T

he offshore oil and gas sector is experiencing a period of continual change. Oil price fluctuations and wider supply and demand factors in the global economy have given oilfield development engineers unprecedented challenges to overcome.

Presented with new considerations in relation to their equipment – much of which has been impacted by a downturn in the industry from its peak of $140 per barrel in 2008 – decision-making in the sector is increasingly price driven.

This also rings true for suppliers, who have refocused on cost as a key commercial driver. The impact has been felt hard in the subsea sector, which takes traditional platform-based equipment and operates it remotely on the seabed. These hydraulic-controlled technologies enable hydrocarbons production in areas that would not usually be financially viable with conventional technologies.

Hydraulic subsea oil and gas production systems are known for their reliability, with components that have been proven to work in even the most strenuous of situations. They have been shown to function across a wide variety of conditions, from average parameters likely to be encountered at any given well site through some more extreme applications with high pressures and temperatures. And, aside from their reliability, hydraulic systems allow for better scaling of operations, and their capabilities can be matched to the demands of a particular operation with ease.

Hydraulic subsea systems also have a long lifecycle and are designed to remain in extreme or challenging conditions for years at a time. In turn, this makes the process of obsolescence management – identifying and managing risk as components naturally reach the end of their lifecycles – easier, and provides operators with a greater assurance in the performance timelines of their subsea systems.

All of this is happening at a time when economic realities continue to drive the extension of field lifespans and therefore of the operating lifespans of subsea systems. Put simply, this means that subsea systems are being made to run in suboptimal conditions for long periods of time. These conditions and operating parameters also require commensurate advances in control fluids, which need to be able to operate at the most rigorous of performance and environmental standards and in a market that is materially different from the one of a few years before.

These factors have implications for suppliers of the control fluids that underpin hydraulic systems. Subsea control fluids are made from a variety of materials including synthetic and mineral base oils, and provide a medium to hydraulically control and operate subsea hardware indrilling rigsoroffshore platforms. They also have an important function in lubrication, component protection and ensuring overall system stability.

Perhaps guilty of being overlooked by operators, control fluids are, in fact, one of the most complex moving parts in a subsea system, so their reliability is essential.

Assurance in these credentials is key – particularly when adding the further complication that the industry has simultaneously consolidated and globalized in tandem with its push towards standardization. This is a significant challenge in an industry where you cannot trial a lubricant in a live system but are required to demonstrate performance from bench testing. And as one of the only components of a subsea control system that spans the entire installation, subsea control fluids must meet the double challenge of being locally compliant and globally consistent.

Fluids must also be designed to be compatible with a wide range of elastomers, plastics, metals and completion fluids, used to control the well in case of hardware failure. This compatibility with completion fluids is especially important during well installation activities, when fluid mixing may occur, potentially leading to line blockages.

A control fluid must do more than simply overcome the technical challenges of subsea operations. It has to comply with a range of stringent legislations, including OSPAR, the convention for the protection of the marine environment of the Northeast Atlantic as signed by 15 countries and the European Union.

Under the requirements of OSPAR, subsea control fluids must undergo rigorous testing, specifically on each substance in the formulation. This testing measures their effects on the four levels of the marine food chain, how quickly they break down in the sea if discharged and their potential for bioaccumulation. The aim of this legislation is to minimize the environmental impact of chemicals used offshore. OSPAR compliance is a commercial driver in itself, with operators selecting manufacturers that have been able to demonstrate that their fluids are environmentally acceptable.

Amidst this standardization push, hydraulic systems represent an opportunity for increased assurance in operations. In turn, control fluids will have an increasingly important role to play in ensuring the commercial success of operators of subsea systems.