Estimation of scattering attenuation in a carbonate reservoir in the Arabian Gulf, Abu Dhabi

Scattering attenuation due to velocity variations occurs as a result of heterogeneity within the layers of the earth. Lithology, porosity, or fluid changes influence the amount of scattering attenuation during wave propagation. We estimate scattering attenuation (Q-1) from Vp logs based on a multiple backscattering (MBS) model and apply Q-1 a means of identifying the structural heterogeneities within the layers of the earth and possibly locating hydrocarbon reservoirs at depth. For the studied Shuaiba formation of the carbonate reservoir, there are three flow units interbedded with two dense layers of carbonates. The average porosity and P-wave velocity of the reservoirs are 18-25% and 3.5 - 4.0 km/s, respectively. The velocity variation over the studied reservoir interval is < 50%. The estimated dominant heterogeneity length of the reservoir is about 10 m. Maximum attenuation occurs at the reservoir interval with the quality factor (Q) as low as 10 due to the large velocity contrast in the reservoir interval. These results will be compared with VSP estimates to separate the intrinsic attenuation due to fluid changes from total apparent attenuation in future studies.