基于纯纵波地震资料的碳酸盐岩储集层识别

Carbonate Reservoir Identification Based on Pure P⁃Wave Data

针对塔里木盆地古喀斯特型碳酸盐岩储集层埋深大、非均质性强、地震资料品质要求高的特点,引入叠前反演获得纯纵波地震资料,代替全叠加地震资料,以提高波阻抗反演及储集层预测精度。数值模拟结果表明:与理论零偏移距地震资料相比,计算的纯纵波地震资料误差几乎为零,而全叠加地震资料会因地震子波类型、入射角度范围、地层界面性质等的不同产生误差。塔中油田中古8井区碳酸盐岩目标层纯纵波地震资料主频提高了8 Hz,储集层预测结果与钻井吻合率提高了7.39%,为塔里木盆地碳酸盐岩储集层预测提供了切实可行的方案。

Regarding the characteristics of large burial depth and strong heterogeneity of the paleokarst carbonate reservoir in the Tarim ba⁃sin,the pure P⁃wave data calculated from pre⁃stack inversion are introduced to replace the traditional full⁃stack seismic data so that the ac⁃curacy of wave impedance inversion and reservoir prediction can be improved.The numerical modeling results suggest that compared with the theoretical zero⁃offset data,the computed pure P⁃wave data have negligible errors,while the traditional full⁃stack data inevitably con⁃tain errors that might associated with different factors,i.e.,wavelet,incidence angle range and reflection boundary.The field data compari⁃son in the Wellblock ZG8,Tazhong area shows that when the dominant frequency of P⁃wave in target carbonate strata has been improved by 8 Hz,the fitting rate of reservoir prediction result with actual drilling result can be increased by 7.39%,which provides practical methods and corresponding standards for the reservoir prediction in the carbonate reservoirs in Tarim basin.