Institut Francais Du Pe'trole

Robert Desbrandes

Guy Norel

Henri Cholet

Pierre Grolet

Acoustic signals are transmitted in a direction substantially perpendicular to the borehole axis, from different levels of at least three determined generatrices of the borehole wall. Reflected acoustic signals are received from the same direction at different levels of these generatrices. A train of signals is derived from each reflected acoustic signal and at least a group of significant elements of this signal train is selected. The groups of significant elements of the signals obtained for the different generatrices are correlated. The interval between signal trains corresponding to the maximum correlation corresponds to one and the same geological formation and is representative of the dip angle of this formation.

Method for determining the dip angle of geological formations traversed

The method of the invention comprises determining the variation of the electric potential on both sides of a central electrode in a borehole, detecting the two levels of the borehole where the potential gradient is zero, and measuring the electric resistivity of the geological formation between these two levels.

Method and device with adjustable focusing for measuring the electric

The device, which is connected to an element to be displaced, comprises a tubular body surrounded by sleeves which are inflated to a diameter slightly smaller than the diameter of the conduit. A motor-pump assembly located in the tubular body provides for the circulation of the fluid through the body so as to cause propulsion of the device within the conduit. Sensors may control automatic operation of the device and inflation of the sleeves to the selected diameter.

Driving device for displacing an element in a conduit filled with liquid

This device comprises a resilient stress-responsive member interconnecting two conduits which can be respectively coupled to upper and lower portions of the downhole assembly, and are surrounded by a protecting sleeve making up with one of said conduits, the lateral walls of an annular space. Annular elements secured to a first of said lateral walls, and slidable on the second of said lateral walls, form the end walls of said space and an intermediate annular piston integral with the second lateral wall, and slidable on the first lateral wall, divides the annular space into two annular chambers communicating respectively with the inner and outer spaces of the downhole assembly of the drill string, and having operative cross sections selected so as to compensate for the axial loads due to the hydrostatic pressure and bottom effect applied to the stress-responsive member.

Device for measuring the stresses applied in use to the downhole

The sonde comprises a measuring wheel carried by an arm which holds it in contact with the borehole wall and rotates it around the sonde axis so that the measuring wheel follows a helical path on the borehole wall as the sonde is raised in the borehole.

Sonde with rotatable pad for carrying out logging measurements in a

This method comprises laying onto the water bottom at least one line of acoustic transducers which are put in energized condition when an iceberg is approaching the location of this line. Acoustic signals are then sequentially transmitted from at least one of said transducers, some of them being reflected by the underwater part of the iceberg and sensed by acoustic receivers located on both sides of the transmitter on the transducer line. The outline of the underwater portion of the iceberg and its draught are determined by automatically drawing the geometrical envelopes of a system of ellipsoids whose foci are the transmitter and the different receivers.

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Sevres, France

Robert Desbrandes