Earth vibrators, such as servo-hydraulic vibrators, are improved to produce more output force and less distortion at very low frequencies by capturing mass from the vehicles which carry them, adding sufficient inertial mass to the reaction mass without adding much vehicle and equipment weight while also avoiding increases to the servo-hydraulic vibrator's stroke length. In particular, improvements to servo-hydraulic vibrators, at low frequencies, will couple some mass from the carrier vehicle frame and its load using non-rigid coupling only when additional mass is needed using dampers connected between the reaction mass and the carrier vehicle's frame, with the added damping being applied by a control system at very low frequencies of output where the vibrator is otherwise unable to produce force equal to its hold-weight.

A seismic shaker is described, the seismic shaker comprising:a base plate;an electromagnetic motor comprising a mover and a stator, the stator being mounted to the base plate, anda guiding mechanism comprising a plurality of rods connecting the stator to the mover, the guiding mechanism being configured to enable a displacement of the mover relative to the stator in a first direction and restrict a displacement in a plane substantially perpendicular to the first direction.

A seismic shaker is described, the seismic shaker comprising:a base plate;an electromagnetic motor comprising a mover and a stator, the stator being mounted to the base plate, anda guiding mechanism comprising a plurality of rods connecting the stator to the mover, the guiding mechanism being configured to enable a displacement of the mover relative to the stator in a first direction and restrict a displacement in a plane substantially perpendicular to the first direction.

The present disclosure discloses a seismic vibrator, a vibration device and a driving apparatus for the same. The seismic vibrator comprises: a base; a mounting plate; a first spring configured to connect the base and the mounting plate, so that the mounting plate reciprocates relative to the base; a coil fixed with the base; a magnet having one end fixed with the mounting plate, and the other end stretched into the coil; a magnetic steel fixed with the magnet, wherein a gap for accommodating the coil is provided between the magnetic steel and the magnet; and a counterweight fixed with the mounting plate. The vibration device comprises the above seismic vibrator and an adjustable base. Compared with the traditional electromagnetic controllable seismic vibrator, the structure of the seismic vibrator provided by the present disclosure is simpler.

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.

A device for identifying the location of pipe is disclosed. The device includes a motor shaft attached at one end to a motor and attached at the other end to a weight; a flexible push rod attached at one end to a tip assembly and attached at the other end to a reel; a power source for powering the motor; and a tip assembly. The tip assembly is threaded into one end of a pipe. As the motor turns the motor shaft, the motor shaft causes the weight to oscillate. As the weight oscillates it causes the tip assembly to vibrate. As the tip assembly vibrates it emits auditory sounds.

A device for identifying the location of pipe is disclosed. The device includes a motor shaft attached at one end to a motor and attached at the other end to a weight; a flexible push rod attached at one end to a tip assembly and attached at the other end to a reel; a power source for powering the motor; and a tip assembly. The tip assembly is threaded into one end of a pipe. As the motor turns the motor shaft, the motor shaft causes the weight to oscillate. As the weight oscillates it causes the tip assembly to vibrate. As the tip assembly vibrates it emits auditory sounds.

A seismic source apparatus, configured to be maneuvered by a vehicle over terrain.

A dipole source for borehole acoustic logging includes a cylindrical shell, a center beam coupled to the cylindrical shell, a movable projector inside the cylindrical shell to impact the center beam, and a cavity acoustically insulating the interior of the cylindrical shell from the exterior of the cylindrical shell. An acoustic logging tool for making measurements of a substrate surrounding a borehole with a body insertable in the borehole is also provided. The body includes an acoustic detector and a dipole source as above, along the axial length. The acoustic logging tool may include a control unit to process data collected from the acoustic detector and obtain information about the substrate surrounding the borehole.

A dipole source for borehole acoustic logging includes a cylindrical shell, a center beam coupled to the cylindrical shell, a movable projector inside the cylindrical shell to impact the center beam, and a cavity acoustically insulating the interior of the cylindrical shell from the exterior of the cylindrical shell. An acoustic logging tool for making measurements of a substrate surrounding a borehole with a body insertable in the borehole is also provided. The body includes an acoustic detector and a dipole source as above, along the axial length. The acoustic logging tool may include a control unit to process data collected from the acoustic detector and obtain information about the substrate surrounding the borehole.