含凝灰储层原始含油饱和度测井评价方法探讨

On Log Evaluation Method of Oil Saturation in Tuffaceous Reservoir

Y油田南一段储层普遍含凝灰,孔隙结构复杂,准确确定储层原始含油饱和度难度大。通过岩心分析、薄片、岩电实验等资料系统分析了凝灰质储层的特点及其测井响应特征,探索了凝灰质含量的计算方法,形成了针对含凝灰储层的原始含油饱和度测井评价方法。研究表明,当孔隙度相同,地层因素与凝灰质含量成正比;地层因素与孔喉半径比和孔隙曲折度成正相关;应用阿尔奇公式采用变参数的方法可反映储层孔隙结构变化,能够很好地确定含凝灰储层的原始含油饱和度。

The sand generally contains tuff in Nanyiduan reservoir, Y oilfield. Because of complex pore structure, the determination of reservoir＇s original oil saturation is exactly difficult. This paper analyzes tuffaceous reservoir characteristics and logging responses through core analysis, sheet analysis and rock electric experiments to explore the methods of calculating tuffaceous contents. The log evaluation method of determining original oil saturation is established for tuffaceous reservoir. The research shows that when the reservoir porosity is the same, the formation factor is in direct proportion to the tuffaceous content, the formation factor is in positive correlation with pore throat radius and pore sinuosity. Archie＇s formula with variable parameters could reflect reservoir pore structure changes, which can be used to effectively determine the original oil saturation in tuffaceous reservoir.