An integrated seismic system and method for monitoring seismic parameters of a subsurface structure is provided. The integrated seismic system includes a base station; a plurality of mobile satellite nodes, each of the plurality of mobile satellite nodes having sensor stations for collecting seismic data from the subsurface structure; and a fiber optic cable extending from the base station to the plurality of mobile satellite nodes and operatively linking the plurality of mobile satellite nodes and the sensor stations; the base station comprising: a light source for sending a light through the fiber optic cable, the light being distributed to the sensor stations and, in the sensor stations, experiencing a change or phase shift related to a physical property being measured; and a seismic acquisition unit for receiving seismic signals from the plurality of mobile satellite nodes via the fiber optic cable and generating seismic parameters therefrom.

A system to obtain information about a subsurface formation, in some embodiments, comprises an array of acoustic transmitters in a first well; a distributed acoustic sensing (DAS) fiber in a second well; and processing logic, in communication with the array of acoustic transmitters and the DAS fiber, that activates the array of acoustic transmitters and the DAS fiber so as to use the Doppler effect to obtain information about the subsurface formation.

A housing for a seismic sensor station has a base and a removable lid, which when assembled together form a shell whereby the base and the removable lid both have a shell side and an exterior side. A sensor spike, protruding outward from the shell, may be attached to the base on the exterior side of the base. The housing is further provided with two cable docking ports, each allowing passage of a fiber optical cable from outside to inside the shell. The two cable docking ports are exclusively provided in the removable lid.

One embodiment includes receiving distributed acoustic sensing (DAS) data for responses associated with seismic excitations in an area of interest. The area of interest includes a sea surface, the water column, a seafloor, and a subseafloor. The seismic excitations are generated by at least one seismic source in the area of interest. The responses are detected by at least one fiber optic sensing apparatus configured for DAS that is in the water column, on the seafloor, in a wellbore drilled through the seafloor and into the subseafloor, or any combination thereof. The embodiment includes determining a function of speed of sound in water using the DAS data, and correcting a digital seismic image associated with the area of interest using the function of speed of sound in water to generate a corrected digital seismic image.

An example method includes at least partially positioning within a wellbore an optical fiber of a distributed acoustic sensing (DAS) data collection system. Seismic data from the DAS data collection system may be received. The seismic data may include seismic traces associated with a plurality of depths in the wellbore. A quality factor may be determined for each seismic trace. One or more seismic traces may be removed from the seismic data based, at least in part, on the determined quality factors.

A well system includes a fiber optic cable positionable downhole along a length of a wellbore and a reflectometer communicatively coupleable to the fiber optic cable. The reflectometer detects and locates a microseismic event using strain detected in reflected optical signals received from the fiber optic cable. Further, the reflectometer computes a set of spectra for waveforms of the microseismic event. Additionally, the reflectometer aggregates each spectrum from the set of spectra that meet an acceptance threshold to generate an aggregate spectrum. Furthermore, the reflectometer applies a fault source model to the aggregate spectrum to determine a magnitude of the microseismic event.

A down-hole apparatus comprises a unitary seamless section defining a chamber, a clamping section to engage a fiber optic cable, actuator electronics enclosed in the chamber, and an actuator to acoustically couple the actuator electronics to the fiber optic cable. The apparatus can include a temperature sensor, a microphone, or a geophone, enclosed by the chamber. The actuator can be an acoustic emitter or a piezoelectric device. The apparatus could be battery-operated by a battery enclosed in the chamber. A sensor enclosed within the chamber could be powered by signals propagated within the fiber optic cable. Additional apparatus, methods, and systems are disclosed.

An optical monitoring system comprising first and second sensor arrays interrogated via first and second optical connections from an interrogator location. The system is configured such that no wavelength is carried bi-directionally in the first and second optical connections. In typical systems the optical connections comprise trunk cables from the sensor arrays to the interrogator location.

Systems and methods may be used to reconstruct particle velocity wavefields from coupling-calibrated fiber-optic data that subsequently enables physically valid construction of the particle velocity wavefields for a hybrid sensor array including both fiber-optic and particle motion sensors. These systems and methods may be used in a variety of borehole geophysical applications, such as structure and reservoir imaging, impedance inversion, attenuation tomography, micro-seismic fracture imaging, focal mechanism analysis, and so on. The systems and methods may also be used in other applications such as geothermal and CO2 storage monitoring.

Fiber optic cable structures suitable for distributed acoustic sensing that are capable of discriminating between stimuli acting on the cable in different directions, the cable structure including a core structure (202, 203, 204) with an optical fiber wound around the periphery of the core structure, the core further including a mass (203) which is movable in a preferred direction within the cable such that movement of said mass in said preferred direction causes a change in length of the fiber wound around the periphery of the core.