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Analysis of Seismic Velocity Change and AVO Response Depending on Saturation of Kerogen and GOR in Shale Reservoirs
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  • Journal title : Geophysics and Geophysical Exploration
  • Volume 19, Issue 1,  2016, pp.29-36
  • Publisher : Korean Society of Earth and Exploration Geophysicists
  • DOI : 10.7582/GGE.2016.19.1.029
 Title & Authors
Analysis of Seismic Velocity Change and AVO Response Depending on Saturation of Kerogen and GOR in Shale Reservoirs
Choi, Junhwan; Lee, Jaewook; Byun, Joongmoo; Kim, Bona; Kim, Soyoung;
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Recently, the studies about rock physics model (RPM) in shale reservoir are widely performed. In shale reservoir, the degree of the maturity can be estimated by kerogen and GOR (Gas-Oil Ratio). The researches on the rock physics model of shale reservoir with the amount of kerogen have been actively carried out but not with GOR. Thus, in this study, we analyzed the changes in seismic velocity and density, and AVO (Amplitude Variation with Offset) response depending on changes in GOR and the amount of kerogen. Since the shale consists of plate-like particles, it has vertical transverse isotropy (VTI). Therefore we estimated the seismic velocity and density by using Backus averaging method and analyzed AVO responses based on these estimated properties. The results of analysis showed that the changes in the velocity with the GOR variation are small but the velocity changes with the variation in kerogen amount are relatively larger. In case, GOR 180 (Litre/Litre) which is boundary between heavy oil and light oil, when volume fraction of kerogen increased from 5% to 35%, the P-wave velocity normal to the layering increased 51%. That is, it helps estimating maturity of kerogen through the velocity. Meanwhile, when rates of oil-gas mixture are large, the effect of GOR variation on the velocity change became larger. In case volume fraction of kerogen is 5%, the P-wave velocity normal to the layering was estimated in heavy oil (GOR 40) but in light oil (GOR 300). The AVO responses analysis showed class 4 regardless of the GOR and amount of kerogen because variation of poisson's ratio is small. Therefore, shale reservoir has possibility to have class 4.
Rock physics model (RPM);Backus averaging method;Kerogen;Gas Oil Ratio (GOR);Amplitude variation with Offset (AVO);
 Cited by
Aki, K., and Richards, P. G., 1980, Quantitative Seismology: Theory and Methods, WH Freeman and Co.

Avseth, P., Mukerji, T., and Mavko, G., 2005, Quantitative seismic interpretation, Cambridge University Press.

Batzle, M. L., and Wang, Z., 1992, Seismic properties of pore fluids, Geophysics, 57, 1396-1408. crossref(new window)

Canada Society for Unconventional Resources, Understanding tight oil, Available from [accessed 01.09.15]

Cander, H., 2013, Finding Sweet Spots in Shale Liquids and Gas Plays with Lessons from the Eagle Ford Shale, AAPG Geoscience Technology Workshop.

Carcione, J. M., 2001, AVO effects of a hydrocarbon sourcerock layer, Geophysics, 66, 419-427. crossref(new window)

Carcione, J. M., Helle, H. B., and Avseth, P., 2011, Source-rock seismic-velocity models Gassmann versus Backus, Geophysics, 76, N37-N45. crossref(new window)

Carcione, J. M., and Avseth, P., 2014, Rock-physics templates for hydrocarbon source rocks, Geophysics, 80(5), D481-D500.

Castagna, J. P., Batzle, M. L., and Han, D.-H., 1995, Fluid effects on bright spot and AVO analysis, SEG Technical Program Expanded Abstracts, 1119-1121.

Clark, V. A., 1992, The effect of oil under in-situ conditions on the seismic properties of rocks, Geophysics, 57(7), 894-901.

Forrest, M., Roden, R., and Holeywell, R., 2010, Risking seismic amplitude anomaly prospects based on database trends, The Leading Edge, 29(5), 570-574.

Hwang, L. F., and Peter J. Lellis, 1988, Bright Spots related to High GOR Oil Reservoir in Green Canyon, SEG Technical Program Expanded Abstracts, 761-763.

Kuster, G. T., and Toksoz, M. N., 1974, Velocity and attenuation of seismic waves in two-phase media, Part I. Theoretical formulations, Geophysics, 39, 587-606. crossref(new window)

Ruger, A., 2002, Reflection coefficients and azimuthal AVO analysis in anisotropic media, Society of Exploration Geophysicists, 10, 39-62.

Sayers, C. M., Guo, S., and Silva, J., 2013, Sensitivity of the elastic anisotropy and seismic reflection amplitude of the Eagle Ford Shale to the presence of kerogen, Geophysical Prospecting, 63(1), 151-165.

Schoenberg, M., and F. Muir, 1989, A calculus for finely layered media, Geophysics, 54, 582-590.

Thomsen, L., Castagna, J., and Backus, M., 1993, Weak anisotropic reflections, in Offset dependent reflectivity, Eds, Soc. Expl. Geophys, 103-114.

Yenugu, M., and Han, D.-H., 2013, Seismic characterization of kerogen maturity, An example from Bakken shale, SEG Technical Program Expanded Abstracts.