Premium
COMMON REFLECTION POINT DATA‐STACKING TECHNIQUE FOR CONVERTED WAVES 1
Author(s) -
TESSMER G.,
BEHLE A.
Publication year - 1988
Publication title -
geophysical prospecting
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.735
H-Index - 79
eISSN - 1365-2478
pISSN - 0016-8025
DOI - 10.1111/j.1365-2478.1988.tb02186.x
Subject(s) - shear waves , offset (computer science) , reflection (computer programming) , stacking , seismic wave , reflector (photography) , point reflection , love wave , mathematical analysis , geology , optics , physics , wave propagation , longitudinal wave , geometry , mechanical wave , shear (geology) , geophysics , mathematics , computer science , programming language , petrology , light source , nuclear magnetic resonance
ABSTRACT For converted waves stacking requires a true common reflection point gather which, in this case, is also a common conversion point (CCP) gather. We consider converted waves of the PS‐ and SP‐type in a stack of horizontal layers. The coordinates of the conversion points for waves of PS‐ or SP‐type, respectively, in a single homogeneous layer are calculated as a function of the offset, the reflector depth and the velocity ratio v p / v s . Knowledge of the conversion points enables us to gather the seismic traces in a common conversion point (CCP) record. Numerical tests show that the CCP coordinates in a multilayered medium can be approximated by the equations given for a single layer. In practical applications, an a priori estimate of v p / v s is required to obtain the CCP for a given reflector depth. A series expansion for the traveltime of converted waves as a function of the offset is presented. Numerical examples have been calculated for several truncations. For small offsets, a hyperbolic approximation can be used. For this, the rms velocity of converted waves is defined. A Dix‐type formula, relating the product of the interval velocities of compressional and shear waves to the rms velocity of the converted waves, is presented.