This paper provides a detailed and critical review of the various deepwater riser solutions being proposed at the present time, and outlines the technical benefits of these systems The solutions include flexible risers, steel catenary risers and hybnd riser systems The authors incorporate their experience of deepwater riser design in locations such as the West of Shetlands, Gulf of Mexico and Offshore Brazil
The paper addresses the technical challenges facing riser designers looking at applications in deepwater and some Innovative solutions being proposed to overcome these challenges Examples Include the use of new flexible pipe cross-section designs, new materials and enhanced riser configuration designs for deepwater
Results of analysis work are presented that demonstrate the benefits of Integrating the riser and mooring system analysis for a floating production system in order to achieve an optimum overall design A new methodology that enables the Interactive and simultaneous design of the riser configuration with the pipe cross-section is also presented
On-line integrity and condition monitoring of riser systems is important to verify these methodologies and the paper addresses some developments In this area, particularly with regard to flexible riser systems
In recent years there has been a drive In the offshore oil industry towards the development of reserves in deepwater locations worldwide While deepwater In Itself presents challenges to riser manufacturers and design teams, these challenges are further compounded when environmental conditions are harsh
These challenges are being met by continuous advances In riser technology The advances In flexible risers are In new cross-section designs, new materials and enhanced riser configuration designs for deepwater Steel risers are providing new alternatives in the form of steel catenary riser technology, and hybrid steel / flexible riser systems bring the best advantages of steel and flexible into one concept All these compliant riser systems are reviewed in this paper
In parallel with technology, riser design methodologies also need to be improved Increased understanding of the problem and the development of advanced analytical techniques which can accurately account for the various hydrodynamic and structural effects In deepwater should result In eliminating unnecessary conservatism and hence reduce costs This should also result In extending the range of feasible solutions available to the user
This paper addresses two important design issues for deepwater application Firstly, the paper presents results which demonstrate the need and benefits of developing a design methodology which integrates the analysis of the complete riser and mooring system Secondly, the paper presents a new method which enables a closer link to be established between the design of the riser configuration and the riser cross-section during the design process
Fig 1 shows schematics of three types of compliant riser systems presently being considered for deepwater application These riser systems are typically connected to monohull FPSO or semi-submersible type floating production vessels Although vertically tensioned steel risers can also be considered as a deepwater option, their application has been limited to TLP solutions, and as such are not reviewed in this paper
