Reducing casing wave effects on sonic logging data by positioning two or more receivers in a borehole in a subsurface formation; receiving, at two or more receivers in a borehole in a subsurface formation, a first signal associated with a first acoustic signal originating from a first transmitter position; receiving, at the two or more receivers, a second signal associated with a second acoustic signal originating from a second transmitter position; creating a dataset based on the first signal and the second signal; identifying casing wave signals in the dataset based at least in part on the second signal; calculating inverse-phase casing wave signals based at least in part on the casing wave signals and the second signal; and reducing effects of the casing wave signals on the dataset using the inverse-phase casing wave signals.

The present disclosure provides a diffracted wave imaging method, device and electronic apparatus. The method comprises: acquiring pre-stack seismic wave field data of a to-be-processed area; extracting target data of a target imaging point; fitting target time sample points in the target data based on the Gaussian model and solving the fitting function to determine a distribution range of the stationary point position signal of the reflected wave in the target data; determining migration imaging data of the target imaging point based on the target data and the distribution range; and determining a diffracted wave imaging result of the to-be-processed area based on the migration imaging data of all the imaging points in the to-be-processed area.

A monitoring system according to the present disclosure includes an optical fiber (10) laid on a ground or a seabed, an optical fiber sensing unit (21) configured to receive an optical signal from the optical fiber (10) and detect a vibration produced in the ground or the seabed based on the optical signal, and an analyzing unit (22) configured to identify a natural phenomenon that has caused the detected vibration based on a unique pattern of the detected vibration.

A system and method for forming a denoised seismic image of a subterranean region of interest is provided. The method includes obtaining an observed seismic dataset for a subterranean region of interest and forming a plurality of common midpoint gathers having a plurality of traces, each trace having an ordinate series of sample values, a common-midpoint location and a unique value of a secondary sorting parameter. The method further includes, for each of the plurality of common midpoint gathers, selecting a set of spatially adjacent common midpoint gathers using a spatial windowing operator and determining a weighted midpoint gather based on the common midpoint gather and the set of spatially adjacent common midpoint gathers. The method still further includes forming a denoised seismic dataset by combining the weighted midpoint gathers using an inverse spatial windowing operator and forming the denoised seismic image based on the denoised seismic dataset.

The present invention pertains to the fields of geology and geophysics, is designed for use for onshore seismic acquisition. The method involves distributing and arranging the elements used in the acquisition of two-dimensional seismic data from dynamite sources, enabling imaging quality to be improved. The use of sources of dynamite with single charges and variable weight at each shot point results in the generation of seismic waves with variable energy that provide reflections with complementary frequency and amplitudes content for use in the geophysical imaging of geological features. The stacking of this incremental content generated by charges of variable weights results in a significant improvement in the resolution of the processed seismic data on both the continuity of stratigraphic reflectors and existing geological framework.

In some implementations, a system may receive a cable map for a deployed cable. The system may receive vibration data indicating a vibration associated with a first section of the cable. The system may determine a characteristic associated with the first section of the cable based on the vibration. The system may determine a location associated with the characteristic based on the cable map. The system may determine that the first section of the cable is associated with the location based on the location being associated with the characteristic. The system may associate the location and a length of a second section of the cable extending from an initial location to the location. The system may receive an input identifying the length of the second section of the cable and may output the location based on associating the location and the length of the second section of the cable.

A method of estimating a position of a well path within a subsurface formation of the Earth, the method comprising determining a well path estimate using navigation measurements from a downhole tool and a position estimate derived from seismic data. A method of geosteering comprising: estimating a position of the well path and controlling a drill bit in response to the estimated position of the well path to follow a desired well trajectory.

A method can include, using a downhole tool, acquiring ultrasonic echo data of a borehole, where the ultrasonic echo data include echoes representative of material and borehole geometry responsive to reflection of ultrasonic energy that has a wide-band frequency range; filtering the ultrasonic echo data using at least one selected filter for multi-band frequency filtering corresponding to different frequency ranges of the wide-band frequency range to generate filtered data; and processing the filtered data to generate attribute values representative of physical characteristics the material, the borehole geometry, or the material and the borehole geometry.

A method and system for analyzing a seismically active field based on expansion of an empirical orthogonal function is provided. The research region of the seismic active field is gridded at equal intervals for the preset research region of a seismic active field; a seismic active field function matrix correlated with the research region of the seismic active field spatially and temporally is constructed according to the gridding of the research region of the seismic active field; and the seismic active field function matrix is expanded with an empirical orthogonal function to obtain a main typical field and a temporal factor thereof, and an anomaly on the temporal factor of the seismic active field is analyzed with a method index, a parameter index and an anomaly index.

A method is described for seismic depth uncertainty analysis including receiving wavelet basis functions and cutoff thresholds and randomly perturbing wavelet coefficients in reduced wavelet space based on the wavelet basis functions and the cutoff thresholds to generate a plurality of random wavelet fields; receiving a reference model in a depth domain; transforming the plurality of random wavelet fields to the depth domain and combining them with the reference model to form candidate models; performing a hierarchical Bayesian modeling with Markov Chain Monte Carlo (MCMC) sampling methods using the candidate models as input to generate a plurality of realizations; and computing statistics of the plurality of realizations to estimate depth uncertainty. The method may be executed by a computer system.