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Subsea technology and deep-sea mining

UiS researchers study a range of issues connected to deep-sea drilling and mining.

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Fluid-Structure-Morphology-Soil Interaction CFD Model: 

With the rapid development of seabed oil industry, the technology of subsea systems draws substantial attention in offshore engineering. It also increases the importance of flow structure interactions around subsea structures (such as subsea manifolds, subsea protection covers and marine pipelines) in different environmental conditions.

In order to achieve good operational conditions and accuracy of the installation process, it is essential to assess hydrodynamic loads acting on subsea structures precisely. Moreover, in areas with soils that are prone to scouring by current and waves, the stability of the structures and associated with the protection will be affected.

The hydrodynamic responses and the flow pattern around the structures will be subsequently altered due to the existence of the scour hole; and it further leads to a change of soil strength beneath the subsea structures, which might cause additional soil displacement.

This research study (supported by UiS-Equinor Academic Program) focuses on developing a computationally-efficient fluid- structure-morphology-soil interaction model based on the understanding of the flow physics and soil mechanics. An open-source CFD code, OpenFOAM is used for the model development. The effects of seabed boundary layer flow on the structures are considered.

The effects of Reynolds number, different configurations of subsea structures, boundary layer thickness of the incident flow and different soil properties are investigated. 

 

Robotic Drilling: 

In recent years, popular topics such as digitalization, machine learning, digital twin and big data have evolved from being envisions of the future to a fully integrated concept, expected to revolutionize drilling efficiency in the industry.

Drilling automation tomorrow is all about exploiting the current state of technologies available to the entire operation of drilling a well. Not only drilling automation can limit costs and reduce the risk to rig personnel and the environment, but also they allow previously inaccessible oil resources to be developed.

There are, however, some challenges in keeping up with the ever-increasing pace of the development. Testing of novel and innovative solutions is often very expensive because of non-productive time during implementation, trial runs and data collection. In addition, the modern technologies require extensive prototyping and R&D before early testing can even commence, considering the potential extent of damage if an error should occur. Of great importance, the introduction of a state of the art system can require significant upgrades across the entire platform, and may thus only be partially implemented because limited data exist on the benefits of performing a full transition.

The research work at UiS is to test a laboratory-scale autonomous drilling rig to utilize fully interchangeable key drilling systems, sensors and tools that are all relatively inexpensive, little- to no risk of incidents involved, full-time access to the systems and immediate on-site results when testing prototypes or implementing models, algorithms etc.

By implementing the control architecture algorithms for real-time optimization of drilling parameters, the drilling rig can increase the performance efficiency and detect and handle incidents that would damage the system. The lessons identified can then be used to further strengthen the understanding of common causes of drilling incidents such as stuck pipe, key seating as well as drill bit wear. This study aims to develop better models that can be related to real-life drilling phenomena.

 

Deep-Sea Mining: 

With the advancement of offshore oil and gas exploration and production technologies, the mining activities in the oceans are no longer unattainable. T

he deep-sea mining industry has attracted growing attention globally as they target mining activities in deeper waters of up to 6,000 m depth. It is known that the Canadian company Nautilus Minerals is now developing a real deep-sea mining project in Papua New Guinea. Meanwhile in Europe, there are two European Union sponsored research projects, known as ‘Blue Mining’ and ‘Blue Nodules’ emphasizing on the ‘breakthrough solution for sustainable deep-sea mining’ and ‘to develop a new highly-automated and technologically sustainable deep sea mining system’.

Multi-disciplinary

The entire deep-sea mining system is highly integrated with multi-disciplinary technology and knowledge, including

  • ship hydrodynamics
  • ultra-deep water ship dynamic positioning
  • riser flow-structure interaction
  • riser internal multi-phase flow
  • complex boundary conditions, including top motion compensation device and bottom flexible jumper connection.

It is known that many of the technologies used in the deep-sea mining have been adopted from the offshore oil and gas industry. However, one of the most significant challenges is to develop a thorough design and optimization package which is capable of considering all relevant dynamic behaviors in the entire deep-sea mining system.

System analysis 

This research study focuses on developing a fully coupled global dynamic analysis package for the deep-sea mining system in the time-domain.

The proposed numerical investigation includes ship potential theory, control algorithm, slender structure finite element modelling, structural dynamics and their coupling effects. Inputs from computational fluid dynamics (CFD) calculation are implemented to accurately addressing the loads during fluid-structure interaction.

This research aims at increased understanding and improved design of the deep-sea mining system.

 

Dynamic Response of FRP Pipelines in Unsteady Flow Conditions: 

Fibre-reinforced polymers (FRP) are advanced materials made of a polymer matrix reinforced with fibers. In last decade there is an increase of the use of Fiber Reinforced Polymeric materials (FRP) in offshore installations (e.g. sea water lift pump column pipes, umbilical, risers, etc).

FRP pipelines have been installed for hundreds of kilometers over hostile environment and offshore platforms Their superior behavior in corroded environments and fatigue loading as well as their high strength and low density, significantly decrease the maintenance cost of pipelines made by FRP materials. Apart from the benefits on maintenance issues, the high stiffness of the laminated pipe wall yields superior mechanical behavior in unsteady flow conditions (e.g. fluid hammer).

Main subject of this research activity is the derivation of models simulating the displacements’ motion and dynamic stresses of thin-walled multi-layered filament wound FRP pipes subjected to fluid hammer conditions. Since the material is anisotropic, and the structural equations are coupled with the fluid equations, this requires complex and demanding computational methods.

 

Demonstrating Safety of Novel Subsea Technologies: 

This project, funded by the Norwegian Research Council and several industry partners (2018-2021), is led by DNV GL and has both UiS and NTNU as academic partners.

The main objective of the project is to enable and accelerate up-take of novel subsea solutions by developing a framework for standardized demonstration of safety, including examples of common acceptable design solutions. The framework will be developed from relevant use-cases, and will support introduction of new safety philosophies, more integrated solutions, and advanced use of sensor data and data analytics, to demonstrate a sufficient level of safety.