Embodiments herein describe a seismic source that includes a reservoir configured to hold compressed gas, a first firing head coupled to the reservoir where the first firing head configured to generate seismic energy by releasing a first portion of the compressed air from the reservoir to form a first gas bubble in a seismic medium, and a second firing head coupled to the reservoir where the second firing head configured to generate seismic energy by releasing a second portion of the compressed gas from the reservoir to form a second gas bubble in the seismic medium. Moreover, at least one first fill line is coupled directly to the reservoir.

Apparatus for the generation of pressure waves for seismic surveys in marine environment comprising a cylinder (3), defining an axis, in which a striker piston (1) and a pump piston (2) are situated, each having two respective opposite sides with respect to said axis, of which a side of the striker piston (1) situated in front of the pump piston (2) is defined first impact side, and a side of the pump piston (2) in front of the striker piston (1) is defined second impact side, the pump piston (2) and the striker piston (1) sliding in the cylinder (3) in a direction parallel to the axis, and the pump piston (2) and striker piston (1) being such as to strike against each other, by means of the first and the second impact sides, the striker piston (1) being driven by activation means pressing on the side opposite to its own impact side, wherein the cylinder (3) comprises, at one of its ends, a chamber (15) having a diameter larger, smaller or equal to that of the portion of cylinder (3) in which the striker piston (1) is housed, wherein in said chamber (15) a part of the pump piston (2) can slide, communication passages which connect the chamber (15) with the water of the marine environment (10), so as to transmit an impulse generated by said impact to the marine environment.

Apparatus for the generation of pressure waves for seismic surveys in marine environment comprising a cylinder (3), defining an axis, in which a striker piston (1) and a pump piston (2) are situated, each having two respective opposite sides with respect to said axis, of which a side of the striker piston (1) situated in front of the pump piston (2) is defined first impact side, and a side of the pump piston (2) in front of the striker piston (1) is defined second impact side, the pump piston (2) and the striker piston (1) sliding in the cylinder (3) in a direction parallel to the axis, and the pump piston (2) and striker piston (1) being such as to strike against each other, by means of the first and the second impact sides, the striker piston (1) being driven by activation means pressing on the side opposite to its own impact side, wherein the cylinder (3) comprises, at one of its ends, a chamber (15) having a diameter larger, smaller or equal to that of the portion of cylinder (3) in which the striker piston (1) is housed, wherein in said chamber (15) a part of the pump piston (2) can slide, communication passages which connect the chamber (15) with the water of the marine environment (10), so as to transmit an impulse generated by said impact to the marine environment.

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.

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.

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.

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.

The shear head device includes a monitoring head having geophones and transmitters inside a cylindrical body. A shear head is coupled to the monitoring head from below. The shear head has a tubular structure with a plurality of apertures formed around an outer surface of the tubular structure. A plurality of cones are coupled with modified tips and disposed within the plurality of apertures. A sheet supports the plurality of cones inside the shear head. The sheet is selectively movable between a first radial position and a second radial position for the modified tips to apply radial force to the rock by adjustment of an internal pressure of the shear head. The transmitters transmit the recorded acoustic emission to a computing system for determining properties of the rock while the shear head device is testing the rock in the bore.

The embodiments herein describe a seismic source that includes at least two firing heads connected to a shared reservoir of compressed gas. When underwater, a controller can instruct the firing heads to fire at the same time or at different times to create gas bubbles that generate seismic energy for identifying structures underneath a body of water. If the firing heads fire at the same, the resulting gas bubble may coalesce to form a single bubble, depending on the size of the respective bubbles and the separation distance between the firing heads. In one embodiment, the firing heads are attached at opposite ends of the shared reservoir (although this is not a requirement). The length of the reservoir, which dictates in part the separation distance of the firing heads, can be set so that gas bubbles generated by the firing heads at substantially the same time coalesce.

A lift based acoustic source is towable in an undersea environment by a towing vessel. A controller provides a combined lift control signal and an acoustic source signal. A control cable is joined between the towing vessel and a towed depressor having an active lift control system. The combined signal is used to control the towed depressor active lift control system. The towed depressor lift fluctuates in response to the source signal to generate the undersea acoustic signal. A hydrophone or hydrophone array can be provided for measuring the generated acoustic signal for feedback and monitoring.