Abudeif Abdelbaset M, Alarifi Nasir, Abdalla Fathy, Bellucci Stefano, Tawfik Faten A
Geology Department, Faculty of Science, Sohag University, Sohag, Egypt.
Geology and Geophysics Department, College of Science, King Saud University, Riyadh, Saudi Arabia.
Sci Rep. 2025 Jul 24;15(1):26911. doi: 10.1038/s41598-025-07801-0.
This study aims to investigate the impact of clays on the quality of the Nubia reservoir in the Saqqara field, Gulf of Suez, Egypt. The research will contribute to a broader knowledge of reservoir characterization, offering valuable insights for similar geological settings in other regions, thereby aiding in the optimization of resource management in global petroleum industries. The shale evaluation procedure involves three primary steps: estimating shale volume, identifying clay minerals, and assessing shale distribution. The neutron-density (N-D) method was employed to estimate the shale volume in the Nubia reservoir, yielding an average of 0.6% across four wells, with a maximum recorded value of 2.2% in well GS323-3. These values represent that the Nubia reservoir contains a negligible amount of shale, indicating that the porosity and permeability are high. Clay mineral analysis, based on a Potassium-Thorium (K-Th) and Potassium-PEF cross-plots, identified the presence of chlorite, illite, montmorillonite, and heavy thorium-bearing minerals, where chlorite and illite enhance the mechanical stability of the reservoir, while montmorillonite may cause issues with swelling and pressure. Thorium-bearing heavy minerals are typically associated with reduced permeability due to their influence on chemical interactions. The shale distribution analysis, conducted using the Thomas and Stieber model, confirms the overall cleanliness of the Nubia reservoir. Most formation data points align with the 0% shale line, indicating high total porosity, while only a few points fall along the dispersed shale line. In conclusion, the findings indicate that the Nubia reservoir exhibits minimal shale content, predominantly clean lithology, and favorable porosity and permeability characteristics. Consequently, the reservoir is classified as high-quality, making it suitable for efficient hydrocarbon production.
本研究旨在调查黏土对埃及苏伊士湾萨卡拉油田努比亚油藏质量的影响。该研究将有助于更广泛地了解油藏特征，为其他地区类似地质环境提供有价值的见解，从而有助于优化全球石油行业的资源管理。页岩评价程序包括三个主要步骤：估算页岩体积、识别黏土矿物和评估页岩分布。采用中子密度（N-D）法估算努比亚油藏的页岩体积，四口井的平均值为0.6%，其中GS323-3井记录的最大值为2.2%。这些数值表明努比亚油藏含有的页岩量可忽略不计，这意味着孔隙度和渗透率较高。基于钾钍（K-Th）和钾-光电因子（Potassium-PEF）交会图的黏土矿物分析确定了绿泥石、伊利石、蒙脱石和富含钍的重矿物的存在，其中绿泥石和伊利石增强了油藏的机械稳定性，而蒙脱石可能会导致膨胀和压力问题。含钍重矿物通常因其对化学相互作用的影响而与渗透率降低有关。使用托马斯和施蒂伯模型进行的页岩分布分析证实了努比亚油藏总体较为纯净。大多数地层数据点与0%页岩线对齐，表明总孔隙度较高，而只有少数点落在分散页岩线上。总之，研究结果表明，努比亚油藏页岩含量极低，岩性主要为纯净岩性，孔隙度和渗透率特征良好。因此，该油藏被归类为优质油藏，适合高效生产油气。
