浅海重力流低渗细粒沉积砂岩储层质量评价与预测以莺歌海盆地东方A区黄流组一段为例

    Quality evaluation and prediction of low permeability fine-grained sandstone reservoir of shallow marine gravity flow: a case study of the First Member of Huangliu Formation in Dongfang A area of Yinggehai Basin

    • 摘要: 莺歌海盆地东方A区高温高压低渗气藏尚未实现规模有效开发,寻找有利储层至关重要。通过激光粒度、铸体薄片、扫描电镜、高压压汞等岩芯测试分析手段,首先研究了储层微观差异特征,并对储层质量差异进行分类评价,然后通过分析储层质量差异与测井曲线间的响应关系,筛选能用于评价储层质量的测井曲线,利用主成分分析方法构建了可反映储层质量好坏的敏感因子曲线,最后基于敏感因子曲线协同波形指示模拟方法对储层质量进行预测。结果表明,储层质量主要由泥质产出特征决定,当储层物性差异较大,但泥质含量与沉积粒度特征相近时,可根据其泥质产状特征将研究区低渗储层质量划分为3个级别,其中,Ⅰ级储层的泥质产状以有序分布的泥质条带为主,发育粗粒粉砂岩,溶蚀作用强烈,Ⅱ级储层主要特征为泥质混杂分布,发育中-粗粒粉砂岩,溶蚀强度中-强,Ⅲ级储层的泥质产状呈杂基分散状态,沉积细粒粉砂岩,溶蚀发育较弱,Ⅰ级与Ⅱ级储层属于优质储层;建立的储层质量分级评价模型累计方差贡献率可达98.1%,能够反映研究区储层质量差异;提出了基于储层质量敏感因子和地震波形指示模拟相协同的储层质量预测方法,预测结果与实钻资料吻合率高,能揭示有利储层的空间展布,对气田的开发决策和井位部署具有指导意义。

       

      Abstract: The high-temperature and high-pressure low-permeability gas reservoirs in Dongfang A Area of Yinggehai Basin have not yet achieved effective large-scale development, making the search for favorable reservoirs crucial. Utilizing rock core testing and analysis methods such as laser granulometry, thin section petrography, scanning electron microscopy, and high-pressure mercury injection, we first investigated the microscopic differences in reservoir characteristics, and classified and evaluated reservoir quality differences. Then, by analyzing the relationship between reservoir quality differences and well logging features, we selected well logging parameters suitable for evaluating reservoir quality. Using the principal component analysis method, we constructed sensitivity factor curves that reflect the quality of reservoirs. Finally, based on the co-simulation method of sensitivity factor curves and seismic waveform indicators, we predicted the reservoir quality. Results indicate that reservoir quality is mainly determined by mudstone production characteristics. When the mud content and the sediment grain size of the reservoirs are similar, the reservoir quality in the study area could be divided into three grade levels based on mudstone production characteristics. For Grade Ⅰ reservoirs, the mudstone production state is characterized by orderly distributed mudstone bands, with deposits of coarse-grained siltstone, and strong dissolution effects. Grade Ⅱ reservoirs are characterized by mixed distribution of mudstone, with medium to coarse-grained siltstone deposits, and moderate to strong dissolution intensity. Grade Ⅲ reservoirs exhibit scattered mudstone production in a dispersed state, with the deposition of fine-grained siltstone in weak dissolution intensity. Grade Ⅰ and Grade Ⅱ reservoirs are favorable reservoirs. The established reservoir quality grading model has a cumulative variance contribution rate of 98.1%, capable of reflecting reservoir quality differences in the study area. A reservoir quality prediction method based on the synergy of reservoir quality sensitivity factors and seismic waveform indicators was proposed. The predicted results are highly consistent with actual drilling data, revealing the spatial distribution of favorable reservoirs. This approach has significant implications for guiding development decisions and well deployment in gas fields.

       

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