Subsea Engineering

Course — SUBS 6330: Pipeline Design

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Term: 

Usually offered in the Fall Semester.

Description: 

This three-credit-hour course introduces detailed analysis and design methods of pipelines that address stress analysis, buckling and collapse of deepwater pipelines. Limit state based strength design methods will be presented where fracture, fatigue and accumulated plastic strain analysis methods will be integrated into a unified failure risk design methodology. Material selection will follow this presentation in the context of quenched, tempered and accelerated cooled steels. The geotechnical aspects of pipeline design and installation will be covered in detail. Methods of pipeline installations will conclude the course. The outcomes from this course include an understanding of pipeline selection/design that meets best industry practices and codes.

Topics Covered: 

An Overview of Subsea Field Layout and Subsea Pipeline Design: The purpose of the first week is to give an overview of a Subsea system, and architecture, and cover some of the basic aspects of a subsea field. A brief overview of Engineering Design challenges for subsea pipeline and subsea design, such as ultra-deepwater and extra high temperature, is presented and discussed. In addition, the design process for pipeline deign will be introduced by giving an overview of some of the calculations and equations that will be presented in detail later in the course.

Pipeline Mechanical Design: The purpose of this lecture is to give an overview of equations and design codes for the mechanical design of a pipeline. Current design codes are also discussed. The main mechanism for wall thickness determination is presented.

Geotechnics and Pipe Soil Interaction: Pipe-soil interaction is an extremely important part to response of a pipeline under the effect of pressure and temperature loads. The ability to model the pipe-soil interaction accurately is important as this may affect calculations such as expansion, and lateral buckling.

Pipeline Stability: The ability for a pipeline to remain in-place, under given hydrodynamic conditions, is extremely important. The fundamentals of pipeline stability are presented. The use of concrete weight coating, to increase the submerged weight, is presented.

Shore Crossing and Route Selection: Pipelines approach the beach and the effect of braking waves needs to be considered. This lecture covers the main aspects of shore approach design. Various design methods are adopted for near shore construction. Routing for pipelines offshore is important, as the shortest route will reduce material costs, but this may not be possible due to seabed features. Details about route selection, and what to look out for is given.

Pipeline Spanning, Self-Burial and Scour: The purpose of this lecture is to give an overview of pipeline spans. Free-span analysis procedure, response amplitude, modal analysis, latest pipeline spans and analysis methods are covered.

Expansion and Global Buckling (Upheaval/ Lateral Buckling, and Walking): Complex design activities include the upheaval and lateral buckling of pipelines. These global responses activities are presented and discussed.

Construction and Installation: Once a pipeline has been made, by welding together pipe joints, the pipeline then has to be installed into the water. S, J and R lay installation methods are the most commonly used methods.

Pipeline Fatigue Design: The design for fatigue is a very important aspects of a design. Traditionally stress ranges are taken from the analysis and the fatigue life is calculated. This lectures looks at the main aspects of fatigue damage for design.

Inspection, Monitoring, Maintenance and Repair (IMMR): The main aim of this lecture is to understand what is IMMR and its objectives. Identify the main considerations associated with IMMR. To identify the main causes of damage, list the modes of inspection and monitoring. Identify the main maintenance issues and define the pipeline repair options and considerations.

Latest Technology and Themes: This lecture looks at the latest technical challenges facing the industry. The advancements of FEA in confronting the Deepwater Pipelines under High Pressure and High Temperature.

Simulation Software Tools: 

Advanced analysis tools are required to evaluate solid finite element analysis along the pipeline.. ABAQUS FE Engine is an advance tool able to model 2D reeling, 3D lateral buckling, 2D trawlboard pullover, 2D upheaval buckling, 2D spanning and 3D spanning. Final project calculations are expected to be benchmarked using ABAQUS and discuss the results on the final project report.

Course Grading: 

The course grade will be based on homework, project, quizzes and final exam.

Project: 

Each team will be completing a project in this course. Project will be the design of a gas export pipeline. Students will conduct strength and fatigue analysis of a pipeline system. Outputs for this project must include wall thickness calculations along the pipeline route, pipe hoop pressure calculations and benchmarking using ABAQUS, VIV fatigue analysis, on-bottom stability, thermal expansion and allowable span length calculation.