oa Fractures Detection Using Multi-Azimuth Diffractions Focusing Measure: A Feasibility Study from the Arab D Reservoir

3D azimuthal P-wave post stack seismic data has been analyzed to investigate the feasibility of using<br>multi azimuth scattering and diffractions focusing measure to detect azimuthal anisotropy anomalies at<br>the Arab D carbonate reservoir; hence, assisting in the identification of potential fractures (i.e. sweet<br>spots). Earlier studies and numerical examples demonstrated the azimuthal variations of scattering in<br>vertically fractured media. Azimuthal variations of the focusing measure for the scattering energy and<br>diffractions are estimated from stack data along a test 3D multi-azimuth sub-line, after segmenting the<br>data into four azimuthal sectors (stacks), each 45 degrees wide, and separating the diffractions and<br>scattering from the reflections, using the plane wave destruction technique. The analysis suggest the<br>presence of azimuthal anisotropy anomalies in the focusing measure and they are generally oriented W<br>-E (~N85E). This conclusion is consistent with the results obtained by using an independent seismic<br>technique which is based on a different but more accurate 3D analysis using 3D azimuthal pre-stack<br>reflection moveout, to study the amplitude variations with offset and azimuth (AVOA) and the normal<br>moveout (NMO) velocity. The intensity of the azimuthal anisotropy anomalies in the focusing measure<br>(hence, potential fractures), along the seismic profile, is also consistent with the results obtained from<br>3D prestack azimuthal anisotropy reflection moveout analysis. The structural geology of the area<br>supports the outcome of this study. This is the first attempt to apply azimuthal scattering and<br>diffraction focusing measure technology as a tool for fracture detection in Saudi Arabia. The technique<br>is fast since it is applied on stack data, as opposed to 3D prestack reflection moveout. This technology<br>could be applied to fracture detection by complementing existing seismic methods; especially in cases<br>where the 3D seismic azimuthal data acquisition is rather challenged and the application of full 3D prestack<br>AVOA and NMO velocity analysis for the target reservoir is less adequate.