Respected Syed Tariq,
What do you think about the source origin Potwar Basin petroleum is salt range formation, Precambrian/Cambrian source rocks. ??
Interesting question but challenging to reply you with greater confidence due to several unknowns. Petroleum concentration in Potwar basin believed to be originated from early Paleocene Patala Formation.Even though, I am not sure how much this claim of the Patala as the principal source have authenticity as I don't know how much data of the source rock has been made public for the benefit of general geology enthusiasts and students> Atleast, there are some very nice company specific reports available in government database which I have reviewed. Probably HDIP might have large dataset for source rocks of Pakistan and they are regularly releasing information through their organ technical publication.
A flimsy paper, published by USGS Patala-Nammal Composite Total Petroleum System,(2004) mentioned about various horizons under the sun in that paper for Kohat-Potwar basin-a claim without any evidence
Salt Range Formation (SRF)has been authentically validated as a potential source by analyzing various outcrop samples collected throughout Salt Range starting from Khewra Gorge in eastern Salt Range up to near Kala Bagh area in the western Salt Range. The SRF has oil shale and low grade shale oil with limited to consistent lateral extent. High TOC have been found in outcrop samples and has oil shales in Dulmial-1 well where TOC was up to 47% and most of the samples have proven increasing genetic potential.
Heavy oil from SRF was first time appeared in Karampur-1 well which was drilled by Shell in 1958 in Punjab Platform. The key factor for any organic rich source rock is the temperature conditions rock subjected to be and apparently despite being organically rich rock SRF found to be thermally not fully mature particularly true in Punjab platform area.
However, if we are able to determine the zone of High TOC oil shale in subsurface oil can be obtained through unconventional production method as we have observed in Canada only if economics allowed and we have resources and know the technology and its application
As far as the Cambrian source potential its not generally considered as source or potential source rock in Pakistan