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A Laboratory Study of Qs/Qp and Vp/Vs Ratios for Water Saturation Estimate in Fractured and Non-fractured Sandstones
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 76th EAGE Conference and Exhibition 2014, Jun 2014, Volume 2014, p.1 - 5
Abstract
The ratio of compressional to shear velocity (Vp/Vs) is indicative of lithology and saturation for reservoir rocks. The ratio of compressional to shear attenuation (Qs/Qp) has been shown to be a more sensitive gas indicator. Using synthetic, silica-cemented, sandstones with aligned penny-shaped voids (fracture density of 0.0298 ± 0.0077) to simulate the effect of fractures in the Earth according to theoretical models, we conducted laboratory ultrasonic experiments to investigate the effects of aligned fractures would have on these relationships. Our results for the non-fractured rock agree with published results, but the fractured rock exhibits different behaviour which could have potential implications for fluid saturation estimation from remote seismic measurements in fractured rocks.