Reservoir characterization using spectral decomposition and post stack seismic inversion of Latif area

Abstract

Identifying stratigraphic traps for hydrocarbon exploration is quite difficult and is risky to interpret using seismic data only hence integrated study is required. Seismic interpretation in such cases provide basis to extend the study. Latif 3D seismic interpretation is perfollned as three reflectors C-interval, C-Sand and B-Interval are marked and their time and depth maps are generated. Petorphysics helped in calculating crucial parameter and inspecting quality of reservoir as porosity, volume of shale and water saturation are calculated using Latif-06 well. Cross plotting various parameters proved good quality of reservoir showing high effective porosity (17%), low water saturation (26%) and low shale volume «30%). 3D seismic attribute has become one of the most important tool in hydrocarbon exploration. Seismic attributes have recently established a high success rate due to high resolution. Prospect zones are generally not continuous laterally and also vary lithology wise, successful placement of well requires the analysis for relevant attribute. Reservoir sand are identified using coherency attribute and acoustic impedance attlibute. Bandwidth attribute improved seismic data quality as it removed the bad signals. Spectral decomposition is used to find the optimum frequency to image the reservoir sands which came out to be 30 Hz. 3D seismic data volume is transfollned into acoustic impedance through post stack seismic inversion which integrates the seismic data and well data. As compared to conventional seismic data analysis for stratigraphic interpretation acoustic impedance inversion provides the better results. Model based and sparse spike inversion is applied and reservoir sands are identified as low impedance. Comparing the results for both inversion techniques showed the model based inversion invelis the data more accurately. Lastly the effective porosity is invelied from model based inverted cube and result matched the petrophysical results as 18% porosity was estimated.