少井区烃源岩叠前地震反演预测方法  

Prestack seismic inversion prediction method for hydrocarbon source rocks in few⁃well areas

作　　者：张卫卫 林鹤鸣 罗明 肖张波 罗伟 高丹 ZHANG Weiwei;LIN Heming;LUO Ming;XIAO Zhangbo;LUO Wei;GAO Dan(CNOOC Limited Shenzhen Branch,Shenzhen,Guangdong 518054,China)

机构地区：[1]中海石油(中国)有限公司深圳分公司,广东深圳518054

出　　处：《石油地球物理勘探》2023年第4期922-932,共11页Oil Geophysical Prospecting

基　　金：中国海洋石油集团有限公司“十四·五”重大科技项目“陆缘裂谷盆地深层/超深层油气成藏条件与成藏机制研究——珠江口盆地珠一坳陷”(KJGG2022‑0403)资助。

摘　　要：少井区烃源岩难以通过井震标定提取准确子波、构建精细低频模型。为此,提出根据盲信号理论的少井区烃源岩叠前地震反演预测方法。首先,根据盲信号理论,利用地震数据高阶统计量提取地震盲子波,再根据贝叶斯理论在复频域内估计模型参数的低频分量;然后,利用得到的地震盲子波及复频域低频模型在复频域内进行弹性阻抗反演;最后,利用烃源岩地震岩石物理模型构建弹性阻抗与烃源岩物性参数之间的关系,并通过弹性阻抗反演得到烃源岩的泥质含量、烃源岩指示因子等物性参数,从而预测少井区烃源岩的空间分布特征,定量评价烃源岩。该方法中,地震子波盲提取是一种统计性子波提取方法,不需要井数据参与,可为少井区烃源岩的叠前地震反演提供先验约束,解决了无井或少井区无法进行确定性子波提取的问题。模型试算和实际资料应用结果均表明该方法可靠、准确。It is difficult to extract accurate wavelets and build fine low‑frequency models through well seismic calibration for hydrocarbon source rocks in few‑well areas.Therefore,a prestack seismic inversion prediction method for hydrocarbon source rocks in few‑well areas based on blind signal theory is proposed.First,according to the theory,the blind wavelets are extracted from the seismic data by higher‑order statistics,and the low‑frequency components of the model parameters are estimated in the complex frequency domain based on Bayesian theory.Then the blind wavelets and low‑frequency model are further employed for elastic impedance inversion in the complex frequency domain.Finally,the relationship between the elastic impedance and physical parameters of hydrocarbon source rocks is established by the seismic petrophysics model of hydrocarbon source rocks.Physical parameters such as the shale content and indicator of hydrocarbon source rocks are obtained by elastic impedance inversion to predict the spatial distribution features of hydrocarbon source rocks in few‑well areas and quantitatively evaluate hydrocarbon source rocks.In this method,the blind seismic wavelet extraction is a statistical method that does not require well data.The extracted blind seismic wavelet can provide priori constraints for the prestack seismic inversion of hydrocarbon source rocks in few‑well areas.The proposed method solves the problem that deterministic wavelet extraction cannot be performed in the no‑well or few‑well areas.The reliability and accuracy of this method are proven by the test results.

关 键 词：少井区 烃源岩预测 盲子波提取 复频域反演 岩石物理 弹性阻抗反演 

分 类 号：P631[天文地球—地质矿产勘探]