The potentiality of anisotropic P-wave elastic impedance for research on fractured reservoirs

In this abstract, firstly, we present new explicit expressionsfor anisotropic EI formulae by replacing the Thomsen'scoefficients with fracture parameters azimuth, density andfillings. This makes anisotropic EI formulae more significantlymeaningful. The synthetic modeling shows thatcrack density in gas-saturated cracked media changes EImore than the water-saturated-fractured media does. Secondly, by comparing the acoustic impedance (AI), isotropicelastic impedance (EI) with the new one, as well as thecorresponding seismic impedance inversion methods, wefind that these different inversion methods are strategies toapproximate the solutions of our geophysical problemswhen the data conditions are different. AI inversion is forthe case of post-stack seismic data with zero offset and zerodegree azimuth angles, and isotropic EI inversion is for thecase of pre-stack seismic data with wide offset and narrowazimuth. So we can infer that anisotropic EI inversion forseismic data with wide offset and wide or full azimuth maybe not impossible.