A hydrophone has a mandrel with a shell and a cylindrical cavity inwardly adjacent to the shell. A passage provides fluid communication between the cylindrical cavity and an exterior environment surrounding the mandrel. The hydrophone further has an optical fiber having an optical sensing section that is at least partially wound on the mandrel. The optical sensing section has an optical characteristic that varies as a function of a radial dimension of the mandrel. The mandrel has a core of solid material having a bulk modulus lower than 0.1 GPa. The cylindrical cavity is between the core and the shell.

Ocean bottom seismic nodes formed of a non-metallic pressure housing that is substantially cuboid shaped, which may be formed of an injection molded plastic. The seismic node may have a detachable hydrophone housing that encloses a hydrophone and protects one or more external electrical connectors, which may have electrical connections that are substantially flat and flush with the hydrophone housing. A modular baseplate may be coupled to a bottom portion of the seismic node. A weight ballast may be positioned between the node housing and the modular baseplate. A mounting bracket may be coupled to an exterior portion of the seismic node without any direct fasteners.

An improved hydrophone is presented that has extremely low acceleration sensitivity, hermetic sealing, and is self-shielded. The hydrophone can also contain an integral amplifier and pressure/depth limiting switch. The hydrophone is also designed such that it can use a single standard piezoelectric sensing element in many hydrophone designs that have different acoustic pressure sensitivities but the same capacitance. Lastly, the sensor is also designed to be low cost in high volumes using standard accelerometer manufacturing techniques. A hydrophone is also designed such that it can use a single standard piezoelectric sensing element that can be incorporated into several hydrophone configurations with varying acoustic pressure sensitivities. The sensor is also designed to be low cost in high volumes.

According to one example, a floodable sensor station is coupled to an optical cable. The optical cable may be floodable. The floodable sensor station may connect floodable optical cables as part of a permanent reservoir monitoring system. The floodable optical cable may house a plurality of floodable optical fiber conduits. The floodable sensor station may be pressure-balanced with its surrounding environment in high-pressure marine depths of 1500 meters or more.

An improved hydrophone is presented that has extremely low acceleration sensitivity, hermetic sealing, and is self-shielded. The hydrophone can also contain an integral amplifier and pressure/depth limiting switch. The hydrophone is also designed such that it can use a single standard piezoelectric sensing element in many hydrophone designs that have different acoustic pressure sensitivities but the same capacitance. Lastly, the sensor is also designed to be low cost in high volumes using standard accelerometer manufacturing techniques. A hydrophone is also designed such that it can use a single standard piezoelectric sensing element that can be incorporated into several hydrophone configurations with varying acoustic pressure sensitivities. The sensor is also designed to be low cost in high volumes.

Method, source array and source element that generate seismic waves. The source element includes an enclosure having an opening covered by a piston; a local supply accumulator fluidly communicating with an interior of the enclosure, a pressure of the fluid inside the local supply accumulator being larger than a pressure of the fluid inside the enclosure; a local supply valve located between the local supply accumulator and the enclosure and configured to control a flow of the fluid from the local supply accumulator to the interior of the enclosure; and a controller configured to control the local supply valve such that the pressure inside the enclosure does not fall below a first preset value based upon an ambient pressure of the enclosure while seismic waves are generated.

Disclosed embodiments provide techniques for automated passive acoustic monitoring with machine learning. An acoustic sensor is accessed. The acoustic sensor includes an embedded acoustic controller which hosts a machine learning model. The acoustic sensor is coupled to one or more hydrophones. The acoustic sensor is deployed in a body of water and is submerged. The acoustic sensor can enter a sleep mode. The hydrophones receive an underwater audio signal. The audio signal can be associated with an acoustic pressure. The acoustic sensor can be woken from sleep when the acoustic pressure is above a pressure threshold. The machine learning model classifies a predicted source of the underwater audio signal. The classifying can be based on filtering the underwater audio signal for a first frequency band associated with a source of interest. The predicted source is reported to a user using a communications device.

Method, source array and source element that generate seismic waves. The source element includes an enclosure having an opening covered by a piston; a local supply accumulator fluidly communicating with an interior of the enclosure, a pressure of the fluid inside the local supply accumulator being larger than a pressure of the fluid inside the enclosure; a local supply valve located between the local supply accumulator and the enclosure and configured to control a flow of the fluid from the local supply accumulator to the interior of the enclosure; and a controller configured to control the local supply valve such that the pressure inside the enclosure does not fall below a first preset value based upon an ambient pressure of the enclosure while seismic waves are generated.

An improved hydrophone is presented that has extremely low acceleration sensitivity, hermetic sealing, and is self-shielded. The hydrophone can also contain an integral amplifier and pressure/depth limiting switch. The hydrophone is also designed such that it can use a single standard piezoelectric sensing element in many hydrophone designs that have different acoustic pressure sensitivities but the same capacitance. Lastly, the sensor is also designed to he low cost in high volumes using standard accelerometer manufacturing techniques. A hydrophone is also designed such that it can use a single standard piezoelectric sensing element that can be incorporated into several hydrophone configurations with varying acoustic pressure sensitivities. The sensor is also designed to be low cost in high volumes.

Method, source array and source element that generate seismic waves. The source element includes an enclosure having an opening covered by a piston; a local supply accumulator fluidly communicating with an interior of the enclosure, a pressure of the fluid inside the local supply accumulator being larger than a pressure of the fluid inside the enclosure; a local supply valve located between the local supply accumulator and the enclosure and configured to control a flow of the fluid from the local supply accumulator to the interior of the enclosure; and a controller configured to control the local supply valve such that the pressure inside the enclosure does not fall below a first preset value based upon an ambient pressure of the enclosure while seismic waves are generated.