Reservoir characterization of Sands of Cretaceous Age, Lower Goru Formation Using Seismic and Well Data of Badin area, Lower Indus Basin, Pakistan (T-1538) (MFN 6264)

Abstract

The study area, Jabo Field within the Badin block, lies in Badin district, Sindh. The area of investigation is situated between Thar Desert and coastal stretches of the Arabian Sea. Major objective of this research is to characterize reservoir potential and to exploit channel reservoirs of Lower Goru B sands. To resolve this issue, advanced seismic techniques like seismic inversion and seismic attribute analysis have been used along with the seismic interpretation and petrophysical analysis of Badin area, Pakistan. Normal faults are present with NW-SE orientation with horsts and graben structures. The closure formed by the horst structure may be consider to be favourable zone for hydrocarbon accumulation. Seismic attribute analysis like spectral decomposition helps to compare the frequency ranges at Lower Goru B sands level. Spectral decomposition indicates the presence of thin bed at Lower Goru B sands level. The bright spots have not been confirmed by trace envelope attribute but high amplitude is present at reservoir level that may be due to change in lithology or encounter of compact lithology. Relative acoustic impedance attribute indicates low acoustic impedance values and this may be considered as the highly porous reservoir zone. Seismic inversion techniques have been applied on the study area. Colored inversion technique indicates the intermediate to low acoustic impedence and high porosity at reservoir level that is enveloped by high acoustic impedance layers from top and bottom so it suggests the incompetent layer has been enclosed by competent layers. Model based inversion also indicates intermediate acoustic impedence values at reservoir level enclosed by less porous layers from top and bottom. Petrophysical analysis showed that three zones are present in Jabo-01 and Jabo-05 wells. Promising reservoir zones in Jabo-01 well are 17 meters and two zones of significant thickness are present in Jabo-05. The zones in Jabo-01 are 3.2 meters, 5 meters and 4.3 meters thick with 32%, 49% and 59% hydrocarbon saturation respectively while the zones in Jabo-05 well are 16 meters and 17 meters with 57.4% and 62.9% hydrocarbon saturation respectively. Overall, seismic data interpretation, petrophysical analysis, high amplitude at reservoir level indicated by attribute analysis and the results from colored and model based inversion supports the presence of significant amount of hydrocarbons present in Lower Goru B sands in the study area.