AVO Analysis - By Haseeb Ahmed M.Phil Geophysics Institute of Geology University of the Punjab AVO ANALYSIS Amplitude versus offset(AVO is primarily the

AVO Analysis - By Haseeb Ahmed M.Phil Geophysics Institute...

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By Haseeb Ahmed M.Phil Geophysics Institute of Geology, University of the Punjab AVO ANALYSIS
Amplitude versus offset (AVO) is primarily the variation in seismic reflection amplitude with change in distance between shot point and the receiver Its another name is AVA (amplitude variation with angle) AVO analysis is conducted on CMP data
FIG. SHOWING AVO (A) & (B)
AVO INTRODUCTION It can physically explain presence of hydrocarbon in the reservoirs and the thickness, porosity, density, velocity, lithology and fluid content of the reservoir of the rock can be estimated.
THE ZOEPPRITZ EQUATIONS Zoeppritz derived the amplitudes of the reflected and transmitted waves using the conservation of stress and displacement across the layer boundary which gives four equations with four unknowns. Inverting the matrix form of the Zoeppritz equations gives us the exact amplitudes as a function of angle
THE ZOEPPRITZ EQUATIONS 1 1 1 1 1 2 1 P 1 2 S 2 2 1 P 1 2 P 2 1 1 P 1 S 1 2 2 1 S 1 1 P 2 S 2 1 2 P 2 1 S 1 1 P 2 2 S 2 1 1 S 1 P 1 2 2 1 1 2 2 1 1 S P S P 2 cos 2 sin cos sin 2 sin V V 2 cos V V 2 sin V V 2 cos 2 cos V V V 2 cos V V V V 2 cos V V 2 sin sin cos sin cos cos sin cos sin T T R R
THE AKI-RICHARDS EQUATION The Aki-Richards equation is a linearized approximation to the Zoeppritz equations . The initial form (Richards and Frasier, 1976) separated the velocity and density terms: S S P P V V c b V V a R ) (
THE AKI-RICHARDS EQUATION Where; , sin 4 , sin 2 5 . 0 , cos 2 1 2 2 2 2 2 P S P S V V c V V b a . 2 , , 2 , , 2 , , 2 1 2 1 2 1 2 1 2 1 2 1 2 t i S S S S S S P P P P P P and V V V V V V V V V V V V
WIGGINS’ VERSION OF THE AKI-RICHARDS EQUATION A more intuitive, but totally equivalent, form was derived by Wiggins .

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