Geochemical evaluation of Khami Group oils in the South Dezful Embayment, Iran
- PDF / 3,263,268 Bytes
- 14 Pages / 595.276 x 790.866 pts Page_size
- 70 Downloads / 176 Views
ORIGINAL PAPER-EXPLORATION GEOLOGY
Geochemical evaluation of Khami Group oils in the South Dezful Embayment, Iran Bahram Alizadeh1,2 · Amir Abbas Jahangard1 · Majid Alipour1 · Ahmadreza Gandomi Sani3
© The Author(s) 2020
Abstract An integrated geochemical study, including GC, GC–MS and stable carbon isotope analyses, was conducted on a suite of oil samples from the Khami Group reservoirs to provide new insights into the Upper Jurassic–Lower Cretaceous petroleum system in the South Dezful Embayment. Possible source rocks were also characterized using Rock–Eval pyrolysis to address the likely potential source rocks. The oil samples representing four major reservoirs (Surmeh, Fahliyan, Gadvan and Dariyan) constitute a single genetic oil family according to bulk and biomarker parameters. High API (> 38°), highly saturated hydrocarbons (Sat > 65%), very low asphaltene content (Asp 2) are the bulk diagnostic characteristics of the studied oils implying more dominant terrigenous nature of the precursor organic matter. The predominance of C29 regular steranes (~ 40%), presence of C29Ts as well as very low gammacerane ( 1.5) in the aromatic fraction suggest that the high sulfur content of the reservoir oils can be a result of higher thermal maturity (Huang and Pearson 1999; Hughes et al. 1995). Further evidence supporting the high maturity of studied oils is provided by the high concentrations of tricyclic terpanes relative to 17α-hopanes, the relatively large concentration of C 19–C22 regular steranes and the sterane isomerization ratios (Fig. 4). Homohopane isomerization ratios of C 32 22S/ (22S + 22R) can be used as a maturity index in crude oils and source rock extracts. The ratio rises from zero to 0.57–0.62 during the maturation, and its specificity is limited to the early oil generation window (Ro
Data Loading...
