PIPELINE ENGINEERING by pyz17071

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									     PIPELINE ENGINEERING

     Multi-Diameter Pigging – Factors
   affecting the design and selection of
   pigging tools for multi-diameter lines



Karl Dawson
PPSA Aberdeen
19th November 2008




                                   www.pipelineengineering.com
               Agenda


•   Why Multi-Diameter Lines?
•   Definitions
•   Pig Selection
•   Pig Design
•   Provision of data for pig design
•   Prototype Development and Validation Testing
•   Case Study
•   Summary
•   Presentation End




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               Definitions


Industry Accepted Definitions:

• Dual-diameter – Operates in 2 distinct diameters

• Multi-diameter – Operates in two or more
  diameters and may operate in a range diameters
  or sizes in between




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          Why Multi-Diameter Lines?
Multi-Diameter lines are installed due to:
   • Cost
       – Procurement
       – Installation
       – Associated features
   • Standardisation – deepwater
       – Valves
       – Connectors
   • Weight
   • Space
   • Necessity
       – Tie-in                              Subsea Pigging Loop
       – Control Pressure losses
                                                    www.pipelineengineering.com
                  Pig Selection

Purpose of Pigging Operation:

   •   Dewatering
   •   Cleaning – debris removal
   •   Gauging
   •   Batching
   •   Inspection
   •   Camera
                                   Wax Removal
   •   Apply internal treatment




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                         Pig Design
Factors Affecting Pig Design:
         • Internal Diameters
             – Range of sizes
         • Bend Radii
             – 5D, 3D or 1.5D
         • Feature definition and configuration
             – Valve
                • Gate
                • Full bore ball
                • Check
         • Lengths of run
         • Transitions
         • Location of features
            – In relation to one another and specified diameters
                                                   www.pipelineengineering.com
            Pig Design Continued

Factors Continued:

• Flow and Pressure Conditions
• Medium
• Expected Debris or Internal Line
Condition                                    Build up of Deposits
• Pig Trap
    – Dimensions
    – Configuration
• Interaction of Pig Characteristics
to Negotiate Features                  Dual Diameter with Unbarred Tee




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                 Provision of Data

Interaction of line and pig features

Influencing factors:
• Interaction
• Variation
• Combination

All available data is of use in the
process of design: ‘Every Little
                                       Wye and Bend Combination
Helps’

Stick to the facts – never assume

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             Prototype Development and
                  Validation Testing

Why Test?

•   Prove design
•   Prove Functionality
•   Gather Data
•   Experience the unpredictable

The overall objective to
maximise tool effectiveness
and to minimise risk               Test Rig Example




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       Case Study 600m Water Depth: 8” x 10” Flooding,
                Cleaning and Dewatering Tool

Operational Requirements:
   • 8” Launcher and pipe work ID = 190.5 mm
   • Connector ID = 179.8 mm
   • 5D bend ID = 190.5 mm
   • Tapered transition = 1 in 6
   • 10” Line ID = 241.3 mm
   • Buckle arrestor = 236.5 mm
   • Length fixed at 400 mm due to laydown head
   • To be back loaded in to laydown head ID = 190.5 mm
   • Bi-directional capability
Functional Requirements:
   • Remove construction debris
   • Flood line for hydrotest
   • Dewater line
                                            www.pipelineengineering.com
              Case Study 600m Water Depth: 8” x 10” Flooding,
                       Cleaning and Dewatering Tool

Pig Design:

   • Mandrel Body

   • Segmented Supports
   active in all diameters

   • Diameter specific seals
   for each line section

   • Symmetrical disc packs
                                            Initial Design
   • Transmitter housing

                                                   www.pipelineengineering.com
            Case Study 600m Water Depth: 8” x 10” Flooding,
                     Cleaning and Dewatering Tool

Test Rig Design:




                                               www.pipelineengineering.com
             Case Study 600m Water Depth: 8” x 10” Flooding,
                      Cleaning and Dewatering Tool
Modifications made following trials:

• Extra discs fitted and radial grooves added
to improve support in larger diameter

• Support flexibility improved in tapered
transitions through reconfiguring the disc
pack

• Quantity of sealing discs reduced to
prevent discs clashing and loss of positive
seal
                                                Final Proven Design
Pig has successfully been run in field
operations
                                                 www.pipelineengineering.com
                  Conclusions
• Involvement in the FEED stage is invaluable for both parties

• Free flow of information is key to an effective and suitable
  design solution

• Changes are ok, but the impact must be assessed

• Testing of the intended design is essential at reducing the
  risk involved in field operations

• With modern design capabilities and functional testing, multi-
  diameter pigging need not be a subject to be avoided,
  instead with careful consideration even the most arduous of
  diametrical variations may prove piggable
                                                   www.pipelineengineering.com
           End



Thank you kindly for listening

    Questions Welcome




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