Pipeline System Design

Pipeline System Design: Pipeline Network Mike Yoon, Ph.D.

Key Topics • System Approach to Design • Pipeline Components • Pipeline Configuration

© 2010 Yoon Consulting

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System Approach to Design • There are four aspects of design that are interrelated in the system approach to design: – – – –

Hydraulic design Mechanical design Geo-technical design Operations and maintenance design

• Decisions in one area of design directly affect or limit the options in another area.

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Hydraulic Design • The hydraulic design is the process of evaluating: – The physical characteristics and quantities of the fluid to be transported, – The number and location of pump stations, – The pipeline route and topology, – The range of pressure and temperatures, – The environmental conditions along the route

• Several hydraulic designs can be viable for any given design basis and route, but the best design should satisfy early use requirements and future capacity plans for the system. © 2010 Yoon Consulting

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Mechanical Design • For a hydraulic design, a number of mechanical designs can be developed to meet the criteria of the design basis. • The mechanical design is governed by the codes and standards, focusing on selection of pipe material and the specification of pipe properties, type, size, and power required of pumps and other equipment or ancillary facilities such as heaters, and the support or burial requirements for the pipeline. • The pipe diameter is selected based on the design flow, with little mechanical design required. However, internal and external pressure, allowable stress, and other considerations affect the final design of the wall thickness for the selected diameter. © 2010 Yoon Consulting

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Geo-Technical Design • The pipeline company is responsible to protect the environment in the vicinity of the pipeline and its business interest from potentially adverse environmental conditions. • Geo-technical design can affect the cost and safety significantly, if the pipeline route lies in challenging environments. • Geo-technical design issues to be addressed are: – – – –

River crossings Horizontal directional drilling Buoyancy control Geohazard management © 2010 Yoon Consulting

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Operation and Maintenance Design • The operation and maintenance design takes into consideration the day-to-day tasks of operating and maintaining the functional integrity of the system. • These include the necessary control systems to operate the system within its design parameters safely and continuously.

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Key Topics • System Approach to Design • Pipeline Components – Line pipe and design pressure – Valves – Joints and Fittings

• Pipeline Configuration

© 2010 Yoon Consulting

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Line Pipe • Specifications for line pipe are given in the following standards: – API 5L, 5LX: Specifications for Line Pipe – ANSI/ASME B36.10M: Welded and Seamless Steel Pipe

• Line pipe is manufactured by several methods, the most common being seamless (SMLS), electric resistance welded (ERW), and submerged arc welded (SAW) in the form of longitudinal and spiral welds.

© 2010 Yoon Consulting

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SMYS • The SMYS of the pipe material means the specified minimum yield strength for steel pipe manufactured in accordance with a listed specification. This is a common term used in the oil and gas industry for steel pipe. • API 5L specifies various strength grades, ranging from Grade B, rated at 35,000 psi (241 MPa) to Grade X120, rated at 120,000 psi (827 MPa), where the Grade X120 refers to the SMYS in 1000 psi.

© 2010 Yoon Consulting

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SMYS vs. Pressure • The pipe yield strength varies with the pipe grade. Shown in the plot is a pipe stress vs. pressure for a given pipe grade. • SMYS is the maximum stress, beyond which the pipe is deformed with additional applied pressure. © 2010 Yoon Consulting

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Pipe Specification and Category • API 5L: This is the umbrella specification for API 5LX, 5LS, etc. It covers Seamless, Electric resistance welded, Electric flash welded, Submerged arc welded, Furnace lap welded, and Furnace butt welded. • API 5LX: Seamless, Electric resistance welded, Electric flash welded, Submerged arc welded • API 5LS: Electric resistance welded, Submerged arc welded

© 2010 Yoon Consulting

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Examples of Allowable Stresses Weld Joint

Specs

Grade

SMYS PSI(MPA)

Joint Factor

Seamless

API 5LX

X70 70,000(482)

1.00

Furnace butt

API 5L

A25 25,000(172)

0.60

Furnace lap

API 5L

Cls 1 25,000(172)

0.80

Furnace lap

API 5L

Cls 2 28,000(193)

0.80

Electric resistance

API 5LX, API 5LS

X70 70,000(482)

1.00

Electric flash welded

API 5LX

X70 70,000(482)

1.00

Submerged arc welded

API 5LX, API 5LS

X70 70,000(482)

1.00

© 2010 Yoon Consulting

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Usage for Types of Line Pipe Seamless

ERW

SAW

Min. Diameter