塔里木盆地古城地区鹰山组一段沉积微相研究

Study on Sedimentary Microfacies of the First Section of Yingshan Formation in Gucheng Area of Tarim Basin

古城6井高产气流的发现,显示塔里木盆地东部古城地区勘探前景较好,但目前对其勘探较为薄弱,而对鹰山组一段(以下简称"鹰一段")沉积相的研究认识更少。古城地区是塔里木盆地深部碳酸盐岩勘探新的接替区域。为此,利用取心井薄片资料,对古城地区鹰一段发育的岩性和岩相进行划分,研究了其沉积微相。塔里木盆地古城地区鹰一段岩性主要为亮晶砂屑灰岩、泥晶-亮晶砂屑灰岩、含生屑粉屑泥晶灰岩,主要发育一套浅缓坡相沉积,划分为颗粒滩和滩间洼地亚相,进一步分为中-高能滩、低能滩、滩间海共3种微相沉积。鹰一段沉积厚度整体上表现为西厚东薄的分异特征,西部位于构造相对高部位,水体较浅,向东部缓慢过渡为较深水沉积;鹰一段沉积时期,整体上高能滩主要发育在研究区中-南部和西部且发育相对较广,为相对有利储集相带发育区;低能滩主要分布在研究区东北部,发育范围小,并且储层物性很差,为差储层发育相带。

With the discovery of high-yielding gas flow in Well Gucheng 6, it indicates that the exploration prospects of Gucheng Area in the east of Tarim Basin are better, but its exploration is relatively weak at present, and the study of sedimentary facies of the First Section of Yingshan Formation is less known, so Gucheng Area is a new replacement area for carbonate exploration in deep Tarim Basin. In Gucheng Area of Tarim Basin, the lithology in the First Section of Yingshan Formation is mainly composed of sparkling sand debris limestone, micrite-sparkling sand debris limestone and bioclastic powder micrite limestone, a set of shallow and gentle slope facies deposits are mainly developed, which are divided into granular beach and intertidal depression subfacies, and further divided into medium-high-energy beach, low-energy beach and intertidal microfacies deposits. On the whole, the sedimentary thickness of the First Section of Yingshan Formation is characterized by the differentiation of being thick in the west and thin in the east. The west is relatively located in the high part of the structure and the water body is relatively shallow. The transition from its first section to the east is relatively slow and the deposits are relatively deep-water deposits.During the sedimentary period of the First Section of Yingshan Formation, the high-energy beach is mainly developed in the middle-south and west of the study area, and its development is relatively wide, which is a relatively favorable reservoir growth zone. The low-energy beach is mainly distributed in the northeastern part of the study area, with a small development range and poor reservoir physical properties, it is a poor reservoir development area in the First Section of Yingshan Formation.