The ABS Brazil Offshore Technology Center, in partnership with the Federal University of Rio de Janeiro (COPPE/UFRJ), has begun work on its first research project – a multiyear study on the application of torpedo piles as an alternative mooring anchor system. The concept has been developed by Petrobras for continued use offshore Brazil.
The study will examine state-of-the art techniques available to simulate soil conditions and determine a set of requirements and criteria that address the holding capacity and structural strength of torpedo piles in operation.
The study is expected to result in the development of a rational approach for the class review and approval of the proposed mooring system. The study was launched in early August and is expected to be completed by February 2012. According to Christiane Machado, ABS Senior Engineer, Technology, upon completion of the study a report with recommendations to the industry will be issued together with guidelines for the design and use of torpedo piles.
The torpedo pile has been recognized as a cost-effective alternative to traditional anchor-based mooring systems. It has been considered for use in mooring floating production systems and mobile offshore drilling units (MODUs). The pile is installed in a free fall operation from a support vessel.
Some of the key considerations surrounding the design of offshore foundation systems, in particular those using torpedo piles, are the uncertainties related to the determination of holding capacity values. The determination of relevant parameters of soil characteristics and the final installed position angles, together with the safety factors to be considered in the design, will be addressed in this study, explains Machado. "We want to provide a set of parametric equations to better estimate anchor weight, installation limits for penetration distance and angles and check the adequacy of the installed pile holding capacity."
Recently, the Center applied for Brazilian governmental funding through FINEP (Research and Projects Financing) to support the development of new technologies for pre-salt related engineering. The work would be carried out in partnership with COPPE/UFRJ and Rio’s tank testing facility, Lab Oceano, and be focused on the development of Rules and guidelines for the global performance of closely moored offshore units. It is anticipated this will become the second research project undertaken by the Center.
Although the research efforts will place a particular emphasis on facilities intended for use in Brazilian waters, broader challenges associated with offshore energy resource extraction will also be addressed. Applied research will be conducted to study a wide range of oil and gas field development issues, particularly those associated with ultra deepwater activity and high temperature and high pressure recovery.
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