August 18, 2020

Feature article – Continuous measurement and control of subsea pipelines to maximise return on investment

Pipelines are subject to multiple forces during their installation and operation in a subsea environment. Forces from such things as surrounding sea conditions, temperature changes and production fluid flow variances can create motions and vibrations in the pipelines, that if not appreciated and managed effectively, can result in possible damage and premature fatigue. Understanding what is happening to a pipeline over a longer period supports operational decision making and can identify efficiencies and possible life extension opportunities. 

Effective management of subsea pipelines 

Effective subsea pipeline management is essential to avoid costly repairs, replacement, or even abandonment. Digital solutions that provide insight through continuous monitoring can address existing design validation and performance assurance challenges, presenting new opportunities for the integrity management of these vital assets.  

It is necessary to recognise what is happening to the pipe over a longer period than an ROV or Pig snapshot inspection can achieve, with the requirement for reliable data to assess pipeline integrity and quantify fatigue damage during operations and extreme events. For example, if the pipeline is being used in dynamic applications, such as for riser sections or flowline spans, then measuring motion and bending over time would quantify load and fatigue exposure, giving a realistic appreciation of the safety factors and system longevity.  

Whilst continuous monitoring provides the necessary insight, it is not yet commonplace on subsea pipelines. Negative experiences of users include difficulty attaching and deploying hardware, limited battery life, data inaccuracy and the overall cost, all hindering its wider adoption.  

Motion Clamp

A new approach to knowledge gathering 

CRP Subsea (formerly Trelleborg Offshore UK) is offering a new approach to pipeline and cable monitoring. Working closely with a major operator, the operation has developed the cost-effective Mimir Motion Clamp. This digital monitoring technology can be integrated into nearby ancillary protection products such as bend stiffeners or buoyancy modules, or attached via a standalone clamp system, negating the need for specialist support.  

This new monitoring system has been designed to provide continuous sensing and recording of pipe motion data, with easy ROV deployment and retrieval, ensuring repeated reliable clamping for many years. It is engineered to be a simple, independent, self-contained, low-cost monitoring solution, allowing for several motion clamps to be deployed along a pipeline. 

On battery power alone, monitoring and recording is through a state-of-the-art multi-sensor array housed within a uniquely hot-swappable pod. The pods are designed to house and protect the motion sensing electronic equipment during operation, providing continuous logging of data and one pod can be replaced simultaneously with another during recovery.  

This solution is further simplified by access to e-learning, product documentation and installation guides, through CRP Subsea’s new Mimir Digital Technician app, powered by Mimir Digital Intelligence. The app also provides an easy way to configure and set-up the motion clamp on the back of the vessel, removing the need for costly additional onsite specialist technicians and support.     

By increasing the accessibility and cost-effectiveness of subsea monitoring, such systems can become more widely adopted within the offshore industry. This will lead to insights and intelligent data, which can increase operator return on investment. The greater knowledge that can be generated from sensors can allow fine-tuning of systems and processes, better quantifying and informing operators and reduce the high OPEX costs associated with existing ROV or Pig survey schedules. The data gathered provides key performance insight and modelling capabilities to support subsea asset integrity management, realising value and carbon reduction opportunities through design and operational efficiencies and field life extension.