherlands
in 40m of water. 2H performed structural analysis of the operations
due to concern over the capability of the installed conductor to
withstand the stresses imparted from the tieback string. Three
potential tieback configurations were considered with stability,
strength and operability analysis carried out for each.
Interact – HRL Morecambe Bay Abandonment RiserHRL was planning
to abandon an observation well in the Irish Sea in 35m of water
using a jack-up rig. 2H performed strength and VIV fatigue analysis
of the riser with and without being supported by slips at the drill
floor. The analysis confirmed the acceptability of the drill pipe
system proposed to be used for the abandonment operation.
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Houston2H Offshore Inc.15990 North Barkers LandingSuite
200Houston, TX 77079, USAT: +1 281 258
[email protected]
London2H Offshore Engineering Ltd.Hollywood HouseChurch Street
EastWoking, Surrey, GU21 6HJ, UKT: +44 1483
[email protected]
Aberdeen2H Offshore Engineering Ltd.Tern Place House, Tern
PlaceBridge of Don Aberdeen, AB23 8JX, UK T: +44 1224
[email protected]
Rio de Janeiro2H Offshore Projetos Ltda.Praça Floriano, 19-22°
andar, Centro, RJ, 20031-924, BrasilT: +55 21 2510
[email protected]
Kuala Lumpur2H Offshore Engineering SDN BHDSuite 31-1, 31st
FloorWisma UOA II 21 Jalan Pinang50450 Kuala Lumpur, MalaysiaT: +60
3 2726 [email protected]
Perth2H Offshore Engineering Pty. Ltd.Level 8, 1008 Hay
StreetPerth, 6000, AustraliaT: +61 (0) 8 9222
[email protected]
Mailing Address:PO Box 7322, Cloisters Square POWA 6850,
Australia
Beijing 2H Beijing Representative Office 9D Xinzhong
BuildingNo.2 Xinzhong West StreetDongcheng District, Beijing,
China,100027T: [email protected]
www.2hoffshore.com
Drilling, Completion & Workover
Production & Export
Marine drilling risers
Jack-up risers
Subsea well conductors
Completion & workover risers
Surface BOP drilling risers
FPS dry tree production risers
Fixed platform well conductors
Jack-up production risers
Steel catenary risers
Freestanding hybrid risers
Flexible risers
Umbilicals
2H Offshore is a global engineering contractor specialising in
the design, structural analysis and integrity management of riser
and conductor systems used in the drilling and production of
offshore oil and gas. Our capability and experience covers all
types of risers, from shallow water fixed platform conductors, to
drilling and production risers used in ultra-deep water.
Areas of Expertise Our business falls into two primary
categories, Drilling, Completion & Workover and Production
& Export. Engineering of the risers used in each area of
activity has many similarities in terms of the skill sets and
experience required to conduct the work, but each area has many
unique characteristics requiring specific experience and knowledge
of the equipment and operations involved. The scope of each area of
activity and overlaps that occur are illustrated below.
To find out more visit www.2hoffshore.com
About 2H Offshore
