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Collaborating Authors
Results
Summary Traditional anisotropic resistivity survey requires performing a set of azimuthal measurements. In an anisotropic heterogeneous medium the possibility of an anisotropy study is restricted by the necessity to carry out the time-consuming azimuthal soundings on a dense grid of observations. On the other hand, at applying the Electrical Imaging in anisotropic media the complete neglect of azimuthal-anisotropy influence can result in noticeable errors of interpretation. The authors propose an alternative method to determine the parameters of anisotropic media based on measuring the second derivatives of the electric potential from a point current source. Such a technology (named tensor measurements) reduces a number of observation azimuths to a single one and at the same time allows obtaining all anisotropy parameters. The efficiency of different tensor arrays is illustrated on the complex 3D model of the dipping interface between an isotropic overburden andan anisotropic basement.
Summary This presentation explains an experience of programming and/or testing the following different magnetic depth estimate techniques: the manual Peters half-slope and Bean ratio methods, the modern (semi-) automatic Naudy, Werner, Euler and SPIT(local wavenumber) methods. In all but the original SPIT method, the moving window concept is critical for reducing the working time possibly from months to hours. The modern methods are superior to the manual methods even if we leave the moving window concept behind. The depth estimate is often inaccurate mainly because the observed data is imperfect, and the real sources are different from the idealized.
Summary A forward acoustic model shows that geologic lithofacies groups can be identified by the character of the wavelet transform of their seismic response even for incident signals with wavelength much larger than the dominant bed thickness. The same model shows that multiple interbed reflections can be neglected. This allows the use of a simple analytical relation of the linear reflection response expressed as a convolution between the incident signal and the scaled derivative of the acoustic impedance. The relation is applied to solve the inverse problem for the acoustic impedance, using orthogonal discrete wavelet transform (DWT) and Fourier transform (FT) methods; good agreement is obtained between the well log wavelet spectrum and both the forward modeled seismic data and the real seismic data.
Summary A tomographic inversion scheme is introduced, that makes use of seismic kinematic wavefield attributes (NIP-wave curvatures and normal ray emergence angles) at given measurement surface positions and zero-offset traveltimes to construct a velocity macro-model. These kinematic wavefield attributes can be extracted from multi-coverage prestack data in a data-driven way by application of the Common-Reection-Surface stack. The model to be inverted for is made up of two parts: the smooth velocity model itself, given by two-dimensional B-splines on a rectangular grid, and the starting positions and starting directions at depth (i.e. local reector dips) of the normal rays corresponding to the input data.
- Europe (0.47)
- North America > United States > Utah (0.16)
- Geophysics > Seismic Surveying > Seismic Processing (1.00)
- Geophysics > Seismic Surveying > Seismic Modeling > Velocity Modeling (1.00)
The analytic signal is composed of a Magnetic data are used on a routine basis to help geological real part, the horizontal derivative of the field, and an mapping. Although geologists often use them in a qualitative imaginary part, the vertical derivative of the field. For a fashion to map lithological units, they can be used to contact, the function describing the magnitude of the analytic determine the depth and dip of these units. Magnetic signal depends on the depth of the source and its magnetic interpretation techniques can be grouped in three major susceptibility. Its shape is independent of the magnetic field categories. Firstly, magnetic data can be interpreted by orientation. Similar relations exist for the thin sheet and the interactively fitting 2D models to profile data.
- North America > Canada > Ontario (0.17)
- North America > United States > Utah (0.16)