Downhole water level detecting apparatus and method

摘要

Water level monitoring apparatus for detecting the level in a formation in the region of a well installation. The detecting apparatus comprises a transmitter 21 for applying electrical signals to a signaling loop at a first location. The signaling loop comprises downhole metallic structure of the well installation 1 and an earth return. The monitoring apparatus also includes a detector 31 for monitoring electrical signals in the signaling loop. Evaluation unit 32 determines the level of water in the formation relative to the downhole metallic structure using the monitored signals. The detector may be located at a second location of the signaling loop. The detector may be arranged to measure signals in the metallic structure between two spaced contacts. The detector may inject signals into the tubing of the well. The detector may be located at the surface. There may be relay stations comprising additional receivers and transmitters.