Abstract:

AVO techniques have been widely used in petroleum exploration. However, when the Aki-Richards approximation is used to calculate the PP wave reflection coefficients, the incident angle is usually used as the angle parameter instead of the average of the incident and refracted angle. This calculation will bring errors to the result of the prestack inversion. The Incident-Angle approximation is the function of the incident angle, which significantly reduces the errors. First of all, an equation named the Incident-Angle Elastic Impedance was proposed based on the Incident-Angle approximation to make the inversion of elastic impedance more accurate. The new elastic impedance was normalized to overcome the problem that its dimensionality varies with the incident angle. One classical AVO model was used to prove its accuracy. Secondly, a new inversion method was established based on the new equation. Comparison of inversion results of the Marmousi2 model with the conventional method showed that the new method was better. Finally, the new method was tested with a set of real data.and the final result matched well with the well-logging data, which proved its strong practicability.