1887
Volume 61 Number 6
  • E-ISSN: 1365-2478

Abstract

ABSTRACT

Modern downhole microseismic surveys often employ geometries in which ray trajectories generated by a collection of locatable events provide full polar and azimuthal coverage, making it possible to estimate the seismic anisotropy. We show that traveltimes and particle motions of the direct P‐ and shear‐waves acquired in such geometries can constrain stiffness tensors of triclinic media. While obtaining all 21 stiffness coefficients of a homogeneous triclinic space simultaneously with locating pertinent microseismic events from data recorded in a single vertical well is relatively straightforward, the same methodology does not necessarily succeed in layered formations because the combination of their vertical heterogeneity and azimuthal anisotropy might invalidate the commonly adopted approximation of the event azimuths by those of the P‐wave polarization vectors. When the event azimuths cannot be derived from the particle motions, traveltimes observed in two or more wells are required to locate the events and build layered triclinic or higher‐symmetry azimuthally anisotropic velocity models. As our numerical tests indicate, the multi‐well event‐location methods are expected to perform better than their single‐well counterparts because they rely solely on triangulation and eliminate the usually pronounced azimuthal uncertainties in the event locations that stem from noises adversely affecting hodogram analysis.

Loading

Article metrics loading...

/content/journals/10.1111/1365-2478.12042
2013-04-24
2024-04-25
Loading full text...

Full text loading...

References

  1. Al HarrasiO.H., Al AnbooriA., WüstefeldA. and KendallJ.‐M.2011. Seismic anisotropy in a hydrocarbon field estimated from microseismic data. Geophysical Prospecting59, 227–243.
    [Google Scholar]
  2. BardainneT. and GaucherE.2010. Constrained tomography of realistic velocity models in microseismic monitoring using calibration shots. Geophysical Prospecting58, 739–753.
    [Google Scholar]
  3. BulantP., EisnerL., PšenčíkI. and Le CalvezJ.2007. Importance of borehole deviation surveys for monitoring of hydraulic fracturing treatments. Geophysical Prospecting55, 891–899.
    [Google Scholar]
  4. ČervenýV.2001. Seismic Ray Theory. Cambridge University Press.
    [Google Scholar]
  5. CrampinS. and YedlinM.1981. Shear‐wave singularities of wave propagation in anisotropic media. Journal of Geophysics49, 43–46.
    [Google Scholar]
  6. CrampinS., StephenR.‐A. and McGonigleR.1982. The polarization of P‐waves in anisotropic media. Geophysical Journal of the Royal Astronomical Society76, 477–485.
    [Google Scholar]
  7. DewanganP. and GrechkaV.2003. Inversion of multicomponent, multiazimuth, walkaway VSP data for the stiffness tensor. Geophysics68, 1022–1031.
    [Google Scholar]
  8. DrewJ., WhiteR. and WolfeJ.2008. Microseismic event azimuth estimation: Establishing a relationship between hodogram linearity and uncertainty in event azimuth. 78th Annual International Meeting, Society of Exploration Geophysics, Expanded Abstracts, 1446–1450.
  9. EisnerL., FischerT. and RutledgeJ.T.2009. Determination of S‐wave slowness from a linear array of borehole receivers. Geophysical Journal International176, 31–39.
    [Google Scholar]
  10. GajewskiD., SommerK., VanelleC. and PatzigR.2009. Influence of models on seismic‐event localization. Geophysics74(5), WB55–WB61.
    [Google Scholar]
  11. GoldinS.V.1979. Interpretation of Seismic Reflection Data. Nedra (in Russian; English translation titled ‘Seismic Traveltime Inversion,’ was published by SEG in 1986).
  12. GrechkaV.2007. Multiple cracks in VTI rocks: Effective properties and fracture characterization. Geophysics72(5), D81–D91.
    [Google Scholar]
  13. GrechkaV. and DuchkovA.A.2011. Narrow‐angle representations of the phase and group velocities and their applications in anisotropic velocity‐model building for microseismic monitoring. Geophysics76(6), WC125–WC140.
    [Google Scholar]
  14. GrechkaV. and MateevaA.2007. Inversion of P‐wave VSP data for local anisotropy: Theory and a case study. Geophysics72(4), D69–D79.
    [Google Scholar]
  15. GrechkaV., SinghP. and DasI.2011. Estimation of effective anisotropy simultaneously with locations of microseismic events. Geophysics76(6), WC141–WC153.
    [Google Scholar]
  16. GrechkaV., TheophanisS. and TsvankinI.1999. Joint inversion of P‐ and PS‐waves in orthorhombic media: Theory and a physical‐modeling study. Geophysics64, 146–161.
    [Google Scholar]
  17. HelbigK.1994. Foundations of Anisotropy for Exploration Seismics. Elsevier.
    [Google Scholar]
  18. MontalbettiJ.R. and KanasewichE.R.1970. Enhancement of teleseismic body phases with a polarization filter. Geophysical Journal of the Royal Astronomical Society21, 119–129.
    [Google Scholar]
  19. PeiD., QuireinJ.A., CornishB.E., QuinnD. and WarpinskiN.R.2009. Velocity calibration for microseismic monitoring: A very fast simulated annealing (VFSA) approach for joint‐objective optimization. Geophysics74(6), WCB47–WCB55.
    [Google Scholar]
  20. PressW.A., TeukolskyS.A., VetterlinkW.T. and FlanneryB.P.2003. Numerical Recipes in Fortran 77: The Art of Scientific Computing. Cambridge University Press.
    [Google Scholar]
  21. RutledgeJ.T. and PhillipsW.S.2003. Hydraulic stimulation of natural fractures as revealed by induced microearthquakes, Carthage Cotton Valley gas field, east Texas. Geophysics68(2), 441–452.
    [Google Scholar]
  22. ThomsenL.1986. Weak elastic anisotropy. Geophysics51, 1954–1966.
    [Google Scholar]
  23. TsvankinI.1997. Anisotropic parameters and P‐wave velocity for orthorhombic media. Geophysics62, 1292–1309.
    [Google Scholar]
  24. TsvankinI. and GrechkaV.2011. Seismology of Azimuthally Anisotropic Media and Seismic Fracture Characterization. Society of Exploration Geophysics.
    [Google Scholar]
  25. WarpinskiN.R., MayerhoferM.J., VincentM.C., CipollaC.L. and LolonE.P.2008. Stimulating unconventional reservoirs: Maximizing network growth while optimizing fracture conductivity. Society of Petroleum Engineers, Paper 114–173.
    [Google Scholar]
  26. ZhengX. and PšenčíkI.2002. Local determination of weak anisotropy parameters from qP‐wave slowness and particle motion measurements. Pure and Applied Geophysics159, 1881–1905.
    [Google Scholar]
http://instance.metastore.ingenta.com/content/journals/10.1111/1365-2478.12042
Loading
/content/journals/10.1111/1365-2478.12042
Loading

Data & Media loading...

  • Article Type: Research Article
Keyword(s): Anisotropy; Microseismic; Triclinic

Most Cited This Month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error