Apparatus for providing electrical signals to be transmitted between a device located inside the well pipe and a region outside the pipe and the process of transmitting electrical energy signals between a device located inside a well pipe and a region outside the pipe

摘要

PCT No. PCT/GB95/01174 Sec. 371 Date Feb. 3, 1997 Sec. 102(e) Date Feb. 3, 1997 PCT Filed May 23, 1995 PCT Pub. No. WO96/00836 PCT Pub. Date Jan. 11, 1996Apparatus for enabling electric signals to be transmitted between a device such as a sonde (46) positioned inside a tubing (38) of a well (30) and a region outside the tubing. In a preferred embodiment the apparatus comprises a transmitter coil (58) in the sonde (46) and a receiver coil (42) coupled to the tubing (38). The sonde (46) is coupled via wireline (48) to the surface and the receiver coil (42) is also coupled to the surface via a permanently installed cable (44). At least one measurement instrument (56) is located in the sonde such that measurement signals passed to said transmitter (58) are coupled to said receiver coil (42) and to the surface. The transmitter and receiver permit bidirectional communication and electrical power can be transmitted from the surface via said permanently installed cable such that single-phase or multi-phase power can be transmitted to drive downhole equipment, which may be coupled to the sonde.