An Experimental Approach for the Offshore Launching of Jack-Ups

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
Claudio A. Rodríguez ◽  
Mário Moura ◽  
Paulo T. T. Esperança ◽  
Jacques Raigorodsky
Keyword(s):  
Feasibility Study ◽  
Experimental Approach ◽  
Model Tests ◽  
Building Site ◽  
Test Setup ◽  
Dry Dock ◽  
Jack Up

Recently, as part of the building contract for the new Brazilian jack-up drilling platforms, an operational challenge was raised: to launch these units from the building site, where neither dry dock nor launching ground ways exist. Economically, the best alternative was to launch these jack-ups using the available barges used commonly for jacket launch. Due to the marked differences between a jacket and a jack-up, the implementation of this novel launch operation required a careful feasibility study. Model tests were required to measure the motions of the barge and the jack-up and to evaluate the loads on the barge rocker arms. The present paper discusses the experimental approach, test setup, calibration procedures, and some results from the hydrodynamics perspective.

Experimental Assessment of the Offshore Launching Operation of a Jack-Up Unit

2014 ◽  
Author(s):  
Claudio A. Rodríguez ◽  
Paulo T. T. Esperança ◽  
Mário Moura ◽  
Jacques Raigorodsky
Keyword(s):  
Experimental Approach ◽  
Experimental Tests ◽  
Model Tests ◽  
Experimental Assessment ◽  
Simulation Tools ◽  
Experimental Campaign ◽  
Preliminary Model ◽  
Stage 4 ◽  
Reaction Forces ◽  
Jack Up

Recently, an experimental campaign was carried out to assess the feasibility of the launching operation of two jack-up units using a barge as the launching platform. This experimental study was divided in four stages. In stages 1 to 3, a series of preliminary model tests were performed in order to provide scientific understanding of the mechanics of the operation, and investigate systematically the influence of launching parameters. The experimental approach developed for testing this operation and the results of the preliminary launching tests have been discussed in detail in a previous paper [1]. Based on the analyses of the experimental results of stages 1 to 3 and, the results of numerical simulation tools, in stage 4, a final launching condition was designed and a new set of model tests were specified to check the safety of the operation. This paper presents the results and analyses of the experimental tests in stage 4. The conditions tested in this stage covered the expected real launching condition and possible deviations in some launch parameters. The tests results include the 6-DOF motions and trajectories of the launched jack-up and the launch barge, and the reaction forces on the barge rocker arms. Later on, the success of the launching operations of P-59 and P-60 jack-up units confirmed the experimental investigation results and the feasibility of this novel launching procedure. Furthermore, it can be concluded that the experimental approach efficiently served as a tool for the assessment of high risk operations.

Assessment of a Jack-Up Offshore Launching Through Model Tests and Field Measurements

2015 ◽  
Vol 137 (1) ◽  
Author(s):  
Claudio A. Rodríguez ◽  
Paulo T. T. Esperança ◽  
Mário Moura ◽  
Jacques Raigorodsky
Keyword(s):  
Experimental Approach ◽  
Field Measurements ◽  
Experimental Tests ◽  
Model Tests ◽  
Efficient Tool ◽  
Simulation Tools ◽  
Preliminary Model ◽  
Stage 4 ◽  
Reaction Forces ◽  
Jack Up

Recently, an experimental campaign was carried out to assess the feasibility of the launching operation of two jack-up units using a barge as the launching platform. This experimental study was divided in four stages. In stages 1 to 3, a series of preliminary model tests were performed in order to provide scientific understanding of the mechanics of the operation and investigate systematically the influence of launching parameters. The experimental approach developed for testing this operation and the results of the preliminary launching tests have already been discussed in detail. Based on the analyses of the experimental results of stages 1 to 3 and the results of numerical simulation tools in stage 4, a final launching condition was designed and a new set of model tests was specified to check the safety of the operation. This paper presents the results and analyses of the experimental tests of stage 4. The conditions tested in this stage covered the expected real launching condition and possible deviations in some launch parameters. The tests results include the 6 degree-of-freedom (DOF) motions and trajectories of the launched jack-up and the launch barge, and the reaction forces on the barge rocker arms. Later on, the success of the launching operations of P-59 and P-60 jack-up units confirmed the experimental investigation results and the feasibility of this novel launching procedure. During the launching of unit P-60, field measurements were performed that confirmed that model tests as an efficient tool for the assessment of high risk operations.

Offshore Launching of Jack-Up Units: An Experimental Approach

2013 ◽  
Author(s):  
Claudio A. Rodríguez ◽  
Paulo T. T. Esperança ◽  
Mário Moura ◽  
Jacques Raigorodsky
Keyword(s):  
Friction Coefficient ◽  
Numerical Simulations ◽  
Experimental Approach ◽  
Offshore Structures ◽  
Model Tests ◽  
Point Of View ◽  
Operation Model ◽  
Oil Platforms ◽  
Jack Up ◽  
Structural Point

Ships and most offshore structures are commonly launched into water from dry docks. But, sometimes due to practical and economical restrictions, launching of some offshore structures takes place at floating launching platforms, usually barges. The latter type of launching is quite “usual” for jacket rigs. To assess the success of the launch operation usually numerical simulations are enough and model tests are usually not required. However, more recently, as part of the construction project of the new Brazilian jack-up oil platforms, an innovative launching operation was required: launching a jack-up using a jacket launching barge. The marked differences between the two types of structures involve hydrodynamic and structural complexities. From the hydrodynamical point of view, due to its greater volume compared to jackets, the jack-up may be subjected to greater loads as enters in water during launching, and then suffers great motions that may affect the barge motions and these, affect back, the jack-up motions. From the structural point of view, the heavier jack-up structure may cause greater stresses on the barge deck and rocker arms that should be properly addressed in order to determine the necessity for reinforcements in the jack-up and/or the barge. To assess the feasibility of this innovative launching operation, model tests were required to measure the motions of the barge and the jack-up and to evaluate the loads on the rocker arms. The present paper describes the experimental approach developed for simulating this unique launching operation. The calibration procedures are outlined and the main results of the systematic set of tests carried out are presented. Furthermore, the influence of some launching parameters such as friction coefficient, position of the center of gravity of the jack-up and initial launching angle are discussed.

Experimental Study of a Tanker Ship Squat in Shallow Water

2014 ◽  
Vol 66 (2) ◽  
Author(s):  
Mohammadreza Fathi Kazerooni ◽  
Mohammad Saeed Seif
Keyword(s):  
Experimental Study ◽  
Shallow Water ◽  
Experimental Approach ◽  
Model Tests ◽  
Ship Hull ◽  
Experimental Results ◽  
Shallow Waters ◽  
Towing Tank ◽  
Ship Model

One of the phenomena restricting the tanker navigation in shallow waters is reduction of under keel clearance in the terms of sinkage and dynamic trim that is called squatting. According to the complexity of flow around ship hull, one of the best methods to predict the ship squat is experimental approach based on model tests in the towing tank. In this study model tests for tanker ship model had been held in the towing tank and squat of the model are measured and analyzed. Based on experimental results suitable formulae for prediction of these types of ship squat in fairways are obtained.

Centrifuge Model Study on the Effect of Lattice Leg and Sleeve on the Postconsolidation Bearing Capacity of Spudcan Foundation

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Yu Ping Li ◽  
Jiang Tao Yi ◽  
Fook Hou Lee
Keyword(s):  
Bearing Capacity ◽  
Model Tests ◽  
Capacity Enhancement ◽  
Centrifuge Model ◽  
Model Study ◽  
Operation Period ◽  
Capacity Improvement ◽  
Jack Up ◽  
Two Sides ◽  
Centrifuge Model Tests

Up to now, the postconsolidation bearing capacity enhancement of jack-up spudcan foundation has been explored using centrifuge model tests and numerical analyses, which however ignored the realistic jack-up lattice leg. This paper investigates both typical lattice leg and sleeve effects on the postconsolidation spudcan bearing capacity using centrifuge model tests, by replicating the entire process of spudcan in normally consolidated clay: “penetration–unloading–consolidation–repenetration.” The experimental results show that the lattice leg and sleeve affect the spudcan bearing capacity in two sides compared with spudcan without leg. First, it increases the transient bearing capacity during initial spudcan penetration; second, less postconsolidation bearing capacity improvement is yielded by the presence of the leg. The former effect is of importance on the prediction of jack-up leg penetration, and the latter effect would suggest a lower risk of spudcan punch-through for realistic offshore jack-up rig during preloading and operation period.

scholarly journals Model Tests on Foundation Stability of Jack-up Rigs

1985 ◽  
Vol 1985 (158) ◽  
pp. 476-482
Author(s):  
Yoichi Hattori ◽  
Masayuki Ushio ◽  
Takaaki Ishihama ◽  
Masahiro Nanjo ◽  
Taizo Kawamura
Keyword(s):  
Model Tests ◽  
Jack Up

How Does Barge-Master Compensate for the Barge Motions: Experimental and Numerical Study

2012 ◽  
Author(s):  
Frederick Jaouen ◽  
Joris van den Berg ◽  
Haite van der Schaaf ◽  
Eelko May ◽  
Jim Koppenol
Keyword(s):  
Time Domain ◽  
Environmental Conditions ◽  
Numerical Study ◽  
Model Tests ◽  
Test Results ◽  
Theoretical Formulation ◽  
Wave Basin ◽  
The Time Domain ◽  
Jack Up ◽  
Economical Alternative

To increase workability and safety in tough environmental conditions, and to create a more economical alternative for jack-up barges, Barge-Master has developed a wave compensating platform for marine and offshore installation barges. To minimize the motions of the crane positioned on top of it, the platform is driven by three hydraulic actuators that compensate for the roll, pitch and heave motions of the barge. To quantify the performance of the platform for different environmental conditions and crane configurations MARIN performed both wave basin model tests and time-domain simulations on the platform. In this paper, the experimental setup is first described and the model test results are presented. Then, the theoretical formulation of the time-domain aNySIM model is described and the numerical results are reported. It is shown that the model tests and time-domain results are in good agreement. The results indicate that the barge motions can be compensated by the platform for more than 90% in 1.2m high sea states. However, it is also shown that the instrumentation, data acquisition and controller system need to be fast and tuned to achieve this optimal compensation.

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