海上高含水油田用无机复合调驱剂实验研究

Experimental research of inorganic composite deep profile control and oil displacement agent for offshore high water cut oil fields

针对海上碳酸氢钠水型的高含水油田,以硅酸钠和氯化钙为主剂、聚羧酸分散剂和乳液聚合物为助剂制备了环保型无机复合调驱剂,并研究了聚羧酸分散剂类型和乳液聚合物质量浓度对调驱剂性能的影响规律。实验结果表明,当聚羧酸分散剂的酸醚比为3.7、分子量为23 800时,聚羧酸分散剂和无机颗粒表面的静电斥力和空间位阻作用相互促进,可达到有效分散效果。配合使用低质量浓度乳液聚合物(500 mg/L),形成的无机复合调驱体系可进一步增强体系的黏度和强度,初始黏度从1.1 mPa·s提升至5.4 mPa·s。封堵实验表明,无机复合调驱剂能够大幅度增加流动阻力,封堵率可达82.3%。该无机复合调驱剂可实现在线注入,具有快速分散、深部调驱和价格低廉等特点,在海上及其他作业空间受限的高含水油田中具有良好应用前景。

An environmentally friendly inorganic composite deep profile control and oil displacement agent was prepared for those offshore high water cut oil fields with formation water containing sodium bicarbonate.Sodium silicate and calcium chloride were used as the main agents,while polycarboxylic acid dispersant and emulsion polymer were used as assistants.The effects of the type of polycarboxylic acid dispersant and the mass concentration of emulsion polymer on the performance of the deep profile control and oil displacement agent were studied.The results showed that when the acid-ether ratio of the polycarboxylic acid dispersant was 3.7 and its molecular weight was 23800,the electrostatic repulsion and steric hindrance from polycarboxylic acid dispersant and inorganic particles achieved an effective dispersing effect.Combined with low concentration of emulsion polymer(500 mg/L),the formulated inorganic composite deep profile control and oil displacement system could enhance the viscosity and strength of the system,and the initial viscosity was increased from 1.1 mPa·s to 5.4 mPa·s.The results showed that this inorganic composite deep profile control and oil displacement agent could increase the flow resistance,with a plugging rate of 82.3%.It could achieve online injection and had the characteristics of rapid dispersing,deep profile control and oil displacement,and low cost.This inorganic composite deep profile control and oil displacement agent had application value in high water cut oil fields.