Seismic attribute and structural style of Miano field, lower Indus basin, Pakistan (T-1492) (MFN 4277)

Abstract

The study area, located in Lower Indus Basin, Pakistan, is selected for the structural and attributes analysis. Eight horizons are marked and named after correlating with well tops of Miano-08 and then in whole area. In time structure map, it is found that the area has undergone transtentional tectonics that causes negative flower structures. Negative flower structures divide the area from Eocene age to Cretaceous age into horst and graben. After Cretaceous only single major fault extends up to Chiltan Formation of Jurassic age. In provided data only one well Miano-08 is producing whereas Gajwaro-01 is abandoned. “B” Sands of Lower Goru Formation acts as reservoir in well Miano-08, shale within Sembar acts as a source. Shale in Lower Goru formation and Upper Goru formation acts as seal for reservoir. Isopach maps are made for the formations of various ages that give thickness trend for these formations. According to Isopach maps, shallow formations have more thickness in center of the area as compared to the edges. Whereas in deeper part (from Cretaceous) thickness of the formations increase towards the eastern side of area. This indicates that source of deposition for these formations were on eastern side at time of deposition. Seismic attributes are applied to identify the lithological distribution, structural deformation of the strata and for identifying the presence of hydrocarbon in the area. RMS (root mean square) amplitude and Instantaneous frequency attributes are used for the purpose of identifying the lithological distribution and their lateral discontinuities. Variance attribute is used for identification of the structural deformation, whereas sweetness attribute is used to identify the possible location of hydrocarbon presence. Sweetness attribute shows the presence of hydrocarbon at reservoir level on seismic section P2092-114 near well Miano-08 location that is producing, but for abandoned well Gajwaro-01 on seismic section PSM 96-115, hydrocarbon presence is not found at reservoir level.