Wireless telemetry through drill pipe

摘要

The present disclosure relates to a telemetry tool for use in a well. The telemetry tool has a hollow, conductive waveguide through which a non-conductive fluid can flow. A transmitter and a receiver are disposed in the hollow interior of the waveguide, separated by some desired distance. A signal is transmitted by the transmitter, propagated by the waveguide, and received by the receiver.

主权项

1. A telemetry tool for use in a well, comprising:
a cylindrical conductive waveguide for providing two-way communication of data and having an interior wherein the cylindrical conductive waveguide comprises drill pipe; a non-conductive fluid within the interior of the waveguide wherein the non-conductive fluid is oil based mud or air; a receiver disposed in the interior of the waveguide; a system for determining a cutoff frequency; and a transmitter disposed in the interior of the waveguide some distance from the receiver; the transmitter transmitting a microwave signal into the interior of the waveguide and using the drill pipe to propagate the microwave signal from the transmitter to the receiver, wherein the waveguide propagates the microwave signal between an uphole wireless interface and a downhole wireless interface and the microwave signal being above the cutoff frequency and having a frequency of 1.0 GHz or greater; and the cutoff frequency is calculated by using a following relation,fc,n⁢⁢m=C⁢⁢pn⁢⁢m′2⁢π⁢⁢awherein C is the speed of light, a is the inner radius of the conductive waveguide, modes with magnetic and electric field patterns are characterized by two indices, m and n;
p′nm is the mth root of the equation:ⅆⅆr⁢Jn⁡(kc⁢r)=0 where Jn(kcr) is the Bessel function of the first kind and nth order, and kc is given by,
kc=(2π*fc)/C fc is the cutoff frequency for a mode.