Abstract: The invention relates to a device for exploring an underground formation crossed by a well inclined significantly to the vertical.

Abstract: The invention relates to a device for exploring an underground formation crossed by a well, suited to work in well portions where the advance thereof under the effect of gravity is difficult, notably in horizontal well portions or in well portions greatly inclined to the vertical. A plurality of rigid exploration modules (Mi) are interconnected end to end, each one including a rigid pipe (1), a flexible leaf (11) fastened to each pipe (1) so as to press against the wall of the well at least one box (18) containing sensitive elements, a linking cable (32) connected to a surface central station (40), and a connecting block (26) comprising an acquisition system (37) connected to the various modules (M1-Mn) by a bundle of electric conductors running through the tubular elements (1), and a deferred electric connection useful in damp conditions between linking cable (32) and the acquisition system.

Abstract: An elastic force generated by a volume of compressed gas in a chamber (7b) of a cavity (7) interior to the body of a well tool (1), acting on a piston (8), is used to open arms (4) intended to anchor the tool to the wall of a well (2). In order to close them, an opposed hydraulic force generated by a pump (13) driven by an electric motor (14) is applied intermittently, which brings piston (8) back to a recoil position. Piston (8) is coupled hydraulically with the cylinders of jacks (5, 6) acting on arms (4). A sufficient elastic force can thus be generated under a very low volume and the characteristics thereof can be readily changed by acting on the gas injection pressure and/or the extent of the dead volume when piston (8) is in a recoil position. Such device can be used for coupling sondes in wellbores for seismic prospecting for example.

Abstract: The mobile seismic system according to the invention is made up by interconnecting reception sections (T1) and of anchoring sections (T2), and possibly emission sections, the assembly being suspended in the well by means of an electro-carrying cable (3). The first sections (T1), which are filled with liquid, are delimited at least partly by a wall transparent to acoustic waves. They contain each one or several hydrophones and an electronic module of acquisition of the signals picked up. The second sections (T2) comprise a body provided with retractable anchoring means (13) and with motor means, either autonomous, or connected, by a hydraulic line running along the reception system, to common motor means located preferably in a lower section so as to be used as a ballast weight. The reception system may be continuous or made up of several parts connected to each other by electric or electro-hydraulic linking means. The system is suitable for seismic prospecting in wells for example.

Abstract: An intervention tool (R1, R2) is installed permanently behind a casing pipe or a tubing, in proximity to a tubular section (5) provided with a lateral cavity (6) . A single-contact or a multicontact plug connected to the device is positioned at the bottom of the cavity. A connecting part (9) provided with a retractable finger (10) is lowered into the pipe (2) at the end of a cable (10) comprising one or several conducting lines . A guide ramp (13) allows the finger (10) to be guided towards the cavity (6) when the part (9) comes close thereto. The end of the finger bears a socket (12) adapted for engaging onto the plug (7) . Signals produced by tool (R1, R2) may thus be collected or transmitted thereto at will and only when necessary, without having to establish a permanent link. The invention tool can be used for active or passive monitoring of an oil effluent reservoir for example.

Abstract: A seismic source for emitting vibrations through rotation of a set of eccentric weights. Two pairs of angularly out-of-phase weights (A1, A2 and C1, C2) rotate in the same direction. One pair of weight (B1, B2) of twice the mass of each of the first pairs of weights (A1, A2 or C1, C2), also angularly out of phase in relation to one another, rotates in the direction opposite to that of the first pairs of weights and at the same speed. All the weights are rotated by electric motors. An electronic set (ME1, ME2) receives control signals (cp1-cp6 and ac1-ac3) representative at any moment of the position of all the weights and out of direction of the generated resulting vibration, and produces electric currents (IMA1-IMA6) driving the motors, as well as currents (ICH, EV) necessary for controlling a hydraulic plant to secure the source against an application wall. The electronic set automatically controls the vibration in order to obtain the desired oscillation direction, frequency and intensity.

Abstract: An anti-bounce device for a mass striking a target element, with the device including a counter-mass and an arrangement for holding the counter-mass spaced from the mass at a predetermined distance and for braking the mass and the counter-mass to delay the counter-mass so as to put the counter-mass in a phase opposition with the mass as the mass bounces after impact thereby dissipating any bouncing forces. The linking and braking arrangement may include a volume of fluid in a chamber provided between the mass and the counter-mass or a layer of damping material interposed between the mass and counter-mass.

Abstract: A signal receiving system adapted to be lowered into a drilling and suspended from an electro-bearer cable and adapted to be coupled with walls of the drilling so as to receive signals propagating in the surrounding formations. One or more expansible chambers are interconnected by ducts and suspended under a rigid body connected to the surface by the electro-bearer cable. Each expansible chamber includes flexible side walls into which are integrated at least one receiving element. The expansible chambers are adapted to be expanded by injecting a compressed fluid produced by a hydraulic system contained in the rigid body. The receiving elements are connected to a signal acquisition device disposed in the rigid body which communicates with a laboratory truck on a surface.

Abstract: An anti-bounce device for a mass striking a target element, with the device including a counter mass and a linking arrangement for holding the counter mass spaced from the mass and a braking arrangement for delaying the counter mass so as to put the counter mass in phase opposition with the mass as the mass bounces after impact thereby dissipating any bouncing force. The linking arrangement may take the form of a volume of fluid in a chamber provided between the mass and counter mass, and the linking arrangement and braking arrangement may also include a layer of a damping material or deformable or flexible elements acting by friction.

Abstract: An anti-bounce device for avoiding the multiple shocks of a moving mass after a first impact against another element. Magnetic arrangements are associated with element for exerting an attractive force on the mass sufficient to prevent possible bouncing. These arrangements comprise, for example electromagnets and circuits for connecting the electromagnets to a current source via a switch. Permanent magnets may also be associated therewith. The direction of the electric current is then chosen so that the electromagnetic forces developed are added to the attractive forces of the permanent magnets or else for cancelling these latter out, which allows the mass to be released.

Abstract: A device for generating acoustic waves in a well by causing a mass falling inside a body to strike a target element and to transmit impacts to the surrounding geological formations by anchoring the body in the well by retractable shoes. A tractive force exerted on the support cable from the surface, after anchorage of the body, causes a support element to move upwards which takes the target element and the mass with it. When the mass is hydraulically locked in its set position, the cable is slackened so that the target element and the support element can come back to the bottom position. In this position, the support element presses on a pusher element which actuates hydraulic locking and releases the mass.