| Summary: | Velocity model is a very important parameter in imaging subsurface
structures of seismic reflection method. Accurate velocity model will provide
accurate subsurface information, otherwise if the velocity model is not
appropriate, it will cause errors in interpretation. This study discussed the use of
constrained dix inversion to improve the velocity model which is usually
constructed using conventional dix transform (unconstrained dix inversion) for
pre-stack depth migration (PSDM) and seismic tomography.
Generally, the velocity model for PSDM was built by dix transform, there
are still a lot of noise (the value of sticking velocity). Then, to improve the
velocity model, we used constrained dix inversion method which utilizes the
velocity trend misfit and damping mechanism to eliminate the noise, so we get a
more stable of velocity model. The initial velocity model is used to pre-stack
depth migration, using Kirchhoff migration method. If seismic section in depth
domain is not matched with the depth of well marker, then the velocity model will
be fixed again using model based tomography method.
Interval velocity results of constrained dix inversion can minimize the
noise from dix transform results. Seismic section result of pre-stack depth
migration using the velocity model from constrained dix inversion as input, gives
better results than migration using the velocity model from conventional dix
transform as input.
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