Abstract: A device for seismic emission in an underground formation comprising one or more vibrators of any type and method for implementing same. According to a preferred embodiment, each vibrator comprises at least one pillar (1) of sensitive elements (of piezoelectric type for example) between two end plates or slabs (2, 3) and a signal generator for applying vibrational signals to the pillar. The pillar (1) is coated with a protective sheath (4) and the vibrator is positioned in a well or cavity (W) and embedded in a mass of a solid coupling material (7) in contact with protective sheath (4) and the two end plates (2, 3) over at least part of each of the respective faces thereof, which provides coupling of the vibrator with the surrounding formation. The vibrators can be buried at intervals in relation to one another in a well. Sequential triggering thereof with selected delays allows reinforcement of the waves emitted by the device in a preferred direction.

Abstract: Seismic emission system for use in an underground formation, using at least one seismic source movable successively in a plurality of prepared activation locations and method for implementing same. The system comprises for example a plurality of coupling devices (1) including each for example two anchor elements (12, 9?) tightly coupled with the formation (by cementing for example). These anchor elements are secured to the seismic source (V) such as a vibrator of any type or an impulsive source by transmission elements (10, 13). The seismic source is coupled with coupling device (1) by fast locking means (18, 19). Coupling devices (1) can be preinstalled at a plurality of prepared activation locations above the formation to be monitored. Seismic monitoring operations can be carried out by moving at least one seismic source successively between the different locations where coupling devices (1) are installed.

Abstract: The invention is a method and device for permanent seismic monitoring of an underground formation by means of one or more seismic emission-reception sets comprising a source (S) such as a vibrator and elastic wave receivers (R1, R2, . . . , Rn) such as geophones and/or hydrophones. A well (W) is drilled into the ground. Seismic receivers (R1 to Rn) are lowered therein and coupled with the surrounding formation. The section of the well is widened in the upper part thereof so as to form a cavity (P) against whose walls the seismic source (S) is pressed. Receivers (R) and source (S) are connected to an outside signal control and acquisition station (ST). The wells (W) can be exploration wells that are drilled for example around wells intended for production of reservoirs containing fluids, or mixed exploration and production wells. Each source can also be coupled with a cavity next to the well.

Abstract: The invention is a method for facilitating discrimination and identification of seismic or microseismic events by means of permanent pickups in an underground zone under development. The method comprises permanent installation of, in one or more wells, elastic wave receivers, geophones and hydrophones leaving the wells clear for development of the zone, at least one reference pickup with direct acoustic coupling with the technical zone development equipment (pickup pressed against a production string for example) for detection of events directly connected with the operation of the wells (valve opening and closure, etc.

Abstract: The invention is concerned with a method of butt-welding two plastic parts each equipped with an identifying code, using an automatically controlled electro-welding machine. A device for performing a welding program is associated with said machine, said program being implemented as a function of the data contained within the identification codes. The data are defined on the basis of a welding law or standard to be applied as a function of various values for parameters relating at least to the thickness and diameter (or cross section) of the part considered at its abutment end, to the temperatures, lengths of time and welding pressure to be employed, the type of material constituting the part and the index or range of indices of fluidity of said material therefore defining the dynamic viscosity so that it would be possible to butt-weld tube parts if the codes of the parts are recognized as being compatible per se.

Abstract: In this process, which incorporates an integral cascade, the coolant mixture issuing from the penultimate stage (1B) of the compressor cycle (1) is delivered to a distillation apparatus (5) the head vapor of which is cooled (in 24) to a temperature significantly lower than the ambient temperature, then separated into two phases (in 6C); the vapor stage is supplied to the last stage (1C) of the compressor, and the liquid phase constitutes a coolant fluid for the hot part (8) of the heat exchange line (7).

Abstract: In this process, which incorporates an integral cascade, the coolant mixture issuing from the penultimate stage (1B) of the compressor cycle (1) is delivered to a distillation apparatus (5) the head vapor of which is cooled (in 24) to a temperature significantly lower than the ambient temperature, then separated into two phases (in 6C); the vapor stage is supplied to the last stage (1C) of the compressor, and the liquid phase constitutes a coolant fluid for the hot part (8) of the heat exchange line (7).

Abstract: A study is made of the changeover time of the voltage between an electrode and a metal work piece buried in the ground and protected against corrosion by an electric current. For this study, it is intended momentarily to interrupt the circulation of the protective current, to read the voltage between the work piece and the electrode, to pass these readings to an analog filter, to smooth these filtered signals by substituting them with values corresponding to a continuous and monotonic postulated function, and then to mathematically reconstruct the change in the voltage signals between the work piece and electrode such as it would be without filtering.

Abstract: This invention relates to corrosion inhibitors of steels, particularly carbon steels or low-alloy steels. They are ternary mixtures with synergetic action containing at least one strong base, at least one molybdate and at least one phosphate. This invention also relates to aqueous compositions of alkali metal halide containing said inhibitors. Such compositions are advantageously used as working fluid in high temperature absorption heat pump systems.