Innovative subsea separation technology wins 2007 EUREKA environmental award

This compact subsea processing equipment will ensure a better use of increasingly scarce resources and is set to improve the economics of offshore oil and gas production. The outcome has resulted in the world’s first subsea separating system for oil, water and sand. Supplied by FMC Technologies, it is to be installed in the Norwegian Statoil Tordis field in the North Sea in the third quarter of 2007. The technology was developed by Dutch project leader CDS Engineering in cooperation with partners Statoil and FMC Technologies.

“By using this technology, you can exploit an oilfield much deeper – so, for instance, you can recover five to 10% more from the original reserves, an enormous advantage,” explains Toine Hendriks, CDS Engineering’s senior process engineer. “It is also expected that this technology will facilitate new oil field developments in deeper and more remote areas, an advantage for the future as most of the easy accessible oil has already been produced. CDS, which is now an FMC Technologies subsidiary, was a small company and this was an expensive project as we literally had to build a 1:1 scale separator in our test lab. Without EUREKA, funding the project would have been difficult,” he added.

Separation equipment plays a crucial role in the oil and gas production process by splitting the wellstream, which may comprise of oil, gas, water and sand, into individual constituents.”By installing a full field subsea separation facility, Statoil expects to improve the Tordis field’s recovery factor from 49 to 55%,” explains Rune Mode Ramberg, Statoil’s subsea processing discipline adviser. Along with other upgrades to the field, the separation system will allow Statoil to extract roughly 35 million extra barrels of oil from the Tordis field. This is achieved by reducing the back pressure towards the Tordis field, by separating water and sand from the wellstream subsea, re-injecting water and sand in a separate well subsea, boosting the wellstream and reducing the receiving pressure at the topside production platform.

From an environmental aspect, less oil will be discharged into the sea. Every day, up to 100.000 barrels of produced water with some residual small oil droplets will instead be re-injected into a separate subsea well. If such oil discharges could be avoided ijn more offshore oilfields, the benefits will be considerable. This technology meets industry’s needs, too, as several European countries are striving to reduce such oil discharges. Moreover, with an ability to handle water and sand more efficiently, this separator will contribute to extending the life of oilfields and to making better use of invested material and capital.