Deepwater subsea infrastructure
Deepwater subsea infrastructure
Thursday, Oct 23, 2014

Deepwater subsea infrastructure includes many key subsea systems and components, connecting wells, manifolds and subsea templates to flowlines, pipelines and risers, which are then connected to the production vessel.The subsea developments in the North Sea are both shallow and deepwater, and although producing oil and gas from deepwater is not new to the industry, it is becoming more essential as the operators are forced to explore and then produce deeper and harder to reach oil targets.

The complexity of the infrastructure can depend on the amount of wells needing drilled and then produced, and can start with one satellite, to a much larger template of up to 8 wells being linked together, then pumped up to the production vessel.

The template can also be used to drill multiple wells, connected to a manifold, which joins the flow of oil and gas from each well, merging them into the one flow line. Subsea Connections offer driverless links between the equipment, which can be intervened by ROVs for inspection, maintenance and repair.

The equipment and components that go into this ‘underwater system’ has meant that manufacturers are beginning to come up with new systems and equipment cut out for high pressures and high temperatures within the harsh deep environment, at greater risk.

The subsea infrastructure itself however, is much more financially economical than previous topside solutions, and this has seen a shift from topside to subsea, meaning a demand for new subsea production equipment, such as power, separation, injection, boosting and compression, as well as the vessels and underwater equipment required to install and connect it all together.

Even though the recovery rates of subsea production isusually less than surface wells, the incentive is there to increase recovery.

This has also meant that due to the risks the entire infrastructure requires more feasibility and conceptual development before committing to one development option.

The high water pressure and temperatures requires reliable equipment with high integrity,along with sophisticated marine vessels, equipped with ROVs and a range ofother equipment for various applications. Huge fleets are required for one development alone, and demand for underwater vehicles is becoming high, meaning the manufactureand construction of both OSVs and ROVs is on the increase.

Technology firms have stepped up to the challenge of this necessity and are coming up with new ways to control, intervene, monitor and communicate with the infrastructure, which can all be managed from the production vessel, sometimes without using a Riser, OSV and in some inspectionand monitoring instances an ROV; all helping reduce the costs.

Subsea umbilical manufacturers are now able to get electrical, hydraulic, chemical injection and fiber optic connections down to the infrastructure and are the lifeline. The umbilical can also bring data and communication back up to the topside, providing important information on what is happening subsea.

With deepwater, there has been a huge shift in communications from copper to fibre, due to fibre allowing data to travel further, with less interference and loss. There has also been new ways of being able to retrofit or adapt existing copper connections to fibre using mulitplexers.

Getting it wrong with testing and reliability has seen subsea developments economically fail, meaning testing of all equipment iscritical for success, and stringent standards apply; the more quality the manufacture and testing of a product, the better.

Reliability can also be down to the suppliers being timely, not allowing delays and essentially adding further costs to the project. Competition is sometimes, therefore, very high, even with the most niche and un-saturated of product markets.

Onshore verification testing can be done virtually to avoid any failures during the system application, which reduces costs, due to the systems being tested using similar conditions to offshore applications, as well as being able to analyse the systems behaviour, during production and distribution.

Manufacturing and service firms are also expanding to adopt their own in-house testing, to provide their own stamp of approval before being put into application, due to quality becoming ever more important in qualifying and winning contracts.

For the operators, lessons from the past have seen inspection, maintenance and monitoring become a must, so that they are prepared for incidents, along with the reassurance that the development is operating safely and efficiently; Asset Integrity Management is now essential.


To do this, operators will require technology, which has its own challenges from the technology firms’ point of view; operators may sometimes be reluctant when confronted with new technological developments. Services companies are the main adopters of technology, and are even willing to buy firms coming up with new innovations.

New conferences, one-to-one meetings, forums and lunch and learns are just some of the ways that technology firms are making inroads into the operators, as they face the challenges of recovering oil from mature and new deepwater developments during a period of stagnant oil economics.

It is no doubt that the pending decline of mature brownfield developments will force many into adopting the technology direct - taking the risks on for themselves, however the cost of R&D may sometimes become a factor.

So in an ever changing world, with oil and gas exploration and production offshore in the UK and Norway heading further into the deep, we are seeing a change from topside production to subsea. Being closer to the wells, along with an increase in efficiency will no doubt increase recovery, however quality is becoming ever more important, due to high maintenance costs and environmental risks.

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