Abstract Rock-physics models are constructed for hydrate-bearing sediments in the Qilian Mountains permafrost region using the K–T equation model, and modes I and II of the effective medium model. The K–T equation models the seismic wave propagation in a two-phase medium to determine the elastic moduli of the composite medium. In the effective medium model, mode I, the hydrate is a component of the pore inclusions in mode I and in mode II it is a component of the matrix. First, the P-wave velocity, S-wave velocity, density, bulk modulus, and shear modulus of the sediment matrix are extracted from logging data.. Second, based on the physical properties of the main components of the sediments, rock-physics model is established using the K–T equation, and two additional rock-physics models are established assuming different hydrate-filling modes for the effective medium. The model and actual velocity data for the hydrate-bearing sediments are compared and it is found that the rock-physics model for the hydrate-filling mode II well reproduces the actual data.
This work was supported by the Institute of Geophysical and Geochemical Exploration (IGGE) CAGS of China (No.WH201207).
Cite this article:
. Rock-physics models of hydrate-bearing sediments in permafrost, Qilian Mountains, China[J]. APPLIED GEOPHYSICS, 2017, 14(1): 31-39.
[1]
Dai, J., Xu, H. B., Snyder, F., and Dutta, N., 2004, Detection and estimation of gas hydrates using rock physics and seismic inversion: Examples from the northern deep-water Gulf of Mexico: The leading edge, 23(1), 60-66.
[2]
Dvorkin, J. P., and Nur, A. M., 1996, Elasticity of high-porosity sandstones: Theory for two North Sea datasets: Geophysics, 61(5), 1363-1370.
Guo, X. W., 2011, Well logging Response Characteristics and Evaluation of Gas hydrae in Qilian mountain permafrost, Beijing: Chinese Academy of Geological Science, 33-42.
[5]
Helgerud, M. B., Dvorkin, J., Nur, A., Sakai, A., and Collett, T., 1999, Elastic-wave velocity in marine sediments with gas hydrates: Effective medium modeling: Geophy. Res., 26(13), 2021-2024.
[6]
Hu, G. W., Ye, Y. G., Zhang, J., et al., 2010, Micro-models of gas hydrate and their impact on the acoustic properties of the host sediments: Natural gas industry, 30(3), 120-124.
[7]
Kuster, G. T., and Toksöz, M. N., 1974, Velocity and attenuation of seismic waves in two-phase media-1: Geophysics, 39, 587-606.
[8]
Lee, M. W., Hutchinson, D. R., and Dillon, W. P., 1996, Seismic velocities for hydrate-bearing sediments using weighted equation: J. Geophys. Res., 101(B9), 20347-20358.
[9]
Li, C. H., Zhao, Q., Xu, H. J., et al., 2014, Relation between relative permeability and hydrate saturation in Shenhu area, south china sea: Applied Geophysics, 11(2), 207-214.
[10]
Li, J. Y., and Chen, X. H., 2013, A rock-physical modeling method for carbonate reservoirs at seismic scale: Applied geophysics, 10(1), 1-13.
[11]
Lu, Z. Q., Zhu, Y. H., Zhang, Y. Q., et al., 2010, Basic geological characteristics of gas hydrate in Qilian Mountain permafrost area, Qinghai Province: Mineral deposits, 29(1), 182-191.
[12]
Mavko, G., Mukerji, T., and Dvorkin, J., 2003, The rock physics handbook: tools for seismic analysis of porous media, Cambridge University Press.
[13]
Muhammed, I. E., Nisar, A., Perceiz, K., et al., 2016, An application of rock physics modeling to quantify the seismic response of gas hydrate-bearing sediments in Makran accretionary prism, offshore, Pakistan: Geosciences Journal, 20(3), 321-330.
[14]
Murphy, W. F. I., 1982, Effects of microstructure and pore fluids on the acoustic properties of granular sedimentary materials: Ph. D thesis stanford Univ., 144-147.
[15]
Pang, S. J, Su, X., He, H., et al., 2012, Geological controlling factors of gas hydrate occurrence in Qilian Mountain permafrost, China: Earth Science Frontiers, 19(1), 1-17.
[16]
Sell, K., Saenger, E. H., Falenty, A., et al., 2016, On the path to the digital rock physics of gas hydrate bearing sediments-processing of in-situ synchrotron-tomography data: Solid Earth, 7, 1243-1258.
[17]
Shankar, U., Gupta, D. K., Bhowmick, D., and Sain, K., 2013, Gas hydrate and free gas saturations using rock physics modeling at site NGHP-01-05 and 07 in the Krishna-Godavari Basin, eastern Indian margin: Journal of Petroleum Science and Engineering, 106(6), 62-70.
[18]
Song, H. B., Matsubayasgi, O., Yang, S. X., et al., 2002, Physical property models of gas hydrate-bearing Sediments and AVA character of bottom simulating reflector: Chinese J. Geophys. (in Chinese), 45(4), 546-556.
[19]
Sun, C. Y., Zhang M. Y., Niu, B. H., et al., 2003, Micro-models of gas hydrate and their velocity estimation methods: Earth science Frontiers, 10(1), 191-198.
[20]
Tang, J., Wang, H., Yao, Z. A., et al., 2016, Shear wave velocity estimation based on rock physics diagnosis: Oil geophysical prospecting, 51(3), 537-543.
[21]
Zimmerman, R. W., and King, M. S., 1986, The effect of the extent of freezing on seismic velocities in unconsolidated permafrost: Geophysics, 51(6), 1285-1290.
[22]
Zhu, Y. H., Zhang, Y. Q., Wen, H. J., et al., 2009, Gas hydrates in the Qilian mountain permafrost, Qinghai, northwest China: Acta Geologica Sinica, 83(11), 1763-1772.
[23]
Zhu, Y. H., Zhang, Y. Q., Wen, H. J., et al., 2010, Gas hydrate in the Qilian mountain permafrost and their basic characteristics: Acta Geoscientica Sinica, 31(1), 7-16.
2017, Vol. 14 
