Anisotropy Effects on Microseismic Event Location

King, Andrew; Talebi, Shahriar

doi:10.1007/s00024-007-0266-8

Cited by 17 publications

(9 citation statements)

References 10 publications

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“…The values of 0.1 to 0.3 are common for both of these parameters, and these values are similar to those obtained by King and Talebi (2007) in a coal mine using similar shot receiver geometries. This degree of anisotropy is relatively common in microseismic monitoring and is evident in large segments of microseismic data.…”

Section: Determining Anisotropy Parameterssupporting

confidence: 82%

“…A simple method to evaluate the importance of anisotropy is to prepare some synthetic cases in which the accuracy of location methods can be tested under controlled conditions (e.g., King and Talebi 2007). The first case considered is a homogenous (no layers) formation with anisotropic properties, given below: α 0 = 15,000 ft/sec; β 0 = 8,000 ft/sec δ = 0.l; ε = 0.2; γ = 0.15 This case assumes that microseisms are evenly distributed on a fracture plane that is in line with the receiver well, and that the fracture height is 250 ft and fracture half-length is 250 ft, with the center of the fracture 1,500 ft away.…”

Section: Synthetic Case Studymentioning

confidence: 99%

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Anisotropy Effects in Microseismic Monitoring

Warpinski¹,

Waltman²,

Du³

et al. 2009

SPE Annual Technical Conference and Exhibition

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The accuracy of microseismic monitoring is highly dependent on the quality of the velocity structure used in the analysis of the arrival time or waveform data. Because most rocks associated with hydrocarbon reservoirs are generally anisotropic, methods must be developed to circumvent the effects of anisotropy or to determine the anisotropy parameters for appropriate inclusion. Some field measurements of horizontal vs. vertical velocities are given to help assess the degree of transverse anisotropy. Synthetic case studies are also provided to show how various monitoring strategies and velocity models can affect the accuracy of the microseismic locations.

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Section: Determining Anisotropy Parameterssupporting

confidence: 82%

Section: Synthetic Case Studymentioning

confidence: 99%

Anisotropy Effects in Microseismic Monitoring

Warpinski¹,

Waltman²,

Du³

et al. 2009

SPE Annual Technical Conference and Exhibition

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show abstract

“…(); and Holt et al . (); to improving the location of micro‐seismic events (e.g., King and Talebi () and Li et al . ()) and the interpretation of their focal mechanisms (e.g., Vavryčuk () and Kawasaki and Tanimoto ()); and to evaluating seismic hazard (Maxwell, Zhang, and Damjanac ).…”

Section: Introductionmentioning

confidence: 99%

Static and dynamic pressure sensitivity anisotropy of a calcareous shale

Ong

Schmitt

Kofman

et al. 2016

Geophysical Prospecting

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Optimizing the productivity of nonconventional, low‐permeability “shale” reservoirs requires detailed knowledge of the mechanical properties of such materials. These rocks' elastic anisotropy is acknowledged but usually ignored due to difficulties in obtaining such information. Here we study in detail the dynamic and static elastic properties of a suite of calcareous mudstones from the nonconventional Duvernay reservoir of Alberta, Canada. The complete set of transversely isotropic elastic constants is obtained from strategically oriented ultrasonic transducers to confining pressures of 90 MPa. Wave speed anisotropies of up to 35% are observed at even the highest confining pressures. Furthermore, the stress sensitivity of the wave speeds, and hence moduli, is itself highly dependent on direction with speeds taken perpendicular to the bedding plane being highly nonlinearly dependent on pressure, whereas those along the bedding plane show, unexpectedly, nearly no pressure dependence. These observations are in qualitative agreement with the preferentially oriented porosity and minerals seen in scanning electron microscope images. These results may be significant to the interpretation of sonic logs and azimuthal amplitude versus offset for principal stress directions, for the concentration of stress within such formations, and for estimation of static engineering moduli from sonic log wave speeds.

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“…The model allows us to do such a study. However, it must be kept in mind that commonly technical issues do not allow for accurate mapping of spatial and temporal distribution of the events (King and Talebi, 2007). Thus we have to balance the accuracy of a geometrical scheme with that available or expected in field measurements.…”

Section: Development Of the Methodology For Microseismic Data Inversionmentioning

confidence: 99%

Subtask 2.2 - Creating A Numerical Technique for Microseismic Data Inversion

Dobroskok¹,

Holubnyak²,

Sorensen³

2009

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Geomechanical and geophysical monitoring are the techniques which can complement each other and provide enhancement in the solutions of many problems of geotechnical engineering. One of the most promising geophysical techniques is passive seismic monitoring. The essence of the technique is recording the acoustic signals produced in the subsurface, either naturally or in response to human activity. The acoustic signals are produced by mechanical displacements on the contacts of structural elements (e.g., faults, boundaries of rock blocks, natural and induced fractures). The process can be modeled by modern numerical techniques developed in geomechanics. The report discusses a study that was aimed at the unification of the passive seismic monitoring and numerical modeling for the monitoring of the hydraulic fracture propagation. The approach adopted in the study consisted of numerical modeling of the seismicity accompanying hydraulic fracture propagation and defining seismic attributes and patterns characterizing the process and fracture parameters. Numerical experiments indicated that the spatial distribution of seismic events is correlated to geometrical parameters of hydrofracture. Namely, the highest density of the events is observed along fracture contour, and projection of the events to the fracture plane makes this effect most pronounced. The numerical experiments also showed that dividing the totality of the events into groups corresponding to the steps of fracture propagation allows for reconstructing the geometry of the resulting fracture more accurately than has been done in the majority of commercial applications.

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Anisotropy Effects on Microseismic Event Location

Cited by 17 publications

References 10 publications

Anisotropy Effects in Microseismic Monitoring

Anisotropy Effects in Microseismic Monitoring

Static and dynamic pressure sensitivity anisotropy of a calcareous shale

Subtask 2.2 - Creating A Numerical Technique for Microseismic Data Inversion

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