Lightening Intervention

If you have been reading our newsletters for a while, you would have picked up on two themes:??

1. “Innovative thinking” extends beyond delivery of brand new technology and encompasses using existing solutions, deployed in a different way?
2. In the energy sector, vessel cost and availability tend to be a huge challenge in achieving efficient project delivery for smaller, isolated or less common scopes - a challenge that can be overcome with vessel conversions: turning a “bare back deck” into an installation or recovery package with portable technology and experienced project engineering.

In this issue, we look at a certain aspect of offshore operations that benefits from both of those lines of thought, to efficiently maintain production from existing fields, without drilling new wells or introducing step outs.?

The topic in question is Riserless Light Well Intervention (RLWI)

What it is

RLWI refers to well intervention operations conducted without the use of a conventional drilling rig. Instead, specialised “downhole” equipment is used to perform tasks to enhance production, optimise well performance or address integrity issues without the need for costly and time-consuming rig mobilisation.?

Some common equipment used for RLWI includes:?

1. Wireline units, consisting of cables (wirelines) used to lower down various tools and equipment into the wellbore for tasks such as logging, perforating, setting plugs or deploying sensors.?

2. Coiled tubing: this is a continuous length of steel or composite tubing, spooled on a reel and inserted into the wellbore to perform tasks like cleanouts or deploying downhole tools. At MDL, we hone holistic experience of handling specialists products like CT, from onshore transpooling – as explained in the previous issue of our newsletter – to bespoke storage and deployment packages as presented in the Swiss Army Knife issue.??

3. Wellhead intervention tools for tasks such as valve manipulation, plug setting, mechanical interventions and other wellhead-related operations, including subsea tooling such as logging and monitoring tools, including pressure and temperature measurement, fluid sampling, casing evaluation and formation evaluation.?

4. Well control equipment to ensure safe intervention activities, such as blowout preventers (BOPs), control systems and surface well control equipment.?

A BOP stack consists of a series of blowout preventers, control systems and associated components installed at the wellhead, to prevent the uncontrolled release of fluids (blowouts). It forms a barrier that can be activated to seal off the wellbore in case of unexpected pressure influxes or other well control issues.?

During RLWI operations, a BOP stack may be deployed as part of the intervention equipment to ensure well integrity and provide pressure control capabilities. The name comes from the fact that they are typically designed to be stackable, meaning that multiple components can be connected together in a stack configuration to provide redundancy and flexibility in controlling well pressures.?

While practical for subsea integration, this design - growing in height with each stack - poses a challenge in over-side deployment without the right on-board handling tools.?

But MDL is here to help turn a challenge into an opportunity, after all!??

On-demand RLWI?

Over the years, MDL has been approached by a number of global offshore contractors looking to expand their service offering into wider Life of Field operations, by enabling their vessel fleet to perform new operations - such as RLWI. The aim was to upgrade their vessels' capabilities and provide the market with a viable alternative, rather than compete with drilling rigs.?

Their interest in MDL came from our track record in delivering portable vertical deployment systems that worked straight out the box (you can find more on these in this issue). Indeed, the philosophy behind MDL designs is based on the proven benefits of MDL’s Portable Vertical Lay System (PVLS) as a prime enabler.??

We’ve applied the same philosophy for on-demand RLWI by designing standard module-based components which can be handled at any dockside with access by road and a suitable assembly area, and easily integrate to form a bespoke package, tailored to the specific scope at hand.?

The MDL RLWI tower configuration consists of two columns constructed by bolting the modules together, which enable the height to be adjusted by the addition or removal of modules to accommodate the RLWI’s longest components.?

During deployment and recovery, the intervention tools are stabilised using cursor frame and guides, located on the tower’s columns. Another handling feature are the stabiliser arms used to extend the operational weather window. These attach and disconnect from the RLWI package using a dedicated device (ask us about the Halo if you want to know more!)?

An X‐Y skidding package is located on the vessel deck, enabling efficient movement and parking of equipment and services required by the RLWI operations.?

The MDL Grillage Foundation supports the tower to distribute the loads into the deck structure, minimising any requirement to provide additional deck strengthening during mobilisation. The tower can be located over the side of the vessel, forward or aft of the moonpool.??

Regardless of the location, the hydraulically-actuated work platform offers a safe and convenient working environment for personnel, and can open to full width of the RLWI component to facilitate efficient subsea deployment.?

?A new string to your bow?

This approach, along with the addition of project-specific key ancillary items, adds value to the vessel - typically a monohull - without the need to undertake a dry dock refit or major vessel reconstruction.??

MDL RLWI is a modular open-frame construction, supplied to the mobilisation port by road in components along with the standard grillage and other supporting assets. The units are integrated prior to the complete assembly being lifted on‐board, optimising the vessel time in port. The costs can be reduced further by utilisation of the vessel's crane for mobilisation and demobilisation activities - reducing dependence on quayside services.?

This solution provides efficiencies for vessel conversions, which are measured in days and not weeks when comparing with integral towers typically used for RLWI operations. And as is the case with all MDL portable packages, the conversion is only for as long as you need it. Our time-conscious approach to sea-fastening design means you can quickly return the back deck to its pre-project state; or deploy the RLWI solution on another vessel of your choosing.?

Ready to maximise your fleet capability and become a leader in cost-efficient Riserless Light Well Intervention? Get in touch with our engineering experts to get you started: https://maritimedevelopments.com/what-we-do/engineering-services/