Patent ID: 6712140
Filing Date: 2004-03-30
Classification: G01V

Abstract:
A borehole radar tool for directionally sensitively locating transitions in the subsurface surrounding the borehole radar tool in use, comprising a generating assembly for generating electromagnetic radiation having a frequency of between 10 MHz and 200 MHz, signal processing means for processing received electromagnetic radiation, and a housing having a substantially cylindrical wall and a central axis which accommodates at least:a transmitting antenna assembly for emitting the electromagnetic radiation generated by the generating assembly, comprising a transmitting antenna and an electroconductive reflector; and a receiving antenna assembly for receiving the electromagnetic radiation reflected by the surrounding subsurface, comprising a receiving antenna and an electroconductive reflector, wherein both the transmitting antenna and the receiving antenna extend parallel to the axis of the housing and both comprise a dipole antenna, each reflector comprising a reflective surface which extends abreast of and parallel to the respective dipole antenna at a distance therefrom, and a space between each reflective surface and that section of the housing which in each case is located opposite thereto being filled with a medium having a dielectric constant of at least 10, wherein the transmitting antenna and receiving antenna extend near the wall of the housing and in that at least that section of the reflector which is located diametrically opposite the transmitting antenna and receiving antenna, respectively, likewise extends near the wall of the housing.