叠前宽角度反演方法优化及应用

Optimization of prestack wide-angle inversion

基于佐普里兹方程精确解的叠前宽角度反演克服了由佐普里兹方程近似式带来的条件限制和近似误差的影响,反演精度高,适用于宽入射角地震资料。但佐普里兹方程描述的弹性参数与反射系数之间的关系复杂,对提高反演算法的稳定性和提高反演精度等技术的要求更高。因此,本文基于贝叶斯理论并采用反演参数间相互约束等方法,通过优化扰动量求取、岩石物理关系约束等关键技术的研发,提高反演的稳定性和精度。在LJL地区利用宽角度叠前反演去除了储层中灰质砂岩的影响,成功地刻画出主力砂体边界。

Avoiding restriction conditions and approximation errors from the approximate formula,prestack wide-angle inversion based on the exact solution of Zoeppritz equations has higher inversion accuracy,and it is suitable for seismic data at large incident angles.However,complex relationships between elasticity parameters and reflection coefficients in Zoeppritz equations make it harder to improve the stability and the accuracy of the inversion algorithm.In view of this problem,a mutual constraint method based on the Bayes theory is proposed.By optimizing the perturbation calculation and relationship of rock physical constraints,the inversion algorithm stability and accuracy are improved.Using this method,we eliminate impacts of calcareous sandstone and depict main reservoir boundaries successfully in the LJL region.