Seismic attributes are known as the seismic data components, which are obtained by computation, measurement, and other methods using seismic data. Seismic attributes can comprise measured time, frequency, amplitude, and attenuation, in addition to combinations of these and leading to a better geophysical and geological interpretation of the seismic data.
Also, the attributes can be derived or measured from typical post-stack of seismic data volumes, and these are the most common types. On the other hand, in an angle-stacks or pre-stack analysis, additional significant pieces of information can be obtained from the individual seismic trace attributes before stacking.
Angle stacks provide a means of accessing the amplitude versus offset (AVO) information of the data. These stack data provide a measurement of the reflectivity at a given angle. In this work, we used the Near and Far Angle stacks to detect the changes in lithology and fluid content in subsurface volumes of rock.
Also, the frequency-domain representation illustrates many significant features that are not obvious in the time domain. Spectral decomposition has progressed from being a tool for stratigraphic analysis to support as a Direct Hydrocarbon Indicator (DHI). The spectral decomposition technique has successfully been applied to the imaging and mapping of bed thickness, geologic discontinuities, and channel delineation.
Spectral analysis was always carried out for Full Stack data for picking the blending frequencies to help with stratigraphic interpretation by improving thin-bed resolution and showing temporal bed thickness variability.
In this research Spectral decomposition was carried out for different AVO angle stacks to delineate the boundaries of the reservoir and the fluid content.
The work has determined the most appropriate frequencies that could be blended to illuminate the presence of both reservoir and gas respectively and map them.
This paper discusses the methodology involved, the calibration, and the choice of the appropriate picking frequencies with the RGB blend colour code for the full stack and different partial angle stacks seismic data.
