Combining P-P And P-Sv Avo To Improve Estimation Of Elastic Parameters

Compressional wave amplitude-versus-offset analysis <br>(AVO) is being widely used in different geological <br>settings as a lithology indicator and also as a direct <br>hydrocarbon indicator. Ambiguities associated to <br>elastic parameters estimation from AVO is <br>commonplace in most inversion procedures used up <br>today. Basic approaches to determine elastic <br>parameters directly from the coefficients of the P-P <br>reflectivity approximation (Rpp) fail because of the <br>uncertainties associated to the third coefficient, which <br>depend on larger incidence angles than intercept (A) <br>and gradient (B) estimates. One way to get around <br>this problem is to use the reflectivity information <br>from P-SV AVO (Rps) in addition to the traditional PP<br> AVO. This procedure can potentially reduce the <br>uncertainties and improve estimation of elastic parameters. <br>In this paper I demonstrate how to extract elastic <br>parameters from P-SV AVO and the way to combine <br>these parameters with those extracted from P-P AVO. <br>A simple low-contrast approximation is derived and <br>is compared with a more accurate, yet more complex, <br>high-contrast approximation. This procedure makes <br>possible to access the uncertainties associated with <br>the parameters estimated from P-SV AVO.