DISTRIBUTION AND HYDROCARBON POTENTIAL OF DATTA SANDS IN UPPER INDUS BASIN, PAKISTAN

Datta sands are producing oil and gas on commercial scale. It has collectively produced more than 1500 million barrels of oil from Toot, Meyal and Dhulian fields. In Pezu, Chonai and Marwat wells, porosity range from 17-30%. The discoveries of Chanda and Mela wells in the sandstone of Datta formation in Kohat sub-basin have made it more important. The formation is widely distributed in western part of the Salt Range and in Surghar, Shinghar, Shaikh Budin Hills in the Marwat Range and western Khisor Range. These delta front facies bear very good reservoir characteristics in thick sandstone beds that are cleaned and quartose. The formation also extends in Kala-Chitta, Hazara and Samana Ranges. The Jurassic sands provide good porosities in the area. The matrix porosity of Datta formation in Potwar ranges from 5% to 18%. Geochemical studies conducted by HDIP and OGDCL on well samples indicate that Datta formation of Jurassic age contain adequate amount of organic matter in some wells. The area contains overturned faulted anticlines, popup structures, or fault block traps. The structures in the area are considered to be formed by the combination of compressional tectonics and salt movement due to which reverse faults and thrusting are common.