Research on anisotropy of shale oil reservoir based on rock physics model
Guo Zhi-Qi1, Liu Cai1, Liu Xi-Wu2,3,4, Dong Ning2,3,4, and Liu Yu-Wei2,3,4
1. Geo-Exploration Science and Technology Institute, Jilin University, Changchun 130021, China.
2. SinoPEC Key Laboratory of Shale Oil/Gas Exploration and Production Technology, Beijing 100083, China.
3. SinoPEC Exploration & Production Research Institute, Beijing 100083, China.
4. National Key Laboratory of Corporation of Shale Oil/Gas Enrichment Mechanism and Effective Development, Beijing 100083, China.
Abstract：
Rock physics modeling is implemented for shales in the Luojia area of the Zhanhua topographic depression. In the rock physics model, the clay lamination parameter is introduced into the Backus averaging theory for the description of anisotropy related to the preferred alignment of clay particles, and the Chapman multi-scale fracture theory is used to calculate anisotropy relating to the fracture system. In accordance with geological features of shales in the study area, horizontal fractures are regarded as the dominant factor in the prediction of fracture density and anisotropy parameters for the inversion scheme. Results indicate that the horizontal fracture density obtained has good agreement with horizontal permeability measured from cores, and thus confirms the applicability of the proposed rock physics model and inversion method. Fracture density can thus be regarded as an indicator of reservoir permeability. In addition, the anisotropy parameter of the P-wave is higher than that of the S-wave due to the presence of horizontal fractures. Fracture density has an obvious positive correlation with P-wave anisotropy, and the clay content shows a positive correlation with S-wave anisotropy, which fully shows that fracture density has a negative correlation with clay and quartz contents and a positive relation with carbonate contents.
. Research on anisotropy of shale oil reservoir based on rock physics model[J]. APPLIED GEOPHYSICS, 2016, 13(2): 382-392.
[1]
Bayuk, I. O., Ammerman, M., and Chesnokov, E. M., 2007, Elastic moduli of anisotropic clay: Geophysics, 72(5), D107−D117.
[2]
Carcione, J. M., 2000, A model for seismic velocity and attenuation in petroleum source rocks: Geophysics, 65(4), 1080−1092.
[3]
Carcione, J. M., Helle, H. B., and Avseth, P., 2011, Source-rock seismic-velocity models: Gassmann versus Backus: Geophysics, 76(5), N37−N45.
[4]
Chapman, M., 2003, Frequency dependent anisotropy due to meso-scale fractures in the presence of equant porosity: Geophysical Prospecting, 51(5), 369-379.
[5]
Chapman, M, Maultzsch, S., Liu, E., and Li, X. Y., 2003, The effect of fluid saturation in an anisotropic multi-scale equant porosity model: Journal of Applied Geophysics, 54, 191-202.
[6]
Deng, J. X., Wang, H., Zhou, H., et al., 2015, Microtexture, seismic rock physical properties and modeling of Longmaxi Formation shale: Chinese Journal of Geophysics (in Chinese), 58(6), 2123−2136.
[7]
Dong, N., Huo, Z. Z., Sun, Z. D., et al., 2014, An inversion of a new rock physics model for shale:Chinese Journal of Geophysics (in Chinese), 57(6), 1990−1998.
[8]
Guo, Z. Q., and Li, X. Y., 2015, Rock physics model-based prediction of shear wave velocity in the Barnett Shale formation: Journal of Geophysics and Engineering. 12, 527−534.
[9]
Guo, Z. Q., Li, X. Y., and Liu, C., 2014, Anisotropy parameters estimate and rock physics analysis for the Barnett Shale: Journal of Geophysics and Engineering, 11, 1−10.
[10]
Guo, Z. Q., Li, X. Y., Liu, C., Feng, X., and Shen, Y., 2013, A shale rock physics model for analysis of brittleness index, mineralogy and porosity in the Barnett Shale: Journal of Geophysics and Engineering, 10, 1−10.
[11]
Hornby, B. E., Schwartz, L. M., and Hudson, J. A., 1994, Anisotropic effective-medium modeling of the elastic properties of shales: Geophysics, 59(10), 1570−1583.
[12]
Hu, Q., Cheng, X. H., and Li, J. Y., 2014, Shear velocity prediction for organic shales based on the single aspect ratio model: Progress in Geophysics (in Chinese), 29(5), 2388−2394.
[13]
Li, Y., Guo, Z. Q., Liu, C., Li, X. Y., and Wang, G., 2015, A rock physics model for the characterization of organic-rich shale from elastic properties: Petroleum Science, 12(2), 264−272.
[14]
Mba, K., and Prasad, M., 2010, Mineralogy and its contribution to anisotropy and kerogen stiffness variations with maturity in the Bakken Shales: 80th Annual International Meeting, SEG, Expand Abstracts, 2612−2616.
[15]
Metwally, Y., and Chesnokov, E. M., 2011, Gas shale: relationships between permeability and intrinsic composition: 81th Annual International Meeting, SEG, Expand Abstracts, 4414−4419.
[16]
Ortega, J. A., Ulm F. J., and Abousleiman, Y., 2009, The nanogranular acoustic signature of shale: Geophysics, 74(3), D65−D84.
[17]
Sayers, C. M., 2005, Seismic anisotropy of shales: Geophysical Prospecting, 53, 667−676.
[18]
Schoenberg, M., and Helbig, K., 1997, Orthorhombic media: modeling elastic wave behavior in a vertically fractured earth: Geophysics, 62(6), 1954-1974.
[19]
Spikes, K. T., 2011, Modeling elastic properties and assessing uncertainty of fracture parameters in the Middle Bakken Siltstone: Geophysics, 76(4), E117−26.
[20]
Vernik, L., and Nur, A., 1992, Ultrasonic velocity and anisotropy of hydrocarbon source rocks: Geophysics, 57(5), 727-735.
[21]
Vernik, L., and Liu, X., 1997, Velocity anisotropy in shales: A petrophysical study: Geophysics, 62(2), 521−532.
[22]
Vernik, L., and Milovac, J., 2011, Rock physics of organic shales: The Leading Edge, 30(3), 318−323.
[23]
Zhang, G. Z., Chen, J. J., Chen, H. Z., et al., 2015, Prediction for in-situ formation stress of shale based on rock physics equivalent model: Chinese Journal of Geophysics (in Chinese), 58(6), 2112−2122.
2016, Vol. 13 
