文昌19-1油田珠江组二段Ⅰ油组沉积相研究

A Study on Sedimentary Facies of Oil Group Ⅰ in Member 2 of Zhujiang Formation in Wenchang 19-1 Oilfield

通过岩石学、测井相特征分析,结合区域构造-沉积背景,对珠江口盆地西部文昌19-1油田珠江组二段I油组沉积相进行了研究,认为该地层主要为滨岸相沉积,共识别出前滨、临滨两种亚相,前滨滩坝、临滨滩砂、临滨泥和海泛泥4种微相。前滨滩坝发育于潮间带,岩性主要为肉红色陆源碎屑质生屑灰岩、灰白色钙质砂岩,块状构造,层理不明显,垂向上为下细上粗的反韵律,自然伽马呈低幅枣核状、锯齿形或箱形;临滨滩砂和临滨泥发育于潮下带,岩性主要为细砂岩、泥质粉砂岩,夹少量泥质条带,波纹层理,常见生物扰动构造,在自然伽马曲线上,滩砂呈中幅漏斗型,临滨泥呈高幅钟形;海泛泥发育于水体加深、水动力减弱的区域,为一套广泛分布的细粒沉积物,岩性主要为泥岩、粉砂质泥岩,透镜状层理,常见生物扰动构造,自然伽马呈高幅锯齿形、钟形。

The aim of this paper is to study the characteristics of sedimentary facies of oil group I in Member 2 of Zhujiang Formation in Wenchang 19-10ilfleld, west Pearl River Mouth Basin, according to the analysis of lithology and logging facies as well as regional structural and sedimentary background. The research shows that this stratum is littoral facies. And the littoral facies can be divided into foreshore and shoreface, which include foreshore beach bar microfacies, shoreface beach sand microfacies, shoreface beach mud microfacies, and flooding mud microfacies. Foreshore beach bar microfacies developed in the intertidal zone, the lithology of which is mainly flesh pink terrigenous clastic mass bioclast limestone and gray calcareous sandstone, with massive structure, unobvious beddings, and reverses rhythm vertically. The low range gamma ray takes the forms of date pit, zigzag or box curves. Shoreface beach sand microfacies and shoreface beach mud microfacies developed in the subtidal zone. The lithology is mainly fine sand and politicsilt stone, and occasional pelitic strip, with ripple bedding, poor cementation, good sorting, and bioturbation structure. The middle range gamma ray form of shoreface beach sand microfacies are funnel curves. The high range gamma rays of shoreface beach mud microfacies are bell curves. Flooding mud microfacies developed in the area where the water deepened, and the hydrodynamic force weakens. And it is a set of widely scattered fine-grained sediments, the lithology of which is mainly mudstone and silty mudstone. With lentoid bedding, and bioturbation structure. The high range gamma rays are zigzag or bell curves.