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Anisotropic Extended Elastic Impedance for Fractured Reservoirs
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 77th EAGE Conference and Exhibition 2015, Jun 2015, Volume 2015, p.1 - 5
Abstract
We propose a new attribute known as Anisotropic Extended Elastic Impedance (AEEI). AEEI, can be calculated in various azimuths, but the most significant azimuths for calculation, are across fractures (AEEI⊥, for = 0 Deg. in example model) and parallel to fractures (EEI for = 90 Deg. in the example model). The Factor A has the seismic anisotropy information, which modifies the Extended Elastic Impedance (EEI), for anisotropic reservoirs such as fractured plays. AEEI, parallel to fractures reduce to EEI. The attribute can be easily inverted and be used for Fracture characterization. We demonstrate this with Horizontal Transverse Isotropy (HTI) models, simulating fractured reservoirs with fluid fill in the cracks. The separation of anisotropic Factor A and EEI terms in the AEEI, where AEEI is a product of those two terms, allows us to input Factor A, extracted from azimuthal seismic data or use modelling to calculate A. The other term EEI, can be inverted from regular full fold seismic data. Therefore, AEEI allows to analyze the reservoir, in situations where either there is no azimuthal seismic data or is noisy, has low azimuthal fold and not suitable for azimuthal amplitude analysis.