%0 Journal Article
%T Rock Physics Diagnostics, Attenuation Measurement and Analyses in Wells
%J Geosciences
%@ 2163-1719
%D 2012
%I 
%R 10.5923/j.geo.20120206.04
%X Attenuation is a rock anelastic attribute that is sensitive to the presence of fluids, degree of saturation, porosity, fault/fracture, and pressure. Attenuation measured in recorded well logs can provide useful guide for hydrocarbon exploration and field development. The work presented in this paper shows how the sensitivity of P- and S-wave attenuation and the elastic modulus (shear, bulk and compressional) can be used to detect the presence and type of fluids in rocks penetrated by wells. P-wave and S-wave inverse quality factors () are estimated from the log data recorded in well A-10 of the Gullfaks Field, North Sea, Norway. The analysis indicates that the P-wave inverse quality factor is generally higher in hydrocarbon saturated rocks than in brine (water) saturated rocks, while the S-wave inverse quality factor does not show a dependence on fluid content. The range of values measured in gas, water and oil saturated sands are 0.56 ¨C 0.78, 0.39 ¨C 0.55, and 0.35 ¨C 0.41, respectively. A cross plot of the ratio of P-wave and S-wave inverse quality factors () with the ratio of P-wave and S-wave velocities () clearly distinguishes gas sand from water sand, and water sand from oil sand. Gas sand is characterised by the highest and the lowest ratios; oil sand is characterised by the lowest and the highest; and water sand is characterized by the and values that plotted between those of the gas and oil sands. The signatures of the bulk modulus, Lame¡¯s first parameter, and compressional modulus show sensitivity to both pore fluid and rock mineral matrix. These moduli provided preliminary identification for sand intervals saturated with different pore fluids.
%K Attenuation
%K Hydrocarbon
%K Elastic Modulus
%K Inverse Quality Factor
%K Pore Fluids
%U http://article.sapub.org/10.5923.j.geo.20120206.04.html