Fault seal evaluation of lower sands of lower Goru formation by using seismic and well data: A case study of Jherruck block, lower indus basin, Pakistan

The Jherruck block is located in Lower Indus Basin in district Thatta, Pakistan. The area is bounded in east by Indian Kutch Basin, in the west by Kirthar Fold Belt, in south by Arabian Sea and in north by Sindh monocline. Twenty seismic lines and four well logs have been used for subsurface structural interpretation and identification. Lower Sands which include Middle Sand, Upper Basal Sand and Lower Basal Sand have reservoir potential and have been interpreted on seismic sections to generate time and depth surface maps. Surface maps recognized that Jamali Deep-1 well was drilled at appropriate crestal location of the structure. Using depth surface maps Allan diagram have been constructed for fault seal analysis. Results revealed that the middle sand was juxtaposed against hanging wall of D-Sand and hydrocarbons moved up dip towards D-Sand. Crestal location of Upper Basal Sand on footwall was juxtaposed against hanging wall of middle sand which acts as conduit lithology for hydrocarbons movement. Despite being complete petroleum play the well was unsuccessful to produce because of these sands juxtaposition.