Flex Lay Projects

Portable is Key to Enable Efficient SURF Lay and Decommissioning

By Andrew Blaquiere, MDL Managing Director

Image courtesy MDL
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As the demand for energy continues to rise, fueled by global population growth and fight against energy poverty in developing economies, competition for access to enabling assets is intensifying. This is particularly true for the offshore industry, where specialist vessels play a crucial role in exploration, development and production.

In this competitive landscape, where new energy developers share the same pool of resources with established oil and gas players, cable layers, anchor handlers and other construction vessels are rapidly becoming in very short supply.

At the same time, operators and EPIC companies are increasingly looking for technologies and solutions to decarbonize their operations and make them safer, faster and more automated.

Something’s gotta give… It’s time to apply alternative thinking to flex lay projects.

Image courtesy MDL

Let’s Start with a Clean Back Deck

MDL has a track record in supporting EPICs and independent operators with packages of portable equipment enabling efficient lay or retrieval of flexibles from “vessels of opportunity” – ships within the client’s fleet or locally available in the region.

Adopting a modular spread approach allows several back-deck layout configurations to be considered depending on the final specification of vessel selected i.e. moonpool deployment, over-side deployment or deployment over stern.

A flexible back-deck solution allows smaller, more cost-effective vessels to be considered which may not have been deemed feasible previously. This may also include a vessel with other equipment on board that could perform other tasks whilst in-field, not just the installation – which carries a whole new host of time and cost benefits on a project.

The MDL differentiator in the portable equipment market is the versatility and capability of its technology.

An example is the MDL Horizontal Lay System (HLS) - an industry-proven alternative that can replicate the functionality of a Vertical Lay System (VLS). The MDL HLS integrates a pipelay tensioner and an overboarding chute, together with other project-specific equipment, into a single modular frame. This integrated system allows the product to be transferred from the horizontal to vertical orientation, facilitating the installation and recovery of risers, with the capability to install or remove the product jewelry such as buoyancy modules, tether clamps, bend stiffeners or restrictors, thanks to the retractable work platform.

The work platform - offering up to 4.5m height clearance - provides a safe working environment for personnel utilizing the systems integrated within the HLS, such as davit arms and runway beams, to install or remove jewelry which, without the right tools, can be a highly manual and time-consuming process considering the volumes of modules to be installed on long lengths of dynamic products. DNV-verification guarantees that this portable package is purpose-built and can therefore be confidently deployed on any vessel of opportunity - ensuring that mission safety is prioritized in both design and operation.

What is also particularly attractive is the compact and integrated nature of the system, which allows it to be transported by road to the port of choice - eliminating dependency on marine transits.

Image courtesy MDL

The Decommissioning Balance Challenge

Efficiently increasing production or power supply is not the only challenge that the global energy players are currently facing as the need for reinstatement of the seabed to its natural state is increasingly becoming a requirement dictated by state laws.

With that, the decommissioning sector is growing in busy markets such as Brazil, Gulf of Mexico, North Sea or Australia, owing to the maturity of their oil and gas infrastructure. As more offshore assets reach the end of their productive lives, there is an increasing demand for recovery services. This can be costly in deep waters, which in their prime required specialist construction vessels to bring the fields to life.

In 2022, MDL was approached by a Brazilian contractor looking for a cost-efficient way to recover SURF from the deep-water Santos basin: using a modular spread on an Offshore Support Vessel (OSV). We had used our HLS as the base case; however, engineering studies with the product specifications, combined with the environment in which the system would operate, highlighted limitations on handling the recovered pipes over a chute.

Due to the friction between the flexible and the chute, the system's recovery capacity was dramatically reduced, even when using a high line pull-capacity tensioner. The solution to reduce friction was to replace the chute with a wheel - giving birth to MDL's Wheeled Horizontal Lay System (WHLS).

The system maintains all the HLS features facilitating recovery of various lengths and diameters of products, including: an integrated hang-off for handling end fittings, davits for overhead handling of products, integrated work platform for over the side or moonpool scopes and an adjustable wheel position to accommodate various product diameters.

Incorporating a wheel into the HLS design boost recovery capacity to match the tensioner's capability without extra space or weight from additional steel structures. The 2-point contact from the wheel profile on the product results in reduced MBR (Minimum Bend Radius) requirements, opening up the OD (outer diameter) window for wider application.

The best part? The compact system can easily move between vessels and can be deployed for both flexible recovery and installation scopes - making it a highly capable enabler for busy markets, addressing those construction vessel shortages.

Image courtesy MDL

Pulling It All Together

Besides designing and manufacturing a brand new technology, MDL assisted the Brazilian contractor with Project Management and Engineering services during the mobilization of the OSV in port, benefitting from MDL’s skilled design team for deck layouts, lift planning and sea fastening, and the company’s experience of managing quayside operations.

This expert support is on hand to ensure the most optimal equipment specification, deck arrangements and even execution methodology when working with spot-market or bare-back tonnage. Storyboards and visualizations bring the whole package to life long before the construction phase to get all stakeholders’ buy-in – which may be the biggest challenge for forward-thinking leaders looking to progress their campaigns in an alternative way.

Honing a track record in problem solving and innovation in the harsh North Sea since 1999, MDL has been enabling constrained projects around the world through a combination of out-of-the-box thinking and highly-capable portable technology deployed on locally available bare-back vessels.

Whether it is a new offshore field or one in advanced phase, MDL is here to support - from feasibility studies and front-end project engineering, to design, equipment supply and operation execution.

Image courtesy MDL

About the Author

Andrew Blaquiere is a mechanical engineer by trade and brings extensive knowledge on risers, moorings and flex-lay operations from a detailed engineering and project management perspective. In 2020 he relocated from MDL US office in Houston, TX to Aberdeen, UK to take on the role of Managing Director.

March - April 2024