Seismic vibrator having composite baseplate

#In a geophysical survey, a seismic source can be carried by a truck and positioned at a predetermined location in an area of exploration. The seismic source can be a single axis vibratory source and can impart compressing P-waves into the earth once coupled to the earth and operated. A vibrator 10 according to the prior art is illustrated in FIG. 1A and is diagrammatically illustrated in FIG. 1B. The vibrator 10 transmits force into the ground using a baseplate 20 and a reaction mass 50.

#As is typical, the vibrator 10 is mounted on a carrier vehicle (not shown) that uses a mechanism and bars 12/14 to lower the vibrator 10 to the ground. With the vibrator 10 lowered, the weight of the vehicle holds the baseplate 20 engaged with the ground so seismic source signals can be transmitted into the earth. The reaction mass 50 positions directly above baseplate 20 and stilts 52 extend from the baseplate 20 and through the mass 50 to stabilize it.

#Internally, the reaction mass 50 has a cylinder 56 formed therein. A vertically extending piston 60 extends through this cylinder 56, and a head 62 on the piston 60 divides the cylinder 56 into upper and lower chambers. The piston 60 connects at its lower end to a hub in a lower cross-piece 54L and extends upward through the cylinder 56. The piston 60's upper end connects to a hub on an upper cross-piece 54U, and the cross pieces 54U-L connect to the stilts 52.

#FIG. 1A shows a vibrator according to the prior art in a perspective view.

#FIG. 1B schematically illustrates the prior art vibrator of FIG. 1A.

#FIGS. 2A-2C illustrate the baseplate for the prior art vibrator in plan, side, and end-section views.

#A. Seismic Vibrator

#FIGS. 3A-3D show perspective, front, side, and cross-sectional views of a seismic vibrator 100 according to certain teachings of the present disclosure. The vibrator 100 has a frame 110, a moveable reaction mass 150, and a baseplate 200. The frame 110 and mass 150 can be constructed mainly of metal, such as steel or the like. By contrast, the baseplate 200 is at least partially composed of a composite material as described in more detail later.

#In general, the vibrator 100 transmits force to the ground using the baseplate 200 and the reaction mass 150, and the vibrator 100 can operate similar to the vibrator detailed previously with reference to FIGS. 1A-1B. As is typical, for example, the vibrator 100 is mounted on a carrier or vehicle (not shown) that uses the frame 110 to lower the vibrator 100 to the ground. With the vibrator 100 lowered, the weight of the vehicle holds the baseplate 200 engaged with the ground so seismic source signals can be transmitted into the earth during operation. Other details of how the vibrator 100 couples to the ground with a vehicle or other carrier are well known in the art and not detailed herein.