Abstract: A technique facilitates evaluation of a fluid flowing through a tubing and includes at least one sensor deployed along an interior of the tubing. Each sensor comprises a plurality of electrodes and insulation material disposed between the electrodes to isolate the electrodes from each other and to facilitate resistivity measurements. The plurality of electrodes comprises electrodes for emitting an electric current and for monitoring voltage so as to enable resistivity measurements with respect to fluid flowing through the tubing. The resistivity measurements may be used to determine a constituent fraction, e.g. a water fraction, of the fluid flowing through the tubing.

Abstract: A technique facilitates evaluation of a fluid flowing through a tubing and includes at least one sensor deployed along an interior of the tubing. Each sensor comprises a plurality of electrodes and insulation material disposed between the electrodes to isolate the electrodes from each other and to facilitate resistivity measurements. The plurality of electrodes comprises electrodes for emitting an electric current and for monitoring voltage so as to enable resistivity measurements with respect to fluid flowing through the tubing. The resistivity measurements may be used to determine a constituent fraction, e.g. a water fraction, of the fluid flowing through the tubing.

Abstract: Body (22) for measuring the resistivity of a formation (9) surrounding a well (10) equipped with a lining (11), comprising: a body (23) of a probe (22), a set of three primary voltage measurement electrodes (ea, eb, ec), an upper electrode (ea) and a lower electrode (ec) and a central electrode (eb), two electrodes (In1, In2), an upper current injection electrode (In1) and a lower current injection electrode (In2) arranged on each side of the set of primary electrodes, characterized in that it also comprises, two secondary voltage measurement electrodes (24, 26) arranged on each side of the set of primary electrodes (ea, eb, ec), and between the two current injection electrodes (In1, In2), the spacing between a secondary electrode (24, 26) and the closest primary end electrode (ea, ec) being more than 1.5 times the spacing between the primary electrodes (ea, eb, ec).

Abstract: Body (22) for measuring the resistivity of a formation (9) surrounding a well (10) equipped with a lining (11), comprising: a body (23) of a probe (22), a set of three primary voltage measurement electrodes (ea, eb, ec), an upper electrode (ea) and a lower electrode (ec) and a central electrode (eb), two electrodes (In1, In2), an upper current injection electrode (In1) and a lower current injection electrode (In2) arranged on each side of the set of primary electrodes, characterized in that it also comprises, two secondary voltage measurement electrodes (24, 26) arranged on each side of the set of primary electrodes (ea, eb, ec), and between the two current injection electrodes (In1, In2), the spacing between a secondary electrode (24, 26) and the closest primary end electrode (ea, ec) being more than 1.5 times the spacing between the primary electrodes (ea, eb, ec).

Abstract: Apparatus for measuring the resistivity of a formation surrounding a borehole having a conductive casing comprises a tool body; first and second current injectors spaced apart on the tool body for injecting current into the casing; and an insulating body portion disposed between the current injectors, at least three ring electrodes being mounted on the insulating body portion between the current injectors.

Abstract: Apparatus for measuring the resistivity of a formation surrounding a borehole having a conductive casing comprises a tool body; first and second current injectors spaced apart on the tool body for injecting current into the casing; and an insulating body portion disposed between the current injectors, at least three ring electrodes being mounted on the insulating body portion between the current injectors.

Abstract: The invention relates to a method and apparatus for studying the resistivity of a geological formation around a borehole fitted with metal casing. An electric current is applied to the casing so as to cause current to leak into said formation at a given level, and said current is shunted by a feedback circuit in contact with the casing on either side of the measurement level, said circuit being organized to ensure that the current flowing along the casing at said level is less compared with the shunt current, the difference between the voltage drops on the adjacent sections of casing situated on either side of the measurement level is determined, and the leakage current (Ifor) is deduced therefrom.

Abstract: The invention relates to a method of surveying a geological formation through which a cased borehole passes, said method being characterized by the fact that: in a first step, current is injected into the casing (11) at a first point (In1) spaced apart longitudinally from said formation so as to cause current to leak into said formation, and electrodes (a, b, c) defining two consecutive sections of casing situated at the level of said formation ,ire used to measure the respective potential drops along said sections; in a second step, current is injected into the casing at a second point (In2) spaced apart longitudinally from the formation and situated on the opposite side thereof from said first point, so as to cause current to leak into the formation, and said electrodes are used to measure the potential drops along said sections; the corresponding measurements of the two steps are combined to obtain the values corresponding to a circuit formed by the casing between the two injection points is and essenti

Abstract: 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.