Abstract: Device for measuring physical characteristics of a porous sample by performing successive drainage and imbibition phases in the presence of a first electricity-conducting fluid and of a second fluid of lower density than the first fluid, by means of a centrifuge whose speed is successively increasing and decreasing. The sample saturated with the first fluid is placed in a vessel (13) fastened to the end of an arm (9) driven in rotation by a motor (10) and communicating, by means of a rotating electro-hydraulic connector (17), with a stationary measuring signal control and acquisition unit (E) including hydraulic fluid displacement means and an acquisition device connected to a capacitive sonde in the vessel, which delivers signals indicative of the position of the interface between the two fluids. The device can be applied for analyzing rocks taken from an underground reservoir for example.

Abstract: A device for connecting, by means of a shielded cable, electrodes to a measuring device, located on either side of a wall (18) separating an enclosure under pressure from the outside environment. The device comprises a rigid protector sleeve (16) made of an insulating material that tightly runs through the wall and extends to the immediate vicinity of the electrode, into which shielded cable (C) is passed. A tube (23) made of a conducting material is arranged in rigid sleeve (16) and in electric contact with the cable shield. A plug (24) is secured to rigid sleeve (16), connected to electrode (15) and electrically linked to core (21) of the shielded cable inside metal tube (23). An electric connector (20) is associated with rigid sleeve (16) outside wall (18) for connection of a shielded wire connected to the measuring device. This device can be used in a system measuring the electrical resistivity of a sample in a frequency range that can reach several ten MHz.

Abstract: Device for connecting, by means of a shielded cable, electrodes to a measuring device, located on either side of a wall (18) separating an enclosure under pressure from the outside environment.

Abstract: The invention is a process and device for performing successive drainage and imbibition phases of a first electrically-conducting fluid and a second fluid of lower density than the first fluid, in a porous sample (1) by means of a centrifuge. Each sample is placed in a main chamber (3) of an elongate vessel (2) fastened to the end of an arm of the centrifuge, together with a spacer (6) whose volume is so selected that, on the one hand, the interface between the two fluids does not come into contact with the sample in operation and, on the other hand, the volume of chamber (3) remaining free around the sample and the associated spacer is greater than, but preferably close to the pore volume of the sample, so as to maximize the displacement amplitude of the interface for a given variation of the volume of fluid displaced. A capacitive sonde (11) in an auxiliary cavity (4), connected to an outer measuring device, is used for measuring the displacements of the interface.

Abstract: A process involves placing a solid sample imbibed or saturated with a first fluid (for example water) in a closed chamber; injecting, via pressure means, another liquid under pressure at a first end of the chamber to drain or expel the first liquid from the sample; and sweeping an opposite end of the chamber with a low pressure liquid, circulated by pumping means, which carries or discharges the drained first liquid outside the chamber. A device for conducting the process includes measuring means for determining the pressure and saturation variations of the sample at at least one point of the length of the sample in the chamber, the amount of fluid discharged from the chamber, and the electrical resistivity of the sample. A progressive variation of the flow of the liquid injected allows complete draining and imbibition cycles to be performed while setting up capillary pressure variation curves and calculating relative permeabilities, without touching the sample.

Abstract: The process mainly consists in placing a sample previously imbibed with a first fluid into a vessel or bucket containing another fluid of different density and in applying a centrifugal force by rotating the bucket at the end of an arm, so as to study the displacements of the fluids in the sample during at least two distinct phases. During the first phase, the rotational speed is increased so as to drain the first fluid from the sample. During the second phase, the rotational speed is progressively decreased. In order to avoid a discontinuity and to allow an imbibition of the sample, it is important to keep the two fluids in permanent contact with the sample. The amount of fluid produced in the bucket by centrifugation may be determined. The fluid produced may also be transferred into a variable chamber, for example inside the same bucket or a second rotating bucket.

Abstract: Water inflow inside a seismic streamer may create parasitic electric connections between lines supplying current to the electronic devices of the streamer and lines transmitting seismic informations, thus damaging the electronic apparatus and making these informations inaccurate. In accordance with the invention streamer sections including sections of supply lines and transmission lines are provided with water inflow detection assemblies, each comprising a closed circuit element surrounding the supply lines, a conducting line connected to a DC voltage generator, and means for detecting any DC voltage therebetween resulting from parasitic connections between the supply lines and the closed circuit element, created by a water inflow.