Institut Francais Du Pe'trole

Other

Compagnie Generale De Geophysique

Gaz De France-service National

Institute Francais Du Petrole

Ifp Energies Nouvelles

Cggveritas Services S.a.

Gdf Suez

Patrick Meynier

Axelle Baroni

Charles Naville

Claude Beauducel

Jean Laurent

Jean Guesnon

Jacques Cretin

Julien Meunier

Claude Mabile

Jean-Claude Dubois

Georges Constantinou

Sylvain Serbutoviez

Frédéric Huguet

Rénate Bary

Frederic Huguet

The present invention relates to a system for emitting seismic waves in an underground formation traversed by a well comprising a casing (). The system comprises a casing seal () allowing passage of a magnetic field, an active part generating seismic waves, made up of magnetic-field active elements () and arranged outside the casing seal, and a mobile magnetic field induction source () arranged inside the casing seal. The invention also relates to a method implementing the seismic wave emission system.

Permanent seismic source

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 () of sensitive elements (of piezoelectric type for example) between two end plates or slabs () and a signal generator for applying vibrational signals to the pillar. The pillar () is coated with a protective sheath () and the vibrator is positioned in a well or cavity (W) and embedded in a mass of a solid coupling material () in contact with protective sheath () and the two end plates () 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. Applications include repetitive seismic monitoring of an underground reservoir during development for example.

Device for seismic emission in an underground formation and method for implementing same

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 () including each for example two anchor elements (') 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 (). The seismic source is coupled with coupling device () by fast locking means (). Coupling devices () 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 () are installed.

Mobile system for seismic emission with fixed coupling devices, and method therefor

An electromechanical device for generating elastic waves in a material medium such as the subsoil in a frequency range where the wavelengths of the waves generated are great in view of the dimensions of the device, and method of implementation. The device comprises one or more vibrators which are buried in the medium, associated with a control system. Each vibrator comprises at least one inertia mass (), several plates () providing mechanical coupling with the medium, electromechanical transducers () connecting inertia masses () to plates (). A control system () applies to the various transducers () respective control signals so that the resulting elastic wavefield generated in the medium by the device is preferentially oriented in one or more directions.

Device for generating focused elastic waves in a material medium such as underground, and method using same

A method and device for seismic exploration of a subsea geologic formation by pickups set on the sea bottom and intermittently connectable to active data acquisition stations () brought nearby. Permanent passive reception stations () comprising a heavy pedestal provided with housings for seismic pickups (geophones (), hydrophone () which receive acoustic or seismic signals from the underlying formation are arranged at the bottom of the water body. When collection sessions for the signals received by the pickups are scheduled, mobile active acquisition stations () connected to permanent passive reception stations () are positioned at the bottom of the water body. The signals picked up are then recorded, for the time required to carry out at least one session of acquisition and recording of the acoustic or seismic signals received by the passive stations in response to the emission of seismic waves by one or more seismic sources. The mobile active acquisition stations () are thereafter recovered at the surface and the records acquired by each one are transferred to a central collection laboratory.

Acquisition method and device for seismic exploration of a geologic formation by permanent receivers set on the sea bottom

A hydrophone which is automatically inhibited when the immersion depth exceeds a predetermined threshold by action, on the push element ( ) of a switch ( ), of a flexible wall that bends under the action of the outside pressure. The hydrophone comprises a tubular body ( ) with two chambers ( ) separated by a partition ( ). One of the chambers is closed by a flexible diaphragm ( ). Switch ( ) is fixed at the center of one of the chambers. Diaphragm ( ) can push down on and actuate push element ( ) by bending. The body can advantageously consist of two parts that can be screwed onto one another, which allows easier adjustment of the inhibition pressure. A pressure-sensitive reception unit (S) is arranged in the other chamber.

Hydrophone with automatic inhibition in case an adjustable immersion threshold is exceeded

A method and device for emitting radial seismic waves in a material medium by electromagnetic induction, used notably for generating seismic waves in cased or uncased wells or in a water mass is disclosed. Emission of radial waves is essentially obtained by radially expanding a metal tube ( ) under the effect of a magnetic pressure generated by electromagnetic induction with elastic waves being created in the medium under the effect of this expansion. The magnetic pressure is obtained by connecting a coil ( ) in line with the tube to a current generator ( ). The winding pitch of coil ( ) can be constant or variable. Tube ( ) can for example be added into a well or hole or it can be a tube portion of a cased well.

Method and device for emitting radial seismic waves in a material medium by electromagnetic induction

A device which picks up elastic waves, such as a geophone for example, in positions far from the natural operating position for which it is designed. The device comprises an electrodynamic pickup including a magnet ( ), a moving coil ( ) placed in the magnetic field, springs ( ) suited to hold the coil in a well-centered static position when the axis thereof is parallel to a selected reference direction (horizontal or vertical, for example) and a current source which applies to the coil an electrical current which corrects any unbalance of the coil in relation to the static position thereof due to an inclination of the axis of the coil in relation to the reference direction. The current source may be for example a source of direct current ( ) and a voltage divider (P) whose division factor depends on the angle between the axis of the pickup and a reference axis or a compensating device suited to minimize the distortion ratio of the geophone.

Electrically inclination compensated device for picking up elastic waves

Compact vibrator for emitting elastic waves in a material medium such as the subsoil. The vibrator comprises a baseplate ( ) intended to be coupled in operation with a surface of this medium, an inertia mass ( ) and at least a pair of electromechanical transducers ( ) comprising each one or more pillars (A, B) made for example of a piezoelectric or magnetostrictive material. Pillars (A) of first transducer ( ) are interposed between baseplate ( ) and a relay plate ( ). Pillars (B) of the second transducer are interposed between relay plate ( ) and inertia mass ( ), on the same side of relay plate ( ) as pillars (A) preferably, so that inertia mass ( ) is positioned in the vicinity of baseplate ( ), which contributes to the compactness and to the stability of the vibrator that can therefore be used on slightly sloping surfaces. An excitation generator ( ) comprising phase shifting means ( ) respectively applies to transducers (A, B) phase-shifted signals that are amplitude-modulable, so that their vibrations combine. The vibrator can be applied: notably for equipping an underground zone under development with periodic seismic monitoring means or for carrying out seismic prospecting operations.

Compact vibrator and seismic monitoring or prospecting method using such a vibrator

The present invention is a system permanently installing measuring sondes against the inner wall of a pipe (,) such as a well or a tube. Measuring sondes (,) are respectively associated with coupling devices (,) that are brought to their coupling points in the pipe by means of an elongate support element (,) such as a cable or a tube. Each coupling device (,) comprises a deformable element (,) made of a shape-memory alloy that is deformed in order to allow displacement thereof along the pipe, and that is brought back to its expanded (convex) shape for example by means of a hot fluid stream that is injected in the pipe by means of a pump (P). In this expanded position, it immobilizes coupling device (,) and presses the sonde (,) against pipe (,) while mechanically decoupling the sonde from support element (,). The support element may be withdrawn if not serving another purpose.

System intended for permanent installation of measuring sondes against the inner wall of a pipe

A system intended for permanent installation of measuring sondes against the inner wall of a pipe (,) such as a well or a tube. Measuring sondes (,) are respectively associated with coupling devices (,) that are brought to their respective coupling points in the pipe by means of a tube (,) positioned by off-centering devices (,) for example. Each coupling device (,) comprises a flexible element (,) carrying sonde (,), that is deformed to a set back position where it is immobilized by a lock (,) so as to allow displacement thereof along pipe (,). In order to release flexible blades (,), a sufficient overpressure allowing to push back the piston of a jack (,) whose cylinder communicates at one end with the inside of pipe (,) is established. In this expanded position, it immobilizes coupling device (,) and presses sonde (,) against pipe (,) while mechanically decoupling it from tube (,). Tube (,) can possibly be withdrawn if it does not serve another purpose. The system can be applied to long-time (notably seismic) monitoring of an underground zone under development; the tube used for putting the sondes into place can be a production tubing.

System intended for permanent installation of measuring sondes in a pipe by means of a fluid pressure-actuated removable lock

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.

Elastic wave exploration tool for wells

The present invention relates to a method for the acquisition of signals during a well drilling operation, wherein the following stages are carried out: shakes are generated by means of a vibration source, the signals resulting from the shakes are detected by downhole and surface measuring means (23; 24) connected to a control unit (22), a code for synchronizing the signals acquired by the downhole (7) and surface means (23; 24) is emitted, the signals supplied by the downhole measuring means (7) are stored in a storage module (11), the signals contained in storage module (11) are collected at the surface, then processings are performed on the synchronized downhole and surface signals.

Method and device for the acquisition of signals while drilling

The invention relates to a device for exploring an underground formation crossed by a well inclined significantly to the vertical. It comprises a plurality of rigid exploration modules (Mi) interconnected end to end, each module including a tube (1), a sonde placed inside the tube, containing one or more sensors and provided with an anchor arm, a guide for guiding the sonde radially between a position of rest and an eccentric working position where it can be pressed against the wall of the well through openings provided in the wall of each tube when it is shifted by opening of the arm, an acoustic decoupler between the sonde and the guide, a transmission system including multiconductor linking cables connecting the various sondes together and connected to a surface central station (40) by a connecting block (26) comprising a deferred electric connection under humid conditions and of an acquisition and transmission system, and a rigid string connected to a surface operating device for driving the exploration assembly into the portion. The invention can be used for seismic prospecting.

Device for exploring an underground formation crossed by a horizontal

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. The connecting block is interposed between the array of exploration modules (M1-Mn) and a rigid string (39) connected to the surface operating device (38) for driving the exploration assembly into the well portion. The invention may be used for seismic prospecting for example.

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Chatou, France

Patrick Meynier