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Shande Yang - One of the best experts on this subject based on the ideXlab platform.
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characteristics of the sum of cross components of triaxial Induction Logging tool in layered anisotropic formation
IEEE Transactions on Geoscience and Remote Sensing, 2014Co-Authors: Decheng Hong, Jiaqi Xiao, Guoyan Zhang, Shande YangAbstract:There are two nonzero cross-components of a triaxial Induction Logging tool in the medium coordinate system in a transversely isotropic (TI) formation. The sum of the cross-components holds dependence on only the horizontal conductivities with little nonlinearity and small shoulder bed effect in a horizontally layered formation. Based on the generalized reflection coefficient method, simplified formulas of the sum are derived to analyze its response characteristics. Numerical results show that the apparent conductivity obtained from the sum is a square-looking log with high vertical resolution. Moreover, the readings almost equal to the true horizontal conductivity of the formation beds. These characteristics can be applied to reconstruct the horizontal conductivity and the formation boundaries with triaxial Induction Logging data.
Decheng Hong - One of the best experts on this subject based on the ideXlab platform.
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characteristics of the sum of cross components of triaxial Induction Logging tool in layered anisotropic formation
IEEE Transactions on Geoscience and Remote Sensing, 2014Co-Authors: Decheng Hong, Jiaqi Xiao, Guoyan Zhang, Shande YangAbstract:There are two nonzero cross-components of a triaxial Induction Logging tool in the medium coordinate system in a transversely isotropic (TI) formation. The sum of the cross-components holds dependence on only the horizontal conductivities with little nonlinearity and small shoulder bed effect in a horizontally layered formation. Based on the generalized reflection coefficient method, simplified formulas of the sum are derived to analyze its response characteristics. Numerical results show that the apparent conductivity obtained from the sum is a square-looking log with high vertical resolution. Moreover, the readings almost equal to the true horizontal conductivity of the formation beds. These characteristics can be applied to reconstruct the horizontal conductivity and the formation boundaries with triaxial Induction Logging data.
Qing Huo Liu - One of the best experts on this subject based on the ideXlab platform.
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applications of the bcgs fft method to 3 d Induction well Logging problems
IEEE Transactions on Geoscience and Remote Sensing, 2003Co-Authors: Zhong Qing Zhang, Qing Huo LiuAbstract:Electromagnetic Induction Logging is one of the most important measurements in borehole characterization of an oil reservoir. With the ever increasing number of deviated and horizontal wells aiming for improved hydrocarbon production, simulation of Induction well Logging in realistic three-dimensional (3-D) environments has become an important subject of research. In this paper, we investigate a fast spectral-domain solver for the second-kind integral equation arising from Maxwell's equations for 3-D Induction Logging. We combine an iterative stabilized biconjugate-gradient (BiCGSTAB) technique with a fast Fourier transform (FFT) algorithm (BCGS-FFT method) to compute electromagnetic fields in 3-D inhomogeneous media at Induction frequencies. The electric field integral equation is discretized through the use of the magnetic vector potential to weaken the singularity associated with the dyadic Green's function. The computational time and computer memory requirements of this BCGS-FFT method are O(NlogN) and O(N), respectively, where N is the total number of unknowns.
Chester J Weiss - One of the best experts on this subject based on the ideXlab platform.
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on coincident loop transient electromagnetic Induction Logging
Geophysics, 2017Co-Authors: Andrei Swidinsky, Chester J WeissAbstract:ABSTRACTCoincident loop transient Induction wireline Logging is examined as the borehole analog of the well-known land and airborne time-domain electromagnetic (EM) method. The concept of whole-space late-time apparent resistivity is modified from the half-space version commonly used in land and airborne geophysics and applied to the coincident loop voltages produced from various formation, borehole, and invasion models. Given typical tool diameters, off-time measurements with such an instrument must be made on the order of nanoseconds to microseconds — much more rapidly than for surface methods. Departure curves of the apparent resistivity for thin beds, calculated using an algorithm developed to model the transient response of a loop in a multilayered earth, indicate that the depth of investigation scales with the bed thickness. Modeled resistivity logs are comparable in accuracy and resolution with standard frequency-domain focused Induction logs. However, if measurement times are longer than a few mic...
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on the electric fields and currents produced by Induction Logging instruments in anisotropic media
Geophysics, 2002Co-Authors: David L Alumbaugh, Chester J WeissAbstract:Electrical anisotropy has attracted the interest of the Induction Logging community for several decades now in their efforts to better characterize potential hydrocarbon reservoirs (e.g., Kunz and Moran, 1958; Moran and Gianzero, 1979; Anderson et al., 1998). Shale formations and thinly laminated sequences of shale and sand are commonly-encountered anisotropic formations (Klein et al., 1995). These types of formations are likely to exhibit one (value of conductivity parallel to the bedding planes, and a different, lesser, value of conductivity perpendicular to beds. This is the case of transverse isotropy . Historically, exploration wells were drilled vertically, and thus were often perpendicular to formation bedding planes. In this situation, conventional coaxial Induction tools induce eddy currents that flow horizontally (i.e., parallel to the bedding planes). Thus conventional Induction tools are only sensitive to the horizontal formation conductivity. This is the primary reason why electrical anisotropy has been largely ignored by many log analysts until recently. However, deviated and horizontal wells have been increasingly used as a new drilling strategy to better characterize the reservoir and lower exploitation costs. The induced currents produced by a sonde located within a deviated or horizontal well are forced to cross bed boundaries, and thus are sensitive to both the vertical and horizontal conductivity of the formation. An arbitrarily oriented magnetic dipole source can be represented as the superposition of one vertical and two horizontal magnetic dipole sources. Whereas transverse anisotropy has no effect on the fields induced by a vertical magnetic dipole, the effects of anisotropy on the two horizontal dipoles are significant. Therefore, a horizontal magnetic dipole exciting a transversely isotropic whole space is a reasonable starting point in understanding Induction Logging in anisotropic media. The Induction problem for a horizontal magnetic dipole source in the presence of anisotropic whole space or …
Kazumi Osato - One of the best experts on this subject based on the ideXlab platform.
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SINGLE-WELL AND SURFACE-TO-WELL Induction Logging
2015Co-Authors: Robert Mallan, Michael Wilt, Barry Kirkendall, Kazumi OsatoAbstract:Extended Logging and surface-to-borehole electromagnetic Induction measurements were performed at the Dixie Valley Geothermal Field as part of an ongoing effort to employ electromagnetic Induction Logging to geothermal reservoir characterization. The principal goal of this effort is to discern subsurface features useful in geothermal production, such as larger scale mapping of geothermal reservoirs and smaller scale mapping of producing fractures in and around geothermal wells. The foremost goal of these measurements is to provide experience and insight that will be used toward the future development of geothermal, geophysical borehole technologies. Extended Induction Logging was performed during October 1998, using the MAIL (Multi Array Induction Logging) system. This system provides near well resistivity structure useful in explicating near well features. Surface-to-borehole Induction Logging was performed during December 1999, using the VEMP (Vertical Electro Magnetic Profiling) system. This system provides regional resistivity structure around the well useful in describing features distant from the well. Combined, these systems provide a comprehensive image of the resistivity structure surrounding the borehole
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SUBSURFACE ELECTRICAL MEASUREMENTS AT DIXIE VALLEY, NEVADA, USING SINGLE-WELL AND SURFACE-TO-WELL Induction Logging
2001Co-Authors: Robert Mallan, Michael Wilt, Barry Kirkendall, Kazumi OsatoAbstract:Extended Logging and surface-to-borehole electromagnetic Induction measurements were performed at the Dixie Valley Geothermal Field as part of an ongoing effort to employ electromagnetic Induction Logging to geothermal reservoir characterization. The principal goal of this effort is to discern subsurface features useful in geothermal production, such as larger scale mapping of geothermal reservoirs and smaller scale mapping of producing fractures in and around geothermal wells. The foremost goal of these measurements is to provide experience and insight that will be used toward the future development of geothermal, geophysical borehole technologies. Extended Induction Logging was performed during October 1998, using the MAIL (Multi Array Induction Logging) system. This system provides near well resistivity structure useful in explicating near well features. Surface-to-borehole Induction Logging was performed during December 1999, using the VEMP (Vertical Electro Magnetic Profiling) system. This system provides regional resistivity structure around the well useful in describing features distant from the well. Combined, these systems provide a comprehensive image of the resistivity structure surrounding the borehole.