The invention relates to a hydrocarbon exploration system, comprising a first vessel (1) having a turret (3) around which the vessel can weathervane, the turret being moored to the sea bed (4), and a second vessel (7) connected with at least one riser (12) to a subsea well (5), the first vessel (1) being connected to the second vessel via a fluid transfer duct (20) comprising a first end section (23) attached to the turret of the first vessel (1), a substantially horizontal mid section (24), and a second end section (22) attached at or near the second vessel (7), the second vessel (7) weighing between 2,000 and 15,000 ton its base being attached to the sea bed via taut tendons (9), the weight exerted by the fluid transfer duct (20) on the second vessel being below 1,000 ton, a power generator being situated on the first vessel (1), power being transferred from the power generator via an electrical swivel on the first vessel.