地震分辨率极限问题的研究

Study of seismic resolution limit.

地震分辨率一直是薄储层和岩性地震勘探研究的主要问题,也是困扰地球物理发展的问题之一。地震分辨率分为垂向(时间)和横向(空间)分辨率,通常教科书和有关的文献均将l/4地震波长定义为时间分辨率的极限,即使按菲涅尔半径定义的空间分辨率的极限,也为1/4地震波长。根据地震视主频和目的层的速度可以计算出空间和时间地震分辨率(1/4波长)极限。按常规的分辨率理论,地震勘探难以获得小于l/4波长储层的地质信息,若想获得小于1/4波长的储层信息,必须提高地震的成像主频。但对于实际地震数据而言,垂向(时间)分辨率受大地吸收衰减和高频信噪比的影响,地震分辨率总是有限的,难以满足地质解释的要求,特别针对中国陆相薄储层更是如此。但地震勘探是否可以突破1/4波长分辨率极限,针对这一问题,本文通过多块三维实际地震数据的研究,表明在相对保持振幅、频率、相位和波形的处理条件下,结合合理的井信息标定和地震属性提取,地震勘探是可以突破l/4波长地震分辨率极限的,这为中国陆相薄储层的地震勘探提供了十分重要的理论基础。

Seismic resolution is always the key issue in thin reservoir and lithologic seismic exploration and is also one of the main problem that is a trouble to geophysical development.Seismic resolution is divided into vertical (time) and lateral(space) resolution.Generally,the 1/4 wavelength of seismic wave is defined as the limit of seismic resolution in notebooks and related literatures,even if according to the Fresnel radius to define the limit of spatial seismic resolution,it is also 1/4 seismic wavelength.It can compute the seismic resolution limit in time and space (1/4 wavelength) according to seismic apparent dominant frequency and the velocity of targets.It is difficult to obtain the geologic information less than 1/4 wavelength by using seismic interpretation according to ordinary resolution theory.If you want to obtain the reservoir information less than 1/4 wavelength,it must raise the dominant frequency of seismic imaging.Because the vertical(time )resolution is affected by attenuation by earth absorption and high S/N ration for practical seismic data,the seismic resolution is limitation and is difficult to meet the needs of geologic interpretation,especially for continental thin reservoirs in China Abstract:.But can the seismic exploration breakthrough the 1/4 wavelength of resolution limit ? Faced with the problem,it is showed by study of many blocks of 3 D seismic data processing that in a processing condition of relatively preserved amplitude,frequency and phase and combining with reasonable drilling information labeling and seismic attributes detection,the paper considered that the seismic exploration can breakthrough the 1/4 wavelength of seismic resolution limit, which provided an important theoretical basis for seismic exploration of continental thin reservoir in China Abstract:.