Written by Terje Varne

Business Development Manager

LinkedIn Profile

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Subsea intervention has long been considered a complex and expensive operational challenge. At Altus Intervention we have a long and active track record in collaborating with leading operators and marine service companies to find new and improved ways to intervene in subsea wells more easily and intelligently. We are now seeing an increased interest in the opportunity for light well intervention (“LWI”) services to be utilized and in this blog I will touch on the benefits, some of our experiences and what we are currently working on.


Globally, the Norwegian sector has very much led the way in subsea intervention for the past 15 years and in some of the harshest of environments successfully demonstrated the deliverability of enhanced recovery rates from operations using LWI solutions. 


It was a privilege for us to be involved in some of the very first LWI projects with Statoil back in 2003 and since then we have seen the range of job scopes delivered from a vessel materially extend from traditional production logging and plug jobs to more challenging scopes.  We are now regularly carrying out successful operations involving smart well valve manipulation, gas lift valve change out, tractor milling, debris removal, straddle installations to isolate water or gas producing zones with lengths up to 100 meters and even tubular repair solutions.   

Since 2003 we have performed riserless light well interventions in over 850 subsea wells across both the Norwegian and UK continental shelf and in West Africa in water depths of 70 to 850 meters. Currently we have the capability to operate in water depths of 1500 meters with ongoing work to qualify for 2000 meter water depths.



In addition, we have performed over 200 hydraulic interventions from vessels with our unique packages of pressure pumping and deployment systems. Example services include scale inhibition treatments, nitrogen displacement, well abandonment, acid stimulation and barrier testing provisions. 

Breaking new ground and developing bespoke solutions has also played a part.  There is an increasing number of subsea wells requiring heavy in-well interventions in more challenging environments. Our team recently engineered a bespoke system that enabled coiled tubing to be undertaken from an LWI vessel. This collaboration between Shell , Helix Well Ops and Altus Intervention won an innovation award (read more) at the SPE ICoTA Well Intervention Conference in 2016. Read the case study. 


Light Well Intervention Coiled Tubing Coiled Tubing Well intervention


Core to our success has been the development of experienced multi-disciplined crews, market leading technology and the provision of a fully integrated service offering. Integrating the service scopes has become a key competency with flexible spreads of equipment mobilized in well planned and engineered packages.

Looking at delivery more broadly, collaboration is clearly critical.  At Altus Intervention I believe we have developed unrivalled execution experience in the delivery of our services – but the way we work with the vessels and marine service companies is equally paramount to our operational success.  This ensures the seamless delivery of the full package for our clients - the vessel, access systems, in-well intervention services and experienced crew. Depth of track record goes a long way in getting this right. This has largely been developed under long-term contracts with major operators in the UK and in Norway with real commitment from all parties to drive out excellence.



A core benefit of LWI is that it reduces the mobilization time and cost of delivering intervention activities.  As an alternative to traditional semi-sub drilling rigs, LWI vessels significantly reduce the cost of the well intervention operations.  You can also perform more interventions on more subsea wells per year using LWI compared to riser based operations. Now a well-established method used by operators to increase field recovery from subsea wells, LWI is also playing a key role in advancing solutions for a growing P&A market.  

So with one of the biggest cost drivers for offshore operations being time we naturally take our execution track record extremely seriously.  With a regular flow of work scopes being executed week in week out we continue to advance techniques, technology and performance.  If I look back over the delivery of operations with Statoil on Island Offshore vessels, we have successfully reduced the average number of LWI operation days per well by 60% in the last 6 years.  The initial target was a 10% reduction but we surpassed this through a joint effort between our service partners and the operator. 


Light Well Intervention graph



I have personally been involved in the development of LWI solutions at Altus Intervention since 2001. There is now without doubt a groundswell of interest in subsea intervention activity. We see growing numbers of subsea wells presenting operators with significant opportunities from LWI.  The lessons learned and the experience developed in the North Sea offers compelling business cases to exploit these opportunities. Challenges and complexity remain but the solutions are accessible and the experience to deliver exists. 

To learn more about our solutions, projects or experience please get in touch.  We believe in making intervention smarter and would love to hear from you.

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