Marine seismic vibrator for low frequency and methods of use
AssigneePGS Geophysical AS
InventorStig Rune Lennart Tenghamn
Life of this patent
Estimating the term…
Abstract
Disclosed are devices and methods for marine geophysical surveying. An example device may comprise a shell, a base plate, wherein the base plate is coupled to the shell, a driver disposed within the shell, an inner spring element disposed within the shell, wherein the inner spring element is coupled to the driver, wherein outer ends of the inner spring element are coupled to outer ends of the inner spring element at spring element junctions, an outer spring element disposed within the shell, wherein outer ends of the outer spring element are coupled to the spring element junctions, and a back mass disposed on the outer spring element.
Claims19
A marine seismic vibrator comprising:
- a shell;
- a base plate, wherein the base plate is coupled to the shell;
- a driver disposed within the shell;
- an inner spring element disposed within the shell, wherein the inner spring element is coupled to the driver;
- an outer spring element disposed within the shell, wherein outer ends of the outer spring element are coupled to outer ends of the inner spring element at spring element junctions;
- and
- a back mass disposed on the outer spring element, wherein the inner spring element and the outer spring element are configured to propagate acoustic waves of opposite polarity.
A marine seismic vibrator comprising:
- a shell;
- a base plate, wherein the base plate is coupled to the shell;
- a linear motor disposed within the shell;
- a moving mass disposed within the shell, wherein a mass of the base plate is less than a mass of the moving mass;
- and
- a spring positioned between the moving mass and the base plate, wherein the spring is coupled to the base plate on one end and to the moving mass on the opposite end.
A method for operating a marine seismic vibrator to generate acoustic waves with opposite polarity:
- towing a marine seismic vibrator through a body of water;
- operating a driver of the marine seismic vibrator to cause an inner spring element of the marine seismic vibrator to move back and forth relative to a base plate of the marine seismic vibrator, the driver being coupled to the base plate;
- and
- transferring movement of the inner spring element to cause an outer spring element of the marine seismic vibrator together with a back mass disposed on the outer spring element to also move back and forth relative to the base plate;
- generating a down-going wave in the body of water and an up-going wave in the body of water, wherein the down-going wave and the up-going wave have opposite polarity;
- reflecting the up-going wave off of a water surface of the body of water to provide a reflected wave, wherein the reflected wave has the same polarity as the down-going wave;
- and
- combining the reflected wave with the down-going wave to produce a composite wave in the body of water.
A method for marine seismic surveying comprising:
- towing a marine seismic vibrator through a body of water;
- operating a linear motor of the marine seismic vibrator to cause a moving mass of the marine seismic vibrator to move back and forth relative to a base plate of the marine seismic vibrator thereby generating acoustic waves with opposite polarity, the linear motor being coupled to the base plate;
- and
- applying a force with a spring to the moving mass that opposes a force produced from the linear motor, wherein the spring is positioned between the moving mass and the base plate, wherein the spring is coupled to the base plate on one end and to the moving mass on the opposite end.
Dependencies are inferred from the claim text.