Effect of crack aperture on P-wave velocity and dispersion
Wei Jian-Xin1,2, Di Bang-Rang1,2, and Ding Pin-Bo1,2
1. State Key Laboratory for Petroleum Resource and Prospecting, China University of Petroleum (Beijing), Beijing 102249, China.
2. CNPC Key Laboratory of Geophysical Exploration, China University of Petroleum (Beijing), Beijing 102249, China.
Abstract：
We experimentally studied the effect of crack aperture on P-wave velocity, amplitude, anisotropy and dispersion. Experimental models were constructed based on Hudson’s theory. Six crack models were embedded with equal-radius penny-shaped crack inclusions in each layer. The P-wave velocity and amplitude were measured parallel and perpendicular to the layers of cracks at frequencies of 0.1 MHz to 1 MHz. The experiments show that as the crack aperture increases from 0.1 mm to 0.34 mm, the amplitude of the P-waves parallel to the crack layers decreases linearly with increasing frequency and the P-wave velocity dispersion varies from 1.5% to 2.1%, whereas the amplitude of the P-wave perpendicular to the crack layers decreases quadratically with increasing frequency and the velocity dispersion varies from 1.9% to 4.7%. The variation in the velocity dispersion parallel and perpendicular to the cracks intensifies the anisotropy dispersion of the P-waves in the crack models (6.7% to 83%). The P-wave dispersion strongly depends on the scattering characteristics of the crack apertures.
WEI Jian-Xin,DI Bang-Rang,DING Pin-Bo. Effect of crack aperture on P-wave velocity and dispersion[J]. APPLIED GEOPHYSICS, 2013, 10(2): 125-133.
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