Abstract: The cyclic water-flooding method is effective for development of oil in low-permeability matrix of limestone reservoir and unsuitable for the oil-wet reservoir.The changing characters of matrix water saturation were analyzed,and the equation for describing the change of matrix water saturation was derived.The laboratory experiment on cyclic water-flooding was made with oil-wet limestone reservoir models by adding cetyl trimethylammonium bromide (CTAB) with wettability alteration and low concentration into the injected water.The results showed that the surface property of oil-wet limestone reservoir changed towards that of water-wet reservoir greatly,and the capabilities of capillary imbibition,water storage and oil displacement were enhanced by using CTAB.The efficiency of cyclic water-flooding could be improved considerably.

Key words: low-permeability matrix limestone, fracture, oil-wet reservoir, wettability alteration technology, cyclic water-flooding, simulation experiment, quaternary ammonium polymer

摘要： 周期注水是开发灰岩储层低渗透基质中原油的一种有效方法,但对于亲油储层效果较差。对基质含水饱和度变化特征进行了分析,建立了基质含水饱和度变化特征方程,提出了周期注水与润湿反转技术相结合的开采方式。利用油湿灰岩裂缝模型,在注入水中加入低浓度具有润湿反转能力的季胺类物质——十六烷基三甲基溴化铵(CTAB)进行了周期注水室内模拟研究。结果表明,CTAB可使油湿灰岩储层的表面性质发生明显变化,基质毛管的自吸及滞水排油能力增强,周期注水开发效果明显改善。

关键词: 低渗基质灰岩, 裂缝, 油湿储层, 润湿反转技术, 周期注水, 模拟实验, 季胺聚合物