First jack-up rig load-out in Viet Nam
This paper presents the design concept and operation results of load-out for the jack-up rig LTI model 116E built on two skid beams (without dry dock facilities). It was the first attempt to build a jack-up rig, almost completely, on two skid beams on the ground and load-out it using the submersible barge “Giant 2”. The major characteristics of load-out structures, which depend on a jack-up rig configuration composed of general jack-up rig type hull and other structures, were its heavy weight of approximately 9,000 metric tons and long length of 74.09m compared to breadth and depth, i.e. x 62.79 x 7.95m. So, special consideration was required for safe load-out operation compared to previous load-out of other offshore structures (jackets, topsides) where the weight was less than 4,000 - 5,500 metric tons. The strength and longitudinal deflection of the jack-up rig were carefully analysed with appropriate weight distribution. All facilities for load-out including ground foundation, strain jack system and pulling system were designed based on the results of this analysis and the friction force between the skid way and hull supports (skid shoe). The ballasting operation for the barge was controlled by the control system (PLC) in the control room. Relative deflection in way of jack-up rig was monitored during the load-out operation. The motion of the jack-up rig during the load-out process, towing to float-off site and float-off phase were analysed and compared to model test results.
The load-out concept and methodologies described here are verified through the successful load-out operation of the first jack-up rig project in Viet Nam. The concept and experience gained can be adopted for the load-out design of extra-heavy structures where the weight is more than 15,000 metric tons. Guidelines for the development of an efficient construction method for offshore and ship type structures are also suggested for future application of this concept.
ALE. Basis of design skidding for the load-out and float-off of the Rig Hull at PV Shipyard. Vung Tau, Viet Nam. 8/2011.
ALE. Basis of sea-fastening for the load-out and float-off of the Rig Hull at PV Shipyard. Vung Tau, Viet Nam. 8/2011.
ALE. Ballast calculation for the load-out of the Rig Hull at PV Shipyard. Vung Tau, Viet Nam. 8/2011.
ALE. Project execution plan for the load-out of the Rig Hull at PV Shipyard. Vung Tau, Viet Nam 8/2011.
American Bureau of Shipping (ABS). Rules for buil ding and classing mobile offshore drilling units. ABS. 2008.
American Bureau of Shipping (ABS). Rules for classification of marine vessels and structure. ABS. 2008.
American Institute of Steel Construction (AISC). Manual of steel construction. 9th edition, AISC. 2005.
American Petroleum Institute (API) API PR 2SK. Design and analysis of station keeping systems for floating structures. API. 1996 - 2008.
Det Norske Veritas (DNV). Rules for planning and execution of marine operations. DNV. 01/2005.
Det Norske Veritas (DNV). Offshore standard, Marine operations, General. DNV-OS-H101. 6/2005.
Det Norske Veritas (DNV). Modeling and analysis of marine operations. DNV-RP-H103. 4/2010.
Germanischer Lloyd (GL). Marine operations. GL. 2007; 4(6).
LeTourneau Technologies Inc. Supper 116E - Operation and maintenance manual. LTI M. 2010.
Le Tourneau Technologies Inc. Hull 255-Two skidway load out and on the barge analysis. LTI American. 2011.
GL Noble Denton International Ltd. Structural analysis of the super 116E bow for the float-off and sail away. GLND. 2011.
No ble Denton International Ltd. Guidelines for load-out/General guidelines for marine transportation. Noble Denton. 2009.
SACS (Structural Analysis Computer System). Program manual-engineering dynamic. EDInc. USA.
Subrata. K. Chakrabarti. Handbook of offshore engineering. Elsevier USA. 2005 (section 14.6, chapter 14 - Load-out method).
Tang H.Hsu. Applied offshore structural enginee ring. GPC. 1984.
1. The Author assigns all copyright in and to the article (the Work) to the Petrovietnam Journal, including the right to publish, republish, transmit, sell and distribute the Work in whole or in part in electronic and print editions of the Journal, in all media of expression now known or later developed.
2. By this assignment of copyright to the Petrovietnam Journal, reproduction, posting, transmission, distribution or other use of the Work in whole or in part in any medium by the Author requires a full citation to the Journal, suitable in form and content as follows: title of article, authors’ names, journal title, volume, issue, year, copyright owner as specified in the Journal, DOI number. Links to the final article published on the website of the Journal are encouraged.