Hakimi Mohammed Hail, Alqudah Mohammad, Mustapha Khairul Azlan, Kahal Ali Y, Lathbl Mahdi Ali, Rahim Afikah, Varfolomeev Mikhail A, Nurgaliev Danis K, Al-Muntaser Ameen A, Saeed Shadi A
Geology Departments, Faculty of Applied Science, Taiz University, 6803, Taiz, Yemen.
Department of Petroleum Engineering, Kazan Federal University, Kazan, Russia, 420008.
Sci Rep. 2024 Aug 16;14(1):19033. doi: 10.1038/s41598-024-68416-5.
Organic rich sedimentary rocks of the Late Cretaceous Muwaqqar Formation from the Lajjun outcrop in the Lajjun Sub-basin, Western Central Jordan were geochemically analyzed. This study integrates kerogen microscopy of the isolated kerogen from 10 oil shale samples with a new finding from unconventional geochemical methods [i.e., ultimate elemental (CHNS), fourier transform infrared spectroscopy and pyrolysis-gas chromatography (Py-GC)] to decipher the molecular structure of the analyzed isolated kerogen fraction and evaluate the kerogen composition and characteristics. The optical kerogen microscopy shows that the isolated kerogen from the studied oil shales is originated from marine assemblages [i.e., algae, bituminite and fluorescence amorphous organic matter] with minor amounts of plant origin organic matter (i.e., spores). This finding suggests that the studied kerogen is hydrogen-rich kerogen, and has the potential to generate high paraffinic oil with low wax content. The dominance of such hydrogen-rich kerogen (mainly Type II) was confirmed from the multi-geochemical ratios, including high hydrogen/carbon atomic of more than 1.30 and high A-factor of more than 0.60. This claim agrees with the molecular structure of the kerogen derived from Py-GC results, which suggest that the studied kerogen is mainly Type II-S kerogen exhibiting the possibility of producing high sulphur oils during earlier stages of diagenesis, according to bulk kinetic modeling. The kinetic models of the isolated kerogen fraction suggest that the kerogen conversion, in coincidence with a vitrinite reflectance range of 0.55-0.60%, commenced at considerably lower temperature value ranges between 100 and 106 °C, which have produced oils during the early stage of oil generation. The kinetic models also suggest that the commercial amounts of oil can generate by kerogen conversion of up to 50% during the peak stage of oil window (0.71-0.83%) at relatively low geological temperature values in the range of 122-138 °C. Therefore, further development of the Muwaqqar oil shale successions is highly approved in the shallowly buried stratigraphic succession in the Lajjun Sub-basin, Western Central Jordan.
对约旦中西部拉朱恩次盆地拉朱恩露头处晚白垩世穆瓦卡尔组富含有机质的沉积岩进行了地球化学分析。本研究将从10个油页岩样品中分离出的干酪根的显微镜观察结果与非常规地球化学方法（即元素分析（CHNS）、傅里叶变换红外光谱和热解气相色谱（Py-GC））的新发现相结合，以解析所分析的分离干酪根组分的分子结构，并评估干酪根的组成和特征。光学干酪根显微镜观察表明，所研究油页岩中分离出的干酪根源自海洋组合（即藻类、沥青质和荧光无定形有机质），含有少量植物源有机质（即孢子）。这一发现表明，所研究的干酪根是富氢干酪根，具有生成低蜡含量高链烷烃油的潜力。通过多种地球化学比值，包括氢/碳原子比大于1.30和A因子大于0.60，证实了这种富氢干酪根（主要为Ⅱ型）的主导地位。这一结论与Py-GC结果得出的干酪根分子结构一致，根据整体动力学模型，这表明所研究的干酪根主要为Ⅱ-S型干酪根，在成岩早期阶段有生成高硫油的可能性。分离出的干酪根组分的动力学模型表明，干酪根转化与镜质体反射率范围为0.55 - 0.60%相吻合，在100至106℃的相当低的温度范围内开始，在生油早期阶段生成了油。动力学模型还表明，在油窗峰值阶段（0.71 - 0.83%），在122至138℃的相对较低地质温度范围内，干酪根转化可达50%时可生成商业量的油。因此，约旦中西部拉朱恩次盆地浅埋地层序列中穆瓦卡尔油页岩层序的进一步开发具有很高的可行性。
