Worley adopt ‘Think globally, act locally’ policy for their integrated subsea strategy

The Pipelines and Subsea team at Worley are based primarily out of their Aberdeen and London offices, with skilled personnel deployed all around the UK. The team is unified through an integrated strategy to deliver the best fit solutions to their customers in the UK and worldwide. With an experienced global presence, Worley are always able to draw on the best local talent across multiple geographical regions, ensuring that they are always able to deliver the best value solution for their growing client base.
 
The team are specialists in providing solutions to offshore and subsea developments and their projects range from early concept stages, all the way through to execution and construction - for conventional energy, as well as renewables and new energy, including electrification and emissions reduction for all types of brownfield and greenfield assets.

Worley are leaders in conceptual development for new energy projects.  This is achieved by building on the foundations of our many years of experience in upstream oil and gas projects and calling on the huge network of subject matter experts within Worley globally. They view each new development as a fresh challenge, seek to establish a vision for excellence for the development and how they can measure success, ensuring all ESG aspects are considered and applied. They seek to understand and implement multiple metrics on how these different drivers interact and use this understanding to screen and rank many alternative development schemes. This approach has been used to create various project plans for the future North Sea developments and also to look at the conversion of existing assets from gas into new energy infrastructure.
 
If the key to securing subsea projects is the funding, then the gateway to its ultimate success is the technical delivery. The team can tackle the biggest of challenges with:
 
1.    Technical ability and expertise - Keeping on top of the latest technologies and software and ensuring continued professional development within the team.
2.    Partnership with the customers and ensuring their team is a key part of the execution, working in collaboration.
3.    Customer local delivery, and ability to draw on the key resources with the right skillsets in a timely manner, for a effective kick-off and delivery.
 
Skills are a critical element for almost any engineering endeavour, including the conventional energy sector. The challenge at this time is that rather than a gradual extension of skills and knowledge, such as has been the case throughout decades of advancement in the Oil and Gas industry, a step change in terms of skills and new areas of knowledge are required to realise marginal conventional energy extraction, the energy transition, and the emissions reduction and associated sustainability mandate.
 
In the context of pipelines and subsea, a drive towards standardisation is helpful and heavy optimisation of offshore infrastructure in a way that very much differs from traditional Oil and Gas measures, and the use of novel computing tools to facilitate operational optimisation and condition-based maintenance in a way that was not previously possible. This includes the use of more novel processes, like PINN/SciML, CEL, and other more advanced numerical methods.
 
These changing requirements place new demands on the key engineering disciplines that form the Pipelines and Subsea team, including Flow Assurance, Pipeline Design & Analysis, and Materials & Corrosion.
 
It is now more important than ever to have a diverse and highly motivated team that can think outside the box and approach problems from new directions. This defines the approach Worley are taking towards recruitment and people development in the Pipelines and Subsea area, with a focus not only on bringing in specialist knowledge and experience, but fostering an atmosphere where people feel comfortable working beyond the limits of their current knowledge  and ensuring that the whole team is always available for support and advice.
 
 Worley case studies :
 
 STRUCTURAL RESPONSE OF SUBSEA PIPE ELBOWS UNDER MONOTONIC AND CYCLIC LOADING, presented at OMAE 2022
 
Pipe bends (elbows) are commonly used components in subsea piping systems protecting the system from failure. Because of their flexibility, they develop significant deformations and may cause either buckling or rupture of the elbow pipe wall.
The main feature in those elbows is the presence of external pressure in subsea systems, which has a destabilizing effect, especially in deep water applications.
The paper, motivated by the use of steel elbows in subsea systems, describes a finite element simulation of elbow response under static and cyclic loading, in the presence of external pressure simulating the response of steel material said loading.
 
 Large deformation finite element analyses to evaluate the influence of the ice gouging process on buried pipes. To be presented at ISOPE 2024
 
Drifting icebergs might come into contact with the seabed resulting in ice scour, which can be identified as traces in bathymetry surveys. Ice scour can pose a significant threat for sub-sea pipelines: for embedded pipelines within the scour zone the moving ice ridge and the displaced  soil can directly impact the pipeline; while for pipelines buried deeper the deformed soil will force the pipe to move simultaneously inducing stressing on the pipeline.

In order to evaluate the influence of the ice gouging process on a typical buried pipe embedded in sand, large deformation finite element analyses (LDFE) were performed utilising the Coupled Eulerian-Lagrangian (CEL) method in Abaqus/Explicit.
This paper evaluates the a 2D plain strain model as well as full 3D pipe response. The resulting pipe stresses should be considered together with induced stresses due to other design aspects, in order to select the appropriate pipe burial depth or mitigation measure.
 

Hydrodynamic forces on near-bed subsea cables. To be presented at ISOPE 2024
 
The design of subsea cables is a complex process involving several engineering disciplines. From the structural analysis and design point of view, the on-bottom stability analysis of an unburied static cable is conducted for the definition of the required cable weight for stability. The stability requirements for Inter-array and Export cables, as well as the installation process and the cable material costs are dominant parameters for the evaluation of the Levelized Cost of Energy (LCOE). There is an opportunity to reduce LCOE for the whole offshore development by optimizing the cable stability weight requirements, which will also reduce the material and installation costs.

This paper focuses on the near-bed oscillatory-flow induced hydrodynamic forces on small-diameter Inter Array Cables, installed on the seabed. For relatively shallow water applications, such as in North Sea, and large waves, the hydrodynamic forces are dominated by the wave loading.

To reach a cost-efficient conclusion for on-bottom stability weight requirements for subsea cables,  Computational Fluid Dynamics (CFD) simulations are conducted in ANSYS Fluent. The analysis aims at investigating the effect of near-bed hydrodynamic conditions on fixed cables on the seabed, taking into consideration the boundary layer that is generated by the wave-induced near-bed oscillatory-flow and the seabed roughness. The resulting drag and lift hydrodynamic forces are evaluated and compared with design code provisions and experimental data.
 
 Response prediction of monopile supported offshore wind turbines using conventional and advanced soil representation methods
 
The design of monopiles under lateral loading has been traditionally conducted using the “p-y method”, which is included in relevant design standards. According to this method, the soil layers around the monopile are represented by equivalent nonlinear springs. The “p-y” design methodology, initially developed for slender piles with diameters up to 1m, may provide non-conservative predictions for large diameter monopiles in certain cases. Recent advances in computational mechanics tools allow for the design of offshore wind turbine (OWT) monopiles using a more sophisticated approach, in which an elastic-plastic continuum representation of the soil is employed.

The current study is numerical and presents a comparison of the “p-y” and 3D FEA soil representation methodologies employed for the analysis of a monopile-supported OWT system under wind loading, also considering scour effects. A typical monopile geometry and North Sea representative metocean data are used as a case study. The analysis focuses on the predicted stress and deformation fields, as well as the predicted modal vibration characteristic. The comparative analysis results show that an overestimation of the system lateral stiffness is possible using the conventional “p-y method”, which results in underestimation of the stress and deformation fields, and it may affect fatigue life predictions.
 

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