摘要
薄层和薄互层油气藏的开发越来越受到重视,但由于地震资料对薄层的分辨能力有限,且传统的褶积模型无法模拟出薄层中复杂的波场传播现象,导致这类储层的地震预测难度较大。针对这一问题,本文以层状介质中的传递矩阵法为基础,发展了一种垂直入射时的反射率法,并运用该方法对多组典型的薄互层模型做正演模拟,然后对正演模拟的结果做频谱分析,研究薄互层对地震反射波的滤波效应。相较于层状介质中的传递矩阵法,垂直入射时的反射率法在更适用于纵波入射下的薄互层研究的同时,大大提升了反射率法正演的效率;而在频域对薄互层反射滤波效应做研究也在一定程度上解决了时域上分辨率不足的缺点。对于薄互层模型的频谱分析结果表明,垂直入射时的反射率法能较好地保留薄互层的层间信息,对根据该方法得出的正演结果做频谱分析,频谱曲线的幅值和陷波点的变化能反映出薄互层中互层数和砂泥比的变化情况,这对于油田后期的精细勘探阶段中薄储层空间展布规律及其性质的确定具有重要的意义。
The exploitation of thin-bedded and thin-interbedded hydrocarbon reservoirs has garnered increasing attention.However,seismic data of thin-bedded reservoirs exhibit low resolution,and conventional convolution models fail to simulate the complex wave field propagation phenomena in thin-bedded reservoirs,complicating the seismic prediction of such reservoirs.Hence,based on the transfer matrix method for layered media,this study developed a normal-incidence reflectance method.Using the new method,it conducted forward modeling on several typical thin-interbedded reservoir models.Then,the forward modeling results were analyzed through frequency spectrum analysis to explore the filtering effects of thin-interbedded reservoirs on seismic reflection waves.Compared to the transfer matrix method for layered media,the normal-incidence reflectance method is more applicable to the investigation of thin-interbedded reservoirs under longitudinal wave incidence,significantly enhancing the forward modeling efficiency.Moreover,studying the reflection filtering effects of thin-interbedded reservoirs in the frequency domain somewhat eliminates the shortcomings of insufficient resolution in the time domain.The frequency spectrum analysis of thin-interbedded reservoir models shows that the normal-incidence reflectance method can effectively preserve the interbed information of thin-interbedded reservoirs.As revealed by the frequency spectrum analysis of the forward modeling results based on this method,the changes in the amplitudes and notch points of frequency spectrum curves can reflect the changes in the number of interbeds and sandstone-mudstone ratios in thin-interbedded reservoirs.This finding is critical for determining the spatial distributions and properties of thin-bedded reservoirs in the fine-scale exploration of oilfields.
作者
罗敬
孙成禹
LUO Jing;SUN Cheng-Yu(School of Geosciences,China University of Petroleum(East China),Qingdao 266580,China)
出处
《物探与化探》
CAS
2024年第4期996-1005,共10页
Geophysical and Geochemical Exploration
基金
国家自然科学基金项目(42174140)。
