珠江口盆地恩平凹陷A 油田 新近系储层钙质砂岩夹层成因

作    者:戴建文1,柴愈坤1,王冠民2,孙爽1,郭飞1,薛亚2
单    位:1 中海石油(中国)有限公司深圳分公司;2 中国石油大学(华东)地球科学与技术学院
基金项目:
摘    要:
珠江口盆地恩平凹陷A 油田新近系主力储层中普遍含有钙质砂岩夹层,对油田的进一步精细开发有较大的 影响,迫切需要准确掌握这些钙质砂岩夹层的成因与分布规律。基于对岩心的精细观察和分析,利用岩石铸体薄片 分析钙质填隙物的成因,结合沉积相、粒度、测井曲线、岩石密度分析和地震反演等手段,确定研究区新近系主力储层 中钙质砂岩夹层主要是沉积成因,少量属于成岩过程中的胶结成因。古珠江三角洲前缘常被波浪改造形成沿岸砂 坝,钙质砂岩夹层主要形成于沿岸砂坝向陆的后滨或坝后混合坪亚相中,是在潮间—潮上带的浅水或者暴露环境下, 海水强烈蒸发形成碳酸盐矿物沉淀,并胶结砂质碎屑颗粒而形成的。钙质砂岩夹层在垂向上与坝后泥坪或潟湖的泥 岩相邻,其分布规律具有相似性。
关键词:钙质砂岩夹层;沿岸砂坝;新近系;恩平凹陷;珠江口盆地

Genesis of calcareous sandstone interlayer in Neogene reservoir of A Oilfield in Enping Sag, Pearl River Mouth Basin

Author's Name: DAI Jianwen, CHAI Yukun, WANG Guanmin, SUN Shuang, GUO Fei, XUE Ya
Institution: 
Abstract:
The main reservoir of A Oilfield in Enping Sag is developed in the front of ancient Pearl River delta of the Neogene Hanjiang Formation and Zhujiang Formation. The fact that main reservoirs of the Neogene system generally contain calcareous sandstone interlayers has a significant impact to refined development of A Oilfield, and it is urgent to accurately understand the origin and distribution patterns of these calcareous sandstone interlayers. Based on detailed observation and analysis of rock cores, this paper uses cast thin sections of sandstone to analyze the origin of calcium interstitial materials. Furthermore, by combining analysis of sedimentary facies, particle size, logging curves, rock density, and seismic inversion methods, it is determined that the calcium sandstone interlayer in the main reservoir of Neogene in the study area is mainly sedimentary origin, with a small amount belonging to the cementation origin during diagenesis. The front of the ancient Pearl River delta is often transformed by waves to form coastal sand bars. The calcareous sandstone interlayer is mainly formed in the onshore backshore or mixed flat subfacies behind the dam of the coastal sand bar. It is formed through carbonate mineral deposition caused by strong evaporation of seawater in the shallow water or exposed environment of intertidal supratidal zone cementing sandy debris particles. The distribution patterns of calcareous sandstone interlayers adjacent to the mudflats or lagoons behind the dam in a vertical direction are similar.
Keywords: calcareous sandstone interlayer; coastal sand bars; Neogene; Enping Sag; Pearl River Mouth Basin
投稿时间: 2024-01-03  
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