Shear wave imaging to determine near-borehole faults for ocean drilling
          exploration

Lee, Sheng-Qing; Tang, Xiaoming; Su, Yongbin

doi:10.1093/gji/ggz023

Cited by 24 publications

(8 citation statements)

References 14 publications

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“…Recent development of single well reflection imaging using acoustic logging data shows the potential of detailed imaging of structures around a borehole. For example, dipole acoustic data successfully detect the azimuth angle of reflectors, and also images structures around a borehole a few tens of meters away from the borehole (Lee et al, 2019). This shows the potential of filling the scale gap between the surface seismic, VSP, and borehole sonic logging.…”

Section: Introductionmentioning

confidence: 83%

Quantitative fracture imaging using least-squares migration and linear-slip model: theory and application to single-well reflection imaging

Minato¹,

Ghose²,

Wapenaar³

2019

Fifth EAGE Workshop on Borehole Geophysics

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Characterizing subsurface fractures is a key to exploring hydrocarbon and water resources, developing geothermal field, and assessing seismic hazard in seismotectonics. Seismic characterization of fractures has been based on the seismic anisotropy using effective medium approach, which considers seismically invisible, small fractures. There is a considerable scale gap between the fracture properties obtained by seismic methods and those from borehole logging. Recent developments of single well reflection imaging show that the use of acoustic borehole logging data successfully delineates detailed structures around a borehole up to a few tens of meter away from the borehole. This shows the potential of filling the scale gap by providing quantitative fracture properties around the borehole. In the context of reflection imaging of individual fractures, we explore least-squares migration (LSM) coupling linear-slip interface model. LSM solves a linearized waveform inversion in order to estimate quantitative properties Fifth EAGE Workshop on Borehole Geophysics 18

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Section: Introductionmentioning

confidence: 83%

Quantitative fracture imaging using least-squares migration and linear-slip model: theory and application to single-well reflection imaging

Minato¹,

Ghose²,

Wapenaar³

2019

Fifth EAGE Workshop on Borehole Geophysics

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“…Achieving the coordinate system on the tool requires the knowledge of azimuth angle of target fractures. A recent study shows successful detection of unknown fracture azimuth by rotating the cross-dipole data (Lee et al, 2019). We assume that the P-SV and SH wavefields can be constructed using the approach, or acquisition is designed for specific fracture(s) whose azimuth is known.…”

Section: Born Approximation To Scattered Wavefield Due To Linear Slipmentioning

confidence: 99%

“…Recently, single-well reflection imaging where sources and receivers are installed in the same borehole receives ample attention. Owing to the developments of directional multipole acoustic tools and sophisticated filtering approaches (e.g., Li and Yue, 2017;Li et al, 2017), single-well imaging enables to locating fine-scale structures around a borehole including fractures up to a few tens of meters away from the borehole (e.g., Tang and Patterson, 2009;Lee et al, 2019). This shows the possibility of high-resolution imaging and quantitative charac-terization of in-situ individual fractures.…”

Section: Introductionmentioning

confidence: 99%

Quantitative imaging of fractures around a borehole using linear slip theory and elastic least-squares migration

Minato

Ghose

Wapenaar

2019

SEG Technical Program Expanded Abstracts 2019

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Single-well reflection imaging using sonic logging data successfully locates fine-scale structures around a borehole including fractures. In order to achieve accurate and quantitative estimation of fracture properties with high resolution, we propose to couple least-squares migration with linear slip theory. The proposed least-squares migration solves linearized waveform inversion where the wavefield is approximated using a Born operator incorporating a linear slip boundary condition. Representing a fracture as a linear slip interface is advantageous in accurate seismic wave modeling and efficient estimation of fracture properties. We derive conventional elastic least-squares migration for imaging perturbations in elastic constants, and new elastic least-squares migration for imaging fracture compliances. The two formulations are tested using numerical modeling where a dipping fracture is embedded in random background medium. The results show that leastsquares migration generally produces higher resolution images for both SH and P-SV wavefields than using adjoint operators. Furthermore, it shows the potential of quantitative estimation of fracture compliances which can be further used in interpreting fracture properties, e.g., fracture infill material and surface condition. The proposed approach, therefore, will be crucial in fracture characterization around a borehole.

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“…In this vein, the earlier study of high-frequency reflection imaging using microearthquakes (wavelength of a few tens of meters) predicted the presence of fractures (e.g., Reshetnikov et al, 2010), and the recent developments in shear-wave reflection imaging using acoustic dipole tools enable using the wavelength of 1-2 meters to reveal structures around a borehole (Tang and Patterson, 2009). More recently, Lee et al (2019) used cross-dipole data and successfully imaged fine structures at a fault system in crystalline rocks around a borehole up to 30 m away from the borehole.…”

Section: Introductionmentioning

confidence: 99%

Seismic Reflection Imaging of Fractures Using Least-Squares Migration and Linear-Slip Theory - Laboratory and Numerical Tests

Minato¹,

Ghose²,

Wapenaar³

2019

1st Conference on Geophysics for Geothermal-Energy Utilization and Renewable-Energy Storage

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Characterizing the mechanical and hydraulic properties of fractures is crucial in hydrocarbon and geothermal field development. Contrary to passive microseismic measurements, active seismic measurements using a borehole, e.g., VSP or sonic logging, have a potential to address aseismic fractures. However, there is a considerable scale gap between the characteristic wavelength in VSP and in sonic logging, which hinders consistent interpretations of active and passive measurements. Recent developments of reflection imaging using microearthquakes and dipole acoustic data successfully image individual fractures or clusters of them around a borehole, which indicates the potential to fill the gap by addressing quantitative fracture properties around a borehole up to a few tens of meters away from the borehole. In this study, we couple the least-squares migration with the linear-slip theory in order to achieve high-resolution reflection imaging of fracture compliances around a borehole, which are then useful to characterize microscale structures at the fracture. Tests in the laboratory successfully characterize the spatially varying fracture compliance due to the partial inclusion of water in the fracture. Numerical modelling tests of the source-receiver configuration of acoustic dipole measurements and random background media shows the potential of the proposed approach for quantitatively imaging fractures around a borehole.

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Shear wave imaging to determine near-borehole faults for ocean drilling exploration

Cited by 24 publications

References 14 publications

Quantitative fracture imaging using least-squares migration and linear-slip model: theory and application to single-well reflection imaging

Quantitative fracture imaging using least-squares migration and linear-slip model: theory and application to single-well reflection imaging

Quantitative imaging of fractures around a borehole using linear slip theory and elastic least-squares migration

Seismic Reflection Imaging of Fractures Using Least-Squares Migration and Linear-Slip Theory - Laboratory and Numerical Tests

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