An approach to porosity prediction from direct inversion of post stack seismic data

In general, 2D Post stack seismic inversion is used to estimate detailed petrophysical properties from conventional seismic data. Seismic inversion transforms a seismic section into acoustic impedance. The resulting impedance section can be used to predict reservoir properties like porosity through integration of some interpretation steps and knowledge about the geology of the reservoir. An unusual approach to porosity prediction from direct inversion of post stack seismic data is carried out in parts of Upper Assam basin, which constitutes one of the most important onshore petroleum provinces in India. Main task of this study is to perform 2D post stack seismic inversion to create a porosity section directly from seismic data. An empirical relation between porosity and acoustic impedance reflectivity has been carried out to generate a porosity wavelet which is used in creating a low frequency model and inverted porosity section. The described method for direct inversion of porosity from seismic data allows us to delineate petrophysical property directly. This results in better resolvability and a better link between the seismic data and the actual lithology. The resulting porosity section shows a good comparison with the general trend of geology of the study area.