Abstract: Systems, tools and techniques for generating downhole parameters of a wellbore penetrating a subterranean formation and having a downhole fluid (108) therein are provided. A downhole tool with sensor pads (118a, 118b, 118c, 118d) is positioned in the wellbore (106) for emitting an electrical signal therefrom and for measuring the electrical signal. A downhole fluid unit is provided for generating downhole fluid measurements from the measured electrical signal passing through the downhole fluid and for generating a downhole fluid distribution profile (430) based on the downhole fluid measurements whereby separation of the downhole fluid may be indicated. A formation unit may be provided for generating formation measurements from the measured electrical signal passing through the subterranean formation.

Abstract: An apparatus for making a resistivity measurement of an underground formation surrounding a borehole is provided. The apparatus includes a conductive tool body, at least one current injector electrode positioned between the tool body and a wall of the bore hole, at least one current return electrode positioned between the tool body and the wall of the bore hole, an electrical measurement device configured to monitor a voltage or a current signal indicative of an impedance imbalance, a regulator connected to the electrical measurement device, whereby the regulator is configured to receive the voltage or the current signal indicative of the impedance imbalance and is configured to generate an adjustment signal based on the voltage or the current signal indicative of the impedance imbalance.

Abstract: An apparatus for making a resistivity measurement of an underground formation surrounding a borehole is provided. The apparatus includes a conductive tool body, at least one current injector electrode positioned between the tool body and a wall of the bore hole, at least one current return electrode positioned between the tool body and the wall of the bore hole, an electrical measurement device configured to monitor a voltage or a current signal indicative of an impedance imbalance, a regulator connected to the electrical measurement device, whereby the regulator is configured to receive the voltage or the current signal indicative of the impedance imbalance and is configured to generate an adjustment signal based on the voltage or the current signal indicative of the impedance imbalance.

Abstract: A method used in electrical investigation of geological formations surrounding a borehole comprising: determining S1 a grid of iso-parameter lines GR in a two-dimensional plane, the parameter being an electrical parameter characterizing the geological formation, injecting in a localized manner a survey current IS into a selected zone SZ of the geological formations GF surrounding the borehole BH, and measuring S2 a measured value of a quantity characterizing the electrical parameter of the selected zone based on the survey current, and interpolating S3 an interpolated electrical parameter value of the selected zone SZ based on the measured value and the grid of iso-parameter lines GR.

Abstract: A tool 1 is used in electrical investigation of geological formations GF surrounding a borehole BH. The tool 1 is comprised in a string of tools TS. The tool 1 comprises a current injection section CIS and a current return section CRS. The string of tools TS comprises at least one other section OS1. The current injection section CIS is electrically decoupled from the current return section CRS. The current injection section CIS is electrically decoupled from the at least one other section OS1 when the current injection section CIS and the at least one other section OS1 are adjacent to each other. The current return section CRS is electrically decoupled from the at least one other section OS1 when the current return section CRS and the at least one other section OS1 are adjacent to each other.

Abstract: An apparatus for making resistivity measurements of an underground formation surrounding a borehole, comprising: a conductive tool body; an insulating pad mounted on the tool body; a current injector electrode and a current return electrode mounted on a face of the pad so as to be positionable in use, adjacent the wall of the borehole, the current injector and return electrodes being electrically isolated from each other; wherein the tool body, pad, and current injector and current return electrodes are arranged such that, in use: (a) the ratio of the electrical impedance between the current injector electrode and the tool body and the electrical impedance between the current return electrode and the tool body on one hand, and (b) the ratio of the electrical impedance between the current injector electrode and the formation, and the electrical impedance between the current return electrode and the formation on the other hand, are substantially equal such that there is substantially no potential dif

Abstract: A system and method for determining a downhole parameter is provided. The system has a sensor positionable on a downhole tool. The sensor comprises insulation positionable on a pad of the downhole tool, and return(s) positionable in the insulation, the return(s) adapted to exchange a current with a power source, the return(s) defining a fluid zone. The sensor comprises a mud button positionable within the fluid zone and in the insulation a distance from the return(s), the mud button exchanging current with the return(s). The mud button and the fluid zone are positioned a distance from the formation such that a majority of the current passing between the return(s) and the mud button passes through the downhole fluid whereby the current exchanged with the mud button generates a measurement of the downhole fluid.

Abstract: A method used in electrical investigation of geological formations surrounding a borehole comprising: determining S1 a grid of iso-parameter lines GR in a two-dimensional plane, the parameter being an electrical parameter characterizing the geological formation, injecting in a localized manner a survey current is into a selected zone SZ of the geological formations GF surrounding the borehole BH, and measuring S2 a measured value of a quantity characterizing the electrical parameter of the selected zone based on the survey current, and interpolating S3 an interpolated electrical parameter value of the selected zone SZ based on the measured value and the grid of iso-parameter lines GR.

Abstract: A tool 1 is used in electrical investigation of geological formations GF surrounding a borehole BH. The tool 1 is comprised in a string of tools TS. The tool 1 comprises a current injection section CIS and a current return section CRS. The string of tools TS comprises at least one other section OS1. The current injection section CIS is electrically decoupled from the current return section CRS. The current injection section CIS is electrically decoupled from the at least one other section OS1 when the current injection section CIS and the at least one other section OS1 are adjacent to each other. The current return section CRS is electrically decoupled from the at least one other section OS1 when the current return section CRS and the at least one other section OS1 are adjacent to each other.

Abstract: The invention concerns an apparatus for investigating the wall of a borehole tilled with non-conductive mud, said apparatus comprising: a pad having an inside face and an outside face for pressing against the wall of the borehole; a set of measurement electrodes mounted on the outside face of the pad, potentials differences being measured between said measurement electrodes in order to provide measured points representative of the resistivity of the formation; both a source electrode and a return electrode adapted to inject current into the formation, the set of measurement electrodes being situated between the source electrode and the return electrode.

Abstract: The invention concerns an apparatus for investigating the wall of a borehole filled with non-conductive mud, said apparatus comprising: a pad having an inside face and an outside face for pressing against the wall of the borehole; a set of measurement electrodes mounted on the outside face of the pad, potentials differences being measured between said measurement electrodes in order to provide measured points representative of the resistivity of the formation; both a source electrode and a return electrode adapted to inject current into the formation, the set of measurement electrodes being situated between the source electrode and the return electrode.