APPLICATION OF PARTIAL CRS-STACK METHOD TO ENHANCE SEISMIC DATASET OBTAINED FROM A COMPLEX GEOLOGICAL STRUCTURE

Ariesty R. Asikin(1) , Ekkal Dinanto(1) , Andri Hendriyana (1) , Rachmat Sule (1)(2) , and Adriansyah(3)

The application of Partial CRS-Stack method is
presented in this paper. This method is
introduced in 2009 and proved as an alternative
method that can produce excellent subsurface
image. The significant advantage of this method
is clearly seen when this method is applied to a
seismic data that is acquired from an area with
complex subsurface structures, in which the
results from conventional stacking method
cannot fulfill the interpreter needs. Since
Indonesian geological framework is dominated
by complex structures, the application of this
method will give a new hope in determining
subsurface structures in a better way.

The Partial CRS-stack method is tested by using
a seismic dataset, which is acquired from
eastern part of Indonesia. Since the seismic data
is obtained from an area with a complex
geological structure, the continuity of reflectors
cannot be seen clearly. To prove the ability of
Partial CRS-stack method, its result is compared
to the result obtained from the conventional
sequences.

The stacked section resulted from Partial CRS-
stack is much better than the result of
conventional one. This could be understood,
since the Partial CRS-stack method uses the
information of reflectors along fresnel zone,
instead conventional method that only uses
information in a CDP. During its calculation,
CRS kinematic wavefield attributes, e.g.
emergence angle (?), radius curvature of normal
ray (RN) and radius curvature of normal incident
point ray (RNIP) must be determined previously,
which indicates the location and behavior of
reflectors. Besides that, the Partial CRS-stack
has some additional advantages; firstly, one can
update velocity model that is obtained from
better quality of velocity spectral; and secondly,
the obtained supergather is amplitude preserved.

As a conclusion, the Partial CRS-stack method
is proved as a good alternative method to give
better seismic sections.  Because of this, the
interpretation of unclear  events that are seen in
the conventional stack section can be avoided.

Keywords: Partial CRS-Stack, CRS kinematic wavefield attributes, complex geological structures.

(1) Geophysical Engineering Department, Institut Teknologi Bandung, (2) Kyoto University, (3) EPTC – Pertamina