Well data transmission system using a magnetic drill string.

摘要

A well data transmitting system for use in transmission of a data signal representative of a drilling parameter sensed by a sensor (16) in a drill string (13) of a magnetic material at a bottom of the well drilled by the drill string to a surface station (17) mounted on the earth's surface. A carrier wave is modulated by the data signal and is then applied to a transmitting coil wound on the bottom portion of the drill string to generate a magnetic flux signal induced in the drill string material. The magnetic flux signal is picked up as an electric signal at a coil disposed around an exposed end of the drill string on the earth's surface. The electric signal is equivalent to the modulated signal and is demodulated so that the data signal can be obtained on the earth's surface. The obtained data signal is recorded in a recorder and is processed in a data processor for controlling well drilling operation. When a plurality of sensors are disposed at the well bottom, a sensor selecting signal is transmitted to the bottom as a similar magnetic flux signal through the drill string material.