叠前地震直接定量反演方法在火成岩储层预测中的应用研究

The application of direct quantitative pre-stack seismic inversion method in igneous reservoir prediction

火成岩油气藏由于其岩性复杂、非均质性强、孔隙及裂缝发育等问题一直是油气勘探难以回避的难点问题.本文结合准噶尔盆地火成岩的特点,以岩心实验数据、录井资料、测井数据为分析基础,研究该地区火成岩岩石物理特征,从众多岩石物理弹性参数中筛选最优的弹性参数,并制作定量分析的岩石物理量版.利用测井曲线正演叠前地震道集模型,分析其火成岩AVO变化特征.直接定量反演时,重点使用Gray F.D的近似Zeoppritz波动方程直接对叠前地震道集反演计算优选出来的弹性参数反射率数据,并通过约束稀疏脉冲反演技术将Gray F.D方程计算得到的叠前地震反射率数据体进行绝对值化,最终实现叠前地震直接定量反演,并利用其结果预测火成岩储层分布.叠前地震直接定量反演方法能够减小计算环节带来的迭代误差,预测结果精度高、可靠性强.

Due to the complex lithology, strong heterogeneity, pore and fracture and other issues of igneous reservoir, which have been an issue and hard to avoid in oil and gas exploration. Combining the characteristics of igneous rock of Junggar Basin, rock-physics characteristics of igneous rock which based on the core experiment data, lithology and well logging data has been researched in them. By analysising a large number of elastic parameters, optimal rock- physics parameter is selected, and quantitative rock-physical version is established. By using the well logging data forward pre-stack seismic model, AVO characteristics variation of igneous rock can also be analyzed. In direct quantitative inversion method, optimal parameterrs seismic reflectivity is calculated by approximate Zeoppritz wave equation of Gray F. D, and absolute value of pre-stack seismic reflectivity is calculated with constrained sparse spike inversion method. Finally the direct quantitative pre-stack seismic inversion is achieved. The results are used to predict igneous reservoir distribution. The direct quantitative pre-stack seismic inversion method can reduce the iterative error of calculation, and predicted results are of high precision and reliability.