| Peer-Reviewed

Estimating On-Bottom Stability of Offshore Pipelines in Shallow Waters of the Gulf of Guinea

Received: 14 May 2016     Accepted: 24 May 2016     Published: 13 June 2016
Views:       Downloads:
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.

Published in International Journal of Mechanical Engineering and Applications (Volume 4, Issue 3)
DOI 10.11648/j.ijmea.20160403.13
Page(s) 115-122
Creative Commons

This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.

Copyright

Copyright © The Author(s), 2016. Published by Science Publishing Group

Keywords

Concrete Weight Coating, Concrete Coating Thickness, Pipeline Wall Thickness, On-Bottom Stability

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.
Cite This Article
  • APA Style

    Ogbonda Douglas Chukwu, Chinwuba Victor Ossia, C. O. Akhigbemidu. (2016). Estimating On-Bottom Stability of Offshore Pipelines in Shallow Waters of the Gulf of Guinea. International Journal of Mechanical Engineering and Applications, 4(3), 115-122. https://doi.org/10.11648/j.ijmea.20160403.13

    Copy | Download

    ACS Style

    Ogbonda Douglas Chukwu; Chinwuba Victor Ossia; C. O. Akhigbemidu. Estimating On-Bottom Stability of Offshore Pipelines in Shallow Waters of the Gulf of Guinea. Int. J. Mech. Eng. Appl. 2016, 4(3), 115-122. doi: 10.11648/j.ijmea.20160403.13

    Copy | Download

    AMA Style

    Ogbonda Douglas Chukwu, Chinwuba Victor Ossia, C. O. Akhigbemidu. Estimating On-Bottom Stability of Offshore Pipelines in Shallow Waters of the Gulf of Guinea. Int J Mech Eng Appl. 2016;4(3):115-122. doi: 10.11648/j.ijmea.20160403.13

    Copy | Download

  • @article{10.11648/j.ijmea.20160403.13,
      author = {Ogbonda Douglas Chukwu and Chinwuba Victor Ossia and C. O. Akhigbemidu},
      title = {Estimating On-Bottom Stability of Offshore Pipelines in Shallow Waters of the Gulf of Guinea},
      journal = {International Journal of Mechanical Engineering and Applications},
      volume = {4},
      number = {3},
      pages = {115-122},
      doi = {10.11648/j.ijmea.20160403.13},
      url = {https://doi.org/10.11648/j.ijmea.20160403.13},
      eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijmea.20160403.13},
      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.},
     year = {2016}
    }
    

    Copy | Download

  • TY  - JOUR
    T1  - Estimating On-Bottom Stability of Offshore Pipelines in Shallow Waters of the Gulf of Guinea
    AU  - Ogbonda Douglas Chukwu
    AU  - Chinwuba Victor Ossia
    AU  - C. O. Akhigbemidu
    Y1  - 2016/06/13
    PY  - 2016
    N1  - https://doi.org/10.11648/j.ijmea.20160403.13
    DO  - 10.11648/j.ijmea.20160403.13
    T2  - International Journal of Mechanical Engineering and Applications
    JF  - International Journal of Mechanical Engineering and Applications
    JO  - International Journal of Mechanical Engineering and Applications
    SP  - 115
    EP  - 122
    PB  - Science Publishing Group
    SN  - 2330-0248
    UR  - https://doi.org/10.11648/j.ijmea.20160403.13
    AB  - 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.
    VL  - 4
    IS  - 3
    ER  - 

    Copy | Download

Author Information
  • Offshore Technology Institute, ETF Gas Engineering Building, University of Port Harcourt, Port Harcourt, Nigeria

  • Offshore Technology Institute, ETF Gas Engineering Building, University of Port Harcourt, Port Harcourt, Nigeria

  • Project Masters Nigeria Limited, East-West Road, Port Harcourt, Nigeria

  • Sections