Abstract: There are disclosed novel lubricating compositions containing a major proportion of a lubricating oil and a minor proportion of an oil soluble polymer additive, and possibly other additives, wherein said polymer additive is a copolymer of ethylene, a monoolefin having 3 to 6 carbon atoms or a monoolefin having 3 to 6 carbon atoms and a non-conjugated diene with one or more specific nitrogenous monomers, said polymer having a reduced viscosity, measured in decalin at 135.degree. C, comprised between 0.5 and 2 and a polydispersity lower than 5.Such a polymer additive improves the oil viscosity index while ensuring the dispersion of the slurry it may contain.

Abstract: In the assembling and laying of an undersea pipe in which the already submerged pipe portion is suspended from a surface support, the end of the submerged pipe portion being supported on a variable inclination laying ramp, and a new pipe section is moved into alignment with the end of the pipe portion and fixed thereto, the submerged pipe portion is so suspended from the surface support that the tension in the pipe portion is maintained substantially constant irrespective of vertical movements of the surface support caused by the action of waves on the surface support.

Abstract: The ends of submerged pipes are connected using a receiver provided with two apertures through which the pipe ends extend, the receiver being adapted to form a watertight enclosure with an intervention unit and housing means for closing the ends of the pipes comprising two stoppers bearing seal means to be applied against the inner walls of the pipe ends and being maintained spaced apart by a first boom, the receiver including means for supporting a sleeve to be connected to the ends of the pipes and a replacement boom located in the sleeve, the connection being performed by introducing the ends of the pipes to be connected into the receiver through the apertures, at least one of the pipe ends being introduced by movement of the receiver relative thereto, closing the ends of the pipes with the stoppers, causing an intervention unit to descend on to the receiver, providing a watertight enclosure therewith, removing the water from the enclosure and placing it under atmospheric pressure, placing the receiver und

Abstract: To enable the release and consequent recovery of a support float which supports a load, e.g. a pipe, as it is lowered to the sea bed, a marker buoy is lowered with the float to be released when the load reaches the sea bed, the marker buoy having an inflated flexible envelope which is trapped in a housing fast with the float and having an opening through which the float can escape only when it has been compressed to a predetermined extent under the effects of a predetermined hydrostatic pressure. The marker buoy is connected to the float by a cable and the float is released from the load either by operations on that cable, or on a release cable connected to the float, on appearance of the marker buoy at the water surface.

Abstract: Device for guiding a drilling string from a floating drilling rig comprises a flexible guide tube having an inner diameter which is constant and an outer diameter which decreases progressively from its median zone toward each end, the median zone being connected by swivel means to lateral and longitudinal members connected to the floating drilling rig.This device is especially adapted for floating drilling rigs having a well through which the string descends.

Abstract: A method and apparatus for determining the position of a plurality of seismic echo receivers on a towed cable by interpolating values obtained by measuring, by means of at least one device positioned among said receivers, the angle between the tangent to the cable and a fixed and known direction. The measuring device can also include apparatus for measuring its depth and its distance from a generator of seismic waves. This provides for more effective use of processes which involve the addition of seismic traces in marine seismic prospecting.