Petroleum Geochemistry of Lower Indus Basin, Pakistan: II. Oil-oil and Oil-source Rock Correlation

Nine crude oils and eight source rock samples from Cretaceous sequences, Lower Indus Basin have been characterized by means of diagnostic biomarker parameters in order to establish genetic liaison among them. The biomarker geochemistry indicators such as relative distribution of C27-C28-C29 ααα-20R steranes, C19 and C23 tricyclic terpanes (TT), C24 tetracyclic terpanes (TeT), hopanes distribution, steranes/hopanes ratio, presence of unidentified compound X (C30 pentacyclic triterpane), and pristane (Pr) to phytane (Ph) ratio suggest that the crude oils contain predominantly terrigenous organic matter (OM). Based on these data, the analyzed crude oils from the Lower Indus Basin are genetically associated and could be classified into a single group. Geochemical correlation studies of crude oils and source rock sediments indicate that Lower Goru shales and Sembar could be the probable source rocks for the petroleum generated from Cretaceous strata, Lower Indus Basin, Pakistan.