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PL02 Pipeline Materials, PL03 Pipeline Mechanical Design, image …

- - - - Linepipe manufacturing
        
        Seamless
        
        Welded
        
        HF-ERW
        (High frequency Electric Resistance Welded)
        
        SAW
        (Submerged Arc Welded)
        
        Spiral weld
      - PSL (Product Specifcation Level)
        
        ✅ PSL2
        
        Has requirements related to:
        
        Carbon equivalent
        
        Max Yield Strength
        
        Max UTS
        
        Fracture Toughness
    - - [DEP] Linepipe for Critical Services
      - IOGP-S616
      - ISO3183
      - API Spec 5L
      - ASME B36.10M
      - [DEP] Material selection for Upstream equipment
    - - API 5L (X65)
        
        SMYS: 65,300 Psi
      - ISO3183 (L450)
        
        SMYS: 450 MPa
      - Higher grade
        
        Higher strength
        
        ❗ Complex welds
        
        Can be considered for onshore as welds are more controlled
        
        Not recommeded for offshore as hard to achieve good weld quality for complex welds
        
        Weld material need to overmatch (or at least match) the parent material
        
        Lower carbon content, better weldability
        
        Higher carbon content of the parent materials creates higher tendency for hard phase formation in the weld which leads to higher hardness and brittleness of the weld
    - - Wall thickness calculation
        
        Pressure containment
        
        Hop stress = PD/2t
    - - Internal corrosion
        
        Corrosion allowance
        
        Dependent on internal corrosion rates & design life
        
        Chemical injections
      - External corrosion
        
        [PRIMARY] Coating
        
        Linepipe
        
        3LPP
        
        3LPE
        
        Field joint coating
        
        FBE
        
        STOPAQ
        
        [SECONDARY] Cathodic protection
        
        Sacrificial anodes
        
        Impressed Current CP
    - - Solids management
        
        Hydrates
        
        Hydrate inhibitor
        
        Insulation
        
        Scale & Emulsions
        
        Wax & Asphaltenes
  - - - PREN number
      - Prone to pitting, chlorides exposure
      - Weldability
      - Strength
        
        Strength: Only by Carbon steel (and not by CRA layer)
    - - Thermomechanically cladded
      - Weld overlay
- - - - Reinforced Thermoplastic Pipe
    - - Conventional Steel Flexible
        
        Code
        
        API17J; API17B
    - - Thermoplastic Composite Pipe
- - - - Hoop stress criteria
        
        ASME B31.4 & 31.8
        
        ISO13623
        
        Generally ⬆ Wall thickness: OD maintain, ID ⬇
        
        When tnom is calculated, a WT is selected
        
        Standard thickness
        
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        Custom thickness
        
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        For shallow water: Hydrostatic Pressure is zero
        
        From deep to shallow: there will be different wall thickness that will affect:
        
        Weldability
        
        Piggability
- - - - 🐌 Drag
        
        Drag coefficient depends on:
        
        Reynolds number
        
        Keulegan-Carpenter number (for waves)
        
        Pipe roughness
        
        ⚡Soil Friction
        
        💩 Soil data
        
        1) Soil friction
        
        Based on soil investigations (type of soil, shear strengths)
        
        Varies depending on whether pipe is partially buried or trenched
        
        Typical values
        
        ☕ Soft silty: 1
        
        ⏳ Sandy, rocky: 0.7
        
        2) Soil spring factor (k)
        
        ✈ Lift
        
        Pipe data:
        
        ⚖ Pipe weight (Submerged)
        
        Installation: Pipeline empty
        
        Operation: Product filled (Minimum product density)
        
        Pipe material, OD, WT
        
        External coating thickness and density
        
        Fluid density
        
        🦥 Inertia
        
        Exerted by accelerating water particles (wave induced)
    - - 🌊Wave
        
        Affect of wave decreases as water depth increases
        
        Wave induced currents are negligible at deep water depths
        
        Problem at shore approach
        
        How do you ensure stability at shore approaches?
        
        Bury the pipeline
        
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        Rock berm
        
        *Note: As pipeline approaches shore, the behavior of wave and currents changes due to the continental shelf/shore.
        Waves and currents are affected by Wave refraction and wave shoaling effects at the shore
        
        *Note: Cofferdams are used for stability of the trench and are temporary installation aids. Will be removed once construction finishes.
        
        Problem 1: Soil liquefaction
        
        Vertical stability conerns due to seabed soil liquefaction under cycling wave loading
        
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        Data:
        
        1) Wave periods
        
        2) Wave direction
        
        3) Significant wave (Hs)
        
        Definition:
        
        Mean of one third highest wave
        
        Average height of the highest 1/3 of the waves in a wave spectrum
        
        Used for stability calculation
        
        Sometimes referred to as "Sea state"
        
        Typical values
        
        ❓
        
        4) Max wave height (Hmax)
        
        Definition:
        
        The largest wave within a measurement period
        
        Greatest vertical distance between a wave crest and its succeeding trough
        
        Also known as "Most probable wave"
        
        Typical values
        
        Between 1.6 to 2 times of Hs
        
        5) Return periods
        
        Typical values for the following design conditions
        
        Installation
        
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        Operation
        
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        Definition
        
        Probability of max wave occurring
        
        Wave theories:
        
        For deepwater
        
        Linear
        
        Airy
        
        For shallow water:
        
        Non-Linear
        
        1) Stokes 5th order
        
        2) Stream
        
        3) Cnoidal
        
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        🎣 Tide
        
        LAT (Lowest Astronomical Tide) is used for OBS
        
        Minimum water depth
  - - - Density:
        
        Ranges from 2243 kg/m3 (dry density) to 3044 kg/m3 (more dense)
      - Thickness
        
        Min: 50mm
        
        Max: 100mm
        
        Thicker than that: Greater chances of cracking and spawling
      - Deep water
        
        If reeling is considered, cannot have concrete coating
      - 📖Code: DEP 31.40.40.30 Concrete coating of linepipe
  - - - No need optimisations
    - - Consider:
        
        Joint probability metocean data
        
        Make it less conservative
        
        Review soil data
        
        Type of soil, effect of soil friction
        
        Consider directionality
        (instead of using omni-direcional)
        
        Omni-directional assumes whole value without resolving
        
        Consider MAX wave and current acting perpendicular to the pipeline
        
        How?
        
        By resolving data into resultant x and y, and find the value that will be perpendicular to the pipeline
  - - - 1) Generalised Stability
        
        Definition
        
        Allows lateral displacement (movement) of pipeline in the range from less than half a pipe diameter, i.e. for a virtually stable pipe, up to a significant displacement of 10 diameters during the given sea state.
        
        • E.g. for 10 inch pipe:
        Allowed movement is 0.5 x 10 inch = 5 inch (Minimum) and
        10*10 inch = 100 inch (Max movement)
      - 2) Absolute stability
        
        Definition
        
        No movement (Conservative, and not practical as this needs more concrete coating to make the pipeline more stable)
- - - - Screening criteria
        
        In-Flow
        (Parallel to pipe)
        
        Cross flow (Perpendicular to pipe)
    - - S-N curve
- - - - Using mathcad sheets/spreadsheets, based on: 1) Different wave theories, 2) Wave height, 3) Water depth and 4) Periods, can be comnverted to current particle velocities, as a function of Hs (Significanr wave height)
  - - - Using "1/7th power law" for steady currents
        
        If you have velocity on the surface (Vs) and you want to find the velocity at a certain water depth (D = depth):
        
        d - depth at which we want to know the velocity
        
        D - Total water depth
        
        Vs - Velocity at water surface
        
        1/7th power law: Vs * [(d/D)^(1/7)]
- - - - Static load (Sagging pipe)
      - Considerations:
        
        ✅
        
        🌊 Wave and currents acting on the pipe
        
        ❌ Number of cycles
        
        Return period
        
        Installation: 1 year
        
        Operation: 100 years
        
        Static loads
      - Max bending stress + Thermal expansion
  - - - 〰 Static span
      - ↕ Cross-flow
      - ↔ In-line
- - - - SCR (Steel Catenary Riser)
      - Reeling
        
        Welds subjected to plastic deformation
        
        Small defects in welds can grow
    - - Fatigue checks
        
        Fatigue life > Design life (by factor by 10)