Methods and systems, including computer programs encoded on a computer storage medium can be used for identifying primary-wave (P-wave) and secondary-wave (S-wave) characteristics of an underground formation by separating P-wave and S-wave modes of seismic data generated by applying a seismic source to a subterranean region of a geological area. Particle motion vectors of a P-wave are parallel to a propagation vector of the P-wave, whereas particle motion vectors of an S-wave are perpendicular to a propagation vector of the S-wave. The parallel and perpendicular relationship between the motion and propagation vectors of the respective P- and S-waves provide a basis for separating P- and S-wave components from a wavefield. The separation methodology extracts P-wave components and S-wave components from the wavefield based on an estimated angle between propagation vectors and wave motion vectors for the wavefield.

Methods and systems including computer programs encoded on a computer storage medium, for utilizing equivalent linear velocity for first arrival picking of seismic refraction. In one aspect, a method includes receiving data for the shot gather record, generating a diving wave equation curve for a particular parameter pair of multiple parameter pairs, and integrating the shot gather record data corresponding to the diving wave equation curve over a selected range of offsets of the shot gather to generate an equivalent linear velocity value for the particular parameter pair and the shot gather record data, selecting, from the equivalent linear velocity values for the plurality of parameter pairs, a greatest equivalent linear velocity value of the equivalent linear velocity values, the greatest equivalent linear velocity value corresponding to a first-arrival parameter pair, and determining, using the first-arrival parameter pair, a set of first-arrival onsets for the selected sub-range of offsets.

A seismic warning system comprises: a plurality of sensors, each sensor sensitive to a physical phenomenon associated with seismic events and operative to output an electronic signal representative of the sensed physical phenomenon; a data acquisition unit communicatively coupled to receive the electronic signal from each of the plurality of sensors, the data acquisition unit comprising a processor configured to estimate characteristics of a seismic event based on the electronic signal associated with a P-wave from each of the plurality of sensors; and a local device communicatively coupled to the data acquisition unit. The plurality of sensors, the data acquisition unit and the local device are local to one another.

A method for processing vertical seismic profiling (VSP) data is provided. The method includes receiving VSP data in response to seismic energy applied to the formation, processing a down-going portion of the VSP data associated with a down-going wave field, outputting a first set of estimation values based on processing the down-going portion of the VSP data, the first set of estimation values estimating at least one of slowness or velocity, processing an up-going portion of the VSP data associated with an up-going wave field, outputting a second set of estimation values based on processing the up-going portion of the VSP data, the second set of estimation values estimating at least one of slowness or velocity, and determining an estimation associated with the formation based on the first and second sets of estimation values.

A system for self-tuning sonic transmitters which transmits a plurality of frequencies into a downhole formation, then identifies which of the transmitted frequencies generates the best response from the formation. The system then uses the best frequency identified for subsequent logging of formation data until a subsequent tuning sequence is initiated.

A method for automatically locating microseismic events based on a deep belief neural network and coherence scanning includes the following steps: randomly selecting data of one three-component geophone; performing arrival time picking and phase identification of microseismic events on the data thereof using a deep belief neural network; and then, on the basis of the obtained arrival time and phases, performing coherence scanning and positioning imaging using the microseismic data received by all three-component geophones. In the image, the space position representing the highest stacking energy may be considered as a real space position where the microseismic events occur, implementing the automatic and accurate locating of the microseismic events.

Reservoir sweep efficiency includes obtaining fluid front arrival times for streamlines in a reservoir. A wellbore is partitioned into independent production zones, and a target flowrate is allocated to each of the independent production zones based on the fluid front arrival times. Partition choke parameters complying with the target flowrates are allocated to generate a completion design, which is presented.

Some implementations relate to a computer-implemented method for creating digital acoustic sensing (DAS) related training data for a learning machine. The method may include moving a first optimal microseismic event location to a first perturbed microseismic event location in each of a plurality of first images. The method also may include modifying first shear waves and first compressional waves in each of the first images based on one or more signal travel times between the first perturbed microseismic event location and a fiber optic cable to form a plurality of training images configured to train a learning machine.

A computer-implemented method can include the following. Seismic vibratory waves through the Earth along a selected vector path are received. An initial value is selected for a first arrival for each of the seismic vibratory waves. Initial values are determined for travel times and velocities of the seismic vibratory waves. Reversed signs of amplitudes of the seismic vibratory waves are determined and corrected. Time intervals are determined based on the initial values of the travel times. Time windowing and filtering in a frequency domain are performed. Final values are determined for first arrivals and travel times for each of the seismic vibratory waves based on the time windowing and filtering. Final values are determined for velocities of the seismic vibratory waves.

A method for borehole measurements may comprise receiving one or more signals from a linear receiver array, computing an arctan of a Hilbert Transform, isolating a first arriving energy, selecting a reference instantaneous phase on a reference receiver, finding the reference instantaneous phase for the linear receiver array, computing a relative travel time shift, combining a reference pick time with a relative time, and determining a travel time. A system for borehole measurements comprise a conveyance, a bottom hole assembly attached to the conveyance, a linear receiver array, wherein the linear receiver array is disposed on the bottom hole assembly, and a computer system connected to the linear receiver array.