overview of surf systems and analysis overview of surf systems & analysis presenter: tarun...
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Overview of SURF Systems and Analysis
Overview of SURF Systems & Analysis
Presenter: Tarun Rewari
Director – Aryatech Marine &
Offshore
Software: OrcaFlex
What does SURF mean?S Subsea constructionU UmbilicalsR RisersF Flowlines
presentation introduction
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Define a deepwater system
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Define a ‘Deepwater System’
Deepwater marine system
Floater system
Whatever we call it (and plenty of definitions), these systems are not rigidly connected to seabed. They have a ‘floater’ with ‘lines’ between floater and seabed
‘deepwater’ marine systems
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Define a ‘Deepwater System’
Though clearly important and linked, this presentation focuses on the design and analysis of SURF systems
Floater
Reservoir
SURF
‘deepwater’ marine systems
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Water Depth
Floater systems range in water depth: 10m <> 2000m
‘deepwater’ marine systems
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Design Life
There are a variety of time frames (though no rigid distinction):
• Permanent systems (life of field, ≈25 years)
• Temporary systems (temp operations, few months)
• Installation (construction / decommissioning, few hours, maybe a day)
Analyses and main components are similar.
Main differences: env. return periods, acceptance criteria
‘deepwater’ marine systems
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Main System Components
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Main Components
• Floaters SURF top end boundary condition with various functions. (FPSOs, Semi-submersibles, TLPs, SPARs, offloading shuttles, drilling, installation /
decommissioning)
• Moorings multi-component wire, chain, polyester used to keep floater on-station. (spread, turret, SPMs, ‘jetty’, catenary, taut, hawsers)
• Risers dynamic pipe (or pipe assembly), to transfer production or injection fluids, control fluids or lift gas between seafloor and floater. (SCR, TTR, flexible, hybrids, export systems (incl. hoses), flexible jumpers)
main system components
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Main Components
• Umbilicals Assembly of hydraulic hoses used to control subsea structures from a host. Loaded statically and dynamically. (power, control, chemical injection, hydraulic fluids, etc)
• Flowlines static flexible pipe on seafloor for transportation of production or injection fluids. (Generally infield, linking subsea structures, or to a production facility. 100’s m < length < several km)
• Jumper short pipe connecting flowlines and (flexible or rigid) subsea structures or close subsea
structures. Loaded statically &dynamically
main system components
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Main Components
• Installation lower to seabed (‘payloads’, anchors, etc)
lay flow- & pipelines (J-, S- & reel-lay)
pre-lay risers & mooringsvessel hook-upfloatoverheavy liftpipelay vessels, barges
• Also recovery for repairs and re-installation, and decommissioning for permanent removal
main system components
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Main Components
• Other parts: bend stiffenerstapered stress jointsmid-water arches (MWAs)
riser towers, riser tethersanchorscranes / winches / tensioner systems payloads (PLETs, PLEMs, BOPs, etc)
J-tubesstingers & rollersmoonpoolsbuoyancy modules & clump weightsdrag chains
main system components
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Main Components – ‘flexibles’TLP Turret moored FPSO
SPM
Semi-submersible
transfer lines
jumpers
flowlines
risers
buoyant ‘steep’ wave
mid-water arch
riser tower
export lines
main system components
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Main Components – ‘rigid lines’
main system components
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Main Components - installation
•Colin Lewis to supply some nice OrcaFlex screenshots of some of the components on the previous slide.
FloatoverJacket launch
S-lay
Pull-in Lower to seabed
Recovery / re-installation
Load transfer
main system components
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Main Analysis Steps
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Main Analysis Steps
High level main systems design loop
In principle a strong feedback loop, though in practice, analysis does not often reflect this
Floater
Moorings
SURF
Installation
Both Concept Selection and main Engineering Design
main analysis steps
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Main Analysis Steps
For floater, moorings, SURF and installation, some or all of the following required:
main analysis steps
Static load screening
VIVanalysis
Extremedynamics
Interference analysis
Fatigue
Concept design
Acceptabledesign
Installation
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Concept / FEED
• Main considerations:– costs
– regulatory issues
– existing infrastructure
– floater availability
– environment
– reservoir characteristics
• Initial evaluation often done through proprietary scenario simulators to evaluate production from different options
main analysis steps
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Acceptance Criteria
for ‘lines’
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Acceptance Criteria
Once analysis completed, results are then assessed against various acceptance criteria:
• Internal loads (components, buckling, utilisation, end loads)
• Interference (clearances with other items)
• Fatigue (predicted vs. life of field)
Above to be checked for all systems (moorings, SURF and installation), though some detailed checks may not apply to all
acceptance criteria, rules & regs
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
• Philosophy varies from code to code• Focus on two different methods for structural design
– Working Stress Design (WSD)
– Limit State Design/Load and Resistance Factored Design (LRFD)
Design Philosophy
acceptance criteria, rules & regs
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
There are many different codes covering several applications:
• Dynamic Systems Codes
• Codes specific to Rigid Risers
• Codes specific to Flexibles (umbilicals, risers, hoses)
• Codes specific to Mooring (incl. anchors)
• Codes specific to Installation (including pipelay, heavy lift, etc)
Codes in Common Use
acceptance criteria, rules & regs
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Floater Types
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Hull Forms
Permanent:
But must also remember wide variety of ‘temporary’ floaters associated with field construction, repair and decommissioning – installation vessels, barges, offloading vessel, pipelay, crane lift, transportation
floater types
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Existing GoM Floaters
floater types
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Free floating hull – many variants
– catenary or taut moorings
– anchors
– vertical or catenary risers
Semi-submersible Hull
XY
Z700 ft
OrcaFlex 8.5b: messabout2.dat (modified 11:48 AM on 4/20/2002 by OrcaFlex 7.5a) (azimuth=230; elevation=0) Statics Complete
floater types
Pontoons
Columns
Bracings
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
• Ballasted hull keeps tendons in tension
• Tension minimises heave
• Inverted pendulum
• Springing / ringing & setdown
Tension Leg Platform (TLP)
floater types
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
• Vertical column floater
• First spars had solid hull
• 2nd generation truss hull
• 3rd generation cell hull
• Mooring similar to semi-sub
• VIM & 2nd order vertical motions
SPARs
VIV strakes
floater types
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Shipshape Hull
Conventional spreadmoor
Single point mooring outside of hull
Single point mooringcontained in hull
floater types
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
• Deck Mating as fixed platform – but with moving hull
• Spar – Loadout and Tow / Upending
• Shipshape – towed
• Semisub/TLP – heavy lift vessel
Hull Installation
floater types
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Mooring & Anchoring Systems
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
• Re-cap on main types– catenary or taut
– spread or single point (weathervaning)
– temporary or permanent
• Mooring line – seabed end termination is a fixed location
– vessel end termination moves with vessel
– weight controlled thru materials (chain, wire rope, synthetic rope)
– accessories (links, eyes, shackles, sockets, fairleads, winches, stoppers)
• Anchor types– drag embedment
– suction caisson
Mooring Systems
mooring & anchoring
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Catenary vs. Taut Mooring
Catenary– heavy in deep water
– line horizontal at seabed
– anchor subject to horizontal forces
– restoring forces by line weight
Taut leg – line non-horizontal at seabed
– anchor sees non-horizontal forces
– restoring forces by line elasticity
– smaller footprint than catenary mooring
mooring & anchoring
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Anchor Types
• Deadweight (gravity base)
• Piling (driven)
• Drag embedment anchors
• Suction anchors
• Vertically loaded anchors (VLA)
• Suction Embedded Plate Anchor (SEPLA)
75 ft
mooring & anchoring
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Additional Mooring Components
• Buoys– may be in-line or attached to the line
– provide buoyancy to reduced load on platform
– add compliance to a mooring line
– generally kept below surface to avoid additional wave loading
• Sinker weights and Deadman– additional clump weights added to lines
– weight line down (invert catenary)
– sinker weights in water column
– dead man on seabed – similar to gravity base anchor
mooring & anchoring
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Mooring Design Codes
• Most common– API RP2SK – Rules for Station Keeping (mooring line and anchors)
– API RP2SM – Synthetic mooring lines
– DNV-RP-E301 – Position Mooring
• Additional for anchors– DNV-RP-E303 – Design and Installation of Suction Anchors In Clay
– DNV-RP-E302 - Design and Installation of Plate Anchors in Clay
– DNV-RP-E301 - Design And Installation Of Fluke Anchors In Clay
• Codes apply different factors of safety for– distinguish between permanent vs. mobile mooring
– intact and damaged condition
– quasi-static vs. dynamic analysis
mooring & anchoring
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Anchor Proof Test
• For the analysis– mooring line analysis gives loads at seabed fixed point
– demonstrate anchor can achieve a prescribed load
• For the installation– vessel pull on mooring line for period of time
– demonstrates that anchor can take intended loads
mooring & anchoring
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Risers
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Riser Systems
• Transportation of production hydrocarbons and other fluids between seabed and floater
– oil/gas – import or export, reinjection
– water – export, injection
• Drilling and work over operations (may also contain hydraulic lines or electrical lines)
• Can be bundle (several lines in one carrier pipe)
• Can be a pipe-in-pipe
• May be added to a facility after initial installation (eg, tieback from new wells)
riser systems
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Common Configurations
JumperJumper
CVARCVAR
Catenary,Catenary,Free HangingFree Hanging
DrillingDrillingRiserRiser
MooringMooringlineslines
RisersRisersArraysArrays
FPSO,FPSO,Barge ...Barge ...
Catenary,Catenary,Lazy-waveLazy-wave
Flexible,Flexible,Steep-SSteep-S
TankerTanker
TLPTLP
LFSdeep
riser systems
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Riser Systems – pros & cons
riser systems
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Riser Systems – pros & cons
riser systems
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Riser Systems – pros & cons
riser systems
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Riser Systems – pros & cons
riser systems
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Umbilicals
Aryatech Marine & Offshore Services
Overview of SURF Systems and Analysis
Umbilical Applications
• Transfer hydraulic and electrical power
• Data logging (electrical or fiber optic)
• Chemicals for well control (methanol)
• Transfer between floater and seabed
• Transfer between wells and manifolds
umbilicals
Aryatech Marine & Offshore Services
OrcaFlex - Latest Developments
OrcaFlex User Group, Aberdeen, 2003www.orcina.com Slide 47 of 4
Tarun Rewari
Director - Aryatech Marine & Offshore
www.aryatech.net