Computational Fluid Dynamics Analysis of Rigs-to-Reefs (R2R) Jacket Structures

Rahman, Mohd Nordin Abdul; Nazri, Muhammad Nadzrin; Alias, Fatin; Fitriadhy, Ahmad; Mohd, Mohd Hairil

doi:10.37934/cfdl.13.1.7283

Cited by 3 publications

(2 citation statements)

References 15 publications

(18 reference statements)

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“…Nevertheless, it was only in 2021 that a geometric model of a platform jacket converted to a RA was used in CFD studies conducted by Rahman et al, [11,12]. In these works, the efficiency of the sinking method (that is, the direction in which the jacket is tipped) in terms of upwelling and back vortex generation are explored, as well as other parameters, such as drag, lift forces and pressure distribution.…”

Section: Introduction 11 Purpose and Motivationmentioning

confidence: 99%

A CFD Analysis of Decommissioned Oil Platforms Jackets on the Brazilian Coast

Gonzalez

Moreira

2021

CFDL

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Every facility reaches the last phase in its life cycle, which is decommissioning. Since the last decade, this subject has been gaining importance in Brazil’s offshore oil and gas companies. For jacket type rigs, one of the methods widely applied after idling the production is the conversion of these structures into artificial reefs (ARs). There are several critical aspects for choosing the best strategy for cutting and sinking a platform jacket, ensuring the success of an AR from a biological point of view. One of them is the influence of marine currents and their fluid-structure interaction which, by maximizing local upwelling and back vortex effects, favours the growth of aggregated flora and fauna. This study consists in the application of computational fluid dynamics (CFD) techniques for studying the marine flow around a disassembled and sunk jacket in the seabed for the purpose of converting it into an artificial reef. An FVM (Finite Volume Method) from a commercial software (most recent version of ANSYS FLUENT®) is applied with the upwind scheme. A k-ε turbulence model on steady state is chosen. Field data about Brazilian coastal currents are collected and analysed from the amount of information available on a Brazilian Navy's meteoceanographic program. Next, different combinations of cutting and sinking a jacket are studied, always keeping a minimum 55m free water column. The objective is to verify where the formation of local upwelling regions - that is, where the vertical velocity component reaches values equal or greater than 10% of the magnitude of the free flow velocity - is more significant, without decreasing back eddy formation. It is observed that the dismemberment of the jacket with the positioning of its parts in an increasing height sequence in the direction of the prevailing current is favourable to generate local upwelling while tipping the structure at 90° to the prevailing current results in the most voluminous back eddy region.

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Section: Introduction 11 Purpose and Motivationmentioning

confidence: 99%

A CFD Analysis of Decommissioned Oil Platforms Jackets on the Brazilian Coast

Gonzalez

Moreira

2021

CFDL

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“…The study shows that the lateral displacement has decreased significantly, and that the displacement and acceleration between floors are clearly reduced, and the study confirmed the use of the isolation method in the ground floor to improve the seismic capacity of the structures. Also, many research was done for computational fluid dynamics (CFD) to study the dynamic movement of water wave to the offshore platform [6][7][8][9]. Fernando R. and Roger M. [10] applied CFD techniques for the sunk jacket in the seabed by using ANSYS software and the finite volume method.…”

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confidence: 99%

Used Isolation System to Reduce the Response of Offshore Structure Considering Soil Structure Interaction

Hasan,

Younus

2023

Civil and Environmental Engineering

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Fixed offshore platforms are structures of steel or concrete located in the middle of the sea used to export oil, trade, or military. These are designed to withstand all types of weather and dynamic loads. The response was very high under applied these loads. This paper includes a proposal to apply a new isolation system to be placed in different places on the offshore platform to reduce vibrations from high water waves. Three cases that be used, fixed-based (column connect directly to the pile), isolation system in the pile head (isolation between column and pile), and isolation system in the pile head and the middle of columns. The dynamic movements in waves were simulated using ABAQUS programs. More accurate elements and real material properties were used to bring the results closer to reality. The Computational Fluid Dynamics (CFD) method was used to study the effect of water-structure interaction and soil-structure interaction. The results show that the use of the isolation system at the base of the offshore platform has a very significant effect on decreasing the response of the platform to the loads placed on it. Where the isolation system works as a hinge at the pile head and is not allowed to move and rotate for the pile, also the moments are zero. As for the shear force, it is the least that can be compared with the other cases.

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