Abstract: In a multicomponent logging tool, a coil is electrically isolated by open circuiting another, substantially orthogonal coil.

Abstract: A logging tool used in a borehole having non-conductive mud. The tool includes a known inductance in series with an electrode. The quality factor of a circuit that includes the electrode, the inductance and the earth formation is indicative of the resistivity of the formation. The quality factor may be determined using either a plurality of signals or by measuring a transient response.

Abstract: A suspended well logging device for use in a wellbore drilled in an earthen formation may include a cable configured to be conveyed into the wellbore; a single twisted pair of conductors positioned in the cable; and a conductive armor surrounding the single twisted pair of conductors. In embodiments, the device may further include a first channel formed using the single twisted pair of conductors; a second channel formed using the single twisted pair of conductors and the armor; and a wellbore logging tool coupled to an end of the cable.

Abstract: Calibration of the arrays of a multicomponent induction logging tool is achieved by positioning the tool horizontally above ground. The upper and lower housings of the tool are connected by a borehole conductivity simulator which as a resistance comparable to that of a borehole. Axial and radial positioning of the transmitter coils is done by monitoring outputs at receiver coils to achieve a minimum.

Abstract: Calibration of the arrays of a multicomponent induction logging tool is achieved by positioning the tool horizontally above ground. The upper and lower housings of the tool are connected by a borehole conductivity simulator which as a resistance comparable to that of a borehole. Axial and radial positioning of the transmitter coils is done by monitoring outputs at receiver coils to achieve a minimum.

Abstract: Impedance measurements made by a galvanic resistivity tool in a borehole in an earth formation are corrected by a factor that depends on the mud conductivity and the mud dielectric constant. Standoff measurements are not necessary.

Abstract: A power source for use in a downhole environment. The power source can include a microgenerator, where the microgenerator is comprised of a motive source, a rotor, a stator, and an electrical load. The motive source can be compressed gas, liquid, two-phase fluid, or combustion gases. The rotor may comprise a magnet and the stator may comprise a coil, such that rotating the rotor coaxially proximate to the stator produces electrical current. The electrical load includes any device used in downhole exploration and production that requires electrical energy.

Abstract: Measurements are made using a plurality of measure electrodes on a pad of a logging tool. The bias and gain of the measurements prior to A/D conversion are altered using measurements made by an additional electrode that is ahead of the measure electrodes.

Abstract: A resistivity imaging device injects currents in two orthogonal directions using two pairs of return electrodes and performing impedance measurements of the buttons placed between the returns.

Abstract: An induction logging device is provided with additional electrodes. One set of electrodes provides voltages that are indicative of the current distribution in the borehole. The output of the first set of electrodes may be used for estimating formation resistivity. A second set of electrodes may be used to provide an image of the formation. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Abstract: A mixed mode tool uses an inductive source and detects galvanic currents and/or potentials at electrodes in proximity to a borehole wall to produce a resistivity image of the earth formation.

Abstract: A mixed mode tool uses an inductive source and detects galvanic currents and/or potentials at electrodes in proximity to a borehole wall to produce a resistivity image of the earth formation. Alternative, the magnetic field produced by a galvanic current is detected by an antenna coil and used to produce a resistivity image. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understand that it will not be used to interpret or limit the scope or meaning of the claims.

Abstract: Measurements made by a multi-component induction logging tool are corrected for tool eccentricity in a deviated borehole. The eccentricity angle is determined from single frequency skin-effect corrected data and is then used to correct multifrequency data. Multifrequency focusing is then applied to the corrected multifrequency data. An inversion is then used to recover formation resistivity and relative dip and azimuth of the borehole. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Abstract: Measurements made by a multi-component induction logging tool are corrected for tool eccentricity in a deviated borehole. The eccentricity angle is determined from single frequency skin-effect corrected data and is then used to correct multifrequency data. Multifrequency focusing is then applied to the corrected multifrequency data. An inversion is then used to recover formation resistivity and relative dip and azimuth of the borehole. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b).

Abstract: A suspended well logging apparatus is provided having downhole well data acquired by a sensor, transmitted to the surface via complementary modems, and conveyed to the surface modem via a data transmission cable linking the modems, the cable having at least one twisted pair of signal conductors positioned within an outer protective sheath, each of the conductors being separately insulated, the at least one twisted pair of signal conductors having a twist rate of at least ? twist per inch, an insulation sheath surrounding the twisted pair of conductors and a tensile load carrier surrounding the insulation sheath, the load carrier comprising a sheath of tensile load carrying filaments enabling self support of the well logging cable.

Abstract: Calibration of the arrays of a multicomponent induction logging tool is achieved by positioning the tool horizontally above ground. The upper and lower housings of the tool are connected by a borehole conductivity simulator which as a resistance comparable to that of a borehole. Axial and radial positioning of the transmitter coils is done by monitoring outputs at receiver coils to achieve a minimum.

Abstract: A resistivity imaging device injects currents in two orthogonal directions using two pairs of return electrodes and performing impedance measurements of the buttons placed between the returns.

Abstract: A logging tool used in a borehole having non-conductive mud. The tool includes a known inductance in series with an electrode. The quality factor of a circuit that includes the electrode, the inductance and the earth formation is indicative of the resistivity of the formation. The quality factor may be determined using either a plurality of signals or by measuring a transient response.

Abstract: A device for guiding energy in a subsurface electromagnetic measuring system is provided, the device including a transmitting member for transmitting an electromagnetic signal into a subsurface medium, an energy-guiding member disposed in magnetic communication with the electromagnetic signal, and a receiving member for receiving a return signal induced from the subsurface medium. A method of guiding energy in a subsurface measuring system is also provided, the method including transmitting an electromagnetic signal into a subsurface medium, modifying the electromagnetic signal using a magnetic field, and then receiving a modified return signal induced from the medium using a receiving member.

Abstract: Calibration of the arrays of a multicomponent induction logging tool is achieved by positioning the tool horizontally above ground. The upper and lower housings of the tool are connected by a borehole conductivity simulator which as a resistance comparable to that of a borehole. Axial and radial positioning of the transmitter coils is done by monitoring outputs at receiver coils to achieve a minimum.