鄂尔多斯盆地马家沟组中组合岩相古地理新认识及油气勘探意义

发布时间：2018-06-12 06:03

本文选题：鄂尔多斯盆地 + 奥陶纪　；参考：《天然气工业》2017年03期

【摘要】：准确的岩相古地理恢复对于预测鄂尔多斯盆地下奥陶统马家沟组中组合白云岩储层分布具有重要的意义。为此,从分析古构造背景对沉积的控制作用出发,基于对大量钻井岩心和岩石薄片的观察结果,结合测井岩石结构组分解释、单因素图分析、地震资料解释等成果,建立了该盆地马家沟组中组合沉积模式,并客观地恢复了马五5、马五7、马五9这3个亚段的岩相古地理。结果表明:(1)马家沟组中组合具有隆、洼相间的沉积特点,中央古隆起东侧发育乌审旗—吴起和神木—榆林—延安2个南北向展布的次一级低隆带,在二者之间发育台内洼地,至盆地东部米脂地区则为o_湖沉积;(2)该盆地元古代发育4条北东向展布的裂陷槽,对奥陶纪沉积格局具有重要的影响,同时控制了马家沟组中组合台内颗粒滩的展布;(3)受隆、洼相间沉积格局和元古代裂陷槽的共同影响,中组合台内颗粒滩主要发育在神木—榆林—延安和乌审旗—吴起2个低隆起带上,并呈北东向近似雁列式分布。结论认为,上述2个低隆起带是该盆地马家沟组中组合优质白云岩储层的主要发育区。
[Abstract]:Accurate restoration of lithofacies and paleogeography is of great significance in predicting the distribution of dolomite reservoirs in the Lower Ordovician Majiagou formation. Therefore, based on the analysis of the controlling effect of paleotectonic background on sedimentation, and based on the observation results of a large number of drilling cores and thin sections of rock, combined with the interpretation of logging rock structure components, single factor map analysis, seismic data interpretation and so on, The sedimentary model of the assemblage in the Majiagou formation in the basin has been established and the lithofacies and paleogeography of the three submember Ma Wu 5, Ma Wu 7 and Ma Wu 9 have been objectively restored. The results show that the assemblage has the sedimentary characteristics of uplift and depression, and the lower uplift zone of Wushenqi and Shenmu Yulin Yanan are developed on the east side of the central paleouplift, and the depression is developed in the platform between them. In the Mizhi area of the eastern part of the basin, there were four trending rift troughs in the Proterozoic, which had an important influence on the sedimentary pattern of Ordovician, and controlled the distribution of grain banks in the platform of the Majiagou formation. The interfacies sedimentary pattern and the Proterozoic rift trough influence the grain beach in the middle assemblage platform mainly developed in the two low uplift belts of Shenmu-Yulin Yan'an and Wushenqi Wuqi and distributed in the form of geese in the north to east direction. It is concluded that the two low uplift zones are the main development areas of the high quality dolomite reservoirs in the Majiagou formation of the basin.
【作者单位】：中国石油长庆油田公司;中国石油杭州地质研究院;中国石油天然气集团公司碳酸盐岩储层重点实验室;
【基金】：国家科技重大专项“大型油气田及煤层气开发”(编号:2016ZX05004-002) 中国石油天然气集团公司科技重大专项“深层油气勘探开发关键技术研究”(编号:2014E-32-02)
【分类号】：P618.13

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