Investigating geochemical characteristics of the Asmari reservoir oils in Qaleh-Nar oilfield, SW Iran

A collection of 4 crude oil samples from Asmari reservoir in Qaleh-Nar oilfield (SW Iran) were subjected to the organic geochemical analyses, including SARA fractionation and gas chromatography (GC). The obtained results represent that the studied samples, which are classified as paraffinic oils on the SARA ternary diagram, are thermally mature (CPI~1) and moderately biodegraded. The pristane/phytane ratios (<1) and TAR values (~0.5) as well as the cross-plots of Pr/nC17 vs. Ph/nC18 and Pr/Ph vs. CPI show that the crude oil samples have been originated from a marine source rock mainly containing type II kerogen, deposited in the reducing condition. The star diagram based on Pr/nC17, Ph/nC18 and the ratios of odd- to even-numbered n-alkanes in the range nC17-nC32 for two oil samples taken from western and eastern flanks of the oilfield shows a good correlation between them, indicating that the Asmari reservoir oils in Qaleh-Nar oilfield have a common genetic family, derived from the same source rock.

کلیدواژه ها:

Dezful Embayment ، Qaleh-Nar oilfield ، Asmari reservoir ، SARA analysis ، gas chromatography (GC) ، petroleum geochemistry