Institut Francais Du Pe'trole

Thierry Lepage

Claude Beauducel

Jacques Cretin

Philippe J Staron

A process and device for measuring the velocity of flow of a fluid stream by measuring the difference between the respective traveltimes of acoustic pulses emitted by means of a generator (G) respectively between two points (P , P ) spaced out along the fluid stream, according to whether they are propagated upstream or downstream in relation to the direction of flow, a difference that is indicative of the displacement velocity of the fluid stream. Measurement of this traveltime difference comprises using an acquisition unit (A) coupled to a processing unit (P) allowing determination of the frequency spectrum of each pulse and measurement of the phase lag affecting at least part of the frequency spectrum of each pulse, resulting from the traveltime thereof. Measurement of the velocity of flow of the fluid stream and of the resulting flow rate is very accurate. The process can be applied in chemical industries, chromatography, etc.

Process and device for measuring the velocity of flow of a fluid stream

In order to restore a clock signal that has been used for coding digitized signals transmitted on a transmission channel, such as a line, the case when the received signals are distorted, the times (ti) when the signals go through their maxima (M) are detected with precision through an analysis of a series of samples (Ep) taken from the signals received during a time 'window' (W) positioned with reference to a local clock. A device determines the amplitude differences between the successive samples and compares the difference configuration as obtained with predetermined standard configurations representative of forms that are acceptable for the maxima. In case when the difference configuration corresponds to no recognized standard configuration, the frequency of the local clock is changed so as to re-establish a sufficient similarity with a standard configuration.

Method and device for regenerating by maxima detection, a clock signal

Monitoring of an underground effluent deposit (2) and the exploration thereof are performed by installing various devices or user modules : reception arrays (Ri, Rj, Rk) such as geophones or hydrophones, condition sensors (C1, C2) , tools requiring electric power supply, etc, in various locations along one or several wells (1) drilled down into a formation, behind well casings or in the annular space between these casings and tubings, and by connecting these devices to a surface station (4), by means of a particularly simple and reliable multi-channel transmission unit. The surface station adapts the commands thereof according to the device to be controlled in return, of receiving all the signals they transmit whether analog or digital and coded, and adapts to several modes of allocation of the transmission channels. With such a system, long-duration monitoring operations may be carried out on a large scale under satisfactory economic conditions.

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Noisy le Roi, France

Thierry Lepage