本文为国家自然科学基金项目(编号41802177，42272188)，中国石油前瞻性基础性技术攻关项目(编号2021DJ0206；2022DJ0507)和中国石油直属院所基础科学研究和战略储备技术研究基金(编号2020D- 5008- 04)联合资助的成果
石炭系是准噶尔盆地最重要的气源岩层系之一，但对其生油潜力的认识程度较低。本文基于地球化学分析(稳定碳同位素和生物标志化合物)、盆地模拟、构造演化恢复、生烃模拟实验和井震联合追踪等手段，厘清了准噶尔盆地东南部原油中石炭系烃源岩的贡献，恢复了原油的成藏过程，刻画了规模有效源灶的分布范围。研究结果表明，准噶尔盆地东南部存在两类原油：第一类原油稳定碳同位素组成重，Pr/Ph值较高，含有丰富的C24四环萜烷和C31藿烷，三环萜烷和伽马蜡烷丰度低，几乎不含β- 胡萝卜烷和重排甾烷，反映母源为淡水偏氧化环境，可能以高等植物生源输入为主，来自上石炭统巴塔玛依内山组烃源岩；第二类原油地球化学特征总体与第一类相反，反映母源为咸水偏还原环境，以细菌和藻类等生源输入为主，对应中二叠统芦草沟组烃源岩。中晚侏罗世，巴塔玛依内山组烃源岩进入生油高峰，发育“自生自储”型和“下生上储”型两类油藏。巴塔玛依内山组烃源岩厚度大，分布广，生油强度＞4×106 t/km2的面积达2031 km2，在阜康凹陷东斜坡和吉木萨尔凹陷发现了两个生油强度＞6×106 t/km2的生油中心。研究成果进一步证实了准噶尔盆地石炭系烃源岩具备较好的生油能力，拓展了盆地东南部石炭系石油勘探新领域。
Although the Carboniferous is one of the most significant gas- source rocks in the Junggar basin, its oil- generating potential remains unclear. This study integrated geochemical analysis (stable carbon isotopes and biomarker fingerprints), basin modeling, structural evolution restoration, hydrocarbon generation simulation, and well- seismic joint tracing to elucidate the contribution of Carboniferous source rocks to oil reserves in the southeastern Junggar basin. We reconstructed the petroleum system evolution and delineated the spatial extent of effective source kitchens. Our results identified two types of crude oil in the southeastern Junggar basin. Type I oil exhibits relatively heavy stable carbon isotopes, a high Pr/Ph ratio, abundant C24 tetracyclic terpanes and C31 hopanes, barren tricyclic terpanes, gammacerane, β- carotane, and rearranged steranes. These characteristics correlated strongly with the Upper Carboniferous Batamayineishan source rocks, suggesting deposition in a fresh, oxygenated environment with organic input mainly from higher plants. In contrast, Type II oil displays geochemical features opposite Type I, reflecting a saline, reducing environment with input mainly from bacteria and algae. This oil type correlates well with the middle Permian Lucaogou source rocks. During the Middle- Late Jurassic, the Batamayineishan source rocks reached the oil- generating peak, forming two types of oil reservoirs: “self- generated and self- stored” and “lower- generated and upper- stored.” The widespread distribution and significant thickness of the Batamayineishan source rocks resulted in an area reaching 2031 km2 with an oil- generating intensity greater than 4×106 t/km2. Two oil- generating centers with intensities exceeding 6×106 t/km2 were discovered: the eastern slope of the Fukang sag and the Jimsar sag. These findings confirm the substantial oil- generating capacity of Carboniferous source rocks in the Junggar basin and highlight a new exploration area for the Carboniferous petroleum system in the southeastern Junggar basin.
龚德瑜,苗一豪,陈棡,王志勇,金颖,程斌,王瑞菊,吴卫安,韩琰.2025.准噶尔盆地东南部石炭系来源原油的发现与勘探意义[J].地质学报,99(3):914-928.
GONG Deyu, MIAO Yihao, CHEN Gang, WANG Zhiyong, JIN Ying, CHENG Bin, WANG Ruiju, WU Wei' an, HAN Yan.2025. Discovery of Carboniferous- sourced crude oil in the southeastern Junggar basin and its implication for petroleum exploration[J]. Acta Geologica Sinica,99(3):914-928.
