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The utilization of the pendulous motion for deploying subsea hardware in ultra-deep water Francisco E. Roveri Petrobras R&D Rogério D. Machado Petrobras.

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Presentation on theme: "The utilization of the pendulous motion for deploying subsea hardware in ultra-deep water Francisco E. Roveri Petrobras R&D Rogério D. Machado Petrobras."— Presentation transcript:

1 The utilization of the pendulous motion for deploying subsea hardware in ultra-deep water Francisco E. Roveri Petrobras R&D Rogério D. Machado Petrobras E&P Pedro F. K. Stock Petrobras E&P Maxwell B. de Cerqueira Petrobras E&P Francisco E. Roveri Petrobras R&D Rogério D. Machado Petrobras E&P Pedro F. K. Stock Petrobras E&P Maxwell B. de Cerqueira Petrobras E&P 17 th FPSO Research Forum April 5 th 2006

2  Smaller subsea hardware and shallow waters: crane barge, crane of SS, AHTS Previous installation of some subsea hardware by Petrobras

3  Crane barge and slings – 420 Te/620 m (1995) Previous installation of some subsea hardware by Petrobras

4  MODU/drilling riser – 240 Te/940 m (2001) Previous installation of some subsea hardware by Petrobras

5 Sheave Method – 175 Te/1900 m (2002) Previous installation of some subsea hardware by Petrobras

6 The Pendulous Method  Disadvantage of wire rope: self weight + axial resonance (DAF)(DAF)  Alternative: special construction vessels (scarce and high daily rates)  installation costs prohibitive  Synthetic fiber rope  issues to be solved: bending and heating + axial resonance (w/o heave compensation) Challenge of deployment in increasing WD (250 Te payload, m WD)

7 K M, M a K C prescribed vertical displacement (X o ) frequency ratio β L = 0... L total

8 Transportation vessel Overboarding HangoffPendulous Motion The Pendulous Method

9  Conceived to overcome the above constraints (DAF1) (DAF1)  Utilization of the Pendulous Motion  Utilization of two workboats  Distance between vessels 80% of cable length  Installation cable, from subsea hardware: wire rope with DBM, polyester and chain  Due to drag the pendulous motion will be very slow The Pendulous Method (cont.)

10 DAF (displacements) Amplitude of dynamic force (KX o multiplier) damping ratio ξ = 0.20 frequency ratio w/w n working region

11 chain polyesterwire rope polyester wire rope and DBM slings manifold General system configuration (side view, just after release)

12 material MBL (Te) Diam. (mm) length (m) mass (kg/m) wet wgt (kgf/m) EA (MN) chain R polyester wire rope Weight in air: 280 Te Dimensions: x 8.50 x 5.15 m (L x B X H) CG 3.15 m above base line (CG≡CB) System components

13  Equipment of complex topology  Volume of the envelope dimensions: 728 m 3  Steel volume: 35.7 m 3 (< 5% total volume)  Some assumptions are needed in order to simplify the computer model  1 st aproach to concentrate drag and added mass at CG  inadequate  improvement  center of pressure and spatial distribution of drag and lift forces Physics of the problem

14 G≡B (1) Suspended at transportation vessel side (2) Just after release G≡B CLCL CNCN CLCL CNCN (3) Clockwise rotation G≡B CLCL CNCN CLCL CNCN (4) Anti- clockwise rotation Physics of the problem (cont.)

15  PROCAP 3000 project Participation in JIPs: VP2002 (Odim), DISH (phases 2&3)  Conceived in 2003, based on the procedure for installation of torpedo pile  Numerical analyses with Orcaflex to demonstrate the feasibility  Model tests at LabOceano (UFRJ) in 2004  1:1 scale prototype test in December 2005 Development of the concept

16  Three distinct phases: equipment at the side of transportation vessel pendulous motion equipment supported by installation vessel Some results of numerical analysis

17 polyester wire rope and DBM chain manifold installation vessel Configuration 10 minutes after release

18 Cable effective tension, installation vessel side

19 Manifold rotation (deg) 1000_sec.avi1000_sec.avi 60_sec.avi60_sec.avi

20  Model tests at 1:35, 1:70 and 1:130 scales for manifold #2 – excessive rotations detected in some cases Model tests

21  Decision to build and install a 1:1 prototype for qualification of the method and installation procedure 1:1 Prototype test

22  increase of sling forces at start additional buoyancy to the distributed buoyancy modules  improvement of hydrodynamic stability dead weight at the equipment bottom – lowers CG a more adequate equipment geometry, e.g., vertical or near vertical (slightly slanted) panels around it Mitigation of excessive rotations

23  Construction of Roncador MSGLs #2 and #3 (1850 m WD) awarded to FMC Pendulous Method to install MSGLs #2 and #3

24  Utilization of conventional spread  Allow deployment of heavy equipment in ultra deep waters  Attenuation of axial force, prevents resonance  Cost effective compared to utilization of specialized installation vessels or rigs (about 30% cost reduction)  Needs improvement on control of rotations at start Conclusions


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