Posts by Collection

portfolio

Portfolio item number 1

Short description of portfolio item number 1

Portfolio item number 2

Short description of portfolio item number 2

publications

Usage of directional common image gathers for shallow seismic source localization

Published in Near Surface Geophysics, 2016

In this paper, we explore using multi-parameter common image gathers (MPCIGs) as a tool for event location. When both estimated event location and used velocity model are correct, the MPCIGs will have no residual moveout. We explore the usage of such gathers for a one-way migration, with unknown source location and origin time.

Download here

Shallow diffraction imaging in an SH-wave crosshole configuration

Published in Geophysics, 2017

We show the advantages of using a pure SH-waves cross-hole acquisition for diffraction imaging. After implementing an automatic model-based direct-waves muting, we migrate diffracted events to a depth imaging offset domain. In it, gathers will be flat only if estimated diffractor location and velocity model are correct.

Download here

Seismic velocity estimation using time-reversal focusing

Published in Geophysics, 2018

We utilize the time-reversal principle for seismic velocity inversion. Recorded data are computationally back-propagated through various velocity models. When the model is correct, energy will be focused at the true source location and origin time.

Download here

Q-factor inversion using reconstructed source spectral consistency

Published in Geophysics, 2018

We utilize a physical objective function for Q-factor inversion. Assuming correct velocity and attenuation models, back-propagation of recorded data should have the same spectral content at the source location. This property is used in a global optimization scheme, allowing for high-resolution Q-model recovery.

Download here

Velocity analysis and subsurface source location improvement using moveout-corrected gathers

Published in Geophysics, 2019

Subsurface sources of known location can be used for velocity model calibration. We show how to conduct this procedure without the need for picking by using moveout corrected gathers.

Download here

Seismic velocity estimation using passive downhole distributed acoustic sensing records–examples from the San Andreas Fault Observatory at Depth

Published in Journal of Geophysical Research: Solid Earth, 2019

Optical fiber recording (DAS) of earthquakes in a downhole array allows the building of high-resolution P and S velocity models, unveiling local geology and in agreement with a conventional geophone survey

Download here

DAS observations and modeling of perforation-induced guided waves in a shale reservoir

Published in The Leading Edge, 2019

Perforation shots conducted in unconventional reservoirs excite guided waves that propagate through the low-velocity shale formation. These waves are recorded by a downhole DAS array and have a wide frequency content. In a cross-well acquisition, guided S-waves are disturbed when propagating through previously stimulated areas.

Download here

Velocity-Based Earthquake Detection Using Downhole Distributed Acoustic Sensing—Examples from the San Andreas Fault Observatory at Depth

Published in Bulletion of the Seismological Society of America, 2019

Using a vertical DAS array, we demonstrate the usefeulness of a velocity-based earthquake detection algorithm.

Download here

Fiber-optic distributed seismic sensing data generator and its application for training classification nets

Published in Optics Letters, 2020

Training a DAS classifier using synthetic data generated geophysical seismic modeling.

Download here

Comparison between Distributed Acoustic Sensing and Geophones: Downhole Microseismic Monitoring of the FORGE Geothermal Experiment

Published in Seismological Research Letters [Accepted], 2020

A downhole vertical DAS array is compared with a set of standard geophones in analyzing microseismic events generated during stimulation of the DoE FORGE geothermal project.

Download here

Near-surface Characterization Using a Roadside Distributed Acoustic Sensing Array

Published in The Leading Edge [Accepted], 2020

Using DAS recording of the ambient seismic field generated by cars and earthquakes, we estimate the S-wave velocity profile and Poisson ratio along the array.

Download here

Fracture properties estimation using distributed acoustic sensing recording of guided waves in unconventional reservoirs

Published in Geophysics [Accepted], 2020

DAS can record high-frequency guided waves excited by perforation shots and propagating in a low velocity shale reservoir. Using a cross-well setup, we can infer stimulation-induced horizontal fracture growth by its effect on guided waves.

Download here

City-scale dark fiber DAS measurements of infrastructure use during the COVID-19 pandemic

Published in Geophysical Research Letters [Under Review], 2020

We measure the effect of COVID-19 on vehicle usage using DAS recordings near Stanford.

Download here

Low-magnitude Seismicity with a Downhole Distributed Acoustic Sensing Array – examples from the FORGE Geothermal Experiment

Published in Journal of Geophysical Research: Solid Earth [Under Review], 2020

Using a downhole vertical DAS array, we detect natural and induced earthquakes with a magnitude completeness better by M = 1 compared to a dense surface seismometer array.

Download here

Dr. Ariel Lellouch

Posts by Collection

portfolio

publications

talks

teaching