A floating offshore facility (1) for offshore hydrocarbon production, comprising an upper deck (11), a lower deck (12), a well bay (13) comprising a plurality of drilling slots and a plurality of production slots surrounding said drilling slots, a cart (20) supporting a drilling riser (17) and being movable together with said drilling riser inside the opening of the plurality of the drilling slots, and a drilling rig (18) movable above the well bay to drill the well through the drilling riser.