Structure and Internal Geometry of the Northern Sulaiman Frontal Ranges, Pakistan: A Better Understanding Towards the Hydrocarbon Potential of Range Fronts Having Foreland-Dipping Monocline

Ahmad, Sajjad ¹; Khan, Moin Raza ²; Khan, Nasir ³; Adhami, Asad Mumtaz ²
(1)Geology Department, Peshawar University, Pakistan, Peshawar, Pakistan. (2) Exploration, Pakistan Petroleum Ltd., Karachi, Pakistan. (3) Exploration, Zhenhua Oil Pakistan, Islamabad, Pakistan.

Commonly the mountain fronts are less explored parts of orogenic belts mainly because of their poor seismic imaging and structural understanding. One of such orogenic fronts is associated with the northern Sulaiman fold belt located along the western transform border of Pakistani Himalayas. The mountain front of northern Sulaiman fold belt consists of foreland-dipping major monocline of the Sulaiman fore deep. The monocline is structurally uplifted along the orogenic front by the East Domanda Fault which is a north south trending and east-dipping regional scale back thrust with concomitant left lateral wrenching. Current structural mapping and modelling conducted in the eastern frontal parts of northern Sulaiman fold belt have revealed the presence of a regional scale, east-verging antiformal stack, comprised of Mesozoic to Eocene rocks having proven petroleum system in the region. Genesis of this antiformal stack is related to east-directed ramping from base Cretaceous detachment. This structural assemblage as a whole is thrust over by the East Domanda Fault giving rise to wedge shape geometry in the subsurface. These types of complex geometric patterns are when coupled with thick shale overburden, the problem of seismic imaging becomes further complicated and hence the hydrocarbon potential of such orogenic fronts remains largely unexplored.

AAPG Search and Discovery Article #90135©2011 AAPG International Conference and Exhibition, Milan, Italy, 23-26 October 2011.