Abstract The Shadegan oil field is one of the fields in the central part of the Dezful Embayment. Little or no geochemical studies have been performed previously in this field. This paper provides valuable information to answer most of the geochemistry ambiguities and issues in this field. Different techniques were used to investigate the genetic types of Asmari and Bangestan reservoirs. Structural characteristics of asphaltenes, biomarker fingerprints, and V/Ni ratio indicates that all oils in the Shadegan field have similar source rock(s) and belong to one oil family. The homologous series of normal alkanes distribution and the absence of 17α(H) 25-hopane reveals that biodegradation has not affected oil samples and planktons/algal or higher plants are dominating organic matters, proved by hopanes/steranes ratio. The Pr/Ph C27 > C28 pattern, and the ternary diagram of steranes confirmed that the source rock deposited in the open marine environment and oil samples originated from marine organic matters. All samples have been sourced from a source rock(s) older than the Upper Cretaceous, as shown by the oleanane ratio. The Kazhdumi Formation is the primary source rock in this field, and some contributions from other source rocks might have occurred. In general, samples indicate maturity before the peak of the oil window in which the Bangestan samples have lower maturity regarding the Asmari samples based on aromatic and saturate maturity parameters. The tracing of oil filling pathways by isopleth maps of 4-/1-MDBT and C29 sterane 20S/(20S + 20R) ratios revealed that each reservoir had been charged from several directions. Although the Upper Asmari and Bangestan reservoirs have been charged laterally, the Lower Asmari has been charged vertically and laterally.

中文翻译：

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伊朗西南部 Dezful Embayment Shadegan 油田的成因、地球化学特征和充注途径

摘要 沙德干油田是德兹富尔湾中部的油田之一。以前在该领域很少或根本没有进行地球化学研究。本文提供了有价值的信息来回答该领域的大多数地球化学模糊和问题。使用不同的技术来研究 Asmari 和 Bangestan 水库的成因类型。沥青质的结构特征、生物标志物指纹和 V/Ni 比表明，Shadegan 油田的所有油都具有相似的烃源岩，属于一个油族。正常烷烃分布的同源系列和 17α(H) 25-hopane 的缺失表明，生物降解并未影响油样，浮游生物/藻类或高等植物在有机物质中占主导地位，由 hopanes/steranes 比率证明。Pr/Ph C27 > C28 模式，甾烷三元图证实了开放海洋环境中沉积的烃源岩和油样来源于海洋有机质。所有样品均来自比上白垩统更古老的烃源岩，如齐墩果烷比率所示。Kazhdumi 组是该油田的主要烃源岩，可能有其他烃源岩的贡献。一般来说，样品表明在油窗口峰值之前的成熟度，其中基于芳香和饱和成熟度参数，Bangestan 样品相对于 Asmari 样品具有较低的成熟度。通过 4-/1-MDBT 和 C29 甾烷 20S/(20S + 20R) 比值的等值线图对石油充注路径的追踪显示，每个储层都已从多个方向充电。