The Prince TLP Steel Catenary Risers: Design and Fatigue Challenges

2003 ◽  
Author(s):  
Basim B. Mekha ◽  
Bart Heijermans
Keyword(s):  
Fracture Mechanics ◽  
Gulf Of Mexico ◽  
Shallow Water ◽  
Fatigue Test ◽  
Water Depth ◽  
Oil And Gas ◽  
Floating Structure ◽  
Critical Flaw ◽  
Steel Catenary Risers ◽  
Insight Into

The Prince field in Ewing Bank Block 1003 in the Gulf of Mexico was developed using a “Moses” Tension Leg Platform in a water depth of 455m (1492 ft). Two 12-inch Export Steel Catenary Risers (SCRs) connected to the TLP were designed for oil and gas transportation. The Prince field water depth is the shallowest so far for SCRs connected to a floating structure. Having the SCRs in such relatively shallow water provided many challenges to the SCRs designers, as well as the TLP hull designers. The SCR design required large departure angles of 24 degrees to mitigate the touchdown area stresses and to accommodate the TLP surge (i.e. near and far) motions. The large SCR departure angles resulted in long suspended sections of the SCRs and consequently long sections were required on the seabed. Also, the SCR configuration caused high static and dynamic horizontal loads that were directed to the TLP hull. The motions of the TLP in this water depth affect the entire SCR length and thus, the fatigue and the corresponding fracture mechanics assessment became a very significant aspect of the SCR design. This paper gives a brief introduction to the Prince TLP and its two export SCRs. It also provides an insight into the challenges faced and overcome during their design. The fatigue approach and results with data from the fatigue test programs are also presented. A summary of the fracture mechanics assessment and the critical flaw sizes derived based on BS 7910 (1999) are given.

Stability of offshore structures in shallow water depth

2011 ◽  
Vol 2 (2) ◽  
pp. 320-333
Author(s):  
F. Van den Abeele ◽  
J. Vande Voorde
Keyword(s):  
Shallow Water ◽  
Water Depth ◽  
Fossil Fuels ◽  
Oil And Gas ◽  
Structural Response ◽  
Offshore Structures ◽  
Exploration And Production ◽  
Subsea Pipelines ◽  
Wave Induced ◽  
Shallow Water Depth

The worldwide demand for energy, and in particular fossil fuels, keeps pushing the boundaries of offshoreengineering. Oil and gas majors are conducting their exploration and production activities in remotelocations and water depths exceeding 3000 meters. Such challenging conditions call for enhancedengineering techniques to cope with the risks of collapse, fatigue and pressure containment.On the other hand, offshore structures in shallow water depth (up to 100 meter) require a different anddedicated approach. Such structures are less prone to unstable collapse, but are often subjected to higherflow velocities, induced by both tides and waves. In this paper, numerical tools and utilities to study thestability of offshore structures in shallow water depth are reviewed, and three case studies are provided.First, the Coupled Eulerian Lagrangian (CEL) approach is demonstrated to combine the effects of fluid flowon the structural response of offshore structures. This approach is used to predict fluid flow aroundsubmersible platforms and jack-up rigs.Then, a Computational Fluid Dynamics (CFD) analysis is performed to calculate the turbulent Von Karmanstreet in the wake of subsea structures. At higher Reynolds numbers, this turbulent flow can give rise tovortex shedding and hence cyclic loading. Fluid structure interaction is applied to investigate the dynamicsof submarine risers, and evaluate the susceptibility of vortex induced vibrations.As a third case study, a hydrodynamic analysis is conducted to assess the combined effects of steadycurrent and oscillatory wave-induced flow on submerged structures. At the end of this paper, such ananalysis is performed to calculate drag, lift and inertia forces on partially buried subsea pipelines.

scholarly journals SHOALING PROPERTIES OF BOUNDED LONG WAVES

1984 ◽  
Vol 1 (19) ◽  
pp. 54 ◽  
Author(s):  
E.P.D. Mansard ◽  
V. Barthel
Keyword(s):  
Shallow Water ◽  
Water Depth ◽  
Second Order ◽  
Long Waves ◽  
Experimental Results ◽  
Wave Groups ◽  
Good Insight ◽  
Set Up ◽  
Theoretical Considerations ◽  
Insight Into

Group bounded long waves which appear as a set-down under a group of high waves and a set-up in between groups are well described for constant water depth. However, their propagation into shallow water and their interaction with the constituent wave groups are not well understood and theoretically described yet. Therefore, model investigations were carried out to study shoaling properties of these second order waves in terms of amplitudes and phases. The tests give a good insight into the phenomenon and suggest distinct shoaling properties. Moreover, experimental results provide a valuable basis for future theoretical considerations.

The Shallow-Water Delta Deposit and Exploration Significance in Huanghekou Depression

2014 ◽  
Vol 522-524 ◽  
pp. 1333-1336
Author(s):  
Hong Zhong Yu ◽  
Jiao Wang
Keyword(s):  
Shallow Water ◽  
Sequence Stratigraphy ◽  
Water Depth ◽  
Oil And Gas ◽  
Oil Field ◽  
Fluvial Sediments ◽  
Exploration Process ◽  
Shallow Layer ◽  
The Common ◽  
Oil Gas

As a new kind of deposition system, the shallow-water delta deposit is accepted increasingly by exploration workers in Bohai oil field. In the oil-gas exploration process, more and more evidence about the existence of shallow-water delta was discovered, such as palaeophyte, mudstone characteristic, log response and so on. From the perspective of sequence stratigraphy, the author of this article analyze the causes of shallow-water delta and think that the water-depth change is the major factor that control the throughgoing of shallow-water deltaic sands body; And summarizes the unique characteristic of shallow-water delta which is different to the common delta deposit. Compared to the traditional fluvial sediments, the deposition system of shallow-water delta has better combination of reservoir and cap and superior condition of oil and gas accumulation, and provide more reliable safeguard to shallow layer oil-gas exploration, especially to lithologic reservoirs exploration.

Analysis on Motions and Green Water of FPSOs in Shallow Water With Non-Collinear Environments

2010 ◽  
Author(s):  
Bin Guo ◽  
Long Fei Xiao ◽  
Jian Min Yang
Keyword(s):  
Shallow Water ◽  
Water Depth ◽  
Wind Waves ◽  
Single Point ◽  
Green Water ◽  
Floating Structure ◽  
Floating Structures ◽  
Head Waves ◽  
Run Up ◽  
Yaw Angle

The paper presents motions and green water of a FPSO in shallow water with different wave headings. In non-collinear directions of wind, waves and current, the FPSO does not always encounter head waves, which probably induces specialties in motions and green water especially because of the complexity of shallow water hydrodynamics. Time-domain numerical simulation and model test are carried out in order to analyze motions of a single-point moored FPSO. Green water and wave run-up along the side of a fixed FPSO are simulated in a 3-D numerical wave tank, and results are compared with that of model tests. It is shown that the influence of the yaw angle on motions of a FPSO is considerable and green water occurs more frequently around the mid-ship when the FPSO encounters a big wave heading. In the same water depth, roll and pitch motions of the FPSO under higher wave are lower instead but green water occurs; in the same wave situation, the motions of the FPSO in a lower water depth are lower, but green water occurs more severely. In general, water depth has an important influence on green water of FPSOs in shallow water. The hydrodynamic character of large floating structures in shallow water, especially the green water, should be taken into account carefully for determining the design load and freeboard of a large floating structure.

Dealing with shallow-water flow in the deepwater Gulf of Mexico

2002 ◽  
Vol 21 (7) ◽  
pp. 660-668 ◽  
Author(s):  
R. M. Ostermeier ◽  
J. H. Pelletier ◽  
C. D. Winker ◽  
J. W. Nicholson ◽  
F. H. Rambow ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Shallow Water ◽  
Water Flow ◽  
Shallow Water Flow

Tubarão Martelo Field Riser System: Shallow Water Challenging

2015 ◽  
Author(s):  
Elton J. B. Ribeiro ◽  
Zhimin Tan ◽  
Yucheng Hou ◽  
Yanqiu Zhang ◽  
Andre Iwane
Keyword(s):  
Shallow Water ◽  
Deep Water ◽  
Oil And Gas ◽  
Vertical Motion ◽  
Oil And Gas Industry ◽  
System Configuration ◽  
Wave Load ◽  
Gas Industry ◽  
Campos Basin ◽  
Water Problem

Currently the oil and gas industry is focusing on challenging deep water projects, particularly in Campos Basin located coast off Brazil. However, there are a lot of prolific reservoirs located in shallow water, which need to be developed and they are located in area very far from the coast, where there aren’t pipelines facilities to export oil production, in this case is necessary to use a floating production unit able to storage produced oil, such as a FPSO. So, the riser system configuration should be able to absorb FPSO’s dynamic response due to wave load and avoid damage at touch down zone, in this case is recommended to use compliant riser configuration, such as Lazy Wave, Tethered Wave or Lazy S. In addition to, the proposed FPSO for Tubarão Martelo development is a type VLCC (Very Large Crude Carrier) using external turret moored system, which cause large vertical motion at riser connection and it presents large static offset. Also are expected to install 26 risers and umbilicals hanging off on the turret, this large number of risers and umbilicals has driven the main concerns to clashing and clearance requirement since Lazy-S configuration was adopted. In this paper, some numerical model details and recommendations will be presented, which became a feasible challenging risers system in shallow water. For instance, to solve clashing problem it is strictly recommended for modeling MWA (Mid Water Arch) gutter and bend stiffener at top I-tube interface, this recommendation doesn’t matter in deep water, but for shallow water problem is very important. Also is important to use ballast modules in order to solve clashing problems.

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