Detecting motion induced noise in towed electromagnetic streamers

摘要

An electromagnetic sensor streamer 12 may include a jacket, at least one electromagnetic sensor E in operational communication with a voltage measuring circuit V1,V2 disposed inside the jacket, and at least one wire coil A,B,C,D. The at least one wire coil is in signal communication with the voltage measuring circuit, and the voltage measuring circuit is configured to determine motion-induced voltages imparted to the at least one electromagnetic sensor in the streamer. This is used to correct detected electromagnetic signals from subsurface formations for the effect of motion induced voltages. The wire coil(s) may be wound on the exterior of the jacket, on a buoyancy spacer or on a sensor holder (32, Fig 4). The electromagnetic sensor may include a pair of electrodes E. Different coils may be wound in different orientations (A1, Fig4; A2, Fig 5) so that components of the motion of the streamer both along and transverse to the axis of the streamer can be determined.