Halliburton Energy Services, Inc.

Chevron U.s.a. Inc.

Kristoffer Thomas Walker

Ruijia Wang

Chung Lung Chang

Baichun Sun

Batakrishna Mandal

David Andrew Barfoot

Mark Elliott Willis

Richard Timothy Coates

Andreas Ellmauthaler

Mark Vincent Collins

John Philip Granville

Brian Edward Hornby

Joonshik Kim

Grant Philip Goodyear

Alexei Olegovich Bolshakov

Yunfei Yang

A method is described for method of processing seismic data including obtaining seismic data, wherein the seismic data was acquired with a plurality of azimuthal receiver elements of a logging-while-drilling tool while a drill bit is drilling a wellbore; decomposing the seismic data into monopole and dipole modes; cross-correlating each receiver pair of the monopole mode and of the dipole mode to generate monopole and dipole waveforms; identifying a time of direct arrival of acoustic energy from the drill bit and applying bulk time shift for the waveforms; stacking corresponding waveforms from the bulk time shift to improve signal-to-noise ratio; processing the stacked monopole and dipole waveform to isolate reflected arrivals; performing migration to obtain a monopole migrated image and a dipole migrated image; and classifying the interface as either a fracture or an impedance contrast. The method is executed by a computer system.

System and method for seismic imaging around wellbores

Apparatus, methods, and systems for determining acoustic velocity behind casing or tubing in a subterranean wellbore. A method may include obtaining a plurality of waveform data sets corresponding to a plurality of propagation path regimes and obtaining a total wavefield across the receiver array. The method may also include determining a Green's function representing each of the plurality of propagation path regimes and determining a noise wavefield by convolving the Green's functions and a known transmitted pressure signal corresponding to the plurality of waveform data sets. The method may also include generating a reduced-noise wavefield by subtracting the noise wavefield from the total wavefield and estimating the acoustic velocity of a formation behind the casing or tubing from the reduce-noise wavefield.

Method and apparatus for geophysical formation evaluation measurements behind casing

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.

Systems and methods for high-resolution travel time and move-out velocity estimation using downhole linear receiver arrays

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.

Shear velocity radial profiling based on flexural mode dispersion

Acoustic waves are obtained from an acoustic logging tool within a borehole passing through a formation. Signal properties in a time domain, frequency domain, or both are determined based on the obtained acoustic waves. A machine learning analysis is used to determine formation slowness based on the determined signal properties and a downhole operational parameter is adjusted based on the determined formation slowness.

Methods and systems for processing slowness values from borehole sonic data

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.

Real-time monopole sonic logging using physics-based artificial intelligence

A portion of an anisotropy formation through which a wellbore is formed can be identified. An estimate of an elastic anisotropy parameter for the portion can be adjusted based on a first quality control analysis using the elastic anisotropy parameter for the portion. The first signal representing the elastic anisotropy parameter for the portion. The estimate of the elastic anisotropy parameter for the portion can be adjusted based on a second quality control analysis using estimates for the elastic anisotropy parameters for two or more portions of the anisotropy formation.

Verifying measurements of elastic anisotropy parameters in an anisotropic wellbore environment

Disclosed are systems and methods for high precision acoustic logging processing for compressional and shear slowness. The method comprises measuring, by a sonic logging tool, sonic data associated with a formation within a borehole, attempting a detection of a first arrival within the sonic data determining whether the attempted detection of the first arrival is accurate, and in response to an accurate detection of the first arrival determining a travel time of the first arrival, generating a coherence map including the first arrival, and determining, based on the coherence map, a characteristic of the formation.

High precision acoustic logging processing for compressional and shear slowness

Systems and methods for downhole signal filtering. A method for downhole signal filtering may comprise defining outliers as isolated values; providing thresholds; determining the outliers from a buffer; computing a difference in slowness between adjacent pairs of values; comparing the adjacent pairs of values to other values in a same window; determining if the adjacent pairs of values vary more than the threshold; assigning a 2D flag array a value of 0 if the adjacent pairs of values vary more than the threshold; and computing a 75% percentile distribution for each adjacent pair of values to determine if each adjacent pair of values are the outliers.

Method for near-real-time, high-resolutionsignal filtering in noisy environments

Disclosed herein is an approach to processing the waveforms measured by a plurality of receivers in a manner that improves signal-detection performance for multiple simultaneously occurring signals, despite disparate signal and noise levels, by applying an waveform pre-processing scheme prior to computing a semblance map therefrom.

Signal detection in semblance methods

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.

Noise removal for distributed acoustic sensing data

Disclosed herein is an approach to improving the accuracy of signal-peak tracking in acoustic logs by supplementing a semblance method used to detect signal peaks in individual coherence-, correlation- or amplitude-based semblance maps with consistency checks based on rock-physics constraints and/or based on history and/or future data for the signal of interest.

Growing community of inventors

Kingwood, TX, United States of America

Kristoffer Thomas Walker