Reducing Risk and Improving Weather Window in Offshore Lifting Operation Cranemaster Technology Kristian Helland Product Manager
Cranemaster Functionality
Cranemaster company Main office Stathelle, Norway Established in 1983 Business: o Cranemaster units o Shock absorbers and special units o Analysis Warehouse in: o Norway, Singapore, Australia Agents in: o Singapore, Perth, Rio de Janeiro, Esbjerg
Working Principle of Cranemaster Pressure Gas Pressure (Nitrogen) Oil MASS Nozzles
Cranemaster Technology & Applications Cranemaster in a nutshell Passive heave compensator and Shock absorber system in one selfcontained unit Limits dynamic force in the hoist wire or crane Limits dynamic force and heave motions in the load Product Range: o o SWL 25 1400 Ton Load Range: 1 1200 Ton Stroke 0,5 4,5 meter
Cranemaster Technology & Applications Applications Transfer lifts Lowering through the Splash Zone Subsea heave compensation Subsea resonance Subsea retrieval Overload protection
Offloading from supply vessel reducing DAF No CM With CM 7
Cranemaster Technology & Applications Applications Transfer lifts Lowering through the Splash Zone Subsea heave compensation Subsea resonance Subsea retrieval Overload protection
Example of Cranemaster in splash zone With CM No CM
Typical weather windows splash zone No Cranemaster Tp / Hs < 1.0 m 1,0 m 1,5 m 2,0 m 2,5 m 3,0 m > 3.0 m < 4 s 0,03 8 % % 0,02 % probability 0,01 % 0,00 % 0,00 % of 0,00 % 0,00 % 4-6 s 0,36 % 1,67 % 1,93 % 1,21 % 0,38 % 0,07 % 0,01 % 6-8 s 0,72 % 2,93 % 3,73 % 4,01 % 3,27 % 2,11 % 1,71 % 8-10 s 0,51 conducting % 3,98 % 6,54 % 6,54 % lift 5,67 % 5,19 % 11,59 % 10-12 s 0,12 % 0,89 % 1,97 % 2,37 % 2,51 % 2,39 % 11,25 % > 12 s 0,13 % 0,40 % 0,87 % 1,32 % 1,35 % 1,62 % 8,61 % With Cranemaster Tp / Hs < 1.0 m 1,0 m 1,5 m 2,0 m 2,5 m 3,0 m > 3.0 m < 4 s 0,03 67 % 0,02 % probability 0,01 % 0,00 % 0,00 % 0,00 % 0,00 % 4-6 s 0,36 % 1,67 1,93 % 1,21 % 0,38 % 0,07 % 0,01 % 6-8 s 0,72 % 2,93 % 3,73 % 4,01 % 3,27 % 2,11 % 1,71 % 8-10 s 0,51 of % 3,98 conducting % 6,54 % 6,54 % 5,67 lift % 5,19 % 11,59 % 10-12 s 0,12 % 0,89 % 1,97 % 2,37 % 2,51 % 2,39 % 11,25 % > 12 s 0,13 % 0,40 % 0,87 % 1,32 % 1,35 % 1,62 % 8,61 % Acceptance criteria: Crane force < X T Short wave periods typically a challenge for splash zone Cranemaster stroke must be longer than boom tip movements Weather statistics North Sea (1973-2001)
Cranemaster Technology & Applications Applications Transfer lifts Lowering through the Splash Zone Subsea heave compensation Subsea resonance Subsea retrieval Overload protection
Important principles for Subsea Heave Comp. Without Cranemaster With Cranemaster
Cranemaster Technology & Applications Applications Transfer lifts Lowering through the Splash zone Subsea heave compensation Subsea resonance Subsea retrieval Overload protection Larger units Increasing depth Wire and load as Vertical Swing
When lowering, system frequency change Example: Foundation Base Structure Weight 205 mt, 175 mt in water, added mass 1300T, cable stiffness 1.5x10 6 kn/m
Wave period Tz=6s: From 500-800s 15
Cranemaster Technology & Applications Applications o Transfer lifts o Lowering through the Splash zone o Subsea heave compensation o Subsea resonance o Subsea retrieval o Overload protection
Lift Engineering Cranemaster Characteristics Hydrodynamic Characterization CM Stroke vs Force Orcaflex Simulation Orcaflex Modelling
EXAMPLE: 1000 T Heave Comp Lift World Record! Gorgon & Jansz field o Operator: Chevron o Installation Company: Subsea 7 20 structures; Manifolds and Foundations o Loads 200 to 1000 ton o Depth 130 1350 meter o Lift-off from barge o Splash zone crossing o Subsea landing Engineering and Implementation support o Orcaflex analysis for all structures o 2 x CM4-700T-4500-A Cranemaster Units o SWL 1400T with Parallell Rigging o Dual Mode Configuration Source: Subsea 7 18
Modelling of Cranemaster properties Splash zone down crossing CM Stroke vs Force With CM (full) Significant wave height Hs, [m] 1.00 1.25 1.50 1.75 2.00 Without CM (full operation) Significant wave height Hs, [m] 1.00 1.25 1.50 1.75 2.00 Peak wave period Tp, [s] 8 10 12 14 Peak wave period Tp, [s] 8 10 12 14 Landing limitations SZ limitations 19
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Reducing Risk and Improving Weather Window in Offshore Lifting Operation THANK YOU!