基于地质模型的无井区复频域地震反演方法  

Complex frequency domain seismic inversion method for well⁃free area based on geological model

作　　者：袁航 瞿晓阳 包凯 YUAN Hang;QU Xiaoyang;BAO Kai(Sinopec Chongqing Shale Gas Co.LTD,Chongqing 408400,China)

机构地区：[1]中石化重庆页岩气有限公司,重庆408400

出　　处：《石油地球物理勘探》2024年第3期558-566,共9页Oil Geophysical Prospecting

摘　　要：对基于模型的反演方法而言,合理的初始模型不仅可以补偿缺失的地震低频信息,也能提高地震反演精度和稳定性。然而,在无井或少井区,地球物理反演面临数据匮乏、资料品质不高的问题,难以直接从井数据中得到较丰富的低频信息,因此获取低频模型是无井区地球物理反演和油藏特征描述的关键。为此,针对新区勘探探索了一种基于地质模型的无井区复频域地震反演方法。首先,在考虑断层影响的基础上,参考地震相定性指导宏观趋势,融合了道积分的低频相对变化,充分运用无井区的地质、地震数据,为无井区反演提供可靠的低频信息。之后,根据复频域反演挖掘地震数据低频信息,将无井初始模型作为复频域反演的低频模型,结合盲信号理论提取地震盲子波,最终得到补充低频信息的复频域无井低频模型,可在一定程度上缓解无井区地震反演的低频成分缺失问题。最后,利用模型和实际工区数据测试了新方法的效果。结果表明,复频域无井反演弹性阻抗与井上弹性阻抗曲线拟合良好,与有井稀疏脉冲反演结果相比,尽管局部精度略低,但复频域无井反演结果的总体趋势及储层展布特征与有井反演结果基本一致,证明了所提方法在无井区的有效性。For model-based inversion methods,a reasonable initial model can not only compensate for the mis-sing low-frequency seismic information but also improve the accuracy and stability of seismic inversion.Ho-wever,in areas with no or few wells,geophysical inversion is faced with the problem of lack of data and low data quality,which makes it difficult to obtain abundant low-frequency information directly from the well data.Therefore,obtaining a low-frequency model is the key to geophysical inversion and reservoir characterization in the well-free area.In view of this,a complex frequency domain seismic inversion method for a well-free area based on a geological model is explored for the new exploration area.Firstly,by considering the influence of faults and referring to the seismic facies to guide the macro trend qualitatively,the relative change of the low fre-quency of the trace integral is integrated,and the geological and seismic data of the well-free area are fully used to provide reliable low-frequency information for the inversion of the well-free area.Then,the low-frequency information of seismic data is mined according to the complex frequency domain inversion,and the well-free ini-tial model is used as the low-frequency model for the complex frequency domain inversion.The seismic blind wavelet is extracted according to the blind signal theory,and the well-free low-frequency model in the complex frequency domain can be obtained to supplement the low-frequency information,which can alleviate the prob-lem of missing low-frequency components of the seismic inversion in the well-free area to a certain extent.Fi-nally,the effect of the new method is tested by using the model and actual working area data.The results show that the elastic impedance curves of the well-free inversion in the complex frequency domain are well fitted with the borehole elastic impedance curves.Compared with the sparse pulse inversion results with well,although the local accuracy is slightly lower,the general trend and reservoir distributi

关 键 词：初始模型 低频模型 拉普拉斯变换 复频域反演 贝叶斯理论 

分 类 号：P631[天文地球—地质矿产勘探]