Institut Francais Du Pe'trole

Compagnie Generale De Geophysique

Institut Francais Du Petrole & Compagnie Generale De Geophysique

Ifp Energies Nouvelles

Institute Francais Du Petrole

Charles Naville

Jean Laurent

Sylvain Serbutoviez

Christian Wittrisch

Patrick Meynier

Jean Guesnon

Claude Mabile

Guy Pignard

Philippe J Staron

Pascal Dedole

Jean Czernichow

Yves R Ollivier

Jean-Claude Lecomte

Philippe Guerendel

Rene Paterna

Hubert Japiot

Rocroi Jean-Pierre

Simon Spitz

A method, having application to petroleum exploration or production, for picking the arrival time of seismic waves and use thereof for orienting the components of a multi-component sensor. After acquisition of seismic data using a VSP type method, with a multi-component sensor, a module signal is constructed by calculating the square root of the sum of the squares of at least two orthogonal seismic components. Arrival times of a direct seismic wave are then picked on an amplitude extremum of this module signal. Based on this picking, the seismic components can then be oriented in a unique reference frame whatever the depth of the sensor. A time window is defined on either side of the picked arrival times and the azimuthal direction is determined by maximizing the energy of the horizontal components within this time window. Finally, the three components are oriented in a reference frame defined with respect to the azimuthal direction, which is identical for each depth.

Method for time picking and orientation of three-component seismic signals in wells

A method for absolute preserved amplitude processing of data obtained by seismic prospecting known as VSP. The method comprises reception, by seismic receivers (R) arranged in a well and coupled with the surrounding formations, of seismic waves generated by a source (S) and reaching directly the receivers (direct or downgoing waves DW) or after reflections on discontinuities (D) (upgoing waves UW). The method has an application of precise measurement of the amplitudes of reflected and diffracted seismic events on monocomponent or tricomponent VSP data, in addition to conventional seismic wave propagation time and velocity measurements.

Method for absolute preserved amplitude processing of seismic well data

A VSP or reversed VSP type seismic prospecting method according to the invention allows disturbances contained in seismic recordings produced by tube waves propagating along wells and refracted in zones close to the surface to be minimized. The method disperses a gas under pressure, having preferably a high compressibility, capable of absorbing these tube waves. The gas may be generated by an explosive chemical reaction set off in situ, at a certain depth of the well (which may constitute the seismic wave source). The method has an application for seismic prospecting or drilling noise monitoring.

Seismic prospecting method and device in wells allowing guided waves filtering

This invention is a method of conducting seismic prospecting operations using a drilling tool (,) acting at the bottom of a well (,), which creates very powerful seismic vibrations, transmitting reference signals representing the vibrations of the tool in real time or later, and correlating the seismic signals picked up by a receiving assembly (,) with the reference signals. The reference signals are furnished by sensors (,) in contact with the drill string and at a distance from the down-hole assembly constituted by tool (,) and associated drill collars (,). In order for these reference signals to be truly representative, a damping means (,) and at least one filtering element (,) designed to attenuate to a great degree the multiple reflections in a frequency range useful for seismic prospecting are interposed into the drill string. The invention has application to the making of seismic recordings.

Method and device for seismic prospecting using a drilling tool acting in a well

The invention is a seismic emission device designed to be immersed at the bottom of a water body (sea, lake, etc.), and method of implementation. The device comprises at least one (and preferably several) self-contained emission units (,) immersible at the bottom of a water body, combining at least one or more seismic wave sources (,), such as air guns for example, suited to be placed in contact with the body, local energy storage (,) which supplies the device a multifunction connection cable (,) connecting each self-contained emission unit to a surface relay unit (,), a communication system (,, Y) providing communication with a central control station (,) located for example on a drilling or production platform (,). VSP repetitive exploration operations can be carried out in a well by activating successively the various emission units and by acquiring the signals picked up by receivers R,placed in a well for example and coupled with the formation. The device can be used for oil prospecting.

Immersible seismic emission device and implementation method

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

A seismic prospecting method allowing positioning in space of geologic events in the neighborhood of a well and calculation of the dip and the direction of dip. Seismic waves are transmitted into the formation, and three-axis seismic sensors placed in the well and coupled with the formation surrounding the well receive seismic data corresponding respectively to components along the three axes of seismic waves reflected by discontinuities in the formation in response to the transmitted seismic waves. Orientation data defining orientation in space of the three-axis seismic sensors is assigned to the seismic data. Processing operators corresponding to the three components are applied in parallel to the seismic data, allowing selection, from polarized waves received at each of multi-axis sensor, of P or S seismic waves useful for characterization of the formation in a neighborhood of the well, locating in space, at each of the multi-axis sensors, respective origin directions of the polarized waves, and positioning in space of the seismic events that generated the polarized waves.

Method for processing oriented multi-component seismic well data

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

Logging method and system for measuring mechanical parameters of the

The method consists in performing seismic prospecting operations by using a drill bit (1) working at the bottom of a well (2), which generates very powerful acoustic jogs, in transmitting in real time or in delayed time reference signals representative of the jogs of the drill bit picked up in the immediate vicinity thereof by bottomhole sensors and in correlating the seismic signals picked up by a reception set with the reference signals coming from the bottom. The reference signals may be transmitted to the surface station through a line (4) included in a drill string (3). Absorbing elements are preferably interposed on the string to damp the vibrations propagating directly towards the surface along the drill string. Resonant elements and possibly acoustic discontinuity elements favouring resonances in the seismic frequency band may also be interposed.

Seismic prospecting method and device using a drill bit working in a well

Seismic impulses irregularly distributed in time (according to a random or a pseudorandom code for example) are transmitted into the soil, and the direct waves and those reflected by the subsoil discontinuities are picked-up by a reception system (G). The frequency spectrum of the emitted and the received signals is divided into several bands, and the components of the signals in each one of the bands are reduced to elementary signals indicating the change of sign thereof (sign bit) and are recorded. Cross-correlation of the elementary signals respectively associated with the emitted and the received signals and stacking of the cross-correlation products associated with each sensor are carried out thereafter for each sensor of the reception system, and seismic sections very comparable to what would be obtained by digitizing the signals received with full precision, as in conventional methods, are achieved with the obtained stacks.

Method and apparatus for subsoil exploration including emission of a

A method of installing a reception device in a cased well at an optimum depth for surveying a formation under production or a localized part thereof and a source of acoustic waves at the surface or in a well. A placing or setting of the device is achieved by associating a plurality of acoustic wave reception units with a tubing lowered into the well and by applying the respective units against the pipe casing of the well by arms and springs or by including the reception units in sondes which are mechanically uncoupled from the tubing during the stages of use, with the reception device being easily moved by displacing the tubing during, for example, interruptions in the production of effluents.

Method and equipment for acoustic wave prospecting in producing wells

The present invention relates to a system for acquisition and separation of the effects of simultaneous sources of electromagnetic field. According to the invention the system comprises an array of n pick-ups (1a . . . 1e) connected to registration means (2), the minimum number n of pick-ups per array being equal to 2s+2, where s is equal to a number of simultaneous sources to be analysed.

Method and system for acquisition and separation of the effects of

A sound wave receiving device associated with a probe lowered into a well at the end of a cable and applied against the wall of the well by opening anchorage arms. In the part of the probe in contact with the wall of the well there is disposed at least one receiver assembly comprising a sensor case connected by a resilient sheath and a sleeve, movable along a cylinder integral with the body, to the rod of a piston sliding in said cylinder. A hydraulic and/or pneumatic system is provided for placing the case in contact with the wall and increasing the force of application of said case.

Device for receiving sound waves in a well

A system is provided for transmitting energy to an apparatus, such as a pulsed or vibratory seismic source, lowered inside a well or drill hole. It includes a structure anchorable in a well, mobile means whose linear displacement with respect to the anchorable structure causes the creation of energy and means for accumulating the energy created, a rigid column connected to said mobile means and drive means disposed outside the well for moving the rigid column linearly. The mobile means and the accumulation means may be formed by a weight and a device for raising this latter or else by a hydraulic system including a linear pump.

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Grigny, France

Charles Naville