Electric Dipole Surface Antenna Configurations for Electromagnetic Wellbore Instrument Telemetry

A method for detecting an electromagnetic signal originating in a wellbore, comprising:

• measuring a voltage induced in at least one electric dipole antenna comprising a pair of electrodes spaced apart by a first distance and having a midpoint therebetween spaced from a surface of the wellbore by a second distance, and at least one of;
• a) shielding an electrical connection between each electrode and an input of a detector circuit, the shielding connected so as to produce common mode noise rejection in the detector circuit,
• b) measuring a voltage induced across a second pair of spaced apart electrodes spaced apart by one half the first distance and having a midpoint therebetween spaced √2/2 times the second distance from the surface of the wellbore and electrically connected in opposed polarity to the at least one electric dipole antenna,
• c) measuring a voltage induced across a second pair of electrodes spaced apart by the first distance and having a common point with and being orthogonal to the at least one electric dipole antenna and electrically connected to the at least one electric dipole antenna, and
• d) wherein the at least one electric dipole antenna is disposed in a second wellbore, the second wellbore having substantially no electrically conductive pipe therein.

A method for wellbore measurement, comprising:

• moving a wellbore instrument forming part of a drill string along an interior of a wellbore;
• making a measurement of at least one parameter using a sensor disposed in the wellbore instrument;
• generating an electromagnetic field in the wellbore, the electromagnetic field comprising encoded signals corresponding to measurements made by the sensor in the wellbore instrument;
• and
• detecting the electromagnetic field at a selected location away from the wellbore, the detecting comprising measuring a voltage induced in at least one electric dipole antenna comprising a pair of electrodes spaced apart by a first distance and spaced at a midpoint therebetween from a surface of the wellbore by a second distance, and at least one of;
• a) shielding an electrical connection between each electrode and an input of a detector circuit, the shielding connected so as to produce common mode noise rejection in the detector circuit,
• b) measuring a voltage induced across a second pair of spaced apart electrodes spaced apart by one half the first distance and having a midpoint therebetween spaced √2/2 times the second distance from the surface of the wellbore and electrically connected in opposed polarity to the at least one electric dipole antenna,
• c) measuring a voltage induced across a second pair of electrodes spaced apart by the first distance and having a common midpoint with and being orthogonal to the at least one electric dipole antenna and electrically connected to the at least one electric dipole antenna, and
• d) wherein the at least one electric dipole antenna is disposed in a second wellbore, the second wellbore having substantially no electrically conductive pipe therein.