Abstract: Sulfided catalysts produced by sulfurizing supported catalysts containing at least one element selected from group IIIB, including the lanthanides and actinides, group IVB and group VB, wherein the catalyst is brought into contact with at least one source of elemental sulfur e.g. flowers of sulfur in an atmosphere of at least one reducing gas other than hydrogen e.g. carbon monoxide. The catalyst is suitable for converting hydrocarbon-containing feeds, such as hydrocracking and hydrotreatment.

Abstract: A riser for drilling with a subsea wellhead and a method for adjusting the boyancy of a pipe. The riser includes tubular elements (1) linked together by connecting devices (2). The elements include a floating device consisting of a box (6) in which a determined volume of gas can be pumped so as to modify the apparent weight of the element in the water. At least one tubular element comprises detectors (12) for measuring the differential pressure between the inside and the outside of the box, a value device (14) for filling the box with gas, a bleed valve device (15) for discharging the gas from the box, a control transmission and reception unit (13) for controlling the filling valve device and the discharge bleed valve device considering the differential pressure measurement.

Abstract: The invention relates to a hydrocarbon synthesis process in the presence of a catalyst that comprises a substrate, at least one metal of group VIII that comprises metal particles, preferably cobalt, characterized in that the group VIII metal particles of the catalyst are deposited on the substrate in the form of aggregates.

Abstract: A well tool in accordance with the invention comprises an attenuation device which attenuates tube waves associated with an elastic wave emission and/or reception set (1, 12). The attenuation device comprises a bubble generator (2) which releases into the well a gas not readily soluble in the well fluid, slightly overpressured in relation to the hydrostatic pressure, in the form of calibrated bubbles which greatly attenuate the parasitic tube waves. The attenuation device is placed above or below the elastic wave emission and/or reception set having a plurality of pickups whose signals are acquired by a local electronic module (14) and/or a source of elastic waves such as a vibrator. A bubble trap (17) is preferably associated with the bubble generator (2) in order to limit the volume of gas to be generated in situ. The invention is applicable to VSP type seismic prospecting and acoustic logging.

Abstract: The catalyst inside a catalytic reaction column is replaced while running the catalytic reaction by diverting a basically monophase fluid to keep it from passing through the catalyst, evacuating from the column the catalyst that has lost at least a portion of its properties, introducing into the column a quantity of catalyst that is approximately equal to the quantity of catalyst that was evacuated from the column, and restoring the circulation of the basically monophase fluid through the catalyst.

Abstract: A seismic prospection method is provided giving better knowledge of the position and of the nature of the geological discontinuities of the subsoil, consisting essentially in picking up seismic waves which are propagated in the ground by means of one or more seismic receivers each having three directional sensors oriented along three orthogonal axes and determining, by combining the signals delivered by the sensors of each receiver, the real position in space and the form of the trajectory described by the center of gravity of each receiver, in response to the waves received, in recording the variations of these different parameters as a function of the distance from the receivers to the transmission location and locating the reception positions where significant variations of these parameters occur.

Abstract: Method for determining the geometry of a seismic wave emission device comprising a plurality of seismic sources (S11, S12, S21, etc.) towed by a ship (1) with different transverse and longitudinal offsets. It comprises the isolated triggering of each of the sources (S11, S12, S21, etc.), the detection of acoustic waves coming therefrom by means of proximity sensors (C) arranged at known distances from other sources and optionally from the ship or from a seismic flute, and the recording of detecting signals by means of an acquisition system on board the ship (1). After various corrections of the distances and various processings performed on the signals, parameters (propagation time, phase shiftings) representative of intersource distances are determined and, consequently, the relative coordinates of the sources with respect to each other and their positions with respect to other points. The previous measurements are completed by other measurements related to the immersion depth of different sources.