Full-waveform based complete moment tensor inversion and source parameter estimation from downhole microseismic data for hydrofracture monitoring

Fuxian Song; M. Nafi Toksöz

doi:10.1190/geo2011-0027.1

Full-waveform based complete moment tensor inversion and source parameter estimation from downhole microseismic data for hydrofracture monitoring

Geophysics ◽

10.1190/geo2011-0027.1 ◽

2011 ◽

Vol 76 (6) ◽

pp. WC103-WC116 ◽

Cited By ~ 72

Author(s):

Fuxian Song ◽

M. Nafi Toksöz

Keyword(s):

Hydraulic Fracturing ◽

Moment Tensor ◽

Fracture Plane ◽

Far Field ◽

Field Range ◽

Full Waveform ◽

Microseismic Data ◽

Fracturing Process ◽

The Moment ◽

Additional Constraints

Downhole microseismic monitoring is a valuable tool in understanding the efficacy of hydraulic fracturing. Inverting for the moment tensor has gained increasing popularity in recent years as a way to understand the fracturing process. Previous studies utilize only part of the information in the waveforms, such as direct P- and S-wave amplitudes, and make far-field assumptions to determine the source mechanisms. The method is hindered in downhole monitoring, when only limited azimuthal coverage is available. In this study, we develop an approach to invert for complete moment tensor using full-waveform data recorded at a vertical borehole. We use the discrete wavenumber integration method to calculate full wavefields in the layered medium. By using synthetic data, we find that, at the near-field range, a stable, complete moment tensor can be retrieved by matching the waveforms without additional constraints. At the far-field range, we discover that the off-plane moment tensor component is poorly constrained by waveforms recorded at one well. Therefore, additional constraints must be introduced to retrieve the complete moment tensor. We study the inversion with three different types of constraints. For each constraint, we investigate the influence of velocity model errors, event mislocations, and data noise on the extracted source parameters by a Monte Carlo study. We test our method using a single well microseismic data set obtained during the hydraulic fracturing of the Bonner sands in East Texas. By imposing constraints on the fracture strike and dip range, we are able to retrieve the complete moment tensor for events in the far-field. Field results suggest that most events have a dominant double-couple component. The results also indicate the existence of a volumetric component in the moment tensor. The derived fracture plane orientation generally agrees with that derived from the multiple event location.

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Accuracy of the moment-tensor inversion of far-field P waves

Geophysical Journal International ◽

10.1093/gji/ggz446 ◽

2019 ◽

Vol 220 (1) ◽

pp. 248-256 ◽

Cited By ~ 1

Author(s):

Yue Kong ◽

Min Li ◽

Weimin Chen ◽

Boqi Kang

Keyword(s):

Moment Tensor ◽

Near Field ◽

Radial Component ◽

Moment Tensor Inversion ◽

Far Field ◽

Field Range ◽

P Waves ◽

Moment Tensors ◽

Nodal Lines ◽

The Moment

SUMMARY The far-field assumption is widely used and suitable for the moment-tensor inversion in which the source–receiver distance is quite long. However, the description of far field is uncertain and an explicit far-field range is missing. In this study, the explicit far-field range is determined and the errors of moment-tensor solutions produced by the far-field approximation are analysed. The distance, for which the far-field assumption is satisfied and the effect of the near-field term can be ignored, is directionally dependent. For the shear dislocation, in the directions near the nodal lines of the far-field P waves, the far-field distance is heavily dependent on the displacement component used to invert moment tensors. The radial component of displacement, which is parallel to the wave propagation direction, is recommended for the inversion and the corresponding far-field distance is quite short. In the directions far from the nodal lines, the selection of displacement components has little influence on the far-field distance. The maximum far-field distance appears in the directions of the pressure and tensile axes of the source and the value is about 30 wavelengths of radiated waves. Using more receivers (>6) in the moment-tensor inversion can shorten the far-field distance. The effect of the near-field term on the moment-tensor inversion for tensile dislocations and isotropic sources (explosion or implosion) can be ignored. The conclusions obtained in this study are helpful for determining the positions of receivers and evaluating the accuracy of moment-tensor solutions, with far-field assumption being applied in the inversion.

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Full-waveform-based characterization of acoustic emission activity in a mine-scale experiment: a comparison of conventional and advanced hydraulic fracturing schemes

Geophysical Journal International ◽

10.1093/gji/ggaa127 ◽

2020 ◽

Vol 222 (1) ◽

pp. 189-206 ◽

Cited By ~ 1

Author(s):

Peter Niemz ◽

Simone Cesca ◽

Sebastian Heimann ◽

Francesco Grigoli ◽

Sebastian von Specht ◽

...

Keyword(s):

Acoustic Emission ◽

Hydraulic Fracturing ◽

Induced Seismicity ◽

Large Scale ◽

Sampling Rate ◽

Fracture Plane ◽

B Values ◽

Full Waveform ◽

Scale Experiment ◽

Fracturing Experiments

SUMMARY Understanding fracturing processes and the hydromechanical relation to induced seismicity is a key question for enhanced geothermal systems (EGS). Commonly massive fluid injection, predominately causing hydroshearing, are used in large-scale EGS but also hydraulic fracturing approaches were discussed. To evaluate the applicability of hydraulic fracturing techniques in EGS, six in situ, multistage hydraulic fracturing experiments with three different injection schemes were performed under controlled conditions in crystalline rock at the Äspö Hard Rock Laboratory (Sweden). During the experiments the near-field ground motion was continuously recorded by 11 piezoelectric borehole sensors with a sampling rate of 1 MHz. The sensor network covered a volume of 30×30×30 m around a horizontal, 28-m-long injection borehole at a depth of 410 m. To extract and characterize massive, induced, high-frequency acoustic emission (AE) activity from continuous recordings, a semi-automated workflow was developed relying on full waveform based detection, classification and location procedures. The approach extended the AE catalogue from 196 triggered events in previous studies to more than 19 600 located AEs. The enhanced catalogue, for the first time, allows a detailed analysis of induced seismicity during single hydraulic fracturing experiments, including the individual fracturing stages and the comparison between injection schemes. Beside the detailed study of the spatio-temporal patterns, event clusters and the growth of seismic clouds, we estimate relative magnitudes and b-values of AEs for conventional, cyclic progressive and dynamic pulse injection schemes, the latter two being fatigue hydraulic fracturing techniques. While the conventional fracturing leads to AE patterns clustered in planar regions, indicating the generation of a single main fracture plane, the cyclic progressive injection scheme results in a more diffuse, cloud-like AE distribution, indicating the activation of a more complex fracture network. For a given amount of hydraulic energy (pressure multiplied by injected volume) pumped into the system, the cyclic progressive scheme is characterized by a lower rate of seismicity, lower maximum magnitudes and significantly larger b-values, implying an increased number of small events relative to the large ones. To our knowledge, this is the first direct comparison of high resolution seismicity in a mine-scale experiment induced by different hydraulic fracturing schemes.

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An effective noise-suppression technique for surface microseismic data

Geophysics ◽

10.1190/geo2012-0502.1 ◽

2013 ◽

Vol 78 (6) ◽

pp. KS85-KS95 ◽

Cited By ~ 32

Author(s):

Farnoush Forghani-Arani ◽

Mark Willis ◽

Seth S. Haines ◽

Mike Batzle ◽

Jyoti Behura ◽

...

Keyword(s):

Surface Wave ◽

Hydraulic Fracturing ◽

Noise Suppression ◽

Signal To Noise ◽

Data Set ◽

Microseismic Data ◽

Receiver Array ◽

Fracturing Process ◽

Suppression Technique ◽

Microseismic Events

The presence of strong surface-wave noise in surface microseismic data may decrease the utility of these data. We implement a technique, based on the distinct characteristics that microseismic signal and noise show in the [Formula: see text] domain, to suppress surface-wave noise in microseismic data. Because most microseismic source mechanisms are deviatoric, preprocessing is necessary to correct for the nonuniform radiation pattern prior to transforming the data to the [Formula: see text] domain. We employ a scanning approach, similar to semblance analysis, to test all possible double-couple orientations to determine an estimated orientation that best accounts for the polarity pattern of any microseismic events. We then correct the polarity of the data traces according to this pattern, prior to conducting signal-noise separation in the [Formula: see text] domain. We apply our noise-suppression technique to two surface passive-seismic data sets from different acquisition surveys. The first data set includes a synthetic microseismic event added to field passive noise recorded by an areal receiver array distributed over a Barnett Formation reservoir undergoing hydraulic fracturing. The second data set is field microseismic data recorded by receivers arranged in a star-shaped array, over a Bakken Shale reservoir during a hydraulic-fracturing process. Our technique significantly improves the signal-to-noise ratios of the microseismic events and preserves the waveforms at the individual traces. We illustrate that the enhancement in signal-to-noise ratio also results in improved imaging of the microseismic hypocenter.

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Adaptive full-waveform moment-tensor inversion of microseismic data

10.1190/segam2021-3594469.1 ◽

2021 ◽

Author(s):

Kai Gao ◽

Lianjie Huang ◽

Yan Qin ◽

Ting Chen ◽

David Coblentz ◽

...

Keyword(s):

Moment Tensor ◽

Moment Tensor Inversion ◽

Full Waveform ◽

Microseismic Data

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New Hydraulic Fracturing Process Enables Far-Field Diversion in Unconventional Reservoirs

10.2118/152704-ms ◽

2012 ◽

Cited By ~ 2

Author(s):

Fraser Mcneil ◽

Klaas A.W. Van Gijtenbeek ◽

Mark Van Domelen

Keyword(s):

Hydraulic Fracturing ◽

Unconventional Reservoirs ◽

Far Field ◽

Fracturing Process

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Analytical models of volcanic ellipsoidal expansion sources

Annals of Geophysics ◽

10.4401/ag-6441 ◽

2013 ◽

Vol 56 (4) ◽

Author(s):

Antonella Amoruso ◽

Luca Crescentini

Keyword(s):

Volume Change ◽

Moment Tensor ◽

Analytical Form ◽

Field Approximation ◽

Analytical Models ◽

Far Field ◽

Total Moment ◽

Double Couple ◽

Single Moment ◽

The Moment

<p>Modeling non-double-couple earthquakes and surficial deformation in volcanic and geothermal areas usually involves expansion sources. Given an ensemble of ellipsoidal or tensile expansion sources and double-couple ones, it is straightforward to obtain the equivalent single moment tensor under the far-field approximation. On the contrary, the moment tensor interpretation is by no means unique or unambiguous. If the far-field approximation is unsatisfied, the single moment tensor representation is inappropriate. Here we focus on the volume change estimate in the case of single sources, in particular finite pressurized ellipsoidal sources, presenting the expressions for the computation of the volume change and surficial displacement in a closed analytical form. We discuss the implications of different domains of the moment-tensor eigenvalue ratios in terms of volume change computation. We also discuss how the volume change of each source can be obtained from the isotropic component of the total moment tensor, in few cases of coupled sources where the total volume change is null. The new expressions for the computation of the volume change and surficial displacement in case of finite pressurized ellipsoidal sources should make their use easier with respect to the already published formulations.</p>

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Discrete-Fracture-Network Generation From Microseismic Data by Use of Moment-Tensor- and Event-Location-Constrained Hough Transforms

SPE Journal ◽

10.2118/168582-pa ◽

2016 ◽

Vol 21 (01) ◽

pp. 221-232 ◽

Cited By ~ 9

Author(s):

Xin Yu ◽

Jim Rutledge ◽

Scott Leaney ◽

Shawn Maxwell

Keyword(s):

Moment Tensor ◽

Fracture Network ◽

Fracture Plane ◽

Fracture Networks ◽

Complex Fracture ◽

Location Uncertainty ◽

Microseismic Data ◽

Uncertainty Estimates ◽

Discrete Fracture ◽

Event Location

Summary Reservoir simulation and prediction of production associated with hydraulic-fracturing require the input of the fracture geometry and the fracture properties such as the porosity and retained permeability. Various methods were suggested and applied for deriving discrete fracture networks (DFNs) from microseismic data as a framework for modeling reservoir performance. Although microseismic data are the best diagnostics for revealing the volume of rock fractured, its incompleteness in representing the deformation induced presents a challenge to calibrate and represent complex fracture networks created and connected during hydraulic-fracture stimulation. We present an automated method to generate DFN models constrained by the microseismic locations and fracture plane orientations derived from moment-tensor analysis. We use a Hough-transform technique to find significant planar features from combinations of the microseismic source locations. We have modified the technique with an equal-probability voting scheme to remove an inherent bias for horizontal planes. The voting mechanism is a general grid search in the space of fracture strike, dip, and location (φ,θ,r, respectively) with grid-cell sizes scaled by uncertainty estimates of φ,θ,r. We constrain fracture orientations with weighting on the basis of the moment-tensor orientations of neighboring events and their associated uncertainties. With two case studies, we demonstrate that our automated technique can reliably extract the complex fracture network on the basis of good matches with the event-cloud trends and the input moment-tensor orientations. We also tested the sensitivity of the technique to event-location uncertainty. With increasing location uncertainty, the details of the fracture network extracted are diminished with events grouping to larger-scale features, but the general shape and orientation of the fracture network obtained are insensitive to the location uncertainty.

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