准噶尔盆地腹部侏罗系油气成藏地球化学分析

GEOCHEMICAL FEATURES OF PETROLEUM ACCUMULATION OF JURASSIC RESERVOIRS IN HINTERLAND OF THE JUNGGAR BASIN

依据生物标志物的分布和组成特征,准噶尔盆地腹部侏罗系三工河组的原油可以分为两类,庄1井和沙1井原油属于第一类,源于下二叠统风城组;南部征沙村地区征1井原油为第二类,源于中二叠统下乌尔禾组,也有侏罗系的贡献。根据流体包裹体均一化温度分布,结合生排烃史与构造配置关系研究,认为征1井三工河组油藏主要成藏期是古近纪以来,油气来自于昌吉凹陷的下乌尔禾组和侏罗系烃源岩;而庄1井和沙1井三工河组油藏具有多源多期油气注入,早白垩世末至古近纪,油气来自于北部盆1井西凹陷风城组,古近纪构造调整以来,混入了来源于昌吉凹陷的油气。各口井原油含氮化合物的分布特征,证实了研究区侏罗系原油近期是从征1井向北运移的。

According to the distribution and geochemical compositions of biomarkers, the crude oils in hinterland of the Junggar Basin could be divided into two groups from the Jurassic reservoirs in hinterland of the Junggar Basin. The oil of Well Zhuang 1 and Well Sha 1 belonged to the Ⅰ -type oil derived from the Lower Permian Fengcheng Formation, and those of Well Zheng 1 belonged to the Ⅱ -type oil generated from the Middle Permian Wuerhe Formation as well as the Jurassic source rocks. Based on the study of the homogenization temperatures and biomarker compositions of fluid inclusions, and synthesized with geological evolution of the Ce-Mo （ Cepaizi-Mosuowan） Paleo-Rise, the history of hydrocarbon generation and accumulation was reconstructed. The oil of Well Zheng 1 might be derived from the source rocks in the Changji Depression after Paleogene. The oil of Well Sha 1 and Well Zhuang 1 might be mainly generated from the source rocks in the Depression West to Well Pen-1 during Early Cretaceous to Paleogene, which had mixed oils from source rocks in the Changji Depression in the later structural adjustment after Paleogene. By the analysis on distribution of nitrogenous compounds of oils in each wells mentioned-above, the results showed that the oils in hinterland of the Junggar Basin migrated lately from the south to the north.