Antenna of an electromagnetic probe for investigating geological formations

摘要

An antenna 3 of an electromagnetic probe used in investigation of geological formations GF surrounding a borehole WBH comprises a conductive base 31 and an antenna element 32. The conductive base 31 comprises an opened non-resonant cavity 33. The antenna element 32 is embedded in the cavity 33 and goes right through the cavity. The antenna element 32 is isolated from the conductive base 31. The antenna element 32 is coupled to at least one electronic module via a first 34A and a second 34B port, respectively. The electronic module operates the antenna so as to define either a substantially pure magnetic dipole, or a substantially pure electric dipole.

主权项

1. An antenna (3) of an electromagnetic probe used in investigation of geological formations (GF) surrounding a borehole (WBH) comprising a conductive base (31) and an antenna element (32), the conductive base (31) comprising an opened non-resonant cavity (33), the antenna element (32) being embedded in the cavity (33) and going right through the cavity, the antenna element (32) being isolated from the conductive base (31), the antenna element (32) being coupled to at least one electronic module via a first (34A) and a second (34B) port, respectively, the electronic module configured to apply a current distribution to the antenna element via one or more of the first and second ports, such that the antenna is operated in a substantially pure magnetic dipole when the current distribution is applied to the antenna such that current increases from a first end of the antenna to a middle portion of the antenna, and then decreases from the middle portion of the antenna to a second end of the antenna, and a substantially pure electric dipole when the current distribution is applied to the antenna such that current increases from the first end of the antenna to the second end of the antenna.