Borehole radar is an electromagnetic tool that can be applied to assist in the delineation of orebody geometry, ideally using routinely drilled cover and exploration boreholes. Successful trials of borehole radar for delineating reef horizons on South African gold and platinum mines have led to the development of a borehole radar system specifically designed for routine application in those eny...

We have employed a few-parameter estimation (FPE) technique to derive information on past surface temperature variations from present-day borehole temperatures. Synthetic experiments show that the FPE t•hnique can separate reasonably well information on century-long trends of surface temperature change from borehole temperatures within a .wide range of noise levels. The technique also allows a ...

We present a method of calculation to simulate the propagation of acoustic and elastic waves generated by a borehole source embedded in a layered medium. The method is formulated as a boundary element technique where the Green's functions are calculated by the discrete wavenumber method. The restrictive assumptions are that the borehole is cylindrical and that its axis runs normal to the layer ...

An impulse-based single-borehole radar prototype has been developed for well logging. The borehole radar is comprised of subsurface sonde and surface equipment. An armored 7-conductor well logging cable is used to connect subsurface sonde and surface equipment which is well compatible with the other well logging instruments. The performance experiments of the prototype have been conducted in a ...

1 International Institute of Earthquake Prediction Theory and Mathematical Geophysics, Russian Academy of Sciences, Moscow, Russia, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles 90095-1567, USA; e-mail: [email protected] 2 International Institute of Earthquake Prediction Theory and Mathematical Geophysics, Russian Academy of Sciences, Moscow, Russia, an...

A new ultrasonic phased array transducer to increase the imaging resolution of the borehole wall is presented for acoustical logging. We fabricate a cylindrical phased array which is made up of 128 piezoelectric elements distributed on the surface of a cylinder uniformly. The working frequency of each element is 0.5MHz. Through the switch array, different combinations of the elements can lead a...