Manifold destiny: A new blueprint for a changing world

At the same time, the risks to equipment, people, and the local terrain and seascape will remain. What the industry needs in the face of all this is cost certainty and reduced CO₂ emissions, derived not just from technical certainty but also execution certainty.

THE NEED TO ADVANCE

With these concerns front of mind, it is no surprise that research into the performance of subsea equipment and service suppliers, published by Kimberlite LLC in May 2020, showed some concern about the capability of suppliers’ offerings to meet those future requirements.

Fig. 1. Every aspect of subsea operations is an opportunity to drive improvement, including the manifolds.

In particular, 45% of those surveyed said that more advances were needed in subsea trees, citing reliability, cost, lead times, and size as areas for improvement. In addition, subsea manifolds were cited separately by another 12%, as a technology area that could be advanced.

We agree. As part of our goal to achieve carbon net zero status, we believe that every single aspect of subsea operations is an opportunity to drive improvement, Fig. 1. Through our work with clients around the world, we have shown that even equipment like manifolds, which come with some fairly entrenched design and engineering philosophies behind them, can deliver substantial improvements to the areas that matter most to customers, shareholders and regulators.

THE STANDARDISATION CONUNDRUM

The pain points of conventional manifolds are clear and well-understood. Often, the largest piece of equipment in any given subsea system—acting as an integrator that bridges trees and flowlines and usually designed and built to field-specific requirements—manifolds do not lend themselves to standardised design and fabrication.

That lack of standardisation is often the cause of lengthy lead times and a typical delivery timetable of anywhere between 24 and 30 months. As a result, the price of a manifold remains stubbornly high. In addition, the size and weight of traditional designs limits the number of build and test locations that can be used, while installation requires heavy-lift vessels that often have limited availability and high day rates. Once installed, thermal and erosion issues may affect flow assurance and compromise operational output.

All this is reflected in the Kimberlite report. When it comes to manifolds, survey respondents were clear that they wanted better availability, lead times, and delivery, as well as technology upgrades and that all-important standardisation.

However, the supply and delivery of manifolds is the very definition of a low-volume environment, which makes standardisation even harder to achieve. In the past 60 years, somewhere between 7,000 and 8,000 trees have been awarded worldwide. That is an annual average of approximately 140, although this figure has risen to 300 per year in the past decade.

Working on the basis that two thirds of these trees are installed with a manifold, and that there are an average of 4.5 trees per manifold, only 45 manifolds are delivered in the entire subsea industry each year. Due to these low volumes, it makes standardisation a challenge.

OUR MANIFOLD MANIFESTO

This is, nonetheless, a challenge we are determined to solve at Baker Hughes. We recognise that at this point in the business, economic and technology cycle, making superficial changes cannot deliver the results that the industry demands. Our approach to standardisation, therefore, is to start at the material level and progress upwards.

Rather than focusing on the design of one of Baker Hughes’ products, the Aptara manifold, in isolation, we started with a broad set of system attributes across the entire subsea production system, drawing on our extensive global experience. By considering product improvements as part of a holistic process, we were able to develop optimal levels of structure and standardisation into our product. This include common forgings, valve and actuator parts between the tree and manifold (including common valve block between the tree and manifold), as well as optimising overall production strategies and maximising the use of lowest-cost production processes.

The result of this approach is a compact, modular manifold design. It shares certain components and production processes—for example, for valves and branch blocks—with the Aptara tree, using standard pressure classes to do so. By using compact branch blocks, the Aptara manifold is lighter, with a much-reduced footprint, which allows for fast and efficient build, transport and installation.

We also identified where standard pipe sizes can be used realistically, to reduce the number of individual parts in the portfolio. This has enabled us to develop configure-to-order manifolds that rely on a limited number of pre-defined components, which reduces highly burdensome lead times.

The holistic approach is not the only thing that makes this possible. Digitalisation is critical. There is a large number of variables to consider. What’s more, the sheer size of our dataset, drawn from many decades of experience in the field, meant we had to make extensive use of data analytics to find the optimum number and design of modules for the manifold design.

RESULTS IN THE FIELD

In practice, this means that 80% of project components can be pre-engineered and digitally configured with speed, operability and reliability in mind. Manufacturing is optimised for repeatability and efficiency, while greater reliance on re-usable parts reduces the maintenance burden. Even relationships with strategic suppliers have been re-structured to optimise costs and lead times.

As a result, Aptara manifolds have already made a measurable difference in terms of sustainability and efficiency to our clients’ operations. CO₂ emissions have been reduced 40%; weld requirements 85%; typical manifold size 55%, and weight 40%. Not to mention, flow assurance has improved, with thermal and erosion capability providing greater flexibility in different operating scenarios and shutdowns.

From design and fabrication, through logistics and delivery, to installation and eventual shutdown, every aspect of the Aptara manifold has been challenged, considered, assessed and re-worked as necessary. Like all elements within our Subsea Connect system, it has been assessed through a “life of field” lens, which takes CO₂ reduction into account, to establish where improvements are possible—and justifiable.

It has proven that such an approach can deliver substantial results. In fact, it has proved that such an approach is necessary to create a sustainable, viable and socially acceptable future for our sector.