Random‐Objective Waveform Inversion of 3D‐9C Shallow‐Seismic Field Data

Pan, Yudi; Gao, Lingli; Bohlen, Thomas

doi:10.1029/2021jb022036

Cited by 14 publications

(6 citation statements)

References 54 publications

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“…While we would also expect a somewhat higher V p / V s ratio in the flowing zones of the lower reservoir due to fracturing, our surface wave study likely has insufficient resolving power to isolate such localized features at depth. Further work is required to image fine‐scale crustal structures beneath linear arrays, using for example, waveform‐based inversion methods (Y. Pan et al., 2021; Zhang et al., 2018) or extraction of refracted body waves and/or reflected phases from the ambient noise wavefield.…”

Section: Discussionmentioning

confidence: 99%

Using Dark Fiber and Distributed Acoustic Sensing to Characterize a Geothermal System in the Imperial Valley, Southern California

et al. 2023

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The Imperial Valley, CA, is a tectonically active transtensional basin located south of the Salton Sea; the area hosts numerous geothermal fields, including significant hidden hydrothermal resources without surface manifestations. Development of inexpensive, rugged, and highly sensitive exploration techniques for undiscovered geothermal systems is critical for accelerating geothermal power deployment as well as unlocking a low‐carbon energy future. We present a case study utilizing distributed acoustic sensing (DAS) and ambient noise interferometry for geothermal reservoir imaging, utilizing unlit fiber‐optic telecommunication infrastructure (dark fiber). The study exploits two days of passive DAS data acquired in early November 2020 over a ∼28‐km section of fiber from Calipatria, CA to Imperial, CA. We apply ambient noise interferometry to retrieve coherent signals from DAS records and develop a bin stacking technique to attenuate the effects from persistent localized noise sources and to enhance retrieval of coherent surface waves. As a result, we are able to obtain high‐resolution two‐dimensional (2D) S wave velocity (Vs) structure to 3 km depth, based on joint inversion of both the fundamental and higher overtones. We observe a previously unmapped high Vs and low Vp/Vs ratio feature beneath the Brawley geothermal system, which we interpret to be a zone of hydrothermal mineralization and lower porosity. This interpretation is consistent with a host of other measurements including surface heat flow, gravity anomalies, and available borehole wireline data. These results demonstrate the potential utility of DAS deployed on dark fiber for geothermal system exploration and characterization in the appropriate geological settings.

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Section: Discussionmentioning

confidence: 99%

Using Dark Fiber and Distributed Acoustic Sensing to Characterize a Geothermal System in the Imperial Valley, Southern California

et al. 2023

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“…Unfortunately, it is challenging to distinguish this upper reservoir with ambient noise results alone due to the limited vertical resolution of the seismic imaging technique used. Further work is required to image fine-scale crustal structures beneath linear arrays, for example, waveform-based inversion method (Zhang et al, 2018;Y. Pan et al, 2021) or extraction of refracted body waves and/or reflected phases from the ambient noise wavefield.…”

Section: Discussionmentioning

confidence: 99%

Using Dark Fiber and Distributed Acoustic Sensing to Characterize a Geothermal System in the Imperial Valley, Southern California

Cheng

Ajo‐Franklin

Nayak

et al. 2022

Preprint

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The Imperial Valley, CA, is a tectonically active transtensional basin located south of the Salton Sea; the area hosts numerous geothermal fields, including significant hidden hydrothermal resources without surface manifestations. Development of inexpensive, rugged, and highly-sensitive exploration techniques for undiscovered geothermal systems is critical for accelerating geothermal power deployment as well as unlocking a low-carbon energy future. We present a case study utilizing distributed acoustic sensing (DAS) and ambient noise interferometry for geothermal reservoir imaging utilizing an unlit fiberoptic telecommunication infrastructure (dark fiber). The study utilizes passive DAS data acquired from early November 2020 over a ˜28-kilometer section of fiber from Calipatria, CA to Imperial, CA. We apply ambient noise interferometry to retrieve coherent signals from DAS records, and develop a spatial stacking technique to attenuate effects from persistent localized noise sources and to enhance retrieval of coherent surface waves. As a result, we are able to obtain high-resolution two-dimensional (2D) S wave velocity (Vs) structure to 3 km depth based on joint inversion of both the fundamental and higher overtones. We observe a previously unmapped high Vs and low Vp/Vs ratio feature beneath the Brawley geothermal system that we interpret to be a zone of hydrothermal mineralization and lower porosity. This interpretation is consistent with a host of other measurements including surface heat flow, gravity anomalies, and available borehole wireline data. These results demonstrate the potential utility of DAS deployed on dark fiber for geothermal system exploration and characterization in the appropriate contexts.

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“…Pan et al . (2021) used a random objective wave function approach to evaluate a shallow 3‐D 9‐C experiment by full‐waveform inversion, but did not perform reflection imaging. Considering seismic imaging of the near‐surface region, there are, to the best of our knowledge, no published reports on 3‐D multicomponent seismic reflection surveys.…”

Section: Introductionmentioning

confidence: 99%

“…Nonetheless, 9-C seismic methods are used in the in the industry to image deeper targets (e.g., Shuck et al, 1996;Hitchings and Potters, 2000;Davis et al, 2003;Clochard et al, 2018). Pan et al (2021) used a random objective wave function approach to evaluate a shallow 3-D 9-C experiment by full-waveform inversion, but did not perform reflection imaging. Considering seismic imaging of the nearsurface region, there are, to the best of our knowledge, no published reports on 3-D multicomponent seismic reflection surveys.…”

mentioning

confidence: 99%

Near‐surface three‐dimensional multicomponent source and receiver S‐wave survey in the Tannwald Basin, Germany: Acquisition and data processing

Burschil

Buness

Schmelzbach

2022

Near Surface Geophysics

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Shallow 3‐D reflection seismic surveys using S‐waves have rarely been carried out, even though S‐waves can provide higher resolution subsurface images than P‐waves. We conducted a 3‐D near‐surface multicomponent source and receiver survey in Quaternary sediments. We employed a small electrodynamic seismic source with a horizontal shaking unit operated in two orientations. Three‐component geophones in an orthogonal layout covering an area of 117×99 m2 were used for recording. Changes in weather and ground conditions, including freezing and thawing during acquisition, directly influenced the data quality and resulted in discernible relative time shifts in the data. Our seismic processing flow included a four‐component rotation of the data from the Cartesian acquisition geometry into the ‘natural’ coordinate frame to orient sources and receivers in radial or transverse orientation to separate different S‐wave polarizations. The rotation increased the signal strength and helped, for example, to improve the quality of the images of the basin base. The irregular offset distribution in the common midpoint gathers impedes filtering to suppress surface waves in the f–k domain. We, therefore, applied a common‐reflection surface processing flow. After regularization, we could better remove the energy of the surface waves. Both stacked 3‐D S‐wave volumes of vertical and horizontal polarizations provide images of the Quaternary overdeepened Tannwald Basin that was partly known from previous P‐ and S‐wave 2‐D surveys. Compared to a P‐wave profile adjacent to the volume, however, the S‐wave volumes provide higher resolution images of the basin base and internal structure. The basin base is well mapped in three dimensions and shows undulations that were not obvious from the P‐wave data. Comparing the S‐wave volumes of different polarizations, we find only minor differences in the stacks and interpretations.

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Random‐Objective Waveform Inversion of 3D‐9C Shallow‐Seismic Field Data

Cited by 14 publications

References 54 publications

Using Dark Fiber and Distributed Acoustic Sensing to Characterize a Geothermal System in the Imperial Valley, Southern California

Using Dark Fiber and Distributed Acoustic Sensing to Characterize a Geothermal System in the Imperial Valley, Southern California

Using Dark Fiber and Distributed Acoustic Sensing to Characterize a Geothermal System in the Imperial Valley, Southern California

Near‐surface three‐dimensional multicomponent source and receiver S‐wave survey in the Tannwald Basin, Germany: Acquisition and data processing

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