QUANTITATIVE SEISMIC INTERPRETATION OF LOWER GORU FORMATION IN KADANWARI AREA, MIDDLE INDUS BASIN, PAKISTAN

Abstract

Middle Indus Basin is an excellent hydrocarbon prone area comprises of many producing fields. Kadanwari field is located in Middle Indus Basin Pakistan, which is comprised of structural cum stratigraphic traps along with other petroleum system elements. The faults are providing the seal at the level of Lower Goru formation. In the western part of block, Lower Goru G sand has been producing whereas the E and D are contributing in the Eastern part. The aim of the present study was to analyze the architecture and hydrocarbon potential of Lower Goru formation in north eastern part of Kadanwari area, by carrying out quantitative seismic interpretation on the given dataset including limited 3D seismic volume of 12 km² and two wells named Kadanwari-10 (K-10) and Kadanwari-11 (K-11). Structural seismic interpretation was utilized in the 3D seismic volume, which is followed by the generation of depth maps. Multi attribute analysis is performed in which structures at the reservoir level are further confirmed by utilizing variance, chaos, curvature, instantaneous and cosine of phase attributes whereas the reservoir quality is estimated through the attributes i.e., relative acoustic impedance and Root Mean Square. Petrophysical analysis was carried out on the wells for the estimation of reservoir properties including effective porosity, volume of shale and water saturation, etc. Post stack seismic inversion had been performed in which the model based technique was utilized for the desired results. Structural interpretation revealed the presence of two steep to vertical faults providing the lateral seal to the Lower Goru prospective zones. Seismic attributes such as variance, chaos, instantaneous phase and curvature did not contribute much in the delineation of small fractures and discontinuities. Relative acoustic impedance and RMS attribute provided the reservoir quality throughout the volume. Petrophysics marked the prospective zones in Lower Goru probable E Sand in both the wells where the porosities are ranging from 0.12 to 0.22, having low to moderate volume of shale about 0.05 to 0.26 and water saturation is in range of 0.12 to 0.38. Model-based seismic inversion applied on 3D seismic cube and wireline log data was helpful in predicting reservoir properties in the Lower Goru probable E Sand interval. The integrated study has gained some success to determine the reservoir properties spatially and between the interfaces in the given seismic cube, thus providing more clue for the exploration in nearby area.