Underwater seismic prospecting device for deep water comprises variable floatability tubes

摘要

The measuring device is formed of an inextensible and incompressible internal pipe (201) with a coaxial external pipe (202) which can be radially expanded. A liquid can be injected into the gap between the pipes to control the floatability of the tube between a negative value resting on the seabed and a positive value floating above the seabed to move from one measuring point to another The underwater seismic system, particularly for great depths, has at least one measuring tube (101) with a submersible vehicle (108) at the head and an inert float (109) at the tail. The inert float at the tail connects to the tube to receive part of the injected liquid and thus modify its floatability in the same way. The inside of the tail float is divided into two compartments by a floating piston (211); a first compartment (209) for the liquid from the tube and a second compartment (210) connected to the sea to balance the pressures. The submersible vehicle has a liquid reservoir (203) and means (206, 207) of injecting the liquid into the tube and recovering it. The inside of the submersible vehicle is divided into two compartments (205, 204) in the same way as the tail float. Both the tube and the tail float have guide ropes to maintain the height of the assembly at a set level above the seabed when the floatability is positive. The submersible vehicle has means of navigation with at least one helix in a transverse tunnel opening on each side of the submersible. An assembly of these tubes are mounted parallel to each other with means of maintaining the gaps between the tubes and controlling the means of navigation. The immersible vehicle has means of anchoring itself to the seabed. The modules have a high density and allow a strong mechanical connection with the seabed