A New Simple And Efficient Technology For Subsea Bulk Oil/Water Separation For Production Enhancement - 3C Cyclonic Separator

Subsea processing technologies are becoming new solutions for subsea production enhancement for new deepwater field developments but especially for brown fields where subsea oil/water separation and water re-injection into reservoir is particular relevant to generate spare capacity on host platform. This usually requires efficient bulk oil/water separation coupled potentially with additional water treatment to cope with stringent residual Oil in Water and Solids in Water requirements in order to re-inject/dispose safely after treatment produced water. SAIPEM is currently developing an efficient and compact liquid/liquid separation system based on cyclonic technology to propose an alternate solution to gravity separation systems (as implemented on Troll and Tordis) having operating limits and potentially fabrication issues; and to propose a solution compliant with deepwater requirements. The SAIPEM cyclone is based on an innovative geometry to improve the system flexibility to tolerate both flowrate and composition variations at the system inlet; but also to propose a self-regulating system tailor-made for subsea applications. Extensive computational works have already been performed to optimize cyclone internal geometry, to improve separation efficiency and to define the system dynamic regulation. All results have been confirmed through an extensive test campaign carried out with a full scale cyclone and two synthetic oils under several flow conditions to simulate all the field lifetime operating conditions. Test campaign proved the excellent separation performances and the efficiency of the system for all tested operating conditions and confirmed the self-regulation of the system. This regulation is largely simplified and limited compared to conventional cyclones and achieved by means of only one single valve infrequently actuated. Based on the excellent results of the qualification test campaign, 3C cyclone appears to be particularly suited for various applications ranging from topsides pre-treatment to deep and ultra-deep water applications. According to some optimizations, 3C cyclone design can be easily adapted for both gas/liquid separation and de-oiling applications, and allows foreseeing full cyclonic subsea stations development providing high separation efficiency, self-regulation, as mitigating sand accumulation issues into the system. In the paper, 3C cyclone development will be presented. Emphasis will be placed on 3C cyclone description, test campaign results, potential applications and subsea station arrangements that might be envisaged following 3C cyclone development activities. Benefits in term of separation efficiency, control, availability, flexibility and arrangement will be also discussed and compared to conventional solutions for the different applications