An integrated production complex includes a gravity-based structure (GBS) accommodating topside modules with process equipment. The GBS has rectangular top and base slabs, an intermediate horizontal slab, internal vertical walls, at least one compartment with a tank to store hydrocarbons and/or respective processed products, and ballast compartments. The top slab has supports, on which the topside modules are installed. The GBS has a rectangular prism central part including the top slab, and a protruding part disposed along the sides of the central part around its entire perimeter and having external vertical walls. Protruding and central parts share the base slab, with the protruding part height less than the central part. The central part has longitudinal and transverse walls forming compartments for tanks and ballast compartments. The protruding part has internal walls that are perpendicular to its external walls and form compartments, some of which are ballast compartments.

The present invention relates to a gravity-based foundation system for offshore wind turbine installation that comprises three floating concrete bases built with self-floating concrete caissons, equipped with valves for filling them with water and emptying the water out enabling their ballasting and anchoring at their final location; a metal structure which connects the floating concrete bases by means of a connecting element to the wind turbine tower, and a metal element which connects the floating concrete bases to the wind turbine, metal element on which a docking area is installed, a maintenance platform and access stairs, and it also relates to a method of installation of the gravity-based foundation system.

An apparatus for installation and protection of subsea cables comprises at least a first tubular member (1) and at least a second tubular member (2). Both these are arranged to be installed subsea with a subsea foundation (3). This allows passage of cable (29) through it. The first tubular member (1) is arranged telescopically within the second tubular member (2) so as to extract outwardly towards seabed (5) from an end portion (7), with respect to the second tubular member (2), only up to a prefixed length. This ensures that a continuous conduit for the cable is obtained through the scour protection of the foundation (3). The present invention also includes a methodology for installation of the apparatus and a method for installing a cable through the scour protection of the foundation, by using the apparatus.