Abstract:
Potwar Sub-Basin is a Himalayan foreland fold and thrust belt in the
Upper Indus Basin of Northern Pakistan. The Potwar Sub Basin is Pakistan's
traditional oil-producing region, the basin has various formations that are
essential for oil and gas development in the region, and it is one of Pakistan's
most productive hydrocarbon-bearing sedimentary Basins. The Salt Range
Formation, Khewra Sandstone, and Patala Formation are all probable source
rocks in the Adhi oil field, whereas the reservoir rocks are Khewra Sandstone,
Tobra Formation, and Sakesar Limestone. Due to the mismatch of source and
depositional environments of organic matter, biomarkers and bulk stable
isotopes were previously utilized to evaluate oils in the Potwar Basin of
Pakistan. Saturated and Aromatic biomarker distributions were used to classify
crude oils from the Potwar Basin, and the results were previously published
but we know very little about the source potential and secondary alterations
based on Light hydrocarbons characterization of Potwar Sub Basin. The
geochemical characterization of Light hydrocarbons of Adhi Oil Field oil
samples and their correlation is carried out using Thompson’s (1983) and
Mango’s (1994) parameters. These parameters were used for the assessment of
thermal maturity, organic input, source rock identification and secondary
alterations. Five oil samples (A-10, A-11, A-15, A-16, A-17) of Adhi oil Field
were studied for geochemical characterization. The parameter used for thermal
maturity (Thompson’s 1983) revealed that the oil samples are normal oils
except the sample A-11 which is Mature. The source related parameters
indicates that oil samples have the same terrigenous source for hydrocarbons.
The secondary alterations assessment parameters showed that none of the oil
sample is biodegraded. The Aromaticity versus Paraffinicity and C₇ oil
correlation star diagram represent that the oil samples are slightly altered by
Evaporative Fractionation.
