A wind turbine system and to a method for operating said system is disclosed. The system further comprises a detection device configured for detecting body waves generated by an earthquake. In one aspect, the present disclosure is directed to a system comprising a wind turbine, in particular to an onshore erected wind turbine, a wind turbine controller for controlling the wind turbine, and at least one detection device, which is connected to the wind turbine controller for transmitting signals. The wind turbine includes at least a rotor having at least one rotor blade, wherein the rotor is rotatably mounted to rotation support means of the wind turbine, and a tower having a top end for supporting the rotation support means and a support end. The detection device is configured to detect and measure earthquake generated primary waves (P-waves). The detection device may include at least one sensor or a plurality of sensors, wherein the sender is configured to detect and/or measure earthquake generated P-waves. Such sensor may be further configured to detect an acceleration caused by the earthquake using a built-in accelerometer and then to calculate and output a synthetic acceleration, and to provide an estimated Japan Meteorological Agency seismic intensity scale (shindo scale) value.

Embodiments of determining a vertically transverse isotropy (VTI) anisotropy along a horizontal section of a wellbore drilled into a formation are provided. One embodiment comprises determining elastic constants C11, C44, and C66 of the horizontal section and determining a vertical compressional slowness of the horizontal section corresponding to an elastic constant C33 of the horizontal section using a model with a condition. The model is built using second sonic log data and second density log data of the vertical wellbore. The condition is that the shear slowness (DTS) of the vertical wellbore is equal to the vertically polarized shear slowness (DTSV) of the horizontal section. The embodiment further comprises determining a VTI anisotropy along the horizontal section using the elastic constants C11, C44, C66, and C33 of the horizontal section.

An apparatus includes a mechanical wave source; a set of mechanical wave sensors in a borehole to provide subsurface wave measurements based on formation waves from the mechanical wave source, and a processor. The apparatus also includes a machine-readable medium having program code to acquire the subsurface wave measurements, select a first set of tool wave measurements based on the subsurface wave measurements, and generate a set of filtered subsurface wave measurements by filtering the subsurface wave measurements based on the first set of tool wave measurements. The program code also includes instructions to generate a time-domain semblance map based on the set of filtered subsurface wave measurements, wherein the time-domain semblance map includes an initial set of compression wave peaks, determine a selected qualified compression wave peak based on a semblance value in the time-domain semblance map, and determine a compression wave slowness based on the selected qualified compression wave peak.

Methods of oil and gas exploration that may include: obtaining wavefield data representing recordings from a propagating wavefield through a geophysical volume; obtaining at least one reference digital image of a portion or all of the geophysical volume generated from the recorded wavefield data, wherein the reference image may have a reference sampling ratio and a reference image quality value; selecting a holographic computational method of imaging the wavefield data; selecting a data subset from the wavefield data based on one or more parameters selected from the group consisting of field sampling, imaging sampling, and image quality; decimating the data subset, wherein the decimated data subset may represent a sampling ratio less than the reference sampling ratio; and generating a new digital image based on the selected holographic computational method of imaging, the data subset, and parameters corresponding to the data sub set.

A method and system for measuring a compressional and a shear slowness. The method may comprise disposing a downhole tool into a wellbore. The downhole tool may comprise a transmitter, wherein the transmitter is a monopole, and a receiver, wherein the receiver is a monopole receiver. The method may further comprise broadcasting the sonic waveform into the formation penetrated by the wellbore, recording a reflected wave on one or more receivers, wherein the reflected wave is a compressional wave or a shear wave, processing the reflected wave into at least one measurement, and applying a validation scheme to the at least one measurement. The system may be a downhole tool comprising a transmitter configured to transmit a sonic waveform into a formation, wherein the transmitter is a monopole, and a receiver configured to record a reflected wave, wherein the receiver is a monopole receiver.

A method may comprise: disposing an acoustic logging tool in a wellbore, wherein the acoustic logging tool comprises a transmitter and a receiver; emitting a flexural wave from the transmitter; recording a four component dipole waveform with the receiver, wherein the four component dipole waveform comprises XX, XY, YX, and YY components; rotating the four component dipole waveform using Alford rotation to produce rotated waveform components, wherein the rotated waveform components comprise XX.sub.Θ, XY.sub.Θ, YX.sub.Θ, and YY.sub.Θ components; comparing a travel time of XX.sub.Θ and YY.sub.Θ components to identify a fast wave and a slow wave from the rotated waveform components; processing the fast wave and the slow wave using high-resolution data-driven processing to obtain a fast wave flexural dispersion curve and a slow wave flexural dispersion curve; determining a frequency dependent anisotropy curve using the fast wave flexural dispersion curve and the slow wave flexural dispersion curve; and determining a low-resolution shear anisotropy.

A method of at least partially deghosting recorded seismic s-waves, wherein recorded seismic data is provided, wherein the recorded seismic data has been recorded at a receiver located beneath the Earth's surface, and wherein the recorded seismic data includes s-wave data. The method may include the steps of finding a model of the Earth's crust for use in deghosting the recorded seismic data using the s-wave data, wherein the model includes at least one region and wherein the model includes the Earth's surface and the location of the receiver, using the model to find a deghosting operator that, when applied to the s-wave data, at least partially deghosts the s-wave data, and applying the deghosting operator to the s-wave data to at least partially deghost the s-wave data.

A method is disclosed for radiaiiy profiling shear velocities of flexural wave modes in a formation. The method includes establishing sensitivity kernels with two non-dimensionalized parameters and using said sensitivity kernels to perform an inversion for radial shear wave velocity profiles. This method may be used for LWD, MWD, or wireline logging operations.

Rock reservoir structure characterization method comprises: acquiring a three-dimensional seismic data volume of a rock reservoir to be characterized; performing a transformation on all the intrinsic mode function components obtained through decomposition to obtain time-frequency spectrum of each intrinsic mode function component, and adding the time-frequency spectrums of all the components to obtain the time-frequency spectrums of the seismic data; performing cross-correlation between each of the time-frequency components of the near-well seismic traces and the synthetic seismic trace obtained by logging data of the same well, and screening out a sensitive component with the highest correlation degree as an input feature, and performing fuzzy C-means clustering and spatial smoothing on the sensitive component with the highest correlation degree to obtain a seismic facies with set standard division; and depicting the rock reservoir according to the seismic facies divided by the set standard.

PP and PS seismic data are jointly inverted in a stratigraphic grid, using different time axes for PP and PS reflections. A ratio of PP and of PS waves'travel times inside a same layer cell maintained to be a function of a ratio of a P-wave propagation velocity and of an S-wave propagation velocity therein. Since PP and PS seismic amplitudes and travel times are due to elastic properties of the same structure, they can be inverted at the same time to provide better estimates of these elastic properties.