Sub sea processing system

A sub-sea processing system for the production of oil and/or gas from one or more wells, the sub-sea system comprising:

• at least one production well producing gas and/or heavy oil with high viscosity in deep water;
• at least one injection or disposal well for the injection of produced water or produced water deposit(s);
• a separator with an inlet and a plurality of outlets for water, oil and/or gas;
• a water injection and circulation pump;
• a heating arrangement;
• and
• a flow control device;
• and
• wherein a water circulation and injection pipe loop interconnects the separator, the injection and circulation pump, the heating arrangement, the flow control device, the at least one production well, and the at least one injection or disposal well, and
• said loop circulates hot water to control the temperature of the fluid flow in said loop, thereby controlling the viscosity and the water cut in the fluid flow entering the separator prior to start up and during production of any of the wells.