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对野外露头、岩心、测井等资料综合分析表明,鄂尔多斯盆地寒武纪经历了2次海进—海退旋回,依据界面特征可划分出2个超层序和4个体系域,在此基础上以体系域为编图单元编制了层序—岩相古地理图。结果显示:SS1超层序海侵体系域早期发育滨岸相碎屑岩沉积,海侵体系域中晚期和高位体系域以混积潮坪、混积台地相为特征,发育含泥白云岩、泥质白云岩、砂质灰岩、泥岩及页岩沉积;SS2超层序海侵体系域形成高能浅滩,发育鲕粒碳酸盐岩和碎屑碳酸盐岩,高位体系域台地相白云岩发育。SS1—SS2超层序形成过程正好构成一个完整的碎屑岩沉积—混合沉积—碳酸盐岩沉积演化序列。SS2超层序发育过程中形成的浅滩和白云岩均为形成油气储层的有利地质体。
The comprehensive analysis of outcrops, cores and logging data shows that the Cambrian of Ordos Basin underwent two sea-regressive cycles, and according to the characteristics of the interface, two super-sequence and four system domains can be divided. Based on this, On the systematic domain as a unit compiled compiled sequence - lithofacies palaeogeography. The results show that in the early stage of transgressive marine system tract of SS1, the coastal shore clastic sediments were developed. The middle and late marine systems and highstand system tracts are characterized by mixed tidal flat and mixed platform facies, with the development of muddy dolomite, Argillaceous dolomite, sandy limestone, mudstone and shale; SS2 super-sequence transgressive system tract forms high-energy shoal, developing oolitic carbonates and clastic carbonate rocks, and highstand system dolostone development. The SS1-SS2 super-sequence formation happens to form a complete sequence of clastic sedimentary-mixed sedimentary-carbonate sedimentary evolution. Shallows and dolomites formed during the SS2 super-sequence development are favorable geologic bodies for the formation of oil and gas reservoirs.