Abstract: The present invention relates to an instrumentation assembly intended for an offshore riser (2) operated from a floater (1). It comprises a central processing unit (PC) connected by conducting cables (27) to: a plurality of modules (21–25) fastened to various points of the riser length, the modules comprising measuring means allowing dynamic location of said points in space, another locating module (26) fastened to the lower end (LMRP) of said riser, a series of detectors (W, C, M/W) for measuring the environment: wind, wave, current, an assembly for measuring the position (DGPS, P) of the floater. The measurements are synchronized with one another, managed and recorded by means of the central processing unit.

Abstract: The present invention relates to an instrumentation assembly intended for an offshore riser (2) operated from a floater (1).

Abstract: A VSP or reversed VSP type seismic prospecting method according to the invention allows disturbances contained in seismic recordings produced by tube waves propagating along wells and refracted in zones close to the surface to be minimized. The method disperses a gas under pressure, having preferably a high compressibility, capable of absorbing these tube waves. The gas may be generated by an explosive chemical reaction set off in situ, at a certain depth of the well (which may constitute the seismic wave source). The method has an application for seismic prospecting or drilling noise monitoring.

Abstract: As assembly and apparatus for analyzing a physical behavior of a drill string. The assembly includes at least two measuring sensors arranged at each end of a portion of a length of the drill string. A processing installation is provided and is adapted to receive, process, record and synchronize at least one signal coming from the sensor.

Abstract: The method consists in performing seismic prospecting operations by using a drill bit (1) working at the bottom of a well (2), which generates very powerful acoustic jogs, in transmitting in real time or in delayed time reference signals representative of the jogs of the drill bit picked up in the immediate vicinity thereof by bottomhole sensors and in correlating the seismic signals picked up by a reception set with the reference signals coming from the bottom. The reference signals may be transmitted to the surface station through a line (4) included in a drill string (3). Absorbing elements are preferably interposed on the string to damp the vibrations propagating directly towards the surface along the drill string. Resonant elements and possibly acoustic discontinuity elements favouring resonances in the seismic frequency band may also be interposed.

Abstract: A method of and a device for remotely-controlling at least one piece of drill string equipment from an instruction issued from the surface. The method includes issuing from the surface a first information sequence to cause a first predetermined action according to a predetermined sequence, detection of a condition indicative of a second sequence resulting from the first sequence, comparison of this second sequence with another predetermined sequence, and operating the equipment only if there is similarity between the latter two sequences. The method can be applied to actuation of a variable-angle bent element.

Abstract: This device comprises means for handling a flexible elongate member, in combination with means for automatically controlling said handling means in response to a detected deformation of the loop portion formed by the flexible member near the storage basket, so as to bring this loop portion back to a preselected geometrical configuration.