【作者】 高玉生；

【导师】 高晋生；

【作者基本信息】 华东理工大学 ， 化学工艺， 2012， 博士

【摘要】 我国普通原油资源贫乏,而稠油资源相对丰富,然而由于稠油(国际命名：Heavy oil)具有高粘度、低温流动性差等特点,给开采和输送带来了极大的困难。常用的加热采输法能耗高,经济效益差,目前应用有限。如何经济高效地开发稠油资源,对于缓解国内原油供需矛盾,确保我国能源战略安全具有十分重要的意义。本文针对高凝稠油和高凝原油凝点高、低温流动性差的特点,尝试采用乳化降凝降粘的方法进行流动性改进研究。通过添加合适的乳化剂和助剂,形成稳定性较好的O/W型乳液,利用油水界面膜对低温析出蜡晶的分割作用,阻止蜡晶形成三维空间网状结构,从而改善高凝稠油和高凝原油的低温流动性能。研究提出了适用于优化高凝稠油乳化剂配方的动态浊度法。通过使用常用的可见光分光光度计,研究下层稀释乳液的浊度随搅拌时间的变化。该法可直接表征乳液形成和破坏过程中分散相油相体积分数的变化和乳液的静态稳定性,经过多次取样能有效地减少试验误差。用其考察了NaOH质量浓度和不同乳化剂对高凝稠油H2乳液乳化效果的影响,并与常规相分离法的试验结果对比,两者十分吻合。针对凝点为47℃、50℃粘度为223.2mPa-s(Ds=105.1s-1)的华北油田高凝稠油H1,通过优化试验得到了适合的复配乳化剂配方：复配乳化剂质量浓度为0.5%(油酸钠和十二烷基磺酸钠的质量比为7：3),多聚磷酸钠、NaOH和聚丙烯酰胺的质量浓度分别为0.15%、0.05%和0.15%。当油水质量比为6：4,搅拌速度和搅拌时间分别为800rpm和20min时,使用去离子水,高凝稠油乳液的凝点降幅为18℃,50℃降粘率达86.8%。对该油田的另一种高凝稠油H2,通过优化试验也得到了合适的复配乳化剂配方。当油水质量比为7：3,搅拌速度分别为250rpm和600rpm时,使用自制的模拟油田矿化水,乳液的凝点降幅分别为20℃和25℃,降粘率分别为89.79%和97.46%(40℃)。若油水质量比为6：4,则乳化降凝降粘效果更好。此外对凝点为54℃的河南油田高凝原油,通过优化试验同样得到了合适的复配乳化剂配方。当油水质量比为59.5：40.5,搅拌速度分别为250rpm和800rpm时,使用去离子水,乳液的凝点降幅分别为8℃和17℃；50℃的降粘率分别为67.83%和88.79%,取得了较好的降凝降粘效果。针对高凝稠油和高凝原油自行合成了具有抗矿化度性能的酰胺型两性乳化剂。通过红外光谱表征了合成产物的分子结构,使用电位滴定法测定了合成乳化剂的含量。研究了合成乳化剂的种类和分子结构对高凝稠油H2乳液稳定性的影响。通过在乳化剂分子中引入酰胺基团,与聚丙烯酰胺间的相互作用显著增强,乳液的稳定性明显改善。通过试验得到合成乳化剂的优化配方为：复配乳化剂质量浓度为0.4%(油酸酰胺丙基二甲基氧化胺与LAO-35的质量比为7：3),NaOH和聚丙烯酰胺的质量浓度分别为0.035%和0.15%。当油水质量比为7：3,搅拌速度为250rpm,使用自制的模拟油田矿化水,通过形成稳定性较好的O/W型乳液,高凝稠油H2乳液的凝点降幅为20℃,与市售乳化剂优化配方的乳化降凝效果相当,40℃的降粘率为96.41%,高于市售乳化剂配方的降粘率,同时研究了相关机理。上述结果,对实现稠油和高凝原油的强化开采和管道输送具有实际应用价值,增加了对这类原油乳化降凝降粘机理的认识。更多还原

【Abstract】 Our country is poor in the conventional crude oil, but is relatively rich in heavy oil, however it brings great difficulty on the exploitation and transportation because of its high viscosity and low fluidity at the low temperature. Now the common heating method applied on the exploitation and pipeline transportation of heavy oil is considered to be high energy consumption, uneconomic and inefficient. Therefore trying to exploit heavy oil source in an economic and efficient way is of great significance to release the contradiction between energy supply and demand, and ensure the security of energy strategy in our country. In this paper, based on the high pour point and low fluidity of waxy heavy oil and waxy crude oil at the low temperature, their fluidities were tried to be improved by emulsifying method. Thus the three dimensional net structure of wax crystals in the waxy heavy oil or waxy crude oil could be prevented by oil/water interfacial membrane due to forming stable waxy oil-in-water emulsion, which would highly improve the fluidity of waxy heavy oil.Dynamic turbidimetric method was proposed to optimize the emulsifier formulas for these oils. The turbidity of diluted sedimentary aqueous phase was measured as a function of stirring time with visible spectrophotometer. The variation of oil volume fraction during the emulsion formation and demulsification processes was characterized with the proposed dynamic turbidimetic method by changing stirring time, the static stability of emulsion was also obtained by changing the standing time during the sampling process, and the experimental error could be reduced by multiple sampling. The influence of mass fraction of NaOH and different emulsifiers on the emulsifying effect of waxy heavy oil emulsion was studied and the results agreed well with those obtained from the phase separation method.The suitable emulsifier formula for waxy heavy oil with the pour point of 47℃and the viscosity of 223.2mPa-s(50℃,Ds=105.1s-1) from Huabei oil field was obtained as follows:the mass concertration of emulsifier mixture(mass ratio of sodium oleate to SDS was 7:3) 0.5%, the mass concertration of sodium triphosphate, NaOH and PAM was respectively 0.15%, 0.05%, and 0.15%. When the mass ratio of oil to water was 6:4 and deionized water was used, by forming stable waxy heavy oil-in-water emulsion with stirring speed and stirring time of 800rpm and 20min, the corresponding pour point and viscosity reduction was respectively 18℃and 86.8%. For another waxy heavy oil H2 from the same oil field, the suitable emulsifier formula was also obtained. When the mass ratio of oil to water was 7:3 and the synthesized mineralized water was used in the experiment, by forming stable waxy heavy oil-in-water emulsions with stirring speed of 250rpm and 600rpm, the corresponding pour point reductions were 20℃and 25℃and the viscosity reductions were 89.79% and 97.46%, while the mass ratio of oil to water was changed from 7:3 to 6:4, the results were better.In addition, a suitable emulsifier formula for waxy crude oil with the pour point of 54℃from Henan oil field were obtained. When the mass ratio of oil to water was 59.5:40.5 and the deionized water was used in the experiment, by forming stable waxy crude oil-in-water emulsions with the stirring speed of 250rpm and 800rpm, the corresponding pour point reduction was respectively 8℃and 17℃and the viscosity reduction was respectively 67.83% and 88.79%.Series of salt resisting amphoteric emuslifiers containing amide group were self synthesized for these oils. The molecular structure was characterized by infrared spectrum and the content was analysed by potentiometric titration. The effects of types of emulsifiers and their molecular structure on the stability of waxy heavy oil-in-water emulsion were examined. Due to the increase of interaction strength with PAM, the emulsion stability was improved significantly by introducing amide group in the synthesized emulsifier. The suitable synthesized emulsifier formula for waxy heavy oil H2 from Huabei oil field was obtained as follows:the mass concertration of emulsifier mixture(mass ratio of oleic acid amidopropyl dimethyl amine oxide to LAO-35 was 7:3) 0.4%, the mass concertration of NaOH and PAM was respectively 0.035% and 0.15%. When the mass ratio of oil to water was 7:3 and the synthesized mineralized water was used in the experiment, by forming stable waxy heavy oil-in-water emulsion with the stirring speed of 250rpm, the corresponding pour point reduction was 20℃, which was equal to that obtained from saled emulsifier formula, and the corresponding viscosity reduction was 96.41%, which was better than that obtained from the saled emulsifier formula. The related mechanism was studied and discussed.The above mentioned results are of significance for the secondary or enhancing recovery and pipleline transportation of heavy oil and waxy crude oil, as well as contribute to recognize the mechanism of fluidity improving for these oils.更多还原