Fri, 15 May, 2020
In collaboration with the University of Leicester and TWI Ltd, NSIRC has begun recruiting for a new PhD Scholarship opportunity to take place in Cambridge, starting in 2020.
PhD research topic: Scaling modelling for annulus environments
Flexible pipes are built from numerous concentric layers of polymeric materials and steel wires. These steel wires provide resistance to the operational loads, while an inner and an outer polymeric sheath provide chemical barrier to the production fluids and saltwater.
When composite pipelines began to be used on oil and gas fields, their design was based on the assumption that the annulus environment, i.e. the space comprised between the two polymeric sheaths, would remain dry and non-corrosive under normal operation.
However, seawater and Carbon Dioxide can over time permeate into the annulus. The result is the creation of a corrosive environment.
Here is what the Oil and Gas Industry wants research to address...
Oil and natural gas production fields with high partial pressures of Carbon Dioxide and Hydrogen Sulphide. These could compromise the integrity of the asset.
High-Pressure Flow Loop, used in the development of new composite pipe materials - Allows a range of tests to be undertaken in an environment that is representative of real-world conditions. Photograph: TWI Ltd
In order to determine corrosion mechanisms, including when changes occur in the annulus, the evolution of corrosion and scale formation could serve as important indicators of the environment and the help to improve prediction of long term performance and asset reliability.
Asset life integrity management
The development of an initial model would help to predict scale formation in the annulus. An understanding of the primary environmental factors and the formation mechanisms, of the polymorphous products in annulus environmental conditions will be key to understanding the corrosion behaviour in occluded annular environments.
The key deliverables of the PhD student project...
- Model the precipitation/formation rate of the different phases of the corrosion scales and effect on dissolution rate of iron in CO2 - containing annulus environments
- Validate the model output by comparing with existing experimental data
This PhD research will investigate...
- Effect of temperature and partial pressure of CO2
- Effect of pH/solution chemistry on the scales formation rate vs. iron dissolution rate
- Effect of degree of confinement on the scales formation rate vs. iron dissolution rate
- Effect of gas flow rate
Some additional experimental work, using advanced surface characterisation techniques, may be required for suggesting possible improvements for overcoming the initial model’s limitations (e.g. pits’ formation, scales transformation)
In long term, this would suggest that a fully developed scales’ formation model, taking into account all affecting parameters, along with obtained experimental data, could be integrated/implemented in corrosion prediction models at the design stage, where all possible scenarios, i.e. changes, should be taken into consideration.
About the University of Leicester
An academic partner of NSIRC since 2014, the University of Leicester was ranked 13th out of 55 in The Guardian University Guide 2020 for course in chemistry subject areas. The city of Leicester is located in the East Midlands region of England and is the burial site of King Richard III. It has a 900 year old cathedral and a proud football team Leicester City F.C.
An introduction to TWI
TWI is a world leading independent research and technology organisation, trusted by some of the largest companies in the world for the knowledge and experience within the oil and gas sector.
Over 800 staff give impartial technical support in welding, joining, materials science, structural integrity, non-destructive testing, surfacing and packaging.
Services include generic research, confidential research and development, technical information, technology transfer, training and qualification.
For more information on this topic, including tuition fees and entry requirements, visit the application page, or email enquiries@nsirc.co.uk.
Work spaces for NSIRC students at TWI in Cambridge. Photo: TWI Ltd
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