准噶尔盆地南缘前陆盆地白垩系生油的新认识

通过对中国大陆东西部盆地构造条件对比及对准噶尔盆地下白垩统烃源岩地化分析，认为虽然整体上我国东部盆地白垩系烃源岩的分布范围广，厚度及质量均好于西部盆地，但准噶尔盆地北天山山前凹陷构造顾沉积条件与东部盆地具有一定的相似性，下白垩统具备了生烃能力，是南缘地区勘探不可忽视的现实烃源岩。通过油源对比，认为吐谷鲁厦霍尔果斯地区原油生物标志特征与清水河等地面原油及沥青特征相似．均来自于下白垩统烃源岩，因而确定了白垩系蛏源岩的可靠性，同时指出了以自垩系为油类推的油气藏分布范围，提出了自垩系烃源岩对山前冲断带油气成藏的贡献及勘探的重点目标区和钻探层位，这将拓宽准南前陆盆地油气勘探的领域，

New Understandings of Cretaceous Oil Generation Zone in Foreland Basin in Southern Margin of Junggar

The comparison of structural conditions in western and eastern basins of China and geochemical analysis of Lower Cretaceous source rocks in Junggar basin are made. It is considered that in the eastern basins there exist vast distributions of Cretaceous source rocks, better reservoir quality and thickness than those of the western basins on the whole, but the structural and depositional conditions in foothill sag in North Tianshan Mountain of Junggar basin are of a certain similarity with those in the eastern basins, i.e., its Lower Cretaceous strata possesses a capability of hydrocarbon generation, being significant and really existing source rocks for petroleum exploration of southern margin of Junggar basin. The oil-source rock correlation indicates that the crude biomarker features from Tugulu and Horgos areas are similar to those from surface crude and asphalt in Qingshuihe area, and these biomarkers were all coming from the source rock of Lower Cretaceous. Therefore, the Cretaceous source rock can be determined reliably. In this paper, the distribution extension of reservoir with oil source of Cretaceous is delineated. The contribution of the Cretaceous source rock to hydrocarbon accumulation in foothill thrust zone is pointed out, and the major target areas and drilling horizons for oil exploration are suggested in this paper. It is expected that the domain of petroleum prospecting in southern Junggar's foreland basin will be wider and wider.