Tectono-Stratigraphic Evolution of Zamzama Gas Field, Kirthar Fold Belt, lower Indus Basin, Pakistan (With Special Emphasis on Development and Distribution of Petroleum System Elements) (T-1434) (MFN 8322)

Abstract

The stratigraphic evolution of Kirthar Province of Kirthar Sub-Basin start from early Cretaceous to recent age where it undergoes many tectonic events that starts from Jurassic to Pliocene (±185 Ma). During this time the region was influenced by three distinct phases crustal extensions, Inversion and compressional phase resulting in a complex tectonic history. Structural Configuration of Kirthar Sub-Basin is characterized by thrusted anticline structure with fault propagation fold geometry that is trending in north south direction. This deformation creates shortening of 20% in southern Kirthar fold belt that is prior for hydrocarbon possible accumulation. The Fort Munro Formation of Kirthar Sub-Basin is the late cretaceous inner marine shale that provides source rock to the existing conventional hydrocarbon accumulation. Average thicknesses of Fort Munro Formation is ranging from 55 to 92 m, with average total organic carbon (TOC) of 1.5% that is thermally mature at temperature ranging from 150oC to 170oC lies in dry gas zone. The thickness and distribution of pab sandstone is gradually increasing from north to southern passive margin. Previous studies reveal that the Cretaceous sediments are thin and high in clay content northward. However, they can only provide a general stratigraphic framework and interpretation of the depositional environments. More detailed and reliable results can be achieved on the basis of core-log integration and hydraulic fracturing will play a crucial role in developing these potential passive accumulations.