Abstract: A system and method for determining formation parameters is provided. The system includes an induction logging tool having a plurality of transmitter coils. The induction logging tool further includes a plurality of receiver coils, each of the receiver coils being spaced apart from the transmitter coils by a predetermined distance and receiving a response signal from the formation. The system includes circuitry coupled to the induction logging tool, the circuitry determining voltages induced in the plurality of receiver coils by the response signal. The circuitry separates real or in-phase portions of the determined voltages from imaginary of ninety degrees out of phase portions of the determined voltages and determines formation parameters using imaginary portions of the measured voltages.

Abstract: A system and method of correcting induction logging data for relative dip, wherein an induction logging tool is utilized to collect initial induction logging data at a plurality of frequencies. The initial induction logging data is then corrected for skin effect and borehole effect, after which, inversion is performed on the processed induction logging data to determine a dip effect correction. The dip effect correction is then applied to the initial induction logging data in order to yield induction logging data that is dip corrected to reflect a zero relative dip. Once dip corrected, the induction logging data can be used with resistivity methodologies generally designed for instances where no dip is present in the formation under analysis. In certain embodiments, the inversion step utilizes an additive correction for the dip effect correction.

Abstract: An example downhole tool incorporating aspects of the present disclosure may include a tool body and a first flexible material coupled to the tool body. A transmitter may be coupled to the first flexible material. A receiver may coupled to the first flexible material, with the receiver having at least two antenna windings positioned in different orientations. A control unit may be communicably coupled to the transmitter and the receiver, the control unit having a processor and a memory device coupled to the processor, the memory device containing a set of instruction that, when executed by the processor, cause the processor to generate an electromagnetic signal in a downhole element using the transmitter, and measure a response of the downhole element to the electromagnetic signal using the at least two antenna windings of the receiver.

Abstract: An estimated value for invasion depth of an invasion zone in a subsurface measurement zone is calculated in a one-dimensional optimization procedure based on multi-array laterolog measurement data. A one-dimensional optimization problem is defined as having the invasion depth as a sole variable measurement zone parameter. The one-dimensional optimization problem is then solved by automated, iterative modification of the invasion depth value. The one-dimensional optimization problem can be a function to minimize a misfit error between (a) multi-array measurement values for resistivity of the subsurface measurement zone, and (b) predicted measurement values calculated in accordance with a simulated measurement zone model based at least in part on the invasion depth.

Abstract: A multi-string corrosion monitoring method includes using a first set of electromagnetic (EM) log data to calculate attributes of a first casing string while attributes of a second casing string are assigned a fixed value. The method also includes using a second set of EM log data to calculate attributes of a second casing string while attributes of the first casing string are assigned a fixed value.

Abstract: Improved algorithm for estimating anisotropic formation resistivity profile using a multi-component induction tool are disclosed. A method for estimating anisotropic formation resistivity profile of a formation comprises obtaining borehole corrected log data and determining at an azimuth angle of the formation. One or more formation bed boundaries are located and initial formation properties are calculated. One of a plurality of inversion windows is sequentially selected and a one-dimensional inversion of each of the sequentially selected one of the plurality of inversion windows is performed.

Abstract: Various embodiments include apparatus and methods that perform a homogeneous inversion processing to data or signals acquired from a multicomponent induction tool operating in a wellbore. The homogeneous inversion processing can be used to provide a quality check of results from radial one dimensional borehole correction processing. Also, the homogeneous inversion processing may be employed as a dip indicator of conventional array induction logging processing. Additional apparatus, systems, and methods are disclosed.

Abstract: Evaluation of formation and fracture characteristics based on multicomponent induction (MCI) log data includes automated calculation of inverted biaxial anisotropy (BA) parameters for the formation by performing an iterative BA inversion operation based on the MCI log data and using a BA formation model that accounts for transfers by axial formation anisotropy to resistivity. The BA inversion operation can be combined with a transversely anisotropic (TI) inversion based on the MCI log data and using a TI formation model, to calculate inverted TI parameters for the formation. The inverted BA parameters and the inverted TI parameters can be used, in combination, to calculate a quantified value for an identification function, to indicate estimated presence or absence of a fracture in the formation.

Abstract: Fast-changing dip formation resistivity estimation methods and systems, including a formation resistivity estimation method that includes estimating an initial horizontal resistivity based upon acquired formation logging data and determining an initial value set of one or more value sets. The method further includes determining each additional value set of the one or more value sets using a 1-dimensional inversion initialized with a previously determined value set of the one or more value sets, and displaying a final value set of the one or more value sets. Each of the 1-dimensional inversions is performed using a cross-bedded formation model, and each of the one or more value sets includes one or more parameters selected from the group consisting of a horizontal resistivity, a vertical resistivity, a formation dip angle, a formation azimuth angle, a tool inclination angle, a tool azimuth angle and a depth.

Abstract: Device, system, and method embodiments provide fluid front monitoring via permanent, casing-mounted electromagnetic (EM) transducers. One or more casing strings have one or more transmit antennas that each encircle a casing string and one or more receive antennas that similarly encircle the casing string, with at least one receive antenna oriented differently from at least one transmit antenna to provide sensitivity to at least one cross-component signal. A processor unit derives an estimated distance to a fluid front, and may further determine a direction and orientation of the fluid front for display to a user. Signals from an array of transmit and receive antennas may be combined, optionally with signals from other boreholes, to locate and track multiple points on the fluid front. In response to the determined location and progress of the front, the processor unit may further provide control settings to adjust injection and/or production rates.

Abstract: At least some disclosed resistivity logging system embodiments include a logging tool and a processing system. The logging tool provides multi-component transmitter-receiver coupling measurements to the processing system. The processing system derives from the measurements initial formation parameter estimates based on a first formation model such as a radially-symmetric formation model having anisotropic, but otherwise homogenous dipping formation. The processing system further derives in one or more selected regions a second set of formation parameter estimates based on a second formation model such as a model having a dipping borehole through a series of horizontal formation layers, each having a vertical transverse isotropy.

Abstract: Calibration tools and procedures that provide one or more calibration methods for multi-component induction tools can include use of a tilted elliptical loop and a circular loop. Measurement signals may be used for analytic calibration of a multicomponent induction tool. Additional apparatus, systems, and methods are disclosed.

Abstract: Various resistivity logging tools, systems, and methods are disclosed. At least some system embodiments include a logging tool and at least one processor. The logging tool provides transmitter-receiver coupling measurements that include at least direct coupling along the longitudinal tool axis (Czz), direct coupling along the perpendicular axis (Cxx or Cyy), and cross coupling along the longitudinal and perpendicular axes (Cxz, Cyz, Czx, or Czy). The processor combines a plurality of the coupling measurements to obtain inversion parameters. Based at least in part on the inversion parameter, the processor performs an inversion process to determine a vertical conductivity and, based in part on the vertical conductivity, determines borehole corrected values for said transmitter-receiver coupling measurements. One or more of the borehole corrected values can be provided as a function of borehole position.

Abstract: Various embodiments include apparatus and methods to utilize signals acquired from a multi-component induction tool operating in a wellbore. The acquired signals can be correlated to an apparent conductivity of a formation and mapped to components of the apparent conductivity tensor conductivity. A multi-stage inversion scheme can be implemented to determine three-dimensional formation parameters from operating the multi-component induction tool. Additional apparatus, systems, and methods are disclosed.

Abstract: Formation properties may be more efficiently derived from measurements of multi-frequency, multi-component array induction tools, by emphasizing the measurements associated with shorter spacings/lower frequencies in certain regions and short-to-middle spacings/higher frequencies in other regions. In at least one embodiment, a disclosed logging system includes a logging tool that when conveyed along a borehole through a formation obtains multi-component transmit-receive antenna coupling measurements with multiple arrays having different antenna spacings; and a processing system that operates on the measurements. The processing system derives from said measurements one or more formation parameter estimates; determines measurement weight coefficients for a cost function based on said one or more formation parameter estimates; and inverts said measurements with said cost function to obtain one or more enhanced parameter estimates.

Abstract: A corrosion monitoring method includes obtaining electromagnetic (EM) log, data along a casing string. The method also includes processing the EM log data to estimate casing thickness of the casing string as a function of position, where the processing includes correcting, for junction effects in the casing string.

Abstract: Tools, systems, and methods are disclosed for multi-component induction logging with iterative analytical conversion of tool measurements to formation parameters. At least some system embodiments include a logging tool and at least one processor. The logging tool provides transmitter-receiver coupling measurements that include at least diagonal coupling measurements (Hzz, Hxx, and/or Hyy) and cross-coupling measurements (Hxy, Hxz, and Hyz). The processor employs an iterative analytical conversion of the cross-coupling measurements into formation resistive anisotropy and dip information. The processor may further provide one or more logs of the resistive anisotropy and/or dip information.

Abstract: Tools, systems and methods for fast formation dip angle estimation, at least some of which include a logging tool that includes at least one transmit antenna, at least one receive antenna and a controller. The controller measures coupling parameters between the transmit and receive antennas, with at least one of the coupling parameters being measured as a function of depth and azimuthal angle. The controller further determines if a surrounding formation is anisotropic and heterogeneous based at least in part on at least one of the coupling parameters, and if so, derives a dip angle from a partial derivative with respect to depth and artificial dip angle of the coupling parameter(s).

Abstract: According to aspects of the present disclosure an example downhole tool may include a tool body and a first conformable sensor coupled to the tool body. The first conformable sensor may include a flexible material, with a transmitter and receiver coupled to the flexible material. The downhole tool further may include an arm extendable from the tool body and a pad coupled to the arm. The first conformable sensor may be coupled to the pad.

Abstract: In some aspects, systems and methods are provided for determining formation properties using data from both a high-frequency dielectric tool (HFDT) and an array induction tool (AIT). The system includes a controller in communication with at least one HFDT, at least one ART (which may be a multi-component AIT), and a processing unit. The acquired ART formation data can be processed and used to set constraints on the processing of the acquired HFDT formation data. In aspects, a set of processed HFDT data can be used to reinitialize the ART data processing, to allow for a repeated or iterative evaluation process. The system and method generate values used to determine one or more formation properties such as a resistivity of the formation, the presence of an invasion in the formation, mud resistivity or permittivity, anisotropy characteristics of the formation, and dipping characteristics of the formation.