A combined metrology method is provided for calculating the distance, the roll and pitch attitudes, and the relative orientations between two undersea points of interest. The method comprises positioning on the sea bottom a long-range acoustic positioning system having acoustic beacons, calibrating the system in order to determine the positions of the beacons relative to one another, deploying a vehicle on the sea bottom, taking a plurality of scenes around each point of interest in order to acquire point clouds, and processing the point clouds in order to calculate the coordinates of points in a common reference frame defined by the array of beacons and centered on the position of one of the acoustic beacons.

A combined metrology method is provided for calculating the distance, the roll and pitch attitudes, and the relative orientations between two undersea points of interest. The method comprises positioning on the sea bottom a long-range acoustic positioning system having acoustic beacons, calibrating the system in order to determine the positions of the beacons relative to one another, deploying a vehicle on the sea bottom, taking a plurality of scenes around each point of interest in order to acquire point clouds, and processing the point clouds in order to calculate the coordinates of points in a common reference frame defined by the array of beacons and centered on the position of one of the acoustic beacons.

A method of recovering a used pipeline from the seabed to the surface comprises attaching a recovery cap to the pipeline at the seabed to surround an end of the pipeline, and then upending at least an end portion of the pipeline underwater suspended beneath the recovery cap. While the upended pipeline is being lifted toward the surface, hydrocarbon contaminants rising buoyantly from the interior and walls of the pipeline are captured within the recovery cap, floating on water within and surrounding the pipeline. The captured contaminants are then conveyed from the recovery cap to a reservoir that is external to the recovery cap. The reservoir can be lifted toward the surface with the upended pipeline, for example, on a lifting line attached to the recovery cap. The reservoir can expand as it fills with contaminants and as hydrostatic pressure decreases, with gas from the contaminants being vented off.

A method of installing a subsea pipeline for tie-in to a subsea structure includes laying, using a pipe laying vessel, an intermediate section of the pipeline on to a pipe restraint device, wherein the pipe restraint device is at or near the subsea structure, or is at or near a location at which a subsea structure will be installed, and the pipe restraint device restricts transverse movement of the pipeline. The intermediate section of the pipeline is configured to be tapped at or near the pipe restraint device for providing fluid communication between the pipeline and the subsea structure.

A method of installing a subsea tie-in conduit comprises unspooling or manufacturing a steel rigid lined pipeline (14) aboard an installation vessel and launching the pipeline progressively from the vessel (10) into water. A distal end of the tie-in conduit is coupled to a proximal end of the pipeline above the surface and is then launched into the water coupled to the pipeline. The suspended weight load of the pipeline is supported by an A&R wire (34) connected to the proximal end (38) of the pipeline, defining a load path that bypasses the tie-in conduit (30). A proximal end of the tie-in conduit may be suspended from that wire. The tie-in conduit is of composite or flexible pipe, hence being pliant relative to the lined rigid pipeline and maintaining its internal corrosion resistance. After landing on the seabed, the tie-in conduit may be deflected relative to the pipeline for connection to a subsea connection point.

A bundle section of a subsea pipeline bundle has a rigid carrier pipe having an end closed by a transverse bulkhead and one or more fluid conduits in fluid communication with an opening that penetrates the bulkhead. Fluid coupling formations such as a spigot or a recess on an outer face of the bulkhead surround the opening. Leak-tight coupling between successive fluid conduits is effected when the bulkheads of two such bundle sections are brought together. This forces together opposed complementary fluid coupling formations of the bulkheads. The bulkheads connect the adjoining bundle sections fluidly and mechanically.

A bundle section of a subsea pipeline bundle has a rigid carrier pipe having an end closed by a transverse bulkhead and one or more fluid conduits in fluid communication with an opening that penetrates the bulkhead. Fluid coupling formations such as a spigot or a recess on an outer face of the bulkhead surround the opening. Leak-tight coupling between successive fluid conduits is effected when the bulkheads of two such bundle sections are brought together. This forces together opposed complementary fluid coupling formations of the bulkheads. The bulkheads connect the adjoining bundle sections fluidly and mechanically.

The present invention provides a lateral and continuous measurement method for soil parameters in a soft soil field. The method mainly comprises the following measurement steps: arranging soil strength measuring apparatuses at the front end of a towing apparatus; arranging soil strain softening relationship measuring apparatuses at the bottom end of the towing apparatus; and measuring interface friction parameters between the soil and a structure. The towing apparatus actively or passively moves in a soft soil layer to ensure that the towing apparatus partially penetrates into the to-be-measured soil layer during movement; and the penetration depth of the towing apparatus is controlled by adjusting counterweight above the towing apparatus and a towing angle.

The present invention provides a lateral and continuous measurement method for soil parameters in a soft soil field. The method mainly comprises the following measurement steps: arranging soil strength measuring apparatuses at the front end of a towing apparatus; arranging soil strain softening relationship measuring apparatuses at the bottom end of the towing apparatus; and measuring interface friction parameters between the soil and a structure. The towing apparatus actively or passively moves in a soft soil layer to ensure that the towing apparatus partially penetrates into the to-be-measured soil layer during movement; and the penetration depth of the towing apparatus is controlled by adjusting counterweight above the towing apparatus and a towing angle.

A process for the manufacture, assembly and continuous construction of tubular sections made of steel or polymer in individual pipelines with gradual movement that is designed to mechanize and automate a process substantially eliminating or mitigating existing inefficiencies and risks, considerably reducing the time vessels need to be moored at piers while paying extremely expensive daily rates, increasing the quality of welds, inspections and the entire process The process including inside the manufactured unit one or more weld cabins and a series of support devices with synchronized driven and free wheels that carry the pipe segments while simultaneously enabling movement of the entire stalk without external interference, following the joining of several pipe segments (welded together), of variable length, in which the embodiments provided in the present invention enable each stalk to be approximately 1.2 km long or longer.