Estimating On-Bottom Stability of Offshore Pipelines in Shallow Waters of the Gulf of Guinea
International Journal of Mechanical Engineering and Applications
Volume 4, Issue 3, June 2016, Pages: 115-122
Received: May 14, 2016; Accepted: May 24, 2016; Published: Jun. 13, 2016
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Authors
Ogbonda Douglas Chukwu, Offshore Technology Institute, ETF Gas Engineering Building, University of Port Harcourt, Port Harcourt, Nigeria
Chinwuba Victor Ossia, Offshore Technology Institute, ETF Gas Engineering Building, University of Port Harcourt, Port Harcourt, Nigeria
C. O. Akhigbemidu, Project Masters Nigeria Limited, East-West Road, Port Harcourt, Nigeria
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Abstract
Pre-installation Stability analyses of pipelines are required to prevent lateral and upheaval buckling in service. In this study, the hydrodynamic forces associated with an offshore pipeline is analyzed, thereby determining limiting steel wall-thickness and submerged weight necessary to prevent collapse and propagation buckling, contain pressure and ensure on-bottom stability. Relevant design equations, Codes and Procedures were integrated to create a comprehensive platform for analyzing lift, drag and inertia forces acting on submerged pipelines. Hence, a user friendly template with multiple design settings has been developed with MathCAD® for on-bottom stability analyses. The analysis tool is based on the absolute lateral stability method in DNV RP F109. A case study of Φ762 mm x 34 km pipeline to be installed Offshore Escravos, Gulf of Guinea is simulated and analyzed using the design tool developed. Pipeline behavior under different environmental and pipeline conditions such as water depth, wave height, steel and concrete thickness were investigated. The results showed that concrete and steel wall thicknesses are the most critical parameters in the on-bottom stability of offshore pipelines. With a determined optimal wall thickness of 20.6mm, concrete thicknesses of 78.796 mm, 61.386 mm, 53.043 mm and 42.58 mm corresponding to 5 m, 10 m, 15 m and 20 m water depths, respectively were obtained. Also, the results showed that for pipes OD > Φ32.5 in (Φ825.5 mm) alternative stability methods may be required as the necessary concrete thickness may exceed allowable limits.
Keywords
Concrete Weight Coating, Concrete Coating Thickness, Pipeline Wall Thickness, On-Bottom Stability
To cite this article
Ogbonda Douglas Chukwu, Chinwuba Victor Ossia, C. O. Akhigbemidu, Estimating On-Bottom Stability of Offshore Pipelines in Shallow Waters of the Gulf of Guinea, International Journal of Mechanical Engineering and Applications. Vol. 4, No. 3, 2016, pp. 115-122. doi: 10.11648/j.ijmea.20160403.13
Copyright
Copyright © 2016 Authors retain the copyright of this article.
This article is an open access article distributed under the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
References
[1]
Gong, S. W., Lam, K. Y., Lu, C., (2000). Structural Analysis of a Submarine Pipeline Subjected to Underwater Shock. International Journal of Pressure Vessels and Piping, 77.
[2]
Mohd. Ridza, B. H., (2007), On-Bottom Stability Analysis and Design of Submarine Pipelines, Faculty of Civil Engineering, University of Technology Malaysia.
[3]
American Petroleum Institute (API), (1999). Design, Construction, Operation and Maintenance of Offshore Hydrocarbon Pipelines - Limit State Design (RP 1111). API Publishing Services, Washington, D.C.
[4]
Det Norske Veritas (DNV), (1988). On-Bottom Stability Design of Submarine Pipelines (RP E305). Veritas Offshore Technology and Services A/S.
[5]
Det Norske Veritas (DNV), (2010). On-Bottom Stability Design of Submarine Pipelines (RP F109). Det Norske Veritas AS.
[6]
Det Norske Veritas (DNV) (2013); Submarine Pipeline Systems (OS F101). Det Norske Veritas AS.
[7]
Ghebreghiorghis, D. A., (2014). On-Bottom Stability Analysis of Subsea Pipelines according to DNV-RP-F109, Faculty of Science and Technology, University of Stavanger.
[8]
Murthy, V. N. S., (2002), Geotechnical Engineering – Principles and Practices of Soil Mechanics and Foundation Engineering, CRC Press, New York.
[9]
Det Norske Veritas (DNV) (1981); “Rules for submarine pipeline systems”, Det Norske Veritas AS, April 1981.
[10]
Tornes, K., Cumming, G., Zeitoun, H., and Willcocks, J., (2009), A Stability Design Rationale - A Review of Present Design Approaches, Proceedings of the ASME 28th International Conference on Ocean, Offshore and Arctic Engineering, 2009.
[11]
Palmer, A. C., and King, R. A., (2008), Subsea Pipeline Engineering, PennWell Corporation, Oklahoma, USA.
[12]
Jas, E., O'Brien, D., Fricke, R., Gillen, A., Cheng, L., White, D., and Palmer, A., (2012). Pipeline Stability Revisited. The Journal of Pipeline Engineering, (4th Quarter):11.
[13]
Det Norske Veritas (DNV) (2000); “Submarine Pipeline Systems, (OFFSHORE STANDARD DNV-OS-F101), Det Norske Veritas AS, January 2000.
[14]
. American Gas Association (AGA), (2002). Submarine Pipeline On-Bottom Stability – Levels 1, 2 and 3 Manuals (PR-178-01132). Pipeline Research Council International (PRCI), Houston, Texas, 2002.
[15]
Ryan, J., Campbell, D., White, D., and Jas, E., (2011), A Fluid Pipe-Soil Approach to Stability Design of Submarine Pipelines, Proceeding of the 30th Offshore Technology Conference (OTC), Houston, Texas., 2011.
[16]
Lammert, W. F., Hale, J. R., and Jacobsen, V. (1989). Improved Basis for Static Stability Analysis and Design of Marine Pipelines. Proceedings of the Offshore Technology Conference (OTC), Houston, Texas, 1989.
[17]
Pierson, Willard J., Jr. and Moskowitz, Lionel A. (1964); “Proposed Spectral Form for Fully Developed Wind Seas Based on the Similarity Theory of S. A. Kitaigorodskii” Journal of Geophysical Research, Vol. 69, p.5181-5190, 1964.
[18]
Mathsoft, (2002), MathCAD® 11 – User’s Guide, Mathsoft Engineering and Education Inc., 101 Main Street, Cambridge, MA, USA.
[19]
Jothi-shankar, M., and Sundar, V., (1980), Wave Forces on Offshore Pipelines, Proceedings of the 17th International Conference on Coastal Engineering, Sydney, Australia, 1980.
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