An autonomous underwater vehicle (AUV) is configured to record seismic signals during a marine seismic survey. The AUV includes a body having a base (B) and first and second sides (A, C), the body having a head part and a tail part; a propulsion system for guiding the AUV to a final target on the ocean bottom; a seismic sensor configured to record seismic signals; and an anchoring system configured to rock or twist the base in a given sequence so that the base (B) penetrates into the ocean bottom.

An exemplary aspect comprises a self contained acoustic beacon comprising: (a) an acoustic transducer; (b) an acoustic amplifier; and (c) a depth calculator. An exemplary aspect comprises a self contained acoustic beacon comprising: (a) an acoustic transducer; (b) an acoustic amplifier; (c) a water sensor; and (d) a battery life controller. An exemplary aspect comprises a self contained acoustic beacon comprising: (a) an acoustic transducer; (b) an acoustic amplifier; (c) a water sensor; and (d) a waterproof cover with at least one water-dissolvable portion, wherein the water-dissolvable portion dissolves within a pre-determined period of time, and wherein the beacon is powered on when water is detected by the water sensor.

Disclosed is an ocean bottom seismic node for recording seismic signals on the seabed. The ocean bottom seismic node may comprise an arched cathedral buoyant body coupled to a substantially flat bottom metal plate. The buoyant body may be formed of hard plastic (such as plastic injection in a mold) and have one or more cathedral type inner structures with columns that form a plurality of interconnected inner chambers, which may be dry or filled with foam and/or act as ballasts. One or more electronic components may be directly attached to the bottom metal plate (and within one or more of the internal cathedral chambers) and covered/protected by the buoyant body that is water and pressure resistant at seabed depths. The edge(s) of the buoyant body may seal around the metal plate on one or more peripheral edges of the plate and buoyant body.

The present disclosure is directed to a helical conveyor for underwater seismic exploration. The system can include a case having a cylindrical portion. A cap is positioned adjacent to a first end of the case. A conveyor having a helix structure is provided within the case. The conveyor can receive an ocean bottom seismometer (“OBS”) unit at a first end of the conveyer and transport the OBS unit via the helix structure to a second end of the conveyor to provide the OBS unit on the seabed to acquire the seismic data.

The present disclosure is directed to loading a helical conveyor for underwater seismic exploration. The system includes a case and a first conveyor having a helix structure provided within the case to support one or more ocean bottom seismometer (“OBS”) units. The case can include a first opening at a first end of the first conveyor and a second opening at a second end of the first conveyor. The system can include a base to receive at least a portion of the case. The system can include a second conveyor positioned external to the case that can move an OBS unit into the first opening at the first end of the first conveyor. The first conveyor can receive the OBS unit and direct the OBS unit towards the second opening at the second end of the first conveyor.

The present disclosure is directed to a helical conveyor for underwater seismic exploration. The system can include a case having a cylindrical portion. A cap is positioned adjacent to a first end of the case. A conveyor having a helix structure is provided within the case. The conveyor can receive an ocean bottom seismometer (“OBS”) unit at a first end of the conveyer and transport the OBS unit via the helix structure to a second end of the conveyor to provide the OBS unit on the seabed to acquire the seismic data. The system can include a propulsion system to receive an instruction and, responsive to the instruction, facilitate movement of the case.

The present disclosure is directed to a skid structure for underwater seismic exploration. The system can include an underwater vehicle comprising a skid structure. A conveyor is provided in the skid structure. The conveyor includes a first end and a second end opposite the first end. A capture appliance is provided at the first end of the conveyor. The capture appliance includes an arm to close to hold a case storing one or more ocean bottom seismometer (“OBS”) units, and to open to release the case. The capture appliance includes an alignment mechanism to align an opening of the case with the first end of the conveyor. A deployment appliance can be at the second end of the conveyor. The deployment appliance can place an OBS unit of the one or more OBS units onto the seabed to acquire seismic data from the seabed.

The present disclosure is directed to underwater seismic exploration with a helical conveyor and skid structure. The system can include an underwater vehicle comprising a sensor to identify a case having a hydrodynamic shape, wherein the case stores one or more ocean bottom seismometer (“OBS”) units. The underwater vehicle includes an arm. The underwater vehicle includes an actuator to position the arm in an open state above a cap of the case, or to close the arm. The underwater vehicle can move the arm to a bottom portion of the case opposite the cap. An opening of the case can be aligned with the conveyor of the underwater vehicle. The conveyor can receive, via the opening of the case, a first OBS unit of the one or more OBS units. The conveyor can move the first OBS unit to the seabed to acquire seismic data from the seabed.

The present application described methods an apparatus for locating and/or monitoring subsea cables (101) having an optical fibre (105) deployed along its length. The optical fibre (105) is connected to a distributed acoustic sensing (DAS) interrogator unit to interrogate the optical fibre to provide a fibre optic DAS sensor. To locate the cable an acoustic stimulus is transmitted into the water from one or more known locations. The time of arrival of an acoustic signal matching the stimulus at the sensing portions of the DAS fibre can be detected and used to determine information about the location of those sensing portions to the known location. The DAS signals returns can also be monitored under ambient conditions to detect any signals indicative of likely damage to the cable.

A method of performing a seismic survey including: deploying nodal seismic sensors at positions in a survey region; activating a plurality of seismic sources; and using the nodal seismic sensors to record seismic signals generated in response to the activation of the plurality of signals.