Direct inversion method for brittleness index factor of compact sandstone

The invention provides a direct inversion method for a brittleness index factor of compact sandstone. The direct inversion method for the brittleness index factor of the compact sandstone comprises the following steps: step 1, deducing an AVO approximation formula containing a brittleness index factor BI, shear modulus mu and density rho; step 2, constructing elastic impedance EI reflecting a brittleness index factor of the deep compact sandstone; and 3, solving the brittleness index factor BI, the shear modulus mu and the density rho of the stratum rock through well seismic constraint. According to the direct inversion method for the brittleness index factor of the compact sandstone, the brittleness index is directly inverted through an elastic impedance inversion principle, and a numerical test and an actual application effect both prove that the direct extraction method for the brittleness index has the characteristics of relatively wide practicability and relatively high precision. 本发明提供一种致密砂岩脆性指数因子的直接反演方