Pipeline Design & Installation Systems

Transcription

1 Pipeline Design & Installation Systems Rigid pipeline subsea tie-backs new operational challenges Paul Georgeson Operations Support Manager Wood Group Kenny

2 Agenda - Overview - Materials - Inspection - Monitored data - Maintenance and repair 2 - Wood Group Kenny

3 Assets Flowlines 820 km Pipelines 2,400 km Source: Douglas Westwood 3 - Wood Group Kenny

4 Areas Operational regions - predominantly Carnarvon basin - expanding into: - Browse - Bonaparte - possibly Canning and the Bight Source: Geological Survey of Queensland 4 - Wood Group Kenny

5 Challenges Considerations for operations - New depths, cold seawater, hydrates - Scarp crossings (through, around, over) - Pipelines passing through new regions - Design lives > 30 years - FLNG operating regimes - Aggressive fluids -CO 2, H 2 S - High temperatures Scarp crossing 5 - Wood Group Kenny

6 Temperature 6 - Wood Group Kenny

7 7 - Wood Group Kenny Materials

8 Material selection - internals Corrosion - water (wet gas) + CO2 = carbonic acid (ph 3.8) - increased temperature and pressure = increased reaction rates Erosion - Velocities in excess of 30 m/s Has led to - change of materials from carbon steel to a CRA - chemical injection - ph stabilisation - change nature of the produced fluid - corrosion inhibitors - barriers via injected film formers 8 - Wood Group Kenny

9 Corrosion resistant alloys Lined and clad pipe and spools, various CRA materials primarily 316L, 625, 22cr Weld materials, can be driven by contractor experience / preference: root, 686 fill and cap L - 22 Cr Design considerations: - Qualification / historical design temperatures of CRA material - Overmatching challenge for some nickel weld consumables at high temperature 9 - Wood Group Kenny

10 Material selection - externals Hydrates - Driving key decisions around external coatings for wet gas flowlines - Rapid cooling -> hydrates Wax - Keep temperatures above wax appearance temperature Top of line corrosion - Prevent condensation and water drop out by keeping hot Has led to - Keep it hot -> insulated lines, MLPP - Let it cool -> continuous MEG injection, MEG regeneration plants 10 - Wood Group Kenny

11 11 - Wood Group Kenny Inspection

12 Corrosion / erosion Operations In-line inspection (ILI) - confirm internal pipeline condition via in-line inspection - work with regulators / licence requirements - manage challenges with schedule and plant considerations such as liquids arrival (flow assurance) - utilise subsea corrosion / erosion monitor data and production chemistry data to justify ILI timings Pre operations - sample during dewatering for water chemistry and bacteria / biocide residuals Source: Rosen 12 - Wood Group Kenny

13 Expansion 13 - Wood Group Kenny

14 Expansion Planned buckle design - DIs displacement initiators (dumb or mechanical) - ZRBs zero radius bends 14 - Wood Group Kenny

15 Expansion Considerations pre start-up - Pre start-up inspections, checking for: - burial around touch down points - third party interaction - Possible interventions to remove seabed material built up around touch down points - Recording details of spans either side of DI 15 - Wood Group Kenny

16 Expansion 16 - Wood Group Kenny

17 Expansion Operations to specify data collection - global positional data -specifically buckle shape (x, y, z) survey data - seabed heights adjacent to pipe and at set distance from top of pipe - lateral displacement at DI - axial movement at DI - conditions of DI surfaces due to movement Pipeline crossing DI 17 - Wood Group Kenny

18 Expansion Operations considerations - global location check campaign to campaign (drafting, GIS, cloud point data, etc) - compare positional data at DI to operational conditions at the time of survey / inspection - run FEA models of buckle shape (x, y, z) from survey / inspection data check stresses and strains 18 - Wood Group Kenny

19 Axial walking Asymmetry in the expansion / contraction Drivers: - Temperature transient - Seabed slope - End tension - Liquid hold up 19 - Wood Group Kenny

20 Axial walking Operations to specify data collection - check location of structure on foundation -end terminations designed to move - check position of spool / flowline interface flange / connector - future intervention if required 20 - Wood Group Kenny

21 Axial walking Operations - record complete operational history of start-up / shut downs and link to structure locations - understand spool loads based on position of structure (and associated connector) and location of spool / flowline connector - model future movements to ensure they remain within design parameters or plan for any intervention requirements 21 - Wood Group Kenny

22 22 - Wood Group Kenny Monitored data

23 Data management Managing data is key, especially with long design lives Make systems as automated as possible - Define integrity operating windows (IOWs) - Production chemistry - MEG system + ph stabilisation / corrosion inhibitors - Water chemistry - Erosion / corrosion monitoring systems - Velocities / temperatures / pressures Regular reporting / dash boards summarising data and asset condition 23 - Wood Group Kenny

24 Data collection from interventions Data recovered from interventions - monitoring of spans / structures / spools - collect data for pipelines / riser motions in operations where there are fatigue concerns Understand met ocean conditions - impact of currents, solitons, tides, cyclones on subsea assets Understand influence of operations on assets - impact of production regimes, slugging, flow rates on motions / vibrations 24 - Wood Group Kenny

25 25 - Wood Group Kenny Maintenance and Repair

26 Pipelines Reaching critical mass for: - formation of a repair club - equipment sharing - tool pool Still CRA repair challenges Storage and location of CRA and CS pipe will be important Smaller pipelines may be as critical as the production system (4-8 MEG / Utility lines) Significantly high pressures in smaller lines, worth spending time considering spares / repairs options 26 - Wood Group Kenny

27 In summary.. - Number of operational challenges which are pushing industry boundaries - Pre-start up data capture critical to understanding asset baseline condition and managing future decisions - Management and analysis of inspection and monitored data will be key in early field life, ensure all calibration work undertaken (project to ops) - Legislative framework to be managed - Longer term larger interventions will be critical and require significant planning - Challenge to industry to ensure Operators get the support and value required 27 - Wood Group Kenny

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