Novel solution to pipeline leaks

Paul Boughton

Engineer and entrepreneur Ian McEwanthe inventor of a novel solution to pipeline leakage problemshas been awarded the Royal Academy of Engineering’s (RAE) Silver Medal for his outstanding contribution to British engineering and commercial development.

An expert in particle-fluid transport problemsMcEwan is the founder of Brinker Technologya spinout from the University of Aberdeen. Brinker Technology uses mechanical Platelets to locate and seal costly pipeline leaks in the oil and water industries – a concept inspired by the human body’s own healing mechanism in sealing small wounds.

Based on biology

The most highly optimised and efficient systems in the world are those which occur in natureas they have continuously evolved over millions of years. It is logical therefore for engineers to seek to extract these good ideas and implement them in other applications – this is the science of biomimetics of which Platelet Technology is a novel example.

Platelets in the blood stream are constantly patrolling veins and become activated when they encounter a cut or wound. Platelet Technology takes this concept and adapts it for use in industrial applications. The technology utilises the fluid flow inside a pipeline to deliver specially designed Platelets to the leak site. When the Platelets reach the vicinity of a leakfluid forces entrain them into it and hold them against the pipe wall. This facilitates sealing and also marks the position of the leak for subsequent detection.

Platelet Technology takes a radically different approach to pipeline integrity in that it seals and then locates leaks in a single integrated process. Whereas conventional leak sealing techniques require direct access to the leak sitethe elegance of Platelet Technology lies in its ability to be implemented remotelymimicking the human body to work with the pressure in the line and seal from the inside.

CruciallyPlatelets are best deployed when there is flow in the lineso they can be implemented as part of a routine pipeline operation causing minimal disturbance to production. When a leak is locatedthe Platelet has already provided a seal so that a decision to maintain flow or to shutdown can be made in the context of a known controlled leak.

The key features of Platelets are that they:

  • Seal and locate leaks in a single integrated processreducing leak lifetime and consequential environmental damage.

  • Are implemented remotely so direct access to the leakage point is not necessary.

  • Require no disturbance to pipeline operation meaning costly shutdowns may be avoided.

  • Provide an alternative means of investigating suspected leaks.

  • Buy additional time for the operator to determine an appropriate course of action in the case of sudden leakage.

Although the concept of Platelet Technology is elegant in its simplicityunderpinning the theory is an extensive use of computational fluid dynamics (CFD) in conjunction with finite element analysis (FEA) and over five years of rigorous physical testing.

When Brinker is presented with a new applicationthe company uses the following engineering process to deliver a solution.

A model of the defective pipeline geometry is created using CFD which enables all conditions in the linesuch as pressureflow rate and fluid density and viscosity to be accurately simulated. Discrete particleswhich represent Plateletsare then introduced into the pipeline and their behaviour around the leak monitored. This modelling generates invaluable information about Platelet dispersion and entrainment rates which facilitates Platelet design and statistical analysis.

FEA is used to model the behaviour of entrained Platelets in position over a leak. This enables the effect of stresses and strains which the Platelet will experience to be monitored and is a key tool when selecting the optimal material for Platelet manufacture.

Using the information obtained from these numerical modelling processesPlatelets are manufactured and subjected to rigorous physical testing. If results of physical tests support those obtained analytically and numerically then there can be a high level of confidence in the solution.

Another important area in the development of a Platelet solution is material compatibility research. The conditions within many high pressure/high temperature pipelines are highly aggressive and a Platelet material must be selected which can withstand these conditions for the required seal duration.

In emergency situationsBrinker Technology use the knowledge obtained from previous operations to fast-track this engineering process to provide the client with the best possible solution within the timeframe available. An example of this was an emergency response application carried out for Shell in August 2005 where the company was able to deliver a solution within five days of initial contact.

Before thatthe first commercial implementation of the technology was in September 2004 on a subsea water injection pipeline in BP’s Foinaven field. The leak was located just downstream of a complex pipeline connection so traditional sealing methodssuch as clampingwere not favourable.

A solution was required to last over the 6–9 month winter period until a planned shutdown in spring 2005.

In order to minimise the number of Platelets to be injected CFD was used to ascertain the behaviour of the Platelets in the vicinity of the leak. A full-scale flow loop was then constructed to enable these results to be physically tested. Further chemical and mechanical tests were then carried out to test the integrity of the seal and to enable its longevity to be predicted.

The next important stage was to design the Platelet injection and retrieval systems which also required thorough testing prior to offshore implementation.

The Platelet deployment was a complete success the leak having been sealed within 24 hours from the start of the offshore operation. Although originally specified for a life in service of 6–9 monthsthe Platelet seal was still fully operational over 16months later.

“Platelet technology is conceptually simple and strikingly elegantyet the engineering and commercial challenges of implementing the concept in practice have been immense” says nominating RAE Fellow professor Roger Falconer. “In the past seven yearsIan has taken the original conceptdriven it through an R&D phaseand recruited and inspired a team of key engineering and business people. Of particular note is his outstanding ability to successfully lead and engineering team within the intensity of an emergency response operationwhen critically important decisions have to be made in quick time.”

“As a newcomer to the oil and gas industryIan has drawn on the full range of engineering skills – technicalmanagerial commercial and personal – to create an environment where an excellent technology concept can thrive and become a major contributor across a range of pipeline industries” added Falconer.

Founded in 1976the RAE promotes the engineering and technological welfare of Britain. The Academy’s Silver Medalsinstigated in 1995are awarded annually to engineers aged 50 or under who have made outstanding contributions to British engineering. Up to four awards may be given each year.


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