A subsea fluid processing system is provided containing a liquid reservoir, an inlet tank, a pump, an outlet system, and a fluid re-circulation loop. The liquid reservoir circulates a primer liquid stream to the inlet tank via the fluid re-circulation loop. The inlet tank further receives a first production fluid stream and mixes it with the primer liquid stream to produce thereby a second production fluid stream having a reduced gas volume fraction (GVF) relative to the first production fluid stream. The pump receives the second production fluid stream from the inlet tank and increases its pressure. Further, the outlet system containing the liquid reservoir receives the second production fluid stream from the pump and separates at least a portion of the primer liquid stream from a principal production stream. The primer liquid includes at least one exogenous liquid not derived from the first production fluid stream.