An apparatus includes particle motion sensors and a streamer that contains the particle motion sensors. The streamer is towed in connection with a seismic survey, and the towing of the streamer produces a turbulent flow. The streamer includes an inner cable and a fluid containing layer. The inner cable includes a material to circumscribe and extend along a longitudinal axis of the streamer and circumscribe at least one of the particle motion sensors. The fluid containing layer surrounds the inner cable to reduce noise that is otherwise sensed by the particle motion sensors due to the turbulent flow.

A sonar device intended to be towed by a surface ship and includes a tow cable and a set of at least one towed device, comprising a towed body, intended to be towed by the surface ship via the tow cable, the towed body being elongate along a longitudinal axis from a first longitudinal end of the towed body as far as a second longitudinal end of the towed body, the towed body incorporating a first linear acoustic antenna comprising a plurality of electroacoustic transducers substantially aligned along the longitudinal axis, the towed device being configured and connected to the tow cable in such a way that the towed body is able, when it is being towed and is fully submerged, to exhibit an orientation the longitudinal axis extends substantially along a vertical axis defined by the force of gravity, at least one towed body of the set of towed bodies being connected to the tow cable by a first hanger and a second hanger of substantially the same length, a first end of the first hanger and a first end of the second hanger being connected to the tow cable and a second end of the first hanger being attached to the towed body at a fixing point of the towed body which point is situated near the first longitudinal end and a second end of the second hanger being attached to the towed body at a second fixing point secured to the first fixing point and situated near the second longitudinal end.

A downhole seismic array is disclosed. The array comprises a load-bearing cable for carrying a series of seismic sensor units arranged along its length. Each seismic sensor unit is attached to the load-bearing cable via a vibration-absorbing material and has a magnet to attach the seismic sensor unit to the well casing.

A deployment module according to the present application enables both compact stowage of a sensor array and expansion of the sensor array into a three-dimensional volumetric array shape that enables improved directionality of the sensors during operation. The deployment module includes a support shell that is configured to retain a cable of the sensor array separately from sensors of the sensor array and an expandable deployment body formed of a superelastic shape memory alloy that uses superelasticity and stored energy for deployment of the sensor array. During deployment, the deployment body is removed from the support shell and the sensors are subsequently pulled out of the support shell. The deployment body then expands and holds the cable to retain the three-dimensional volumetric shape of the deployed array.

Embodiments may be directed to marine geophysical surveying and associated methods. At least one embodiment may be directed to incorporation of a lock mechanism in a sensor streamer that interlocks the outer jacket with one or more of the spacers to prevent relative rotation between the outer jacket. An embodiment may provide a sensor streamer that includes an outer jacket, a plurality of spacers, and a locking mechanism. The outer jacket may be elongated in an axial direction and comprise an outer jacket surface and an inner jacket surface. The plurality of spacers may be positioned in the outer jacket at spaced apart locations in the axial direction, wherein each of the plurality of spacers comprises a spacer body having an outer spacer surface. The locking mechanism may interlock the outer jacket with at least one of the plurality of spacers.

A seismic survey system is provided. The system can include a source array including a first sub-source array and a second sub-source array. The system can include a streamer coupled with the first sub-source array and a streamer coupled with the second sub-source array. The system can include a receiver array including a plurality of receivers. The system can include a lateral cable coupled with at least one of a first diverter or a second diverter and at least one of the first sub-source array or the second sub-source array. The system can include a positioning cable coupled with the first diverter and a positioning cable coupled with the second diverter. The system can include a power cable. The system can include a seismic data acquisition unit array including a plurality of seismic data acquisition units disposed on a seabed.

An attachment system for releasably attaching a sensor node to a cable when in a coupled state includes a clamp base and a clamp grip. The clamp base is fixed to a surface of the sensor node. The clamp base further includes a latch that is biased in a latched position when the attachment system is in both the coupled state and an uncoupled state. The clamp grip is pivotably attached the clamp base and biased in an open position when the attachment system is in the uncoupled state. The clamp grip is secured to the clamp base by the latch when the attachment system is in the coupled state.

A method for calculating a velocity vp(f, T.sub.opt) of a spatially aliased wave that propagates along a cable includes tensioning the cable, wherein plural sensors are distributed along the cable; measuring with the plural sensors a parameter that is associated with vibrations that propagate along the cable; calculating a phase velocity vp(f) of the spatially aliased wave that propagates along the cable, as a function of a time frequency fin a spatial-temporal frequency domain FK; calculating a model-based velocity vp(f, T) of the spatially aliased wave as a function of the time frequency f and a tension T in the cable; and calculating the velocity vp(f, T.sub.opt) of the spatially aliased wave using a model-guided regression, which is based on the phase velocity vp(f) and the model-based velocity vp(f, T). The velocity vp(f, T.sub.opt) is a function of the temporal frequency f.

Various embodiments include apparatus and methods implemented to take into consideration gauge length in optical measurements. In an embodiment, systems and methods are implemented to interrogate an optical fiber disposed in a wellbore, where the optical fiber is subjected to seismic waves, and to generate a seismic wavefield free of gauge length effect and/or to generate a prediction of a seismic wavefield of arbitrary gauge length, based on attenuation factors of a plurality of wavefields acquired from interrogating the optical fiber. In an embodiment, systems and methods are implemented to interrogate an optical fiber disposed in a wellbore, where the optical fiber is subjected to seismic waves, and to convert a seismic wavefield associated with a first gauge length to a seismic wavefield associated with a different gauge length that is a multiple of the first gauge length. Additional apparatus, systems, and methods are disclosed.

In certain embodiments, an assembly has intermediate pods magnetically, but not galvanically, coupled along an electrically conductive cable. Each pod has a magnetic core surrounding and inductively coupled to the cable and one or more coils inductively coupled to the magnetic core. The pod transmits, for example, outgoing current pulses on the cable by inducing electrical signals in the cable using a transmitter coil and the magnetic core. In addition, the pod repeats, for example, incoming current pulses on the cable by inducing electrical signals in the cable using the transmitter coil and the magnetic core, based on electrical signals induced in a receiver coil via the magnetic core by the incoming current pulses. Such an assembly can function as a data collection system for scientific research and/or as an early-warning system for events, such as earthquakes and tsunamis, without having to modify the cable itself.