鄂尔多斯盆地演武地区延9油层组沉积相研究

Study on the Sedimentary Facies of Yan 9 Reservoirs in Yanwu Area of Ordos Basin

摘要: 演武地区延9油层组是鄂尔多斯盆地延安组重要油层组之一，但一直以来对其沉积相的研究程度较低。结合整个鄂尔多斯盆地的构造及沉积演化特征，综合运用沉积学、岩石学、测井地质学、层序地层学等理论为指导，通过对泥岩颜色、岩石学特征、沉积构造特征、古生物标志以及测井相标志的详细研究认为，演武地区延9油层组属辫状河三角洲沉积体系，发育辫状河三角洲平原亚相，并进一步将其划分为分流河道、分流间洼地、天然堤、沼泽等4个主要沉积微相类型。根据延9油层组沉积微相的展布及演化规律，并结合区域沉积和构造背景，建立了其沉积模式。

Abstract: The Yan 9 Reservoir of Yanwu Area was one of the important oil-bearing formations of Yan’an Formation in Ordos Basin, the research degree on the sedimentary facies of the sedimentary facies was lower. Combined with the structure and sedimentary evolution characteristics of the whole Ordos Basin, by synthetically using the geological theories, such as petrology, sedimentology, log-ging geology, sequence stratigraphy and so on, and through researching in detail the mudstone color, petrological characteristics, sedimentary structural characteristics, paleontologic evidence and logging facies markers, the result showed that Yan 9 Reservoir of Yanwu Area belonged to a braided river delta sedimentary system, where developed braided river delta plain facies. It is further divided into 4 sedimentary microfacies, i.e. the distributary channel, the inter-flow de-pression, the natural levee, and the swamp. According to the distribution and evolution of sedi-mentary microfacies in the Yan 9 Reservoir, and combined with regional sedimentary and tectonic background, the sedimentary mode of the Yan 9 Reservoir is established in the study area.