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%) and raised saturates/aromatics ratio (Sat/Aro > 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 (< 10%) and moderate C₃₅/C₃₄ homohopane (< 1) are consistent with the mixed marine–terrigenous dysoxic organic matter input. The oils are assumed to be originated from Early Cretaceous source rocks at the peak of the oil generation window in a kitchen area located to the south of the studied region (i.e., the Binak–Borazjan Trough). The hydrocarbons were migrated from this kitchen to the structurally shallow-seated reservoirs in the center and west of the Kharg-Mish local paleo-high. The Khami Group reservoirs are not effectively sealed by the thin Hith anhydrites, and the Kazhdumi Formation finally trapped the migrated hydrocarbons. This study improves our knowledge regarding one of the active petroleum systems in the South Dezful Embayment, enhancing petroleum exploration success by navigating further drillings into the more prosperous targets.

中文翻译：

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伊朗南部Dezful Embay内Khami Group油的地球化学评价

对来自Khami Group油藏的一套油样进行了包括GC，GC-MS和稳定碳同位素分析在内的综合地球化学研究，以提供对南Dezful沉积区上侏罗统-下白垩统石油系统的新见解。还使用Rock-Eval热解法对可能的烃源岩进行了表征，以解决可能的潜在烃源岩。根据体积和生物标记参数，代表四个主要油藏（苏尔梅，法赫利扬，加德万和达里扬）的油样构成一个单一的遗传油族。高API（> 38°），高饱和烃（Sat> 65％），非常低的沥青质含量（Asp <2％）和提高的饱和物/芳烃比（Sat / Aro> 2）是所研究油类的大量诊断特征，表明前体有机物具有更主要的陆源性。C的优势_29种常规甾烷（〜40％），存在C ₂₉ Ts以及极低的γ-甘油（<10％）和中等C ₃₅ / C ₃₄高耸（<1）与海洋-陆源低氧有机质混合输入一致。假定这些油来自于研究区域南部（即Binak–Borazjan槽）南部一个厨房区域中产油窗峰值处的早白垩世烃源岩。碳氢化合物从该厨房迁移到了Kharg-Mish局部古高中西部的结构较浅的储层。Khami Group储层没有被稀薄的Hith硬石膏有效地封闭，而Kazhdumi组最终捕获了运移的碳氢化合物。这项研究提高了我们对南德兹富尔河道的一个活跃石油系统的认识，并通过进一步钻探更繁荣的目标来提高石油勘探的成功率。