WELL MONITORING

摘要

Downhole water level detecting apparatus for detecting the level of water in a formation in the region of a well installation. The detecting apparatus comprises a transmitter (21) for applying electrical signals to a signalling loop at a first location. The signalling loop comprises downhole metallic structure of the well installation (1) and an earth return. The detecting apparatus also includes a detector (31) for monitoring electrical signals in the signalling loop, and an evaluation unit (32) arranged for determining a level of water in the formation relative to the downhole metallic structure in dependence on the monitored signals.