Abstract: Formation properties may he 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: 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: 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: Method and system for improving the speed and accuracy of determining formation properties using multiple logging data are disclosed. Logging data relating to the formation of interest is obtained and used as an input. High frequency noise is then removed from the logging data and bed-boundary determination is performed using the logging data. An adaptive low pass filter is applied to the logging data and the logging data is inverted. The inverted logging data is then visually interpreted.

Abstract: In some embodiments, an apparatus and a system, as well as a method and an article, may operate to calculate a map that transforms fast modeled measurement results into accurate modeled measurement results within a modeled data space, to make actual measurements using a tool disposed in a borehole, to transform a plurality of modeling parameter vectors into the fast modeled measurement results via modeling, to transform the fast modeled measurement results into the accurate modeled measurement results using the map, to locate a matching modeling parameter vector as one of the plurality of modeling parameter vectors that matches the accurate modeled measurement results to the actual measurement, and to display at least a portion of the matching modeling parameter vector to represent at least one property of a geological formation. Additional apparatus, systems, and methods are described.

Abstract: Various embodiments include apparatus and methods to provide a skin-effect correction. The skin-effect correction can be based on a pre-calculated correction coefficient library. In various embodiments, a skin-effect correction procedure can be applied that only uses a single-frequency R-signal measurement. In addition, an embodiment of a skin-effect correction procedure using a single-frequency R-signal measurement can be applied whenever the quality of the data from one of the multiple frequencies normally used in a multi-frequency method is reliable. 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 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 performs a multi-step inversion of said transmitter-receiver coupling measurements to obtain values for model parameters. Based at least in part on the model parameters, the processor determines borehole corrections for the transmitter-receiver coupling measurements and may further provide one or more logs derived from the borehole corrected transmitter-receiver coupling measurements.