Patent ID: 11920466
Assignee: WELLDATA (SUBSURFACE SURVEILLANCE SYSTEMS) LIMITED
Field: Civil engineering (Other fields)
Classification: CPC E  G | IPC E  G

Claim 14:
15. An apparatus as claimed in claim 14, wherein, in use, in a transmission path, an electromagnetic signal propagates from the transmitter through the second tube, the second tube extends through the wellhead and/or the Christmas tree, in said transmission path, the electromagnetic signal propagates through a connector, in said transmission path the electromagnetic signal propagates through the first tube until a fluid/fluid interface(s) is met, at said fluid/fluid interface the electromagnetic signal is at least partially reflected, the reflected electromagnetic signal then propagating through the first tube, the connector, and the second tube in a received path, the reflected signal being received by the receiver, and
the electromagnetic signal comprises a microwave signal, a millimetre or radio signal; and
the electromagnetic signal comprises a TE-nn, TEnn or TEMnn mode.