Abstract
The relationship between fluid density and saturation and sonic wave velocity of rock samples taken from the WXS Depression in the South China Sea was studied by an oil-water replacement experiment under simulated in-situ temperature and pressure conditions. Two kinds of low-density oils (0.691 and 0.749 g/cm3) and two kinds of high-density oils (0.834 and 0.873 g/cm3) were used to saturate the rock samples at different oil-saturation states, and the saturated P- and S-wave velocities were measured. Through Gassmann’s equation, the theoretical P- and S-wave velocities were also calculated by the fluid replacement method. With the comparison of the measured values and the theoretical values, this study comes to the following conclusions. (1) With the increase of oil saturation and the decrease of water saturation, the P-wave velocity of rock samples saturated by low-density oil increases and the changing rule is in accord with the effective fluid theory; the P-wave velocity of rock samples saturated by high-density oil decreases and the changing rule goes against the theory. (2) With the increase of oil density (namely 0.691→0.749→0.834→0.873 g/cm3) when oil saturation is unchanged, P-wave velocity increases gradually. (3) The S-wave velocity is always stable and is not affected by the change of oil density and saturation. The results can be used to constrain pre-stack seismic inversion, and the variation rule of sonic wave velocity is valuable for hydrocarbon identification in the study area.
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References
Deng J X, Wang S X and Yu J. Experimental results in partially saturated sandstone under condition of different pressure and their theoretical interpretation. Oil Geophysical Prospecting. 2005. 40(5): 530–534 (in Chinese)
Domenico S N. Effect of water saturation on seismic reflectivity of sand reservoirs encased in shale. Geophysics. 1974. 39(6): 759–769
Goertz D and Knight R. Elastic wave velocities during evaporative drying. Geophysics. 1998. 63(1): 171–183
Huang K, Xu Q Z, Yang X H, et al. Oil, gas and water distribution detection forward modeling with elastic parameters of core samples under simulated condition. Chinese Journal of Geophysics. 1998. 41(Supplement): 414–421 (in Chinese)
Hu X H, Li C W, Li X, et al. Experiments on acoustic characters of low porous and permeable sandstones. Well Logging Technology. 2004. 28(4): 273–276 (in Chinese)
Jiang L X and Shi X J. Relation between wave velocity in sandstone and fluid content in porous medium under high frequency condition. Oil Geophysical Prospecting. 1998. 33(3): 355–362 (in Chinese)
Jiang W Z, Zhang C G, Huang W X, et al. Acoustic characteristics of core under high temperature and high pressure. Journal of Jianghan Petroleum Institute. 2004. 26(1): 51–53 (in Chinese)
Knight R and Nolen-Hoeksema R. A laboratory study of the dependence of elastic wave velocities on pore scale fluid distribution. Geophysical Research Letters. 1990. 17(10): 1529–1532
Liu Z P, Wu X W and Chu Z H. Laboratory study of acoustic parameters of rock. Chinese Journal of Geophysics. 1994. 37(5): 659–666 (in Chinese)
Mavko G, Mukerji T and Dvorkin J. The Rock Physics Handbook. New York: Cambridge University Press. 1998. 71–90
Shen L D and Shi G. Effect of lithologic character, petroleum and effective overburden pressure on compressional wave and shear wave velocity. Chinese Journal of Geophysics. 1994. 37(3): 391–398 (in Chinese)
Shi G and Shen L D. Experimental study of how water saturation in limestone influences the velocities of P wave and S wave. Oil Geophysical Prospecting. 1990. 25(4): 469–479 (in Chinese)
Shi G and Yang D Q. Determination of the elastic wave velocities in porous rocks with the change of overburden pressure and its universal significance. Science in China (Series D). 2001. 31(11): 896–901 (in Chinese)
Shi G, Shen W L and Yang D Q. The relationship of wave velocities with saturation and fluid distribution in pore space. Chinese Journal of Geophysics. 2003. 46(1): 138–142 (in Chinese)
Shi X J, Xu G M, Jin P, et al. The laboratory study of influence of water saturation on rock’s velocity and attenuation. Chinese Journal of Geophysics. 1995. 38(Supplement 1): 281–287 (in Chinese)
Xie J Z, Chu Z H and Liu Z P. A study on acoustic characteristics of oil-saturated sand in the process of water flooding. Well Logging Technology. 1997. 21(6): 401–404 (in Chinese)
Xu Q Z, Wu J H and Zhang L F. Rock wave velocity and resistivity in fluid flooding process under stratal condition. Geophysical Prospecting for Petroleum. 2000. 39(1): 124–126 (in Chinese)
Zhang Y H and Li C W. Experimental study of the relation between specific property of P-wave and water saturation in rock. Well Logging Technology. 1995. 19(1): 6–10 (in Chinese)
Zhang Y H, Hu X H and Li C W. Experiments on identification of gas in sandstone formation with acoustic parameters. Well Logging Technology. 2000. 24(3): 194–197 (in Chinese)
Zhao F Z, Cai M L and Sai F Y. Experimental study on acoustic wave and resistivity of rock under high temperature and pressure. Well Logging Technology. 1998. 22(Supplement): 3–5 (in Chinese)
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Pei, F., Zou, C., He, T. et al. Experimental study of the relationship between fluid density and saturation and sonic wave velocity of rock samples from the WXS Depression, South China Sea. Pet. Sci. 8, 43–48 (2011). https://doi.org/10.1007/s12182-011-0113-5
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DOI: https://doi.org/10.1007/s12182-011-0113-5