Application of Partial CRS Stack Method to Determine Class of AVO in Gas Reservoir: Synthetic Case Study


Similar to CRS-Stack method that is developed previously, the Partial CRS-Stack that presented
in this paper has advantage, which is can providing more traces in the resulted CDP supergathers. This
method was introduced in 2009 and proved as an alternative method that can produce excellent
subsurface image. Beside of that, theoretically, the characterization of gas reservoir can be done more
easily and clearly if it is conducted in the CDP supergather rather than normal CDP gather.
The Partial CRS-stack method is tested by using a synthetic seismic dataset, which was made
from a complex geological structure model that contains a gas reservoir. One of the reason why the
stacked section resulted from Partial CRS-stack is much better than the result of conventional one is
because this new method uses the information of reflectors along Fresnel zone, instead conventional
method that only uses information in a CDP. With an assumption that the CRS Supergather is a preserved
amplitude data (after Baykulov, 2008), we would like to prove its ability in conducting gas reservoir
characterization by applying this method to synthetic dataset, e.g. by determined the class of AVO by
using the cross plot analysis. As we know that class of AVO is divided into several classes and each class
has its own characteristic in cross plot analysis. Cross plot analysis is a plotting between intercept versus
gradient so we can know about type of rock that we had in the reservoir.
Since the quality of the seismic data increases, the results of cross plot analysis could show the
type of reservoir in a better way. The Partial CRS-stack method also 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 and also it can enhance the analysis of gas reservoir