摘要
为了实现三维倾斜界面真正的共反射点叠加,获得更加精确的P波速度模型,进行可靠的AVO/AVA分析,形成与三维多分量PS转换波共转换点道集配套的技术,在常速介质共反射点精确走时的基础上,推导并给出三维倾斜界面P波共反射点道集近似双曲时距关系及NMO速度;认识到近似时距在偏移距与深度比小于2时具有较高的拟合精度;指出P波共反射点道集NMO速度是P波速度、界面倾角、界面倾向和测线方位的函数,且随测线方位变化而呈现椭圆特征.与P波共中心点道集NMO速度不同.P波共反射点道集NMO速度小于介质速度.且随界面倾角增大而减小;椭圆长轴方向为倾斜界面走向方位,短轴方向为倾斜界面倾向方位.
In order to realize stacking at Common-Reflection-Point gather from 3D dipping interface for P-wave, acquire more accurate P-wave velocity model, perform reliable AVO/AVA analysis and form technology matching with processing of PS-wave at Common-Conversion-Point gather, hyperbolic moveout and NMO velocity were deduced approximately from exact time-distance relationship. Moreover hyperbolic moveout compared with theoretical travel time has high fitting precision when x/z is less than 2. The NMO velocity of P-wave at Common- Reflection-Point gather from 3D dipping interface is the function of P-wave velocity in the media, dip angle, strike and azimuth of the survey line,and is showing elliptical features varied with the azimuth of the line. The NMO velocity is less than the media velocity and decreased as dip angle increased. The major axis of NMO velocity ellipse represent for the strike of dipping interface, the minor axis of the ellipse is consistent with the orientation of dipping reflector.
出处
《地球物理学进展》
CSCD
北大核心
2012年第4期1633-1639,共7页
Progress in Geophysics
基金
中国地震局地质研究所基本科研业务专项(DF-IGCEA-0607-1-1)
国家自然科学基金(41104076
41104026
40874029)
国家科技重大专项(2011ZX05035-001-002
2011ZX05035-003-006HZ)资助
关键词
三维倾斜界面
共反射点道集
NMO速度
3D dipping interface, Common-Reflection-Point gather, NMO velocity
