【作者】 吕志凤；

【导师】 王宗贤；

【作者基本信息】 中国石油大学 ， 化学工程与技术， 2008， 博士

【摘要】 聚合物驱是一种重要的三次采油技术,为中国胜利油田原油稳产提供了重要保证。但由于污水中含有一定量的水解聚丙烯酰胺（HPAM）,而且污水油含量高、油珠平均粒径小、悬浮物含量高,处理难度很大。目前对含聚污水中乳化活性物质的组成、稳定性影响因素及处理对策还缺乏深入认识。本论文首先对孤岛采油厂含聚采油污水中乳化活性物质进行了系统分离及组成结构表征,在此基础上研究了乳化活性亚组分及污水中残余HPAM对乳状液稳定性的影响,考察了污水中各亚组分及HPAM对不同结构水处理剂作用效果的影响,提出了含聚采油污水处理对策,研发了针对孤岛油田含聚采油污水的处理剂并进行了现场试验,取得了明显效果。用石油醚和三氯甲烷依次萃取孤二联和孤五联含聚污水中的油分,得到弱极性组分F1和强极性组分F2;然后用石油醚沉淀及甲醇/异丙醇抽提,将两个组分分成六个亚组分。六个亚组分的结构组成分析及乳化性能研究结果表明,固体亚组分SF41和SF42的H/C低,相对分子质量高,杂原子含量高,金属钙、铁含量高(SF42相对分子质量高达4533,总杂原子含量25.3%,钙、铁含量分别达到2357mg·kg^-1和455.8mg·kg^-1),低浓度下( < 0. 5g·L^-1)界面活性强,乳化能力强;液体亚组分SF1和SF31酸值高(SF31酸值高达23.9mgKOH·g^-1),界面活性和乳化能力均较强;黏稠液体亚组分SF32和SF2酸值较低,界面活性和乳化能力相对较弱;各亚组分按界面张力由小到大排序为:SF42≤SF41 < SF31≈SF1 <SF32≈SF2。孤二联含聚污水中酸性物质以石油酸和降解HPAM为主,降解HPAM约占酸性物质的30%;孤二联含聚污水中的轻质石油酸以单环环烷酸、四环环烷酸和脂肪酸为主,其中环烷酸的含量远大于脂肪酸的含量。脂肪酸以C16和C18为主,单环环烷酸以C14¹8为主,四环环烷酸以C18²1为主;孤二联含聚污水中降解HPAM水解度为30.1%,相对分子质量为2.26×106。孤二联含聚污水比孤五联含聚污水稳定性强的原因是污水中HPAM含量及三氯甲烷萃取物含量高,而且高酸值亚组分SF31的含量高。污水中HPAM与强极性亚组分SF31、SF42有很强的相互作用,当HPAM质量浓度大于200mg·L^-1,亚组分SF31与SF42质量浓度的比值在3¹0之间时,含聚乳状液的稳定性很强;HPAM、强极性物质、无机固体颗粒是含聚污水中悬浮物的重要组成成分,无机固体颗粒质量浓度在0⁵0mg·L^-1范围内,对乳状液的稳定作用很强;HPAM的盐敏效应导致盐质量浓度超过1800mg·L^-1后,乳状液的稳定性增强,盐质量浓度超过7000mg·L^-1以后,zeta电位变成正值;因此,含聚污水不易用聚铝等以电中和作用为主的絮凝剂进行处理。对于不含聚的模拟乳状液,水处理剂PAC、PDMDAA、PAMAM系列都具有较好的处理效果,但HPAM的盐效应导致具有一定阳离子度的高相对分子质量处理剂CPAM^-1与污水中较大相对分子质量HPAM在较宽的浓度范围内都有很强的协同破乳絮凝作用;高相对分子质量、强极性亚组分SF42与HPAM共同稳定的乳状液比弱极性亚组分SF2所稳定的乳状液更难处理;CPAM^-1与污水及采出液剧烈混合时处理效果更好,污水中浮油与CPAM^-1有协同除油效果,适合在井排加药,提高处理效果,减少污油的产生。研发了针对孤二联和孤五联含聚污水处理的复合阳离子处理剂FX-02和FX-05。现场实验取得了明显的效果,孤二联和孤五联外输污水油含量分别由试验前的平均2700 mg·L^-1和950 mg·L^-1降为平均180 mg·L^-1和144 mg·L^-1。更多还原

【Abstract】 Polymer flooding technology is an important technology in tertiary oil recovery, which plays a significant role in maintaining oil production in old oilfield of China such as Shengli Oilfield. Compared with the produced water from water flooding, the produced water from polymer flooding contains more oily substances and degradation products of hydrolyzed polyacrylamide （HPAM）, which makes it more difficult to treat. At present, although flocculation is widely used in treating polymer flooding produced water, the composition and property of the oily substances in polymer flooding produced water have not been completely elucidated, and there is still not a standard way to choose appropriate flocculants effectively and efficiently. This paper is intended to carry out the basic study on separation, analysis and emulsifying activity of sub-fractions of oily substances in polymer-flooding produced water, and then to intensively investigate the interaction between sub-fractions and flocculants as well as the effect of other components on the process, aiming at developing a useful way to screen out effective flocculants and efficient ways for the treatment of the oily water produced by polymer flooding.The oily substances in the produced water from a polymer flooded reservoir of Gudao, Shengli, were extracted by petroleum ether and trichloromethane successively. Then, the two fractions were separated into six sub-fractions based on polarity by using solvent deposition and extraction. The results of composition, structure and emulsifying activity of these sub-fractions showed that high heteroatom content （25.3% for SF42）, high molecular mass（Mm） （4533 for SF42）, high metal content (Ca 2357 mg·kg^-1 and Fe 455.8mg·kg^-1 for SF42), low H/C ratio, and strong emulsifying capacity are observed for solid sub-fractions SF41 and SF42 at low concentrations. SF31 and SF1, which contributed to the stability of polymer- flooding produced water, had higher acid values (23.9mgKOH·g^-1 for SF31) and stronger emulsifying activity than SF2 which had weaker emulsifying activity. The interfacial tension for these sub-fractions is arranged as follows:SF42≤SF41 < SF31≈SF1 < SF32≈SF2.The acid substances in polymer-flooding produced water of Gudao2# were dominated by petroleum acid and degradation products of HPAM, the percentage of degradated HPAM was about 30%. The light petroleum acids in water produced by polymer flooding in Gudao2# were mainly composed of C16 and C18 aliphatic acids, C14^-18 naphthenic acids and C18²1 tetracyclic naphthenic acids, and the amount of naphthenic acids were more compared with the aliphatic acids. The hydrolytic degree of HPAM in water produced by polymer-flooding in Gudao oilfield was 30.1% and its Mm was 2.26×106.The contents of HPAM and polar materials extracted by CHCl3 and its sub-fraction SF31 which acid value was the highest among six sub-fractions in produced water of Gudao2# were high than those in produced water of Gudao5#. The strong interaction between HPAM and polar sub-fractions such as SF31 and SF42 was observed, and the emulsion was extremely stabile and the oil content in water was high when HPAM concentration surpassed 200mg·L^-1 and the content ratio of SF31 and SF42 was among 3¹0. HPAM, polar sub-fractions and inorganic particles were the important components of the suspended solids in water produced by polymer flooding, and the emulsion was extremely stabile when the concentration of the inorganic particles was 0⁵0mg·L^-1.The emulsion was more stable and Zeta-potential became positive as NaCl concentration up to 7000mg·L^-1 in the present of HPAM, and especially the interaction between HPAM and salt was a key factor to impact the efficiency of the treatment of the polymer-flooding produced water. Because of the strong synergistic flocculation between cationic polyacrylamide (CPAM^-1, as flocculant) and HPAM in the produced water, CPAM^-1 had a good performance of treating polymer flooding produced water in Gudao oilfield than other flocculants such as PAC and PDMDAA. The strong interaction between HPAM and high Mm, strong polarity sub-fractions SF42 and high acid number SF31 caused the emulsions were more difficult to depose than emulsion composed of HPAM and weak polarity sub-fraction SF2.The efficient mixing between produced liquid and CPAM-1 can increase collision frequency that leads to adhesion of oil droplets and increasing flocculation efficiency. The floating oil also increases flocculation efficiency because the destabilized oil droplets can adhere to it. To improve water treatment efficiency and reduce waste oil creation, the water treating agent should be injected at well-drain.Two water treating agents FX-02 （for Gudao2#） and FX-05 （for Gudao5#） which main component was CPAM^-1 were developed. The oil content of the treated water decreased from 2700mg·L^-1and 950mg·L^-1 to 180mg·L^-1and 144mg·L^-1 in Gudao2# and Gudao5#.更多还原