Electromagnetic survey systems and methods with rotation-corrected motion compensation

摘要

A disclosed electromagnetic survey system includes one or more streamer(s) having multiple electromagnetic sensors and motion sensing units. Each motion sensing unit has one or more accelerometer(s) to measure motion perpendicular to an axis of the streamer, and a rotation sensor to measure rotation about the axis. The measurements of the accelerometer are adjusted based on measurements from the rotation sensor. The survey system also includes one or more processor(s) that determine, for each electromagnetic sensor, a motion signal based on the adjusted measurements. A described electromagnetic survey method includes processing acceleration and rotational motion measurements to obtain an orientation of motion sensing units as a function of time. The measured acceleration is manipulated based on the orientation to obtain one or more velocity signal(s) for each motion sensing unit. Interpolation is performed on the velocity signals to determine at least one velocity signal for each electromagnetic sensor.

主权项

1. An electromagnetic survey system with motion-induced noise voltage compensation comprising:
a pair of source electrodes with electric voltage applied between them; a towed streamer with an electromagnetic sensor pod that includes an electromagnetic sensor to detect an electromagnetic field parameter and to output a corresponding voltage signal indicative of an electromagnetic sensor measurement; a motion sensing unit associated with the electromagnetic sensor, wherein the motion sensing unit comprises,
an accelerometer to measure acceleration motion perpendicular to an axis of said streamer; anda rotation sensor to measure rotational motion about said axis; and at least one processor that determines for the electromagnetic sensor:
a motion signal as a function of time based at least in part on measured acceleration motion perpendicular to the axis and measured rotational motion about the axis, anda corrected electromagnetic sensor measurement from at least the voltage signal and the motion signal, wherein the corrected electromagnetic sensor measurement represents removal of an estimated motion-induced noise voltage from the voltage signal.