Brittleness Index Research Based on the Anisotropic Seismic Rock Physics for Tight-oil Sandstone

Current seismic rock physics model for tight sandstone is not sufficient to depict its complicated microstructure. In this paper, we build a seismic rock physics model from five aspects which are clay type, filler content, pore connectivity, pore type and vertical fracture. The new Brittleness index is established based on the new rock physical model. In order to detect the superiority of the new Brittleness index in brittleness prediction, we compare it with other conventional Brittleness indexes in aspects of brittleness sensitivity and physical response. The results show that the ability to characterize the mineral’s brittleness of new brittleness indexes is much stronger than the ability of conventional brittleness indexes. And the analysis about cross-plot colour-coded by the new Brittleness index could support the favoriable informations for elastic property and brittle characteristics in “sweet spot” zone of tight sandstone oil reservoir. In theory, the above characteristics of new brittleness index are more conductive to brittleness evaluation for tight sandstone oil reservoir.