【作者】 吴本芳；

【导师】 高晋生；

【作者基本信息】 华东理工大学 ， 化学工艺， 2011， 博士

【摘要】 随着对石油需求的不断增长,大量的石油被开采了出来。易开采输送的常规石油资源越来越少,高凝高粘等非常规石油资源的开发利用已经成为21世纪的重要能源项目之一。分析原油组成与其流动性发现,原油凝点高不仅与其蜡含量高有关,而且还与其中石蜡的碳链长度有关；原油粘度大不仅与其胶质含量高有关,而且还与其中石蜡的支化度高有关。针对河南油田高凝油蜡含量高,凝点高达50℃以上,对市售降凝剂感受性差的现状,本文展开开发新型高效降凝剂的降凝研究。合成和表征新型聚合物型降凝剂和大分子型降凝降粘剂,考察其降凝性能。在0.01%加剂量及90℃热处理温度条件下,合成聚合物SMA-a1、LMZ-10和SMA-1分别使河南高凝油14#的凝点降低6℃、7℃和8℃,都比市售降凝效果好的聚合物DTA的降凝幅度5℃有所提高。表明本试验合成的聚合物较市售聚合物降凝剂的降凝效果好,为合成新型高效的聚合物降凝剂打下基础。研究发现聚合物的降凝性能与其相对分子质量有关。当大分子的组成结构与原油中石蜡的碳链分布特征具有匹配性时才显出好的降凝效果。分析蜡晶显微照片表明,经降凝剂处理后的石蜡所析出蜡晶尺寸变大,有序性增强。蜡晶变大使单位原油体积内蜡晶数目减少,蜡晶不易相互联结,因而原油的凝胶化温度降低,凝点降低。进一步验证了降凝剂通过改变蜡晶积聚状态而降凝的机理。针对河南油田特稠油实际开采中,存在现有降黏剂耐高温性能差,在蒸汽吞吐、蒸汽驱高温条件下易分解丧失降黏性能从而严重影响原油采收率的现状,本文展开耐高温高效降黏剂的开发研究。开发的降粘剂SF耐高温性能强,可耐高温260℃-300℃；降粘效果显著,当SF复配剂在特稠油乳状液中含量为400ppm-2200ppm时,可使河南特稠油1#25℃黏度由202.7 Pa.s降至其乳状液黏度162.1 mPa.s以下,达到了现场应用常温(25℃)粘度低于200mPa.s的降粘要求,25℃降粘率高达99.92%以上,且操作条件在一定范围内变化对降粘效果影响不大,具有加剂量少、降粘效果显著及操作条件范围较宽的优势。实施了SF的工业试生产及其在河南油田的现场应用。对河南油田T4-2123井添加SF降粘后,与未加剂降粘的第1-5轮次注蒸汽吞吐的生产相比,采出液含水由73.6%降到23.6%,下降50%；油汽比由0.029提高到0.391,增加0.362,大幅度提高了采出程度,周期生产效果好。同时与添加其它降粘剂降粘的第6轮次注蒸汽吞吐的采出液含水43.4%相比,也显示出可大幅度降低采出液含水率,提高采出程度,达到较好的生产效果的优势。现场应用的降粘结果表明,降粘剂SF对T4-2123井特稠原油降粘效果最好,50℃降粘率达到88.7%,较其它两种市场竞争降粘剂A(73.6%)和B(75.6%)的降粘率都高,而且SF形成的特稠油乳液在室温下静置4小时以上,粘度回复不大,表明SF不仅能够显著降低特稠油粘度,且稳定性也较好,达到了现场应用的要求。分析原油乳状液的显微照片表明,未加SF的原油乳状液呈W/O型,大多数液滴呈W/O型小液滴,仅有少量的O/W型大液滴；加入SF后的原油乳状液呈O/W型,液珠的分散相为油,连续相为水。由此可推断乳化降粘机理为,降粘剂分子分布于油水界面中,从而形成了相对稳定的低黏度油水乳状液,获得稠油特稠油降粘效果。油溶性降粘剂降粘技术能够克服乳化降粘技术的缺点,是一种很有前途的方法。低含水稠油特稠油的开采及脱水特稠油的管输,都需要采用油溶性降粘剂,然而国内外关于油溶性降粘剂的研究和应用却很少。为此,本文展开针对河南脱水特稠油添加油溶性降粘剂的降粘研究。合成和表征了新型聚合物型及大分子型油性降粘剂。合成的大分子型油性降粘剂FM-18、UP-16和EY-18,在50℃-70℃较高温区都较市售降粘性能好的聚合物型流动性改进剂EVA的降粘效果好,在6000ppm加剂量条件下,FM-18、UP-16和EY-18对河南脱水特稠油2#50℃的降粘率84.1%、79.6%和85.6%都明显高于EVA的58.7%。这与聚合物EVA相对分子量高在较高温区因自身分子体积的溶胀缠绕对原油产生增粘负作用有关。研究表明,开发大分子油性降粘剂具有可提高较高温区(50℃-70℃)降粘率的优势,为添加油性降粘剂使其在实际有效输送温区50℃-70℃内维持高效降粘以实现远输脱水特稠油开辟了新途径。通过红外、DSC、原子力显微图象及透射电镜图象等分析表明,加入油性降粘剂后的胶质结构特征发生了明显的变化,初步验证了油溶性降粘剂可通过改性胶质而降粘的机理设想。采用温度和剪切速率两个影响因素建立了河南脱水特稠油2#全温区(80℃-38℃)和较高温区(80℃-50℃)内的神经网络预测模型,能较准确地预测管输原油的黏度值,相对误差分别为0.177和0.293。对加热降粘管输脱水特稠油及加剂降粘管输脱水特稠油都具有一定的推广应用价值。更多还原

【Abstract】 Nowadays a great deal of oil has been exploited with the increasing demand. As a result, the conventional oil sources which can be easily exploited and transported become less day by day. Consequently, the exploitation and utility of unconventional oil sources, such as high pour point and high viscosity crude oil has being regarded as one of the important energy projects in century 21.Based on the analysis of the composition and fluidity of crude oil, it can be concluded that the high pour point of crude oil is relative not only to the high wax content but also to the carbon chain length of wax and that the viscosity of crude oil is relative not only to the high colloid content but also to the high branch of wax.In order to solve the special pour-point reduction of the high pour-rpoint oil with high wax content, high pour-point above 50℃and bad impressibility to the commercial pour-point depressants in Henan oilfields, this paper was engaged in the investigation on exploring for new-style and high-efficiency pour-point depressants. In this paper, two new-style pour-point depressants, namely, copolymers and macromolecules have been purposely synthesized and characterized, the pour point depressing performance of which was studied. With the addition of 0.01% dosage and under the disposing temperature of 90℃, the synthesized copolymers SMA-al, LMZ-10 and SMA-1 made the pour-point of the high pour-point oil 14# of Henan reduced by 6℃,7℃and 8℃, and the pour depression effect of these pour-point depressants is improved in comparison with that of the commercial copolymer DAT with 5℃pour depression effect. These results show that the pour depression effect of the copolymers synthesized by us is better than that of the commercial copolymer pour-point depressants and our exploration also pave a way for the syntheses of new-style and high-efficiency copolymer pour-point depressants. It was found that the pour point depressing performance of copolymers depend on their relative molecule weights. As the composition and structure of macromolecules match the carbon chain distribution characteristic of wax in crude oil their pour point depressing performance is good. The analysis results of micrograms of wax crystals show that the size and order of wax crystals crystallized from crude oil disposed by pour-point depressants increase. The number of wax crystals in per crude oil volume becomes less with the sizes of wax crystals becoming bigger, which results in less coupling among wax crystals, and thus the gelation temperature and pour point of crude oil is lowered. The mechanism that the aggregate state of wax crystals is improved to reduce pour point by pour-point depressants is further confirmed.In order to solve the practical exploitation problems of extra-heavy oil in Henan oilfields, such as the badly heat-resistant property of existent viscosity-reducing agents, easy decomposition to lose their viscosity-reducing performance under high-temperature condition driven by steam, and other factors which badly effect the recovery ratio of crude oil, this paper was engaged in the investigation on exploring for high-temperature-resistance and high-efficiency viscosity-reducing agents. The developed viscosity-reducing agent SF has excellently high-temperature-resistance performance and show notably viscosity-reducing effect in a temperature range of 260～300℃. As the content of agent SF in extra-heavy oil emulsion attains the value of 400～2200 ppm, it can make the viscosity of extra-heavy oil 1# of Henan at 25℃reduced from 202.7 Pa-s to 162.1 mPa-s, and the viscosity-reduced viscosity meets the viscosity requirement of locale application under 200 mPa-s and for a viscosity-reducing rate of over 99.92% at 25℃. Moreover, this method has following merits: (i) operation conditions in a certain degree do less effect upon viscosity-reducing performance; (ii) the dosage of SF is less; and (iii) viscosity-reducing effect is obvious in a broad operation condition. The industry-test production and locale application of SF in Henan oilfields have been implemented. The locale test of SF in oil T4-2123 of Henan shows that the water content of the mined liquids lowers from 73.6% to 23.6%(decrease by 50%) and the ratio of oil and gas increases from 0.029 to 0.391 (increase by 0.362) compared with those of the production mined by steam without the addition of viscosity-reducing agents in oils 1-5. Clearly, the use of SF greatly improves the mined quantity, and thus the periodic yield improves. Meanwhile, the use of SF obviously decreases the water ratio and improves the mined quantity even compared with the water content of 43.4% in the production mined by steam in the addition of other viscosity-reducing agents in oil 6. The viscosity-reducing results in locale application disclose that the viscosity-reducing effect of SF is best to the crude oil from T4-2123 well, with a viscosity-reducing rate of 88.7% which is higher than those of other two competing viscosity-reducing agents A (viscosity-reducing rate of 73.6%) and B (viscosity-reducing rate of 75.6%) in market. Moreover, the viscosity of resulting extra-heavy oil emulsion only rebounds little when under the room temperature over 4 hours, which attains the requirement stability of locale application. The analysis results of micrograms of the emulsion of crude oil show that the emulsion of crude oil without addition of SF is in W/O type with most liquid drop being small liquid drop of W/O type and a few liquid drop being big liquid drop of O/W while the emulsion of crude oil with addition of SF is in O/W type with oil as dispersed phase and water as continuous phase. Thus it can be inferred that the viscosity-reducing mechanism through emulsification originate the formation of relatively stabile low-viscosity O/W emulsion which results from the distribution of viscosity-reducing agent molecules on the interface of oil and water, and thereby obtaining the viscosity-reducing effect of heavy oil and extra-heavy oil.Viscosity-reducing technique of oil-soluble viscosity-reducing agents can overcome the disadvantage of viscosity-reducing mechanism through emulsification and is a promising method. Furthermore, the exploitation of viscous and extra-heavy crude oils with little water content and pipeline transportation of dehydrated extra-heavy oil all need to adopt oil-soluble viscosity-reducing agents. However, the research and application related oil-soluble viscosity-reducing agents are very few all over the world. So viscosity reduction of the oil-soluble viscosity-reducing agents for the dehydrated extra-heavy oil in Henan is studied in this paper. Novel copolymer-sorted and macromolecule-sorted viscosity-reducing agents were synthesized and determined. The viscosity-reducing performance of the synthesized macromolecule-sorted viscosity-reducing agents FM-18, UP-16 and EY-18 is better than that of commercial copolymer-sorted fluidity improver EVA with good viscosity-reducing performance in a temperature range of 50～70℃. In the dosage of 6000 ppm, the viscosity-reducing percentages of FM-18, UP-16 and EY-18 upon oil 2# at 50℃are 84.1, 79.6 and 85.6, respectively, which are obviously higher than that of 58.7% of EVA in the same dosage. The disadvantage about copolymer EVA is that EVA with the relatively great molecular weight will swell and intertwist at higher temperature to produce viscosity-increasing effect upon crude oil. Investigation results show that exploitation for macromolecule-sorted oil-soluble viscosity-reducing agents can improve the viscosity-reducing effect at a higher temperature range (50～70℃), which will pave a new way for the realization of the long-distance transportation of dehydrated extra-heavy oil through the addition of oil-soluble viscosity-reducing agents to maintain high-efficient viscosity reduction in the practical efficient transportation temperature range (50-70℃). Based on the analyses of IR, DSC, SEM and TEM, it can be confirmed that the structure feature of colloid changes to certain extent after the addition of oil-soluble viscosity-reducing agents and the viscosity reduction mechanism of oil-soluble viscosity-reducing agents through modifying colloid to reduce viscosity is tentatively proved. The neural network prediction model of the dehydrated extra-heavy oil 2# of Henan in a whole-temperature range (80～38℃) and a higher-temperature range (80～50℃) was established according to the two effect factors, temperature and shear rate. It can relatively accurately predict viscosity value of pipeline-transported crude oil with relative errors of 0.177 and 0.293, respectively. It is worthy to popularize use in pipeline-transported dehydrated extra heavy oils by heating or adding agents to reduce viscosity.更多还原