Patent ID: 6556014
Filing Date: 2003-04-29
Classification: G01V,Y02A

Abstract:
A device for detecting changes in resistivity or dielectrical properties in the near-well area around a well in a geological formation, comprising:a tubing string, the tubing string being electrically conductive and having a linear dimension with a first end and a second end; an electrical energy source; a signal generator electrically coupled to the electrical energy source, the signal generator being capable of generating electrical signals; a transmitter antenna coupled to the tubing string in a fixed first position and electronically coupled to the signal generator, the transmitter antenna configured to emit electromagnetic waves guided along the tubing string, and having an impedance; a receiver antenna coupled to the tubing string in a fixed second position a distance along the linear dimension apart from the fixed first position of the transmitter antenna, the receiver antenna being capable of receiving electromagnetic waves along the tubing string; a canceling device coupled to the tubing string and positioned near the receiving antenna, the canceling device being capable of canceling in the receiving antenna the electromagnetic waves emitted by the transmitter antenna; a device for receiving signals induced in the receiver antenna by received electromagnetic waves, the device for receiving signals being electronically coupled to the receiver antenna; a signal processing device electronically coupled to the device for receiving signals, the signal processing device being capable of providing a processed signal output; and a communication device electronically coupled to the signal processing device, the communication device being capable of transmitting signals representing the processed signal output and receiving a control signal.