Noise-cancelling streamer cable
AssigneeTeledyne Exploration Company
InventorCarl O. Berglund
Life of this patent
Estimating the term…
Abstract
In a seismic streamer cable, stress sensors are co-located with the hydrophones in the cable. The stress sensors are responsive to mechanical stresses applied to the cable but it are substantially unresponsive to acoustic waves propagating in fluid media. The signal outputs from the stress sensors are combined with the signal outputs from the corresponding co-located hydrophones to cancel spurious signals due to bulge waves.
Claims13
A seismic cable section for use in a body of water, the cable section including an elongated, flexible, tubular jacket that contains a volume of floatation fluid, comprising:
- first means, mounted within said cable section, for generating electrical output signals in response to acoustic waves;
- second means, mounted in said cable section adjacent said first means, for generating electrical output signals in response to mechanical stress induced in said flexible tubular jacket;
- and
- third means for recombining the electrical output signals from said second means, in opposite polarity, with the electrical signals from said first means.
A seismic cable section for use in a body of water, the cable section including an elongated, tubular, flexible jacket containing a volume of floatation fluid, comprising:
- a plurality of spaced-apart hydrophones mounted within said jacket for providing electrical signals in response to acoustic waves propagating in fluid media;
- a corresponding plurality of hollow, cylindrical, spaced-apart stress sensors mounted adjacent each said hydrophone, the external surface of each said stress sensor being in physical contact with the inner surface of said flexible jacket, said stress sensors providing an electrical signals in response to radially-applied mechanical forces, said stress sensors being substantially unresponsive to acoustic waves propagating in a fluid medium;
- signal-receiving means electrically coupled to said hydrophones and to said stress sensors;
- and
- means incorporated with said signal-receiving means for combining, in opposite polarity, electrical signals from said stress sensors with electrical signals received from said hydrophones.
In a seismic streamer cable for use in a body of water, a method for dynamically cancelling spurious signals resulting from mechanical stress applied to said cable, comprising:
- detecting acoustic waves propagating in fluid media and converting said detected acoustic waves to a first time-varying electrical signal wave train having a characteristic signature;
- measuring the magnitude of mechanical stresses applied to the cable and converting the measurements to a second time-varying electrical signal wave train having a characteristic signature;
- and
- subtracting said second electrical signal wave train from said first electrical signal wave train.
Dependencies are inferred from the claim text.