31 - Subsea Pipelines

Abstract

Subsea pipelines are used for a number of purposes in the development of subsea hydrocarbon resources. The subsea pipelines include export (transportation) pipelines; flowlines to transfer product between platforms, subsea manifolds, and satellite wells; flowlines to transfer product from a platform to export lines; water injection or chemical injection flowlines; and pipeline bundles. The design of subsea pipelines during subsea field development is usually performed in the following three stages: conceptual engineering; preliminary engineering or pre-engineering; and detail engineering. The continuity of engineering design from conceptual engineering and preliminary engineering to the detailed design is essential to a successful project. The object of the design process for a subsea pipeline is to determine, based on given operating parameters, the optimum pipeline size parameters. These parameters include pipeline internal diameter; pipeline wall thickness; grade of pipeline material; type of corrosion coating and weight; and thicknesses of coatings. The design process required to optimize the pipeline size parameters is an iterative one.