Abstract: A deformable downhole article for use in a wellbore includes a tubular component configured for placement in a wellbore, a deformable material disposed around an outer surface of the tubular component, and an electrically conductive element comprising a carbon nanotube (CNT) material bonded to the deformable material. To form such a deformable downhole article, a deformable material is disposed around an outer surface of a tubular component, and an electrically conductive element comprising a carbon nanotube (CNT) material is bonded to the deformable material. In use, the deformable downhole article may be positioned within a wellbore, and the deformable material may be expanded to an expanded state. Expansion of the deformable material may strain the carbon nanotube (CNT) material of the electrically conductive element, and an electrical property of the electrically conductive element may be measured to deduce information about the state of the deformable material.

Abstract: Disclosed is an apparatus for estimating a property of an earth formation penetrated by a borehole. The apparatus includes a carrier configured to be conveyed through the borehole and having a first transmitter electrode configured to inject electrical current into the formation and a first measurement electrode configured to receive electrical current for measurement due to the current injection in order to estimate the property of the earth formation. A controller is configured to determine a phase difference between injected electrical current and received electrical current. A first bucker amplifier is coupled to the first measurement electrode and configured to apply a voltage to the first measurement electrode based on the determined phase difference in order for a phase of current received by the first measurement electrode to be substantially in phase with the current injected by the first transmitter electrode.

Abstract: Disclosed is an apparatus for estimating a property of an earth formation penetrated by a borehole containing an oil-based drilling fluid. The apparatus includes an electrode disposed at a carrier and configured to inject alternating current into the formation. An electrically conductive plate is disposed between the first electrode and a borehole wall. An electrical insulator is disposed between and contacts the first electrode and the conductive plate. The apparatus is configured to prevent the drilling fluid from being disposed between the first electrode and the conductive plate. A first sensor is used to measure an electric field established between the first electrode and the conductive plate. A processor is configured to receive a measurement of the electric field to use as a floating reference signal to determine a phase difference with respect to a measured electrical quantity related to the injected electrical current in order to estimate the property.

Abstract: Disclosed is an apparatus for estimating a property of an earth formation penetrated by a borehole. The apparatus includes a plurality of electrodes disposed downhole and configured to inject an electrical current into the earth formation using an applied voltage and/or measure electrical current resulting from an injection of the electrical current. The apparatus also includes a processor configured to perform a series of formation measurements that include injecting current into the earth formation using a unique subset of electrodes in the plurality of electrodes and measuring current in the earth formation using one or more electrodes not used for the current injecting. The processer sums the measured currents for the electrodes wherein the sum of electrical currents for at least one electrode that measured electrical current is substantially in phase with the applied voltage; and uses the sum of in phase currents to estimate the property.

Abstract: A method and apparatus for steering a drilling assembly within a reservoir of an earth formation is disclosed. The drilling assembly is positioned within the reservoir between a conductive upper layer having a DC magnetic field and a conductive lower layer having a DC magnetic field. A sensor of the drilling assembly measures a magnetic field in the reservoir resulting from the DC magnetic field of the conductive upper layer and the DC magnetic field of the conductive lower layer. A processor uses the measured magnetic field to steer the drilling assembly within the reservoir.

Abstract: A logging tool for use in a borehole to obtain multicomponent resistivity induction measurements using collocated coils wherein each of the transverse antennas comprises a pair of mirror-image coils symmetrically disposed about an axis of the logging tool.

Abstract: A device, method and system for measuring characteristics of a geologic formation using a floating reference signal having a mud chamber, an electrode disposed within the mud chamber, and an electrically conductive plate disposed within the mud chamber, the plate separated from the electrode. An alternating current source is provided on the electrode, whereby an electric field is be maintained between the electrode and the conductive plate. An opening in the mud chamber allows drilling fluids to pass there through.

Abstract: Disclosed is an apparatus for estimating a property of an earth formation penetrated by a borehole. The apparatus includes a carrier configured to be conveyed through the borehole. A first transmitter electrode and a second transmitter electrode are disposed at the carrier and configured to inject an electrical current into the earth formation. A first measurement electrode and a second measurement electrode are disposed at the carrier and configured to measure the electrical current to estimate the property of the earth formation. A first bucker amplifier is coupled to the first measurement electrode and a second bucker amplifier is coupled to the second measurement electrode, wherein the first and second bucker amplifiers are configured to equalize electrical potentials of areas in front of the first and second measurement electrodes.

Abstract: Disclosed is an apparatus for estimating a property of an earth formation penetrated by a borehole. The apparatus includes a carrier configured to be conveyed through the borehole and having a first transmitter electrode configured to inject electrical current into the formation and a first measurement electrode configured to receive electrical current for measurement due to the current injection in order to estimate the property of the earth formation. A controller is configured to determine a phase difference between injected electrical current and received electrical current. A first bucker amplifier is coupled to the first measurement electrode and configured to apply a voltage to the first measurement electrode based on the determined phase difference in order for a phase of current received by the first measurement electrode to be substantially in phase with the current injected by the first transmitter electrode.

Abstract: Disclosed is an apparatus for estimating a property of an earth formation penetrated by a borehole containing an oil-based drilling fluid. The apparatus includes an electrode disposed at a carrier and configured to inject alternating current into the formation. An electrically conductive plate is disposed between the first electrode and a borehole wall. An electrical insulator is disposed between and contacts the first electrode and the conductive plate. The apparatus is configured to prevent the drilling fluid from being disposed between the first electrode and the conductive plate. A first sensor is used to measure an electric field established between the first electrode and the conductive plate. A processor is configured to receive a measurement of the electric field to use as a floating reference signal to determine a phase difference with respect to a measured electrical quantity related to the injected electrical current in order to estimate the property.

Abstract: Disclosed is an apparatus for estimating a property of an earth formation penetrated by a borehole. The apparatus includes a plurality of electrodes disposed downhole and configured to inject an electrical current into the earth formation using an applied voltage and/or measure electrical current resulting from an injection of the electrical current. The apparatus also includes a processor configured to perform a series of formation measurements that include injecting current into the earth formation using a unique subset of electrodes in the plurality of electrodes and measuring current in the earth formation using one or more electrodes not used for the current injecting. The processer sums the measured currents for the electrodes wherein the sum of electrical currents for at least one electrode that measured electrical current is substantially in phase with the applied voltage; and uses the sum of in phase currents to estimate the property.

Abstract: Disclosed is an apparatus for estimating a property of an earth formation penetrated by a borehole. The apparatus includes a carrier configured to be conveyed through the borehole. A first transmitter electrode and a second transmitter electrode are disposed at the carrier and configured to inject an electrical current into the earth formation. A first measurement electrode and a second measurement electrode are disposed at the carrier and configured to measure the electrical current to estimate the property of the earth formation. A first bucker amplifier is coupled to the first measurement electrode and a second bucker amplifier is coupled to the second measurement electrode, wherein the first and second bucker amplifiers are configured to equalize electrical potentials of areas in front of the first and second measurement electrodes.

Abstract: A method and apparatus for estimating at least one parameter of interest in an earth formation using a signal from a receiver where a quadrature component of a signal at a plurality of frequencies is used to estimate a misalignment angle between the receiver and a transmitter. The apparatus may include at least one receiver, at least one transmitter, and at least one processor configured to excite the transmitter and estimate the misalignment angle. The method may include acquiring data at a plurality of frequencies, estimating a misalignment angle, and estimating at least one parameter of interest using the misalignment angle. The method may include performing multi-frequency focusing on the signal received at each of the plurality of frequencies.

Abstract: An apparatus, method and computer-readable medium for evaluating an earth formation are disclosed. The apparatus includes at least one coil on a logging tool conveyed in a borehole in the earth formation. Passage of a current through the coil induces an electrical current in the earth formation. At least two electrodes associated with the logging tool and in proximity to a wall of the borehole have a potential difference in response to the induced electrical current that is indicative of a property of the earth formation. The at least one coil may be mounted on a mandrel of a downhole assembly. The electrodes may be positioned on a first pad extendable from a mandrel of the downhole assembly.

Abstract: A method and apparatus for steering a drilling assembly within a reservoir of an earth formation is disclosed. The drilling assembly is positioned within the reservoir between a conductive upper layer having a DC magnetic field and a conductive lower layer having a DC magnetic field. A sensor of the drilling assembly measures a magnetic field in the reservoir resulting from the DC magnetic field of the conductive upper layer and the DC magnetic field of the conductive lower layer. A processor uses the measured magnetic field to steer the drilling assembly within the reservoir.

Abstract: A device, method and system for measuring characteristics of a geologic formation using a floating reference signal having a mud chamber, an electrode disposed within the mud chamber, and an electrically conductive plate disposed within the mud chamber, the plate separated from the electrode. An alternating current source is provided on the electrode, whereby an electric field is be maintained between the electrode and the conductive plate. An opening in the mud chamber allows drilling fluids to pass there through.

Abstract: Measurements made by a multi-component logging tool in a borehole are inverted to obtain three principal resistivities (or conductivities) and three associated angles of a bi-axially symmetric formation traversed by the borehole.

Abstract: A device, method and system for measuring characteristics of a geologic formation using a floating reference signal having a mud chamber, an electrode disposed within the mud chamber, and an electrically conductive plate disposed within the mud chamber, the plate separated from the electrode. An alternating current source is provided on the electrode, whereby an electric field is be maintained between the electrode and the conductive plate. An opening in the mud chamber allows drilling fluids to pass there through.

Abstract: A multicomponent induction logging tool is used on a MWD bottomhole assembly. Multifrequency focusing that accounts for the finite, nonzero, conductivity of the mandrel is applied. Using separation of modes, the principal components and a direction of a conductivity tensor are determined. The results are used for reservoir navigation in earth formations. 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 transmitter on an instrument is used to induce currents in an earth formation when it is turned on or off. A Fourier transform is applied to transient measurements made in the receivers. A multifrequency focusing of the transformed data is used for applications like determination of a distance to an interface in the formation, controlling the drilling direction, determination of formation resistivities and formation strike directions.