Schlumberger Technology Corporation

Prad Research and Development Nv

Services Petroliers Schlumberger

Schlumberger Holdings Limited

Prad Research and Development Limited

Jan W Smits

Brian Oliver Clark

Joseph P Varkey

Reza Taherian

Ruben Martinez

Ollivier Faivre

Charles Woodburn

Jean Claude Trouiller

Pierre Eisenmann

Vladimir Hernandez-Solis

Dominique Benimeli

Jose Ramon Lozano-Gendreau

Hifzi Ardic

Peter Gillan

Dylan H Davies

Attilio Pisoni

Jacque R Tabanou

Kuo-Chiang Chen

Gary Hazen

Dean Homan

Steve Bonner

Hanming Wang

Richard Rosthal

Simon Bittleston

A cable assembly for use in a hydrocarbon well of extensive depth. The cable assembly may be effectively employed at well depths of over 30,000 feet. Indeed, embodiments of the assembly may be effectively employed at depths of over 50,000 feet while powering and directing downhole equipment at a downhole end thereof. The assembly may be made up of a comparatively high break strength uphole cable portion coupled to a lighter downhole cable portion. This configuration helps to ensure the structural integrity of the assembly in light of its own load when disposed in a well to such extensive depths. Additionally, the assembly may be employed at such depths with an intervening connector sub having a signal amplification mechanism incorporated therein to alleviate concern over telemetry between the surface of the oilfield and the downhole equipment.

Extended length cable assembly for a hydrocarbon well application

An integrated electrode resistivity and EM telemetry tool and obtaining both formation resistivity and telemetry data from the integrated tool. An integrated electrode resistivity and EM telemetry tool having a drill collar including a first portion and a second portion separated by an insulated gap and telemetry cartridge carrying telemetry circuitry including a voltage source generating a voltage drop across the insulated gap and an axial current on a drill string that returns through an earthen formation includes an insulated measure electrode connected to the first portion, and resistivity measurement circuitry functionally connected to the measure electrode and the telemetry circuitry.

Integrated electrode resistivity and EM telemetry tool

A method of measuring the resistivity of drilling mud in a borehole passing through a terrestrial formation includes the steps of a) inserting a sonde into the borehole, the sonde having an elongate body provided with at least one annular current electrode (A , A&prime; ) and at least two annular guard electrodes (A, A&prime;, A , A&prime; , A , A&prime; ) situated on either side of the annular current electrode; b) performing computed focusing to simulate an operating mode in which at least one current I is emitted into the surrounding formation from the annular current electrode, the current I being focused in the formation by emitting two currents I and I&prime; from the two annular guard electrodes situated on either side of the annular current electrode; and c) producing a signal representative of the resistivity R of the drilling mud from the simulated operating mode. Apparatus for measuring the resistivity of drilling mud in a borehole includes the sonde, and electronic circuitry for performing computed focusing and computing a signal representative of the resistivity R of the drilling mud on the basis of the computed focusing.

Methods and apparatuses for measuring the resistivity of drilling mud in a borehole

The invention relates to a method of measuring the resistivity of a drilling mud by means of a sonde provided with an annular current electrode (A.sub.0) and with annular guard electrodes (A, A'), current I.sub.0 being emitted into the surrounding formation together with focusing currents I and I'. A signal representative of R.sub.m is produced in response to I.sub.0. Various apparatuses for implementing the method are described. Another method implements a technique of computed focusing. Corresponding apparatuses are also described.

Method/apparatus for measuring mud resistivity using a focused-electrode

A method and apparatus for determining the geometrical characteristics of a well, including insertion of a sonde of elongate shape into the well, the sonde including azimuth electrodes (A.sub.azi), an annular current electrode (A.sub.0), and at least one annular current return electrode (A). The annular current electrode (A.sub.0) emits a current I.sub.0, which flows essentially in a column of mud situated inside the well and returns to the annular current return electrodes. Signals are induced in response to the current I.sub.0 from which can be determined the geometrical characteristics of the well. Alternative embodiments include an apparatus which is symmetrical about the azimuth electrodes. High resolution measurements are obtained by computed focusing. In a first effective operating mode, currents i.sub.1 and i'.sub.1 are emitted from guard electrodes A.sub.1 and A'.sub.1 located on either side of the current electrode (A.sub.0,A'.sub.0), the current I.sub.0,1 emitted by the annular current electrode being equal to 0. In a second effective operating mode, a current I.sub.0,2 is emitted from the current electrode (A.sub.0,A'.sub.0) towards the guard electrodes, the total current I.sub.t,2 emitted from the sonde into the formation being equal to 0. Computed focusing is performed on the basis of the above two effective operating modes to simulate an operating mode in which (i) a current I.sub.0.c is emitted into the surrounding formation from the current electrode (A.sub.0,A'.sub.0); and (ii) the current I.sub.0,c is focused in the formation by emitting two currents I.sub.1,c and I'.sub.1,c from respectively the guard electrodes (A.sub.1,A'.sub.1).

Methods and apparatus for measuring characteristics of a formation

A method and apparatus for evaluating the geometrical characteristics of a well, comprising insertion of a sonde (12) of elongate shape into the well, the sonde including azimuth electrodes (A.sub.azi), an annular current electrode (A.sub.0), and at least one annular current return electrode (A). The annular current electrode (A.sub.0) emits a current I.sub.0, which flows essentially in a column of mud situated inside the well and returns to the annular current return electrodes. Signals induced in response to the current I.sub.0 are measured by the azimuth electrodes from which can be determined the geometrical characteristics of the well. An alternative embodiment includes an apparatus which is symmetrical about the azimuth electrodes.

Method and apparatus for measuring geometrical characteristics of a

A logging method and apparatus for investigating the geometrical characteristics of a borehole comprises an array of circumferentially spaced apart azimuthal current electrodes (Aaz.sub.i) disposed on a sonde (21), and an annular current electrode (A) longitudinally spaced apart from the array of azimuthal electrodes. In a method of investigating the geometrical characteristics of the borehole, currents (Ic.sub.i) are emitted between the azimuthal electrodes and the annular electrode (A). Monitor electrodes (M, Maz.sub.i) are respectively associated with the current electrodes (A, Aaz.sub.i). The potential differences (Vc.sub.i) between annular monitor electrodes (MAz.sub.i) are detected. In response to the detected potential differences, output signals (Rc.sub.i) are generated indicative of the distances between the sonde and the wall of the borehole in a plurality of directions around the sonde. The technique can be applied to azimuthal resistivity measurements of earth formations for correcting said measurements for sonde eccentring and/or the irregular shape of the section of the borehole.

Logging method and apparatus for investigating geometrical

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Paris, France

Jan W Smits