Design And Installation Of Auger Steel Catenary Risers

Phifer, E.H.; Kopp, Frans; Swanson, R.M.; Allen, Don; Langner, Carl G.

doi:10.4043/7620-ms

Cited by 19 publications

(5 citation statements)

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“…Figure 5 shows the cross-section of the riser under investigation, where the inner layer of 3 mm is duplex stainless steel, and the rest of 14 mm is carbon manganese steel. The sizing of the riser is as per the existing riser of Auger TLP [17] . X-ray computed Tomography test on the FGM build confirmed that it is free from porosity and micro-cracks.…”

Section: Functionally Graded Materialsmentioning

confidence: 99%

Functionally graded material and its application to marine structures

Chandrasekaran

Setiapraja

2022

SUSTAIN MAR STRUCT

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Marine structures are exposed to harsh weather conditions, demanding special pre-requisites in design and functional perspectives. Under dynamic loads of larger magnitude, the material-centric design procedure alone is not feasible to ensure the safe disbursement of loads. The compliant offshore structures resist loads primarily by their geometric novelty, and hence their design is form-dominant and no more strength (material) dominant. Large displacements in the rigid body modes in the horizontal plane under lateral loads require their construction material to possess enough ductility to absorb this energy. Steel is one of the most competitive materials for marine structures as it offers good ductility, but corrosion in the marine environment is a major concern. It undergoes strength and functional degradations and therefore requires serious investigation. In the present study, functionally graded material (FGM) is proposed to substitute for steel in marine applications. The method of fabricating FGM and assessing its mechanical and durability properties are discussed. Results show that FGM possesses strength and durability properties at par with the conventionally used X52 steel for marine risers. The presented study will be a major initiative towards future research in exploring competent materials which will be strong and sustainable in the marine environment.

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Section: Functionally Graded Materialsmentioning

confidence: 99%

Functionally graded material and its application to marine structures

Chandrasekaran

Setiapraja

2022

SUSTAIN MAR STRUCT

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“…6), and Lazy Wave configurations in steel and titanium have been proposed as deep-water riser systems for TLP and Semisubmersibles. Free Hanging Risers in steel have been installed in the Gulf of Mexico (Ref.…”

Section: Deep Water Systemsmentioning

confidence: 99%

Efficient Integrated Analysis Methods for Deepwater Platforms

1999

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Deep Water Floating Production Systems is an integrated dynamic system of risers, moorings and a floater responding in a complex way to loading from wind, waves and currents. The great challenge in selecting the proper strategies for efficient analysis is addressed in terms of analysis techniques and principles of selecting analysis approach. Available analysis methods are discussed with emphasis on treatment of important non-linear effects. A large potential for reduction of the computational efforts involved has been identified based on a careful selection of response model and method of analysis. Efficient analysis will therefore to a large extent depend on the analysts' experience regarding physical system behavior and insight on available analysis methods. A userfriendly computer implementation of advanced as well as simplified methods is hence the basis for cost efficient analysis of Deep Water Production Platforms. Structural reliability analysis is a consistent way of handling uncertainties. This methodology provides a probabilistic basis for decision making under uncertainty with due consideration of cost. Application of methodologies for tension leg platforms, semi-submersibles, deep draft floaters and more conventional ship shaped units are discussed.

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“…The SCR configuration forms catenary due to its own weight. The SCR also offers benefit over the top tensioned riser because the SCR requires no heave compensation at the hang-off point (Phifer et al, 1994). On the seabed, the SCR needs no special bottom connection.…”

Section: Introductionmentioning

confidence: 99%

“…The steel catenary riser (SCR) has emerged to be one of attractive choices for recent deep water environments (Phifer et al, 1994). The steel catenary riser consists of simple rigid steel pipe hanging freely from the floating production system to the seabed.…”

Section: Introductionmentioning

confidence: 99%

Feasibility Study of Selected Riser Concepts in Deep Water and Harsh Environment

Gemilang

Karunakaran

2017

Volume 5B: Pipelines, Risers, and Subsea Systems

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Todays, oil and gas sources are explored in deep water and harsh environment. A riser system is one of the major sub-facilities to transfer oil and gas from the seabed to the host platform. One of the well-known riser systems, the Steel Catenary Riser (SCR), has been an attractive choice for the riser system in deep water. However, the main challenge of the SCR is large motions from the host platforms due to the harsh environment. The large motion of host platforms may induce excessive buckling and fatigue at the touchdown point. The key component of the large motion of the host platform is the downward velocity at the hang-off point where the top-end of the riser is attached to the host platform.By screening the downward velocities at the hang-off point in the time history graph, the time at which the critical responses (i.e. buckling utilization, bending moment and compression) peak is identified. This study investigates the feasibility of the SCR configuration in terms of the capability to cope with the vessel motion. Several types of the SCR configurations are proposed in this study. The selected configurations of SCR in this study are conventional SCR, Weight Distributed SCR (WDSCR), and Steel Lazy Wave Riser (SLWR). The feasibility of the three riser configurations was analyzed in terms of strength and fatigue performance to understand the limitation of one over the other. The strength assessment of the risers was performed by using load cases, the screening approach was based on different extreme downward velocities at the hang-off point. The checks were according to DNV.The fatigue performance of the risers was checked considering both wave-induced fatigue and fatigue due to vortex induced vibration. Overall, from the extreme response analysis study, results showed that a feasible conventional SCR configuration can be obtained if the downward velocity at the hang-off point is restricted below 2.6 m/s. It is also found that the downward velocity at the sag-bend of the conventional SCR is restricted below 3.03 m/s. On the other hand, a feasible WDSCR configuration can be obtained, if the downward velocity at the hang-off point is restricted below 3.2 m/s. It is also found that the downward velocity at the sag-bend of the WDSCR is restricted below 3.43 m/s.The heavy cross section of WDSCR reduces the critical responses (i.e. bending moment, compression and utilization) at the TDP and extends the feasibility of the SCR. The results showed that the SLWR configuration can cope even with a downward velocity of 6 m/s at the hang-off point. The "lazy wave" configuration efficiently absorbs the vessel heave motions. Thereby the SLWR configuration is proven to be the most robust configuration to cope with large motion of the host platform. This study proves that although the SCR feasibility is limited due to vessel heave motion, innovative solutions can be established to extend its feasibility in order to cope with the vessel heave motion in harsh environment.

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Design And Installation Of Auger Steel Catenary Risers

Cited by 19 publications

References 0 publications

Functionally graded material and its application to marine structures

Functionally graded material and its application to marine structures

Efficient Integrated Analysis Methods for Deepwater Platforms

Feasibility Study of Selected Riser Concepts in Deep Water and Harsh Environment

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