Drill pipe telemetering system with electrodes exposed to mud

DETAILED DESCRIPTION It is therefore an object of the invention to provide a pipe section with telemetering means that do not require cleaning of the exposed electrical metal parts thereof prior to making up the joints of a pipe string consisting of such pipe sections.
It is a further object of the invention to provide a pipe section with telemetering means, which pipe section can be manufactured relatively easily and at relatively low cost.
The pipe section according to the invention has an inner wall defining a throughbore and terminating at the ends thereof with mechanical coupling means adapted for effecting detachable interconnection with adjoining identical pipe sections.
The pipe section is provided with electrical transmission means comprising electrode means located near the ends of the section, with an insulated electrical conduit interconnecting said electrode means, and with an amplifier connected with said insulated electrical conduit.
The electrode means are insulated with respect to the pipe section and are arranged to electrically cooperate with the electrode means of the adjoining identical pipe sections.
In this interconnected position of adjoining pipe sections, the electrode means are situated in a space that communicates with the said throughbore or the exterior of the pipe sections.
It is observed that the electrode means of pipe sections according to the present invention will be in contact with borehole fluid such as drilling fluid, when a pipe string having these pipe sections included therein is used in a bore hole or well.
The electric signals that should be passed between the sender-electrode and the receiver-electrode of each pair of electrically cooperating electrodes carried by adjoining sections will thereby partly leak away via the bore hole fluid to the metal bodies of the pipe sections, and only for part thereof be received by the receiver-electrode.
The reduction in signal strength is compensated in each pipe section by the amplifier that is included in the electrical transmission means of the pipe section