This website uses cookies to improve your experience. If you continue without changing your settings, you consent to our use of cookies in accordance with our cookie policy. You can disable cookies at any time.

×
Advanced search
Skip main navigation
Close Drawer MenuOpen Drawer Menu

Previous
Next
No AccessGEOPHYSICSVolume 81, Issue 1

Ultrasonic velocity and attenuation anisotropy of shales, Whitby, United Kingdom

Authors:
https://doi.org/10.1190/geo2015-0211.1

ABSTRACT

We have conducted ultrasonic experiments, between 0.3 and 1 MHz, to measure velocity and attenuation (Q−1) anisotropy of P- and S-waves in dry Whitby Mudstone samples as a function of stress. We found the degree of anisotropy to be as large as 70% for velocity and attenuation. The sensitivity of P-wave anisotropy change with applied stress is more conspicuous than for S-waves. The closure of large aspect-ratio pores (and/or micro cracks) seems to be a dominant mechanism controlling the change of anisotropy. Generally, the highest attenuation is perceived for samples that have their bed layering perpendicular (90°) to the wave path. The observed attenuation in the samples is partly due to the scattering on the different layers, and it is partly due to the intrinsic attenuation. Changes in attenuation due to crack closure during the loading stage of the experiment are an indication of the intrinsic attenuation. The remaining attenuation can then be attributed to the layer scattering. Finally, the changes in attenuation anisotropy with applied stress are more dynamic with respect to changes in velocity anisotropy, supporting the validity of a higher sensitivity of attenuation to rock property changes.

REFERENCES

  • Best, A. I., J. Sothcott, and C. McCann, 2007, A laboratory study of seismic velocity and attenuation anisotropy in near-surface sedimentary rocks: Geophysical Prospecting, 55, 609–625, doi: 10.1111/j.1365-2478.2007.00642.x.GPPRAR0016-8025CrossrefWeb of ScienceGoogle Scholar
  • Carcione, J. M., J. E. Santos, and S. Picotti, 2012, Fracture-induced anisotropic attenuation: Rock Mechanics and Rock Engineering, 45, 929–942 10.1007%2Fs00603-012-0237-y#.RMREDX1434-453XCrossrefWeb of ScienceGoogle Scholar
  • Chichinina, T., S. Sabinin, and G. Ronquillo-Jarillo, 2006, QVOA analysis: P-wave attenuation anisotropy for fracture characterization: Geophysics, 71, no. 3, C37–C48, doi: 10.1190/1.2194531.GPYSA70016-8033AbstractWeb of ScienceGoogle Scholar
  • Ghadeer, S. G., and J. Macquaker, 2012, The role of event beds in the preservation of organic carbon in fine-grained sediments: Analysis of the sedimentological processes operating during deposition of the Whitby Mudstone Formation (Toarcian, Lower Jurassic) preserved in northeast England: Marine and Petroleum Geology, 35, 309–320, doi: 10.1016/j.marpetgeo.2012.01.001.MPEGD80264-8172CrossrefWeb of ScienceGoogle Scholar
  • Hornby, B., 1998, Experimental laboratory determination of the dynamic elastic properties of wet, drained shales: Journal of Geophysical Research, 103, 29945–29964, doi: 10.1029/97JB02380.JGREA20148-0227CrossrefWeb of ScienceGoogle Scholar
  • Houben, M., A. Barnhoorn, M. Drury, C. Peach, and C. Spiers, 2014, Microstructural investigation of the Whitby Mudstone (UK) as an analog for Posidonia Shale (NL): 76th Annual International Conference and Exhibition, EAGE, Extended Abstracts, doi: 10.3997/2214-4609.20141056.CrossrefGoogle Scholar
  • Imber, J., H. Armstrong, S. S. Clancy, S. S. Daniels, L. Herringshaw, K. McCaffrey, J. Rodrigues, J. Trabucho-Alexandre, and C. Warren, 2014, Natural fractures in a United Kingdom shale reservoir analog, Cleveland Basin, northeast England: AAPG Bulletin, 98, 2411–2437, doi: 10.1306/07141413144.AABUD20149-1423CrossrefWeb of ScienceGoogle Scholar
  • Jones, J., and H. Wang, 1981, Ultrasonic velocities in Cretaceous shales from the Williston Basin: Geophysics, 46, 288–297, doi: 10.1190/1.1441199.GPYSA70016-8033AbstractWeb of ScienceGoogle Scholar
  • Lucet, N., and B. Zinszner, 1992, Effects of heterogeneities and anisotropy on sonic and ultrasonic attenuation in rocks: Geophysics, 57, 1018–1026, doi: 10.1190/1.1443313.GPYSA70016-8033AbstractWeb of ScienceGoogle Scholar
  • Mavko, G., T. Mukerji, and J. Dvorkin, 2009, The rock physics handbook, 2nd ed.: Cambridge University Press.CrossrefGoogle Scholar
  • McArthur, J. M., T. J. Algeo, B. van de Schootbrugge, Q. Li, and R. J. Howarth, 2008, Basinal restriction, black shales, re-os dating, and the Early Toarcian (Jurassic) oceanic anoxic event: Paleoceanography, 23, PA4217, doi: 10.1029/2008PA001607.POCGEP0883-8305CrossrefWeb of ScienceGoogle Scholar
  • Piane, C. D., J. Sarout, C. Madonna, E. H. Saenger, D. Dewhurst, and M. Raven, 2014, Frequency-dependent seismic attenuation in shales: Experimental results and theoretical analysis: Geophysical Journal International, 198, 504–515, doi: 10.1093/gji/ggu148.GJINEA0956-540XCrossrefWeb of ScienceGoogle Scholar
  • Pyrak-Nolte, L. J., L. Myer, and N. Cook, 1990, Transmission of seismic waves across single natural fractures: Journal of Geophysical Research, 95, 8617–8638, doi: 10.1029/JB095iB06p08617.JGREA20148-0227CrossrefWeb of ScienceGoogle Scholar
  • Rasolofosaon, P. N. J., and B. E. Zinszner, 2002, Comparison between permeability anisotropy and elasticity anisotropy of reservoir rocks: Geophysics, 67, 230–240, doi: 10.1190/1.1451647.GPYSA70016-8033AbstractWeb of ScienceGoogle Scholar
  • Rubino, J. G., T. Muller, L. Guarracino, M. Milani, and K. Holliger, 2014, Seismoacoustic signatures of fracture connectivity: Journal of Geophysical Research, 119, 2252–2271.JGREA20148-0227Web of ScienceGoogle Scholar
  • Sayers, C. M., 1994, The elastic anisotropy of shales: Journal of Geophysical Research, 99, 767–774, doi: 10.1029/93JB02579.JGREA20148-0227CrossrefWeb of ScienceGoogle Scholar
  • Sayers, C. M., 2013, The effect of anisotropy of the Young’s moduli and Poisson’s ratios of shales: Geophysical Prospecting, 61, 416–426, doi: 10.1111/j.1365-2478.2012.01130.x.GPPRAR0016-8025CrossrefWeb of ScienceGoogle Scholar
  • Thomsen, L., 1986, Weak elastic anisotropy: Geophysics, 51, 1954–1966, doi: 10.1190/1.1442051.GPYSA70016-8033AbstractWeb of ScienceGoogle Scholar
  • Toksöz, M., D. Johnston, and A. Timur, 1979, Attenuation of seismic waves in dry and saturated rocks: I—Laboratory measurements: Geophysics, 44, 681–690, doi: 10.1190/1.1440969.GPYSA70016-8033AbstractWeb of ScienceGoogle Scholar
  • Vernik, L., and X. Liu, 1997, Velocity anisotropy in shales: A petrophysical study: Geophysics, 62, 521–532, doi: 10.1190/1.1444162.GPYSA70016-8033AbstractWeb of ScienceGoogle Scholar
  • Wang, Z., 2002, Seismic anisotropy in sedimentary rocks: Part II — Laboratory data: Geophysics, 67, 1423–1440, doi: 10.1190/1.1512743.GPYSA70016-8033AbstractWeb of ScienceGoogle Scholar
  • Winkler, K., and A. Nur, 1979, Pore fluids and seismic attenuation in rocks: Geophysical Research Letters, 6, 1–4, doi: 10.1029/GL006i001p00001.GPRLAJ0094-8276CrossrefWeb of ScienceGoogle Scholar
  • Yin, H., 1992, Acoustic velocity and attenuation of rocks: Isotropy, intrinsic anisotropy, and stress induced anisotropy: Ph.D. thesis, Stanford University.Google Scholar
  • Zemanek, J., and I. Rudnick, 1961, Attenuation and dispersion of elastic waves in a cylindrical bar: Journal of the Acoustical Society of America, 33, 1283–1288, doi: 10.1121/1.1908417.JASMAN0001-4966CrossrefWeb of ScienceGoogle Scholar
  • Zhu, Y., and I. Tsvankin, 2006, Plane-wave propagation in attenuative transversely isotropic media: Geophysics, 71, no. 2, T17–T30, doi: 10.1190/1.2187792.GPYSA70016-8033AbstractWeb of ScienceGoogle Scholar