准噶尔盆地腹部车—莫古隆起中段头屯河组存在证据及其研究意义

准噶尔盆地腹部中晚侏罗世发育的车-莫古隆起形成诸多类型的地层圈闭,是油气运移的长期有利指向区,研究区目的层段(J/K不整合面附近)是否存在头屯河组对本区勘探很有意义.基于单井岩性电性组合特征、古生物、粘土矿物、地层接触关系等方面的资料,发现车-莫古隆起中段白垩系底界面下普遍发育的红层段是头屯河组的特征标志层,具有头屯河组特有的Classopollis-Quadraeculina-Piceaepollenites孢粉组合,粘土矿物组合上具有富含伊利石、不含或含少量高岭石的特征而区别于较富含伊利石、高岭石的下部层段,连井地层对比及地震剖面标定也表明车-莫古隆起中段存在较薄层头屯河组分布的平台区.这一新认识对本区圈闭评价和成藏条件评价等有指导作用.

Evidence of Existence and Research Significance of Toutunhe Formationin Middle-Che-Mo Palaeo-Uplift within the Central Part of Junggar Basin

Various types of stratigraphic traps formed during the formation of Che-Mo palaeo-uplift in Middle-Late Jurassic are target areas of prolonged oil-gas migration-accumulation,and hence the existence or nonexistence of Toutunhe Formation in the target strata near the unconformity between Jurassic and Cretaceous is of great importance to the exploration work of the study area.Based on charatersitics of the litho-electrical assemblage,paleontology,clay minerals,stratigraphic contact relationships in the strata beneath J/K unconformity,some evidence can be found as follows:a typical red layer is developed commonly,the strata have typical Classopollis-Quadraeculina-Piceaepollenites spore assemblage and typical clay mineral assemblage(rich illite,insufficient kaolinite),and a thin Toutunhe Formation platform can also be seen on the seismic horizon flattening section and stratigraphic correlation section.The existence of Toutunhe Formation will be helpful to the oil-gas exploration in the study area in such aspects as trap estimation,reserve calculation,and oil-gas accumulation condition evaluation.