Combination motion and acoustic piezoelectric sensor apparatus and method of use therefor
AssigneeSeamap USA, LLC
InventorRichard E. Pearce
Life of this patent
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Abstract
Sensors used in mapping strata beneath a marine body are described, such as used in a flexible towed array. A first sensor is a motion sensor including a conductive liquid in a chamber between a rigid tube and a piezoelectric motion film circumferentially wrapped about the tube. A second sensor is a traditional acoustic sensor or a novel acoustic sensor using a piezoelectric sensor mounted with a thin film separation layer of flexible microspheres on a rigid substrate. Additional non-acoustic sensors are optionally mounted on the rigid substrate for generation of output used to reduce noise observed by the acoustic sensors. Combinations of acoustic, non-acoustic, and motion sensors co-located in rigid streamer housing sections are provided.
Claims22
A method for collecting seismic data, the method comprising:
- towing a seismic streamer through a marine body above a marine body floor and below a marine body surface of the marine body, wherein the seismic streamer further comprises a plurality of sensors and a streamer cable coupled to the sensors, and wherein at least one of the sensors further comprises an acoustic-motion sensor that has an acoustic sensitivity to acoustic energy in the marine body and a vertical sensitivity to gravitationally vertical acceleration of the acoustic-motion sensor;
- generating a shock wave in the marine body within an acoustic range of the seismic streamer, wherein, responsive to the shock wave, a first seismic wave is reflected from the marine body floor and a second seismic wave is reflected from strata layers below the marine body floor, wherein the first seismic wave reflects off the marine body surface to generate a third seismic wave that propagates downward from the marine body surface towards the streamer cable, and wherein the third seismic wave interferes with the first seismic wave at the streamer cable;
- detecting the first seismic wave and the second seismic wave using the acoustic-motion sensor to generate an acoustic signal responsive to the acoustic sensitivity;
- detecting the third seismic wave using the acoustic-motion sensor to generate a vertical acceleration signal responsive to the vertical sensitivity;
- combining the acoustic signal and the vertical acceleration signal to improve a signal-to-noise ratio of the acoustic signal responsive to the acoustic sensitivity;
- and
- cancelling noise in the acoustic signal from turbulent flow around the seismic streamer using a combined output of a first portion and a second portion of an acoustic piezoelectric film enabling the acoustic sensitivity, wherein the first portion is attached using a first adhesive loaded with flexible microspheres to enable force sensitivity of the first portion to deformation from the turbulent flow, and wherein the second portion is not attached using the flexible microspheres.
A method for collecting seismic data, the method comprising:
- detecting, at an acoustic-motion sensor located in a marine body, a first seismic wave and a second seismic wave to generate an acoustic signal, wherein the first seismic wave and the second seismic wave are reflected from a marine body floor of the marine body upwards towards the acoustic-motion sensor, and wherein the first seismic wave is reflected from the marine body floor and the second seismic wave is reflected from strata layers below the marine body floor;
- detecting a third seismic wave using the acoustic-motion sensor to generate a vertical acceleration signal, wherein the third seismic wave is the first seismic wave reflected from a marine body surface of the marine body downwards towards the acoustic-motion sensor;
- combining the acoustic signal and the vertical acceleration signal to improve a signal-to-noise ratio of the acoustic signal;
- and
- cancelling noise in the acoustic signal from turbulent flow around the acoustic-motion sensor using a combined output of a first portion and a second portion of an acoustic piezoelectric film, wherein the first portion is attached using a first adhesive loaded with flexible microspheres to enable force sensitivity of the first portion to deformation from the turbulent flow, and wherein the second portion is not attached using the flexible microspheres.
Dependencies are inferred from the claim text.