A method for identifying a seismic event includes extracting a portion of a plurality of seismic data signals based on energy levels in the plurality, comparing the extracted portion to a known pattern and determining a correlation, and identifying the seismic event based on the correlation. A computer program product and devices for implementing the method are provided.

Time lapse or 4D seismic data are corrected for geologic overburden and seismic recording system effects. The data from a survey at one time of interest is processed within a selected frequency band and the reservoir level is normalized by the overburden. The results are used to extract reservoir amplitudes from the data of that same survey. Frequencies where overburden signal-to-noise ratios vary dramatically between time lapse surveys may then be avoided in processing of data from the area of interest.

A hydrophone has a pair of end caps each disposed on a different open end of an air-backed cylinder of a piezoelectric ceramic material. An electrode or lead extends through one of the end caps and into the cylinder, and has a shape and a lateral width that extends across an interior of the cylinder and abuts an inner surface of the cylinder at multiple points.

The invention comprises a method for mapping a volume of the Earth's subsurface encompassing a selected path within said volume, comprising dividing the volume of the Earth's subsurface into a three-dimensional grid of voxels and transforming detected seismic signals representing seismic energy originating from said volume of the Earth's subsurface when no induced fracturing activity is occurring along said selected path and conducted to a recording unit for recording into signals representing energy originating from the voxels included in said grid of voxels, and utilizing said transformed seismic signals to estimate spatially continuous flow paths for reservoir fluids through said volume of the Earth's subsurface to said selected path.

A method for processing seismic data includes receiving, by a seismic data processing system, signals representing seismic data recorded at a remote location. In addition, the method includes receiving, by the seismic data processing system, identification of a sensor via which the signals were acquired. Further, the method includes retrieving, by the seismic data processing system, a sensor transfer function that corresponds to the sensor and relates the motion of the sensor to the signals. The method also includes generating, by the seismic data processing system, based on the sensor transfer function and a reference transfer function, an inverse filter that when applied to the signals changes parameters of the signals to correspond to the reference transfer function. Moreover, the method includes applying, by the seismic data processing system, the inverse filter to the signals to conform the parameters of the signals to the reference transfer function.

A distributed acoustic sensing method that includes sending a sequence of optical pulses along an optical fiber, of at least two different widths, demodulating backscattered light from the optical fiber to obtain interferometric phase measurements as a function of position, combining the interferometric phase measurements to obtain a set of fade-resistant phase measurements, and storing or displaying the set of fade-resistant phase measurements. A distributed acoustic sensing system that includes a transmitter that sends a sequence of optical pulses along an optical fiber, of at least two different widths, a receiver that demodulates backscattered light from the optical fiber to obtain interferometric phase measurements as a function of position and combines interferometric phase measurements to obtain a set of fade-resistant phase measurements, and a storage or display device.

Embodiments relate to a sensor cable that may be reconfigurable to have various combinations of seismic sensors. An apparatus may comprise a sensor cable and seismic sensors distributed throughout a volume of the sensor cable and along all three axes of the sensor cable, wherein the seismic sensors are assigned to sampling groups that are reconfigurable and not hardwired.

Computer systems and methods are provided for seismic wavefield processing, including time domain reconstructed full wavefield inversion (TDRFWI) of seismic survey data. Suitable methods include forward propagating a source signal based on a model of a subsurface region, generating a residual based on the forward-propagated wavefield in comparison to field data, back propagating the residual to generate a reconstructed source perturbation, and adding the reconstructed source perturbation to the source signal to generate a reconstructed source wavefield. The reconstructed source perturbation can be forward propagated to generate a reconstructed wavefield perturbation, and added to the reconstructed wavefield perturbation to reconstruct the wavefield. The propagations can be performed in the time domain, and the model can be updated based on the reconstructed wavefield and reconstructed source perturbation to generate high fidelity subsurface images.

A method for generating acoustic waves under water includes actuating first and second pistons with an actuator system provided inside an enclosure of a source element, to generate a wave having a first frequency, and actuating the first and second pistons with a pressure mechanism attached to the enclosure, to control a pressure of a fluid inside the enclosure such that a pressure of the fluid is substantially equal to an ambient pressure of the enclosure. The enclosure has first and second openings and the first and second pistons are configured to close the first and second openings.

Systems, methods, and apparatuses related to coupling an autonomous seismic node to the seabed. In one embodiment, the node may comprise a plurality of holes on a bottom surface of the node and a plurality of openings on one or more sides and/or surfaces of the node. The bottom surface may comprise a coupling plate that is coupled to the node and/or coupled to a housing or casing that substantially surrounds a pressure node housing. The node may be configured to route water vertically from the bottom holes through the side openings and/or upper holes to decrease the potential of cavitation and fluidization of the seismic sediment and increase the seismic coupling of the node to the seabed.