1887
Volume 68, Issue 3
  • E-ISSN: 1365-2478

Abstract

ABSTRACT

In downhole microseismic monitoring, accurate event location relies on the accuracy of the velocity model. The model can be estimated along with event locations. Anisotropic models are important to get accurate event locations. Taking anisotropy into account makes it possible to use additional data – two S‐wave arrivals generated due to shear‐wave splitting. However, anisotropic ray tracing requires iterative procedures for computing group velocities, which may become unstable around caustics. As a result, anisotropic kinematic inversion may become time consuming. In this paper, we explore the idea of using simplified ray tracing to locate events and estimate medium parameters. In the simplified ray‐tracing algorithm, the group velocity is assumed to be equal to phase velocity in both magnitude and direction. This assumption makes the ray‐tracing algorithm five times faster compared to ray tracing based on exact equations. We present a set of tests showing that given perforation‐shot data, one can use inversion based on simplified ray‐tracing even for moderate‐to‐strong anisotropic models. When there are no perforation shots, event‐location errors may become too large for moderately anisotropic media.

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2019-12-10
2024-04-26
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References

  1. Al‐HarrasiO., 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. ČervenýV.2001. Seismic Ray Theory. Cambridge University Press.
    [Google Scholar]
  4. GrechkaV.2014. Shear‐wave group‐velocity surfaces in low‐symmetry anisotropic media. Geophysics80, C1–C7.
    [Google Scholar]
  5. GrechkaV.2017. Algebraic degree of a general group‐velocity surface. Geophysics82, WA45–WA53.
    [Google Scholar]
  6. GrechkaV. and HeiglW.2017. Microseismic Monitoring. Society of Exploration Geophysicists.
    [Google Scholar]
  7. GrechkaV. and YaskevichS.2013. Inversion of microseismic data for triclinic velocity models. Geophysical Prospecting61, 1159–1170.
    [Google Scholar]
  8. GrechkaV. and YaskevichS.2014. Azimuthal anisotropy in microseismic monitoring: A bakken case study. Geophysics79, KS1–KS12.
    [Google Scholar]
  9. Jarillo MichelO. and TsvankinI.2017. Waveform inversion for microseismic velocity analysis and event location in VTI media. Geophysics82, WA95–WA103.
    [Google Scholar]
  10. Jarillo MichelO. and TsvankinI.2019. 3D waveform inversion of downhole microseismic data for transversely isotropic media. Geophysical Prospecting67, 2332–2342.
    [Google Scholar]
  11. LiJ., LiC., MortonS.A., DohmenT., KataharaK. and ToksözM.N.2014. Microseismic joint location and anisotropic velocity inversion for hydraulic fracturing in a tight Bakken reservoir. Geophysics79, C111–C122.
    [Google Scholar]
  12. MaxwellS., ShemetaJ. and N House Inc.2006. Integrated anisotropic velocity modeling using perforation shots, passive seismic and VSP data. EAGE Conference and Exhibition incorporating SPE EUROPEC 2006, Extended Abstracts.
  13. MaxwellS.C., ZimmerU. and WolfeJ.E.2009. Seismic velocity model calibration using dual monitoring well data. SPE Hydraulic Fracturing Technology Conference, 19–21 January, The Woodlands, Texas.
  14. MichaudG., LeaneyW., BennettL., McClayM., AinsworthK., KaiserM.et al. 2009. Dual treatment monitoring with a horizontal receiver array. 2nd EAGE Passive Seismic Workshop – Exploration and Monitoring Applications 2009, Extended Abstracts.
  15. 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, WCB47–WCB55.
    [Google Scholar]
  16. RutledgeJ.T. and PhillipsW.S.2003. Hydraulic stimulation of natural fractures as revealed by induced microearthquakes, Carthage Cotton Valley gas field, east Texas. Geophysics68, 441–452.
    [Google Scholar]
  17. SayersC.2005. Seismic anisotropy of shales. Geophysical Prospecting53, 667–676.
    [Google Scholar]
  18. ThomsenL.1986. Weak elastic anisotropy. Geophysics51, 1954–1966.
    [Google Scholar]
  19. ThomsenL. and DellingerJ.2003. On shear‐wave triplication in transversely isotropic media. Journal of Applied Geophysics54, 289–296.
    [Google Scholar]
  20. TsvankinI.1997. Anisotropic parameters and P‐wave velocity for orthorhombic media. Geophysics62, 1292–1309.
    [Google Scholar]
  21. TsvankinI.2001. Seismic Signature and Analysis of Reflection Data in Anisotropic Media. Elseiver.
    [Google Scholar]
  22. Van DokR., FullerB., EngelbrechtL. and SterlingM.2011. Seismic anisotropy in microseismic event location analysis. The Leading Edge30, 766–770.
    [Google Scholar]
  23. VavryčukV.2001. Ray tracing in anisotropic media with singularities. Geophysical Journal International145, 265–276.
    [Google Scholar]
  24. VernikL. and LiuX.1997. Velocity anisotropy in shales: a petrophysical study. Geophysics62, 521–532.
    [Google Scholar]
  25. WessonR.L.1971. Travel‐time inversion for laterally inhomogeneous crustal velocity models. Bulletin of the Seismological Society of America61, 729–746.
    [Google Scholar]
  26. YaskevichS., LoginovG., DuchkovA. and SerdukovA.2016. Pitfalls of microseismic data inversion in the case of strong anisotropy. Applied Geophysics13, 326–332.
    [Google Scholar]
  27. YousefB., AngusD., HildyardM., VerdonJ. and PerryM.2013. Full waveform model validation of microseismic shear‐wave splitting fracture parameter inversion. 2nd EAGE Workshop on Naturally Fractured Reservoirs.
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