The subsea portfolios of the vast majority of oil and gas companies, large and small, are growing not only in terms of their size and total numbers but also with regard to their diversity and technological complexity.

Three leaders in this field are Chevron, BP, and Total, each having their own take on the specific needs of the upstream industry to meet the challenge of developing and producing subsea projects of the future. With the sector’s future growth directly linked to the fast-expanding deepwater and ultra-deepwater field development boom around the world, the development of new and enhanced subsea technologies is an integral part of many companies’ overall deepwater technology investments.

Chevron is a case in point. The US major’s total subsea production figure in 2010 was around 500,000 boe/d. By 2015, that figure is forecast by the company to soar to roughly 800,000 boe/d, with more than 20 major capital projects lined up in its investment queue for approval.

Peter Blake, Subsea Systems manager for Chevron, spoke about the company’s approach at the recent Subsea 2012 event in Aberdeen. Chevron’s global subsea presence is one of the largest in the industry, he said, and it is still growing. “Technology plays a vital role, with projects becoming more complex and technology-driven. For us, subsea technologies are a key part of the overall deepwater technology investment,” he said.

As an example, he mentioned 12 unspecified projects and their subsea technology needs; these included several needing various combinations of at least three of the following:

Instrumented pipeline protection (HIPPS);

Multiphase flowmeters;

Subsea sampling;

Chemical injection distribution;

Intelligent well completion;

Subsea boosting;

Subsea power; and

Direct electrical heating.

Blake stressed the need for technology investment to be focused, collaborative, and leveraged, and he also highlighted what he regarded as critical elements for long-distance subsea tiebacks: hydrocarbon/water separation and solids management, riser umbilical and flowline design and integrity, boosting and gas compression, produced water reinjection, power distribution, and reliable monitoring and control.

Flexibility is critical

Flexibility and the ability to interchange modules also will be a key requirement. According to Blake, “When it comes to subsea systems, we are now looking at very long field lives. The system we put in on day one is not what we will be using in year 20. So we need to be more flexible with our subsea systems.”

Blake also outlined a specific example of where technology collaboration is driving the industry forward. The Subsea Wet Insulation Systems (SWIS) Joint Industry Project (JIP) has been under way since 2007, addressing a number of serious challenges faced in recent years by users of wet subsea flowline and equipment insulation systems in up to 3,000 m (10,000 ft) water depth. These challenges have threatened the schedules and budgets of major offshore projects and reduced confidence in the long-term integrity of wet insulation systems.

The goal of the JIP is to identify and develop solutions for these challenges, move the industry (both users and suppliers) forward by increasing its understanding of the causes of these issues, and improve the performance and reliability of wet insulation systems, thus reducing risks.

Specific objectives include long-term simulated service testing to establish the performance of available insulation systems at field operating conditions; nonlinear modeling prediction of linepipe and system performance; and development of guidelines for the design, specification, qualification, inspection, and application of these systems.

Co-managed by Chevron and Statoil, the JIP has 13 participants and has a budget of US $4.5 million. The JIP’s work is still ongoing, with major players such as Total and Hess recently joining the project.

This kind of collaborative approach will be increasingly typical as the industry uses subsea technologies to produce its deepwater and ultra-deepwater assets.

“Subsea infrastructure is the delivery vehicle for the reservoir: we need to understand subsurface uncertainty and deliver the right system at the right time,” Blake said. “Subsea major capital projects are a significant part of Chevron’s strategy, and upcoming large subsea projects will need strong project management skills and leadership with a focus on improving on-time delivery performance, aftermarket support, and experienced support personnel.”

He also pointed out that Chevron has increased its planned investment in subsea technology R&D over the next five years, and it will continue to operate its Center of Excellence model for subsea, with hubs in Aberdeen, Perth, and Houston. The company also is set to more than double its number of subsea engineers.

Subsea gas/liquid separation

Luc Riviere of Total’s R&D Deep Offshore team, presenting at the same event, highlighted the company’s successes in deepwater West Africa, especially the Pazflor project in Block 17 offshore Angola.

Among several industry firsts, Pazflor saw the first implementation of subsea gas/liquid separation – an advance that enabled the project’s economic viability. It is the first project to deploy a development plan based on gas/liquid separation at the mudline spanning several reservoirs, with a trio of subsea separation units (SSUs) installed. Each one consists of four retrievable packages: a gas-liquid separator, two hybrid pumps to boost the liquids, and a manifold to distribute the effluents to the separator and pumps. The hybrid pumps combine multi-phase stages compatible with the presence of gas in the liquid and a centrifugal stage to improve efficiency.

Riviere said that with many more marginal fields to be developed via subsea tiebacks, the industry is now able to largely meet the challenge thanks to recent advances in subsea processing, subsea gas/liquid separation, electrical heating of flowlines, all-electrical systems, and the arrival of new installation vessels.

Image- Critical Elements for Long Distance Tieback

Horizon disaster showed subsea capabilities

Dave Turner, BP vice president, Subsea Production Operations, stressed how even the worst events can have a positive input. According to Turner, the Deepwater Horizon accident:

Pushed the limits for complex simultaneous operations and multi-ROV operations;

Operated multiple major vessels in close proximity for an extended period of time;

Constructed complex novel seabed systems;

Connected the system to dynamic positioning vessels in short timeframes;

Conducted extensive monitoring campaigns; and

Demonstrated the skills of the subsea industry. Turner went on to highlight the importance of areas such as condition monitoring and integrity management, internal learning and improvement, and tools and technology advances (BP is working on areas such as HIPPS, production boosting, and HP/HT).

He concluded that the recruitment of fresh talent into the subsea arena remains a crucial challenge. “The glue that holds all this together is human capability and capacity ... and human capability is the greatest challenge we have across the subsea supply chain. As an industry, we need to work on this together,” he concluded.