Construction and Installation of the Prince TLP
Authors: Rawles William S. , Chaplin David E. 
Published: October 2008

This paper will discuss the construction and installation of the new generation MOSES TLP for the Prince field located in 1,472 feet of water in the Gulf of Mexico. Discussion regarding the field development and development of the MODEC MOSES TLP can be found in OTC paper #14173. Discussion will cover the construction philosophy and methods utilized with specific focus on the hull fabrication. The paper will also address material selection, tracking and control; Quality Assurance and Quality Control; construction methodology; loadout; testing and commissioning of hull systems; and installation of the TLP. Finally, the paper will highlight lessons learned from the construction and installation of the first MOSES TLP.

Introduction

The success of the Prince TLP construction program was due to the dedication and experience of the project team, and the hard work and diligence of the hull fabricator, AMFELS, Inc. The construction plan relied upon design decisions that built upon existing TLP technology, incorporation of modern and efficient shipbuilding methodology, and the use of practical construction philosophy geared towards continuous improvement. Keeping the above in mind, the design team was able to utilize the construction efficiencies found in modern shipyards and reduce the overall construction cost of the new generation MOSES TLP.

Construction of the Hull

The design team reviewed the construction philosophies of past TLP fabrication projects in order to understand and realize the efficiencies found in modern shipbuilding techniques and methodology. The decision was made to move away from the cylindrical shapes of the traditional TLPs and utilize flat plate construction to the fullest extent possible. Since we were moving away from the traditional fabrication yards and toward modern shipyards, the design team reviewed specifications and procedures for the following:Material selection, traceability and controlQuality Assurance and Control,Weight Management, andDimensional Control

keeping shipyard procedures and techniques in mind. This review resulted in the development of more stringent project specifications and procedures that required joint and aligned shipyard and Contractor efforts that contributed to the success of the project.

Material

In an effort to achieve the highest quality, and reduce the potential for defects due to material, the construction program included very stringent material selection, approval, traceability, and control requirements. A project specific steel manufacturing specification was utilized. The specification was based on past TLP experience with some tightening of certain chemical and mechanical properties. The specification placed tighter restrictions on carbon, titanium, aluminum, carbon equivalent and Pcm. This tightening of the steel properties was to improve the weldability and reduce the potential for weld defects that are normally attributable to the parent metal.

Material traceability was considered one of the key elements for a successful construction program. The Prince TLP specifications required 100% traceability of all steel utilized in the construction program. A material traceability procedure was developed and used to control receipt, storage, and issuing of material, and to trace the material through the construction process.