Case Study: Ultra Deepwater Marine Riser Analysis

Introducing our latest case study on an Ultra Deepwater Marine Riser Analysis project...

AS Mosley was recently contracted to support marine riser operations from a new build Ultra Deepwater (UDW) drillship, as part of a long-term drilling programme offshore Indonesia. Global riser analysis was performed for the shallow (500m), mid (1000m) and ultra deep (1900m) water depths to cover all planned marine riser operations.

Read the full case study here.

For more information on our riser analysis support, visit our services pages or get in touch with us directly.


Building relationships and co-operation are way to go


This week, the Press and Journal interviewed our Director, Andrew Mosley, as part of their weekly initiative to ask small businesses key questions.

How and why did you start in business?

I started in an old converted church and expected to be twiddling my thumbs waiting for the phone to ring.

But the timing was right and there were plenty of companies needing specialist experience designing intervention riser systems.

My grandfather had run his own company and was an early influence; he sowed the seed of enterprise.

How did you get to where you are today?

I left school at 16 and served an apprenticeship in toolmaking.

I then started night school before leaving full-time employment to study maths and physics, which I funded with part-time jobs.

I later joined British Aerospace as a graduate subsea engineer, and embarked on a double degree at Cranfield and Compiegne Uninversity in France.

By the time I entered the oil industry I was confident academically and practical, perfect for engineering analysis.

I worked with a wellhead manufacturer before starting AS Mosley 20 years ago.

Who helped you?

I am a firm believer in co-operation, and enjoy building relationships with other businesspeople for mutual support.

I joined the Federation of Small Businesses, which has provided me with ongoing assistance, while my wife, Doris, has helped to keep me grounded and positive.

What has been your biggest mistake?

All mistakes are opportunities to learn and improve.

My biggest opportunity for improvement was not expanding the business sooner.

What is your greatest achievement?

After failing my 11-plus, I feel proud to now hold three engineering degrees.

But my greatest achievement is my physics “O” Level, which gave me the confidence I needed to achieve academically.

If you were in power in government, what would you change?

I’d seek a close relationship with our Europeans partners.

I remember the excitement and optimism after the Single European Act was signed in 1986, so feel sad with how things have turned out.

What do you still hope to achieve?

I’ve been renovating my house for the past 17 years. It would be nice to finally sit back and enjoy it.

What do you do to relax?

My wife and I feel blessed to have a large family, which keeps us busy.

As well as enjoying the outdoors, my wife and I teach Scottish dancing in the reeling tradition.

We organise two dances a year in Oyne as fundraisers for the local community.

What are you currently reading, listening to or glued to on the TV?

Being dyslexic, I am a slow reader. I am currently plodding through Barry Cunliffe’s Britain Begins, a history of the origins of the British and Irish peoples. It’s fascinating.

What do you waste your money on?

Kilt paraphernalia and lawnmowers.

It took me 10 years living in Scotland before I wore a kilt but I’m now hooked, with a vast wardrobe.

Lawnmowers … well you can never have enough.

I spend more time on my Stiga Titan than I do in my car.

How would your friends describe you?

Sociable, friendly and fun-loving.

I don’t take myself too seriously.

What would your enemies say about you?

I am quite tolerant so don’t attract many enemies.

What do you drive and dream of driving?

I drive a Land Rover Defender, which I bought during the record winter snows of 2010.

Someone later said you should never drive your Land Rover in the winter because it corrodes the ungalvanized chassis – always do your research.

We haven’t had a bad winter since – never panic buy.

The best thing about the Defender is that you always get a wave from other owners.

It’s nice to have a friendly car that gets waved at – it gives me feeling of belonging.

I dream of driving a Volkswagen I.D. Buzz, a fully electric version of the classic micro camper van planned for release in 2022.

Landing String Selection and Global Riser Analysis completed for BP’s Shah Deniz

AS Mosley has recently completed Landing String selection and Global Riser Analysis on BP’s Shah Deniz field.

Shah Deniz is situated in the Caspian Sea and is BP’s largest ever gas discovery and one of the biggest gas-condensate fields in the world. Shah Deniz Stage 2 is a $45 bn project that will supply Caspian gas to Europe for the first time via the Southern Gas Corridor.

AS Mosley was contracted to specify 7 5/8” Landing String and perform Global Riser Analysis for the proposed completion operations over a range of water depths from 70m to 580m from the Istiglal semi-submersible vessel.

The project was a success, with the fatigue life of the critical component in the system greatly improved by incorporating advanced analytical techniques.  This involved applying a full operational stress histogram to detailed non-linear Stress Transfer Functions for the critical hot spots. The improvements in accuracy resulted in a significant increase in fatigue life sufficient for the duration of the campaign.

To read the full case study on this project visit:


Fraser completes first marathon, raising £2500 for charity

Congratulations go to Fraser Garrow of AS Mosley, who recently completed the Edinburgh Marathon in aid of PSC Support, raising £2500…and counting.

PSC Support helps people affected by Primary Sclerosing Cholangitis (PSC), a rare auto-immune liver disease affecting one in 10,000 people in the UK.  As well as driving research, the charity provides crucial support to sufferers.

Fraser was diagnosed with PSC two years ago.  Although the condition causes fatigue, he continues to enjoy his life-long hobby of running.  Following a hilly half marathon last year, he decided to embark on the challenge of a full Marathon.  After 16 weeks of intense training, he crossed the finishing line in just 3 hours, 28 minutes - a super time for his first marathon!

Fraser comments: “Even though I’m a keen runner, this was a real test! But the fact I was doing it for such a worthy cause, helped get me through.  I feel very proud to have contributed and to have helped raise awareness of PSC.  Currently, there is no known cure for the illness, so the support provided by PSC Support is even more important for those battling the condition.  It was a great experience and I’m pleased to have bagged my first marathon before I turn 30 (just!).”

For more information about PSC Support, visit  To read Fraser’s story or donate to the cause visit:  Virgin Money Giving

Go Fraser! 


AS Mosley secures 5-year contract from BP

PRESS RELEASE: AS Mosley secures 5-year contract from BP

Analysis engineering firm, AS Mosley, has secured a five-year framework global agreement with oil major BP to undertake Global Riser Analysis projects at an international level.

The new contract has given the firm confidence to grow, as it kicks off a recruitment drive to take on and train up more Analysis Engineers in Aberdeen. AS Mosley has been working with BP in the UK for the last 20 years, carrying out Global Riser Analysis work for the oil company in the North Sea and West of Shetland.

Andrew Mosley, Director at AS Mosley comments: “This is good news for us and its good news for Aberdeen.  It gives us confidence to grow.  Training graduates in Analysis Engineering can take at least two years, so we need to be sure to have enough work to support any expansion.  This, along with other new projects that have been secured over the last few months, gives us the cushion we need to strengthen our team.  We are looking to take on two Engineers as well as a Graduate Engineer over the next three months and hope to take on more over the coming year.”

AS Mosley was established in 1997.  The firm specialises in the design and analysis of riser systems, subsea equipment and platform conductors.  It works globally from its base in Aberdeenshire, carrying out specialist analysis and consultancy for existing equipment and new innovations.

For more information on AS Mosley visit


Wellhead Monitoring – Measured Fatigue Damage Validation at OMAE 2017

AS Mosley will attend OMAE 2017 in Trondheim, 25-30 June, for the publication of a paper which we co-authored in collaboration with BP and Fugro. The paper will be presented under the Rigid Risers symposia and is titled ‘Wellhead Monitoring – Measured Fatigue Damage Validation (OMAE2017-61081)’.

Our analysis supported BP in the North Sea with a real time monitoring campaign to measure wellhead fatigue damage. This technical paper describes the method validation, utilising measured data for calibration and refinement of the analysis models. Valuable lessons were learned which continues to build on our expertise in the area of wellhead integrity.

The OMAE2017-61081 paper abstract is presented below, please contact us if you have any questions, we would love to hear from you!

'A monitoring system is deployed on a BOP-stack and riser during drilling of production wells West of Shetland to record fatigue accumulation in the wellhead and conductor.  Data is relayed to the vessel in real-time so that well operations can be planned to manage fatigue life.  The monitoring assures the asset integrity maintained during construction and work-over operations throughout its lifecycle.

Motion measurements of the BOP-stack and riser are analysed in conjunction with a finite-element model of the wellhead-BOP-riser-vessel system to determine stresses at various welds.  The main drawback of such approach is that “measured” fatigue still relies on the model accuracy, which cannot be guaranteed due to inevitable uncertainty associated with many parameters used in modelling.

This paper describes validation of the modelled subsea stack and its foundation characteristics against measurements so that “measured” fatigue is as accurate as possible.  This involves (1) determining the depth of BOP-stack centre of rotation; (2) identifying the BOP-stack characteristic frequency, and (3) matching stress responses derived from measurements taken at different heights on the stack.  Model parameters (e.g. soil stiffness and added mass) are tailored to optimise agreement with measurements thereby improving the accuracy of “measured” fatigue estimations.' Copyright OMAE 2017.

AS Mosley to attend Offshore Technology Conference 2017

Specialist engineering consultancy AS Mosley is aiming to develop new links with energy industry businesses around the world at the Offshore Technology Conference (OTC) this spring.

The company, which is based in the Aberdeenshire village of Oyne, will have a presence on the Scotland Pavilion which will be hosted by Scottish Development International while the event runs in Houston’s NRG Centre from Monday, May 1 to Thursday, May 4.

In 2016, OTC attracted 2,600 oil and gas exhibitors and 68,000 delegates from 120 countries around the world.

Andrew Mosley, managing director of AS Mosley, is looking forward to attending the event and making new contacts with those working in the global energy industry.

He said: “The Offshore Technology Conference is one of the biggest energy industry events of the year and we are keen to raise our profile to delegates and make them aware of what we can offer.

“We believe that our bespoke services, skills and experience will be of great interest to many companies who are looking to extend the life of their assets and maximise production in oil fields around the world.

“We’re delighted to be supported by Scottish Development International and are keen to make the most of this opportunity to develop new links across the global energy industry.”

Founded in 1997, AS Mosley provides high-end, bespoke engineering analysis and design services to operators, manufacturers and service organisations worldwide.

It specialises in designing and performing structural strength and fatigue assessment of subsea exploration and production equipment subjected to complex loading including static, dynamic, thermal, hydrodynamics and vortex induced vibrations.

With a range of engineering capabilities including global riser analysis, well integrity, conductor assessment and lightweight intervention, the company is committed to the safe operation of subsea oil and gas assets in the most challenging of environments.

The OTC 2017 Scotland Pavilion brochure is available to view online at:

AS Mosley enhances engineering service with Python programming

Independent engineering consultancy AS Mosley is continuing to improve its specialist automation of global riser analysis to deliver optimised designs of risers and subsea equipment.

The Oyne-based consultancy has recently integrated Python programming with its global riser analysis and IT systems which allows its engineers to increase efficiency and productivity.

Two ‎Subsea Analysis Engineers from AS Mosley, recently attended Python interfacing to OrcaFlex Workshops to learn more about the OrcaFlex programming interface. This knowledge is currently being used to further automate pre and post-processing of OrcaFlex simulations.

Managing director Andrew Mosley, said: “Fast design optimisation using Python is a great addition to our analysis capability which will allow us to offer cost-effective engineering solutions for clients.”

“At a time when costs focus the mind of the global energy industry we are proud to offer a competitive service, delivered to the highest possible standards.”

AS Mosley provides high-end, bespoke engineering analysis and design services to operators, manufacturers and service organisations worldwide. It specialises in designing and performing structural strength and fatigue assessment of subsea exploration and production equipment subjected to complex loading including static, dynamic, thermal, hydrodynamics and vortex induced vibrations.

With a range of engineering capabilities including global riser analysis, well integrity, conductor assessment and lightweight intervention, the company is committed to the safe operation of subsea oil and gas assets in the most challenging of environments.

Quality commitment confirmed through re-certification for internal Integrated Management Systems (IMS)

AS Mosley's commitment to ensuring that quality remains at the heart of our routine business operations has been reinforced again through certification renewal for our Integrated Management System (IMS). AS Mosley is pleased to announce the certification renewal for our internal Integrated Management System was received on the 31st of January 2017.

The Integrated Management System enables us to ensure that our services and products meet our client needs and expectations, continually improve occupational health and safety, maintaining a zero accident record and reduce our impact upon the environment. Through the maintenance of our internal quality management systems we are able to monitor and manage quality across all our business operations, benchmark our performance and strive to continually improve our business operations and services benefitting our clients.

Certification renewal for our internal Integrated Management System was received on the 31st of January 2017, inclusive for the following standards: ISO 9001:2015 Quality Management, ISO 14001:2015 Environmental Management and OHSAS 18001:2007 Occupational Health & Safety. For the latest copies of our certification certificates please visit our certification page

For more information about AS Mosley and our services please email

Managing Director attendance at ICoTA Europe lunch and learn

Managing Director Andrew Mosley was pleased to attend the ICoTA Europe lunch and learn session on the 24th January in Aberdeen which was hosted by the winners of the 2016 Innovation Award, Shell, Helix Well Ops and Altus Intervention. The session discussed the innovative subsea coiled tubing intervention riser system which was designed for the Well Enhancer vessel. The development of this system and success of the initial operations campaign was recognised as a significant step in the continued development of intervention by the oil and gas industry.

AS Mosley was contracted to perform global riser analysis in support of the design of the intervention system and were pleased to hear directly about the success of the initial offshore campaign conducted in 2016 from all parties.

AS Mosley provided site specific global riser analysis in support of the Central North Sea coiled tubing operations for the operator and for a number of other prospective fields. The Well Enhancer was custom designed with a dynamically positioned well intervention and saturation diving system. The vessel includes provision for Wireline operations through a 7 3/8 u201d 10K Subsea Intervention Lubricator (SIL) and for coiled tubing operations through a 5 1/8 u201d 10K Intervention Riser System (IRS). This is the first coiled tubing development of its kind within the oil and gas industry and is a significant step in the continued development of the intervention industry. Already there is more interest from other operators to follow on from this campaign with riser-based coiled tubing intervention. Looking forward, there is great potential for riser-based coiled tubing intervention to be a growth area within the industry.

If you are interested to find out more about the global riser analysis services AS Mosley provide, or any of our other capabilities, please contact us directly on +44 (0)1464 851144 or email