Subsea Pipeline Detailed Design
Many design works between FEED and detailed engineering phases are similar, the detailed engineering phase extends all issues of FEED phase with more detailed designs to give the technical inputs for all procurement and construction of the pipeline project. Following design issues should be included in the detailed engineering phase based on the FEED phase.
Pipeline Spanning Assessment
Prepare a spanning analysis for the pipeline to include the following conditions:
- Installation condition;
- Operating condition;
- Hydrotest condition; and the following VIV limiting criteria for dynamic analysis:
- In-line vibrations;
- Cross-flow vibrations.
Pipeline Global Buckling Analysis
Prepare a global buckling analysis for the pipeline for the following operating conditions:
- Lateral buckling analysis;
- Upheaval buckling analysis.
Installation Methods Selection and Feasibility Demonstration
Perform for the pipelines:
- An installation feasibility study for available installation methods;
- Economic comparison for the all methods of pipeline installation;
- Perform cost comparison between pre-installed riser and conventional method;
- Perform tie-in methodology study that subsea pipeline connected with onshore pipeline;
- Performpreliminary analysis for the selected pipeline installation methods.
Consultant should consider pipeline installation via a conventional pipe-laying barge, bottom tow, off-bottom tow and surface tow or any other installation methods.
Pipeline Quantitative Risk Assessment
The assessments carried out in this work are as follows:
- Trawl impact frequency of the pipeline;
- Pipeline response to trawl pullover load;
- Frequency/probability of anchor drop from commercial cargo vessel impacting the pipeline;
- Consequence of anchor drop to pipeline.
Pipeline Engineering Drawings
Prepare a set of pipeline engineering drawings as follows:
- Pipeline overall field layout;
- Pipeline route drawing;
- Pipeline approach at respective platform;
- Pipeline end fitting details;
- Pipeline field joint details;
- Pipeline or subsea cable crossing details (if any);
- Pipeline shore approach drawings (if any);
- Typical pipeline installation drawings;
- Any other drawings required.
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 Det Norske Veritas, On-Bottom Stability Design of Submarine Pipelines, DNV-RPE305, (1998).
 Det Norske Veritas, On-Bottom Stability Design of Submarine Pipelines, DNV-RPF109, (2007).
 Kellogg Brown & Root Inc., Submarine Pipeline On-Bottom Stability - vol. I & II, PR-178-01132, (2002).
 American Petroleum Institute, Design, Construction, Operation, and Maintenance of Offshore Hydrocarbon Pipelines, (Limit State Design), API-RP-1111, (2009).
 American Petroleum Institute, Specification for Line Pipe, API Specification 5L, fourty second ed., (2000).
 US Department of the Interior, Minerals Management Service, 30 CFR 250, DOIMMS Regulations, Washington D.C., (2007).
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 Det Norske Veritas, Fracture Control for Pipeline Installation Methods-Introducing Cyclic Plastic Strain, DNV-RP-F108, (2006).
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