VSP正演模拟研究西湖凹陷多次波形成机制  

Using VSP Forward Modeling to Study Multiples Forming Mechanism in Xihu Depression

作　　者：张雷 刘卓亚[2] 

机构地区：[1]中海石油(中国)有限公司上海分公司 [2]中国地质大学,北京

出　　处：《中国石油勘探》2014年第4期62-69,共8页China Petroleum Exploration

摘　　要：西湖凹陷地震资料品质普遍较差,其主要原因是该区地震地质条件的显著特点是砂泥岩薄互层发育,速度和密度不存在大的突变或大的台阶状变化,难以形成强反射界面,决定了地震层间多次波发育。众所周知,地震多次波压制一直是地球物理学界的难题,为了解决这一难题,利用VSP正演模拟研究西湖凹陷的多次波形成机制,识别产生多次波的主要界面或层段,为数字处理中压制多次波提供依据。研究思路是以西湖凹陷实际钻井资料为基础,研究多次波的运动学规律与动力学特征,然后用VSP正演模拟等手段找出产生多次波的主要层段或界面,确定多次波的相对强度及影响有效波的主要多次波类型。研究结果得知该区所有较强的反射界面都可产生多次波,影响地震成像质量的多次波类型是各种不同路径的多次波叠加后的复合多次波。Usually, the quality of seismic data of Xihu Depression is not quite well. The main reasons result from the characteristics of the seismic geological conditions in this area, such as development of thin sand-shale interbedding, no abrupt change or big bench between velocity and density, and difficult to form strong reflection interface, leading to development of multiples in seismic intervals. It is well-known that seismic multiples suppression is always a bottleneck in geophysics. To solve this bottleneck, VSP forward modeling is used to study the multiples forming mechanism of Xihu Depression in order to identify the main interfaces and horizons of multiples and provide the basis for suppression of multiples in digital processing. The dynamic laws and dynamic characteristics of multiples are studied on the basis of the data from actual drilling in Xihua Depression. Then VSP forward modeling is used to find the main horizons and interfaces of multiples and determine the relative strength of multiples and the types of main multiples affecting effective seismic waves. The research results indicate that all strong reflection interfaces in this area can produce multiples. The multiples that affect the quality of seismic imaging are compound multiples stacked with multiples from the different paths.

关 键 词：西湖凹陷 多次波 VSP正演模拟 形成机制 

分 类 号：P631.4[天文地球—地质矿产勘探]