湖相砂质碎屑流与底流改造砂沉积特征对比

Deposition characteristics comparison between sandy debris flow and bottom current rework sand in lacustrine basin

吕鹏佶

LYU Pengji

中国石油辽河油田分公司勘探开发研究院，辽宁 盘锦 124010

基于苏北盆地曲塘次凹阜三段研究成果，结合取心井岩心资料，重点研究了陆相湖盆砂质碎屑流与底流改造砂的成因机制、岩性特征、沉积构造及物性特征差异。对比结果表明：砂质碎屑流属于块体流沉积，而底流改造砂的形成机制受到风驱底流的控制，主要为长期活跃的底流；底流改造砂较碎屑流砂体而言，石英体积分数降低，岩屑体积分数升高，黏土体积分数升高，砂体明显减薄；碎屑流砂体沉积构造主要是块状层理，而底流改造砂体的沉积构造主要有波状交错层理和水平层理，普遍发育泥岩纹层；底流改造砂体储层物性差，孔渗相关性差。这2类砂体在湖相深水区中呈交互沉积，为苏北盆地曲塘次凹阜三段地层“满凹含砂”奠定了物质基础。

Based on the research of the third Member of Funing Formation in Qutang sub?鄄sag of Subei Basin and the core data, this paper focuses on the differences of formation mechanism, lithology, sedimentary structure and reservoir physical characteristics of sandy debris flow and bottom current rework sand deposits in lacustrine basin. The results show that sandy debris flow belongs to mass transport flow, and the formation mechanism of bottom current rework sand deposits is bottom current of long?鄄term activity under the control of wind. Compared with the sandy debris flow deposits, the characteristics of bottom current rework sand deposits have low quartz content, high debris content, high clay content, and thin body thickness. The sedimentary structure of sandy debris flow deposits is mainly massive bedding； while the sedimentary structures of bottom current rework sand deposits are mainly wavy cross bedding and horizontal bedding and commonly mudstone laminae is developed. Bottom current rework sand deposits have a poor reservoir property and a poor correlation between porosity and permeability. In the deep lake region, this two types of sand bodies are alternately deposited and have laid a sufficient material foundation for containing sand deposition everywhere in the sub?鄄sag of the third Member of Funing Formation in Qutang sub?鄄sag of Subei Basin.

10.6056/dkyqt201902004