Abstract: A transmitter on a bottomhole assembly (BHA) is used for generating a transient electromagnetic signal in an earth formation. A processor estimates the distance to a resistivity interface using a signal produced by a receiver on the BHA. The transmitter-receiver distance may be less than 1 m. The estimation of the distance is done in real time using a thin conductive sheet approximation.

Abstract: An apparatus and method for estimating a parameter of interest of an earth formation involving alignment information between non-collocated oriented receivers and their corresponding non-collocated oriented transmitters. The method may include generating signal responses indicative to energy transmitted into an earth formation; estimating differences in alignment between transmitters and receivers; using the estimated differences in alignment to compensate for misalignment; and estimating a parameter of interest using the misalignment compensated signals. The misalignment estimate may include an inversion of at least one measurement from an alignment sensor. The apparatus may include a bottom hole assembly with oriented transmitters, oriented receivers, one or more alignment sensors, and at least one processor configured to compensate for misalignment using information about difference in alignment between at least one oriented transmitter and at least one oriented receiver.

Abstract: Measurements made by a multi-component induction logging tool may be corrected for tool eccentricity or the presence of a fracture in the earth formation. The corrected measurements may then be used in conjunction with a multi-array measurement to determine horizontal and vertical formation resistivity.

Abstract: An apparatus and method for calibrating a multi-component induction logging tool. The method may include orienting a Z-transmitter coil to be substantially orthogonal to at least one Z-receiver coil, positioning an X-transmitter coil disposed on the logging tool so that the X-transmitter coil is substantially parallel to a conducting surface; encompassing the Z-transmitter coil, the X-transmitter coil, and at least one Z-receiver coil of the logging tool with at least one conducting loop of a calibrator; and calibrating the logging tool using the calibrator. The apparatus may include a calibrator configured to receive the logging tool. The Z-transmitter coil and the Z-receiver coil may be located on separate subs that are detachable from one another.

Abstract: A multicomponent induction logging tool uses a nonconducting mandrel. A central conducting member including wires that electrically connect at least one of the antennas to another of the antennas. Electrodes disposed about the transmitter antenna form a conductive path through a borehole fluid to the central conducting member.

Abstract: An apparatus and method for estimating a parameter of interest of an earth formation involving alignment information between non-collocated oriented receivers and their corresponding non-collocated oriented transmitters. The method may include generating signal responses indicative to energy transmitted into an earth formation; estimating differences in alignment between transmitters and receivers; using the estimated differences in alignment to compensate for misalignment; and estimating a parameter of interest using the misalignment compensated signals. The misalignment estimate may include an inversion of at least one measurement from an alignment sensor. The apparatus may include a bottom hole assembly with oriented transmitters, oriented receivers, one or more alignment sensors, and at least one processor configured to compensate for misalignment using information about difference in alignment between at least one oriented transmitter and at least one oriented receiver.

Abstract: Electrical property contrast difference maps of the subsurface formations may be produced using surface and/or near surface array of transmitters and receivers tuned to emit and receive electromagnetic (EM) signals. The electrical property may be resistivity or conductivity. The maps may be time based. A time based trend change may be used to predict the location and movement of fluids within the hydrocarbon bearing or any other subsurface zones where resistivity and/or conductivity values of the fluids within these zones change over time.

Abstract: A method for identifying drilling induced fractures while drilling a wellbore into a formation is disclosed. The method includes: obtaining multi-component induction data collected by a drill string including a multi-component induction tool; processing the data to estimate values for principal components; and identifying drilling induced fractures from the principal components. An instrument and a computer program product are disclosed.

Abstract: An apparatus and method for calibrating a multi-component induction logging tool. The method may include orienting a Z-transmitter coil to be substantially orthogonal to at least one Z-receiver coil, positioning an X-transmitter coil disposed on the logging tool so that the X-transmitter coil is substantially parallel to a conducting surface; encompassing the Z-transmitter coil, the X-transmitter coil, and at least one Z-receiver coil of the logging tool with at least one conducting loop of a calibrator; and calibrating the logging tool using the calibrator. The apparatus may include a calibrator configured to receive the logging tool. The Z-transmitter coil and the Z-receiver coil may be located on separate subs that are detachable from one another.

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: A multicomponent induction logging tool uses a nonconducting mandrel. A central conducting member including wires that electrically connect at least one of the antennas to another of the antennas. Electrodes disposed about the transmitter antenna form a conductive path through a borehole fluid to the central conducting member.

Abstract: A transmitter on a bottomhole assembly (BHA) is used for generating a transient electromagnetic signal in an earth formation. A processor estimates the distance to a resistivity interface using a signal produced by a receiver on the BHA. The transmitter-receiver distance may be less than 1 m. The estimation of the distance is done in real time using a thin conductive sheet approximation.

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 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: Measurements made by a multi-array/multi-frequency induction resistivity logging tool in a borehole are used for determining the length of fractures in an earth formation and the resistivity of the unfractured formation when the fractures have a resistive fluid. A look-up table based on modeling of a fracture by a pair of wings is used.

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.

Abstract: A method for presenting a formation property to a user includes estimating an initial property of the formation using a tool conveyed in a borehole and estimating a relationship between the tool and the formation based on information received from the tool. The method also includes presenting the user a first output based at least in part on the initial property and presenting a second output based at least in part on the relationship proximate the first output.

Abstract: Electrical property contrast difference maps of the subsurface formations may be produced using surface and/or near surface array of transmitters and receivers tuned to emit and receive electromagnetic (EM) signals. The electrical property may be resistivity or conductivity. The maps may be time based. A time based trend change may be used to predict the location and movement of fluids within the hydrocarbon bearing or any other subsurface zones where resistivity and/or conductivity values of the fluids within these zones change over time.

Abstract: A transient electromagnetic borehole system uses an arrangement of sensors deployed in a borehole for reservoir monitoring. Non-conductive casing sections may be used along with an efficient transmitter configured to provide measurements up to 300 m from the borehole. By using multiple receivers, the method can also be used without nonconductive casing.

Abstract: A method for estimating a property of a portion of an earth formation ahead of a borehole penetrating the formation, the method includes: conveying a logging tool through the borehole; receiving one or more first signals from a previous depth of the logging tool; constructing a model of the earth formation using the one or more first signals; predicting one or more second signals from the portion of the earth formation ahead of the borehole using the model; receiving one or more third signals from the portion of the earth formation ahead of the borehole; calculating a difference between the one or more third signals and the one or more second signals; and estimating the property from the difference.