Pipeline Overview

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A pipeline is a most economical mean of transporting liquids and gases over long distances. Although they require high initial capital investment, they far more than compensate for the expenses made during their construction.

Index

  1.  About  Pipelines
  2. Types of Pipelines.
  3. Major Advantages of Pipelines.
  4. Disadvantages of Pipelines.
  5. Construction Methodology.
  6. Tenders to Float
  7. Material Procurement
  8. Recent Developments.
  9. Cost Breakup for a Pipeline Project
  10. Stages of Pipeline Project
  11. Energy Savings Due to Pipelines.
  12. Pipelines in India
  13. Pipeline Engineering Terms
  14. Pipeline Risk Management
  15. Pipeline Quality and Assurance and Control
  16. Pipeline Construction Safety and Environment.

About Pipelines

Pipelines are used for transporation of Gases, Liquids and Solids. Various gases transported are Natural Gas, LPG and LNG. Most commonly transported liquids are Crude Oil, Petrolium products and water. Pipelines are also used for transporation of solids in suspension form e.g. Iron Ore, coal etc. Various petrolium products like Motor Spirit, HSD, ATF etc. are transported by pipelines.

Types of Pipelines

  1. Offshore submarine pipeline laid on sea bed – Marine offloading Terminals and Outfalls.
  2. Onshore cross country pipeline laid 1 meters underground – Trunk Pipelines.
  3. Spur/Branch Pipelines

Major Advantages of Pipelines

Major advantages of pipelines w.r.t. other modes of material transport are low cost of transportation, accessibility to remote areas, less time for transportation. Pipe lines are environment friendly, require least energy requirement and have lowest cost of maintenance. They have minimum impact on land use pattern with negligible loss of product in transit. Their high reliability and multi product transportation facility makes them attractive mode of product transport.

Disadvantages of Pipelines

Major disadvantage of pipelines is their high initial cost. Also there is a problem of dead stock / inventory in pipelines.

Construction Methodology

Various engineering aspects must be taken care of during pipeline construction. These aspects are Quality assurance, Quality Control, Applicable codes and standards, Contractor specifications, HSE Requirements. Requirements of pipeline coating at yard, dumpsite and laying of pipelines needs to be considered.

Tenders to float

Various tenders needs to be floated for pipeline construction. These include Survey Tender, Pipe coating tender, Pipeline Installation Tender etc.

Material Procurement

  1. Line Pipes
  2. Valves and Actuators
  3. Scraper Traps, QOEC, Pig Signallers
  4. Flow Tees and Insulating Joints
  5. Induction Bends
  6. Flow Meters
  7. Pumps and Compressors
  8. OFC Cables

Recent Developments.

  1. Automatic Welding & Automatic UT
  2. Micro-Tunneling for pipeline construction
  3. Internal flow coating on line pipes for gas pipelines
  4. 3LPP coating on High Temperature pipelines

Cost Breakup for a Pipeline Project

Sr.No. Item Description Percentage of Capital Cost
Liquid Lines Gas Lines
1 Survey, ROW and Compensation 2% 1%
2 Line Pipe Steel Cost 33% 45%
3 Main Line Materials 2% 3%
4 Coating of Pipes 11% 6%
5 Main Line Construction 33% 25%
6 Cathodic Protection 1% 1%
7 Telecommunications, SCADA and RCPs 5% 2%
8 Pump / Compressor Stations 5% 12%
9 Delivery Terminal Facilities 2% 1%
10 Project Management 5% 4%
  SubTotal 100% 100%

 Stages of Pipeline Project

  1. Conceptualization
    1. Establish Requirement
    2. Evaluate Alternatives
    3. Finalize the Concept
  2. Feasibility Study
    1. Pipeline route Study and Selection
    2. Hydraulic Studies and Optimization
    3. Establish Project Cost
    4. Project Implementation Scheme
    5. Environmental Impact Assessment and Risk Analysis
  3. Basic Engineering
    1. Process Design and Sizing
    2. Optimization Studies
    3. Route Surveys and Investigations
  4. Detailed Engineering
    1. Engineering Design basis
    2. Route Engineering and Engineering Analysis
    3. Specifications and Job Standards
    4. Engineering for Procurement
    5. Installation Engineering and Construction Procedures

Energy Savings Due to Pipelines.

Sr.No. Transportation Mode Energy Consumption in Percentage of Energy Transported
1 Liquid Pipelines 0.5
2 Liquid -> Coastal Transportation 0.8
3 Liquid  ->Trains Transportation 1
4 Liquid -> Trucks Transportation 3.2
5 Coal -> Trains 0.8
6 Coal -> Coastal 1.1
7 Natural Gas Pipelines 2

Pipelines in India

Sr. Code Route Size Distance Product Owner Contr. Year
1 HBJ Hazira-Bijaipur-Jagdishpur 36”/18” 1800 km Gas GAIL EIL 1986
2 KBPL Kandla-Bhathinda 22”-14”-10” 1450 Km Product IOCL EIL 1996
3 GREP HBJ Up-Gradation 36” 505 Km Gas GAIL EIL 1997
4 MMPL Mumbai-Manmad-Indore-Delhi 18”-14” 1200 Km Product BPCL EIL 1998 2003 2007
5 JLPL Jamnagar – Loni 16” 1269 Km LPG GAIL EIL 2000
6 VSPL Vijaiwada-Secundarabad 16” – 14” 220 Km Product HPCL EIL 2002
7 CKPL Cochin-Karur 18”-14” 289 Km Product Petronet EIL 2002
8 MBPL Mangalore-Bangalore 24” 380 Km Product HPCL EIL 2003
9 VSPL Vizag-Secundarabad 12”-10” 600 Km LPG GAIL EIL 2003
10 DVPL Dahej-Vijaipur 42” 610 Km Gas GAIL EIL 2004
11 MDPL Mundra-Delhi 18” 1037 Km Product HPCL EIL 2006
12 PSPL Pune-Solapur 14”-12” 343 Km Product HPCL EIL 2006
13 NSPL Numalighar-Siliguri 16” 401 Km Product OIL EIL 2007
14 DPPL Dhabhol-Pune Gas GAIL EIL
15 VBPL Vadinar-Bina Crude BORL EIL
16 VDBPL Vijaypur-Dadri-Bawana Gas GAIL EIL
17 MBPL Mundra-Bhatinda Crude HMPL EIL
18 BKPL Bina-Kota Product BPCL EIL

Pipeline Engineering Terms

  1. Assembly : An arrangement of pipes and components such as a crossing, a pig trap, a block valve station or a riser.
  2. Barred tee : Tee-piece provided with bars across the internal bore of the branch pipe to prevent entry of a pig.
  3. Block valve : Valve for interrupting the flow or to shut-in a section of a pipeline. A block valve is normally either fully opened or fully closed.
  4. Branch pipe : Pipe connected to a pipeline of equal or larger diameter, using a tee-piece.
  5. Cold bend : A bend made from linepipe at ambient temperature, normally on the construction site, using a mechanical bending machine.
  6. Commissioning : An activity where the fluid to be transported is initially introduced into a pipeline.
  7. Consequence : The result of an event in terms of human safety, damage to the environment and economic loss.
  8. Design factor : Ratio of the hoop stress created by the design pressure and the SMYS of the pipeline material.
  9. Design pressure : The internal pipeline pressure used in the determination of the pipeline wall thickness requirements.
  10. Emergency shutdown valve : Valve for isolating a pipeline from a plant in case of emergency situations within the plant.
  11. Flammable fluid : A flammable fluid has a flash point lower than 100 °C.
  12. Flowline : A pipeline transporting untreated hydrocarbons and other reservoir fluids.
  13. Fluid : A substance which is transported through a pipeline in liquid or gaseous phase, or a combination of these.
  14. Hot bend : A bend made under factory conditions by hot working billets, plates or pipes.
  15. Incidental pressure : Pressure occurring in a pipeline with limited frequency and during limited periods of time. Incidental pressures include surge pressures, and thermal pressures if not occurring a significant portion of the time.
  16. Injection line : A pipeline transporting gas, water or other fluids for injection into a well or a group of wells.
  17. Isolation valve : Valve for isolating a pipeline from a plant connected to it.
  18. Line pack : In a gas transmission system, the line pack is the quantity of gas in excess of the gas inventory in the system required to meet deliveries. The line pack is used to continue deliveries for some period following interruption of supply upstream.
  19. Liquid hold-up : Quantity of liquids present in a two-phase pipeline.
  20. Loading line : A pipeline between an onshore facility and an offshore loading facility, e.g. a single point mooring.
  21. Maximum allowable incidental : The maximum pressure that is allowed by pressure ANSI/ASME B31.4/8 to occur in a pipeline with a limited frequency and during limited periods of time.
  22. Maximum allowable operating : The maximum pressure at which a pipeline is pressure allowed to be operated under steady state process conditions, in accordance with ANSI/ASME B31.4/8.
  23. Maximum operating temperature : The maximum temperature to which the pipeline or section of pipeline is expected to be exposed during normal operational activities, including start-up and shut-down operations, but excluding abnormal situations, e.g. fires.
  24. Minimum operating temperature : The minimum temperature to which the pipeline or section of pipeline is expected to be exposed during normal operational activities, including start-up and shut-down operations, controlled blowdown, but excluding abnormal situations, e.g. pipeline ruptures.
  25. Off-plot : A location outside designated plant boundaries.
  26. Offtake line : A pipeline transporting fluid from a larger pipeline.
  27. On-plot : A location inside designated plant boundaries.
  28. Operating envelope : A defined set of key parameters or parameter ranges which must be adhered to during operation of the pipeline in order to prevent loss of technical integrity.
  29. Overpressure protection valve : Valve intended to protect the pipeline against overpressure by preventing pressure from a source building up in the pipeline.
  30. Pig : A device which can be propelled through a pipeline by fluid flow and normally used for cleaning, batching, inspection or other activities.
  31. Pig trap : An ancillary item of pipeline equipment, with associated pipework and valves, for introducing a pig into a pipeline or removing a pig from a pipeline.
  32. Pipeline : A system of pipes and other components used for the transportation of fluids, between (but excluding) plants. A pipeline extends from pig trap to pig trap (including the pig traps), or, if no pig trap is fitted, to the first isolation valve within the plant boundaries or a more inward valve is so nominated.
  33. Pipeline code : An industry or national code written for the purpose of designing, constructing and operating pipelines.
  34. Pipeline end manifold (PLEM) : An item of subsea equipment, comprising piping and valves, at the end of a pipeline, to which single point mooring hoses are connected.
  35. Pipeline leak : An uncontrolled fluid release from a pipeline.
  36. Plant : An installation, such as well-head, processing facility, pressure boosting station, storage tank, offshore platform, refinery, etc., with defined boundaries and which is not normally accessible to the public.
  37. Pre-commissioning : A series of activities, including cleaning and possibly drying, executed to prepare the pipeline for commissioning.
  38. Pressure equalisation line : Small bore pipe with valves to allow equalisation of pressure across a larger valve, avoiding damage to the seats of the larger valve.
  39. Pressure relief safety valve : Valve for protecting a pipeline against overpressure by releasing fluid from the pipeline.
  40. Remote vent line : A pipeline used for discharging light gaseous fluids to atmosphere.
  41. Riser : A vertical, or near vertical, section in a pipeline.
  42. Risk : The product of the probability of an event occurring and the consequences of the event when it has occurred.
  43. Sectionalising block valve : Main valve for sectionalising a pipeline, in order to limit the release of line contents in case of pipeline leak or rupture.
  44. Shore approach : That section of a pipeline which crosses the sea shore, or major river/estuary shores. The shore approach includes the area of breaking waves and extends to the highest water mark.
  45. Single point mooring (SPM) : A device for mooring a ship and transferring fluid between a pipeline and that ship.
  46. Slugcatcher : A device located at the downstream end of a two-phase pipeline, for the primary separation of the liquid and gas phases, and the temporary storage of liquids generated by pigging and transient flow conditions. There are two types of slug catchers: the vessel type and the finger type.
  47. Specified minimum yield stress : The level of stress which produces 0.5 percent total (SMYS) strain (API definition). This stress is specified by the Principal and guaranteed by the Manufacturer/Supplier.
  48. Sphere : A spherical shape pig, used for batching and liquid hold-up removal in two-phase pipelines.
  49. Sphere tee : A jacketed tee-piece with a perforated inner pipe to prevent entry of a sphere into the branch pipe.
  50. Spurline : A pipeline transporting fluid into a larger pipeline.
  51. Stable fluid : A stable fluid has an NFPA reactivity grade number of zero.
  52. Surface safety valve : Valve, part of the well-head assembly, applied as isolation valve between flowline and wellhead.
  53. Surge pressure : Pressure due to mass flow velocity changes, caused by operational activities, e.g. valve closures, pump shut-down or start-up.
  54. Technical integrity : Technical integrity of a facility is achieved when, under specified operating conditions, there is no foreseeable risk of failure endangering safety of personnel, environment or asset value.
  55. Test pressure : The pressure at which the pipeline will be or has been tested for strength.
  56. Thermal pressure : Pressure due to thermal effects on the fluid in the blocked-in pipeline or blocked-in pipeline sections.
  57. Toxic fluid : With reference to EP-55000 Section 40 Part 1, toxic fluids include all fluids in the slightly toxic, toxic and highly toxic categories.
  58. Trunkline : A main transmission pipeline to which spurlines and offtake lines may be connected.
  59. Two-phase pipeline : Pipeline transporting fluids where both the liquid phase and the gas phase are present at pipeline pressure and temperature conditions.

Pipeline Risk Management

  1. The risk associated with the pipeline, in terms of the safety of people, damage to the environment, and loss of income, depends on the expected failure frequency and the associated consequence, which is directly related to the type of fluids transported and the sensitivity of locations of the pipeline.
  2. In this context, pipeline failures are defined as loss of containment.
  3. The potential pipeline failures, causes and their consequences, should be inventorised and taken into account in the design and the operating philosophy.
  4. The most common pipeline threats which may lead to the loss of technical integrity are given below.
    1. Internal corrosion and hydrogen induced cracking (HIC).
    2. Internal erosion.
    3. External corrosion and bi-carbonate stress corrosion cracking.
    4. Mechanical impact, external interference.
    5. Hydrodynamic forces.
    6. Geo-technical forces.
    7. Growth of material defects.
    8. Over pressurisation.
    9. Thermal expansion forces.
  5. Notwithstanding the requirements of the ANSI/ASME B31.4/8 , the factors which are critical to public safety and the protection of the environment should be analysed over the entire life of the pipeline, including abandonment.
  6. The risk should be reduced to as low as reasonably practicable, with the definite objective of preventing leaks.
  7. The level of risk may change with time, and it is likely to increase to some extent as the pipeline ages.

Onshore Pipelines

A formal quantitative   risk  assessment   (QRA) should be carried out in the following   situations   with   the   location   classes   as   defined in (3.3.3):

    1. Fluid category  B  and  C  in  location classes 3 and 4.
    2. Fluid category D in all location classes.
  1. The assessment  should  confirm  that  the selected    design    factors    (3.4.1)    and proximity distances (3.3.4) are adequate.

 Offshore Pipelines

A formal quantitative risk assessment (QRA) shall be carried out for pipelines connected to permanently manned offshore complexes, except for pipelines transporting category A fluids. The   necessary   riser protection  and  safety  systems  shall  be derived from this assessment.

  1. The risk depends firstly on the expected frequency of failure, due to internal and external corrosion, external loading (e.g. impacts, settlement differences, free spans), material or construction defects, and operational mishaps.
  2. Secondly, it depends on the consequences of the failure, based on the nature of the fluid in terms of flammability, stability, toxicity and polluting effect, the location of the pipeline in terms of ignition sources, population densities and proximity to occupied buildings, and the prevailing climatic conditions.
  3. The expected frequency of failure and the possible consequences may be time-dependent and should be analysed over the entire life of the pipeline.
  4. Risks levels can be reduced by using lower design factors (e.g. higher wall thickness or stronger steel),  rerouting,  providing additional protection  to  the  pipeline, application of facilities to minimise  any released fluid volumes, and controlled methods of operation, maintenance and inspection.
  5. NOTE: Pipelines with a wall thickness lower than 10 mm  are susceptible  to penetration, even by small mechanical excavators. External interference by third parties is a major cause of pipeline failures. Specific precautions against this type of hazard should be addressed; this is particularly relevant to onshore pipelines transporting category C and D fluids.

Environmental impact assesments

  1. An environmental impact assessment (EIA) shall be carried out for all pipelines or groups of pipelines.
  2. EIA is a process for identifying the possible impact of a project on the environment, for determining the significance of those impacts, and for designing strategies and means to eliminate or minimise adverse impacts.
  3. An EIA should consider the interaction between the pipeline and the environment during each stage of the pipeline life cycle.
  4. The characteristics of the environment may affect pipeline design, construction method, reinstatement techniques, and operations philosophy.

Economic risk.

  1. The economic risk is associated with deferment of income, cost of repair, and other costs such as liabilities to the public and clean-up costs.
  2. The economic risk should be evaluated for each phase of the pipeline operating life, and should be compatible with the overall objectives of the Principal.
  3. For the predicted life cycle conditions, the design shall take due account of operations, inspection and maintenance requirements, as well as established operating philosophy and practices, agreed  in  advance  with  the  personnel  responsible  for  the  operation  of  the pipeline.
  4. These include manning levels for the operation, integrity monitoring and maintenance of the pipeline system, the requirements for telecommunications and remote operations, means of access to the onshore right of way, etc.
  5. The design of pipelines which are continuously in operation should address the requirement for bypass at components which need regular maintenance.

Pipeline Quality and Assurance and Control

  1. Review and Approval of Contractors QAP for all activities.
  2. Review and Approval of Contractors Inspection and Test Plans (ITP’s) with reference to standard ITP’s of EIL before start of work.
  3. Review and approval of job procedures and inspection formats based on ITP’s for all pipeline activities.
  4. Quality audits and resolution of non-conformances (NC’s) observed during execution of work and quality audits.

Pipeline Construction Safety and Environment.

  1. During all stages of the pipeline construction, the Contractor shall work to the highest achievable safety and environmental standards.
  2. The safety performance of all staff involved in the work shall be monitored and recorded.
  3. Regular safety inspection of the construction sites shall be carried out, to ensure compliance with the relevant procedures, as well as maintaining awareness of all staff regarding potential hazards.
  4. The aspects related to the management of safety during the construction phase are covered in Shell Standard EP 55000 Sections 15 and 16.

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