破乳剂对复合驱乳状液的破乳机理研究

针对模拟采出液和三元复合驱矿场采出液,研究了破乳剂对复合体系界面张力和膜强度的影响.破乳剂浓度增加,二元复合体系界面张力降低,而三元复合体系界面张力升高.破乳剂分子部分顶替乳化剂分子并显著降低了界面膜强度.     

脂肽复配型弱碱三元复合驱界面流变性质研究在实验教学中的设计与探索

采用悬滴法通过对界面面积变化及动态界面张力变化的测试,研究脂肽复配型弱碱三元复合驱界面张力以及扩张模量随时间、浓度的变化,并采用SPSS软件对实验数据进行非线性拟合,得到三因素的扩张模量预测模型,分析界面流变性质。该实验操作简单,实验体系设计灵活,同时与油田现场科研项目联系紧密,不仅丰富了物理化学实验有关界面化学实验课程设计,还可以引导学生关注实际生产,激发学生学习兴趣,训练学生软件应用能力及数据分析能力,符合应用型本科培养要求。通过科教融合的培养模式,提升学生处理实际问题的综合能力。     

表面活性剂复合体系提高原油采收率研究

为了提高中后期油田原油的采收率,采用聚丙烯酰胺和非离子-阴离子型表面活性剂NPAC构建了一种二元复合驱油体系。以油水界面张力性能、黏度、老化稳定性、乳化能力、洗油率等作为评价指标,研究并优化NPAC活性剂复合体系对提高原油采收率的试验条件,为油田回注提供理论与实践参考。研究表明:聚丙烯酰胺和NPAC二元复合体系综合性能优异,原油洗油率达到32. 4%,乳化指数为2. 1。该研究对指导表面活性剂/聚合物二元复合体系对提高油田原油采收率具有重要意义。     

TODGA/HNO_3萃取La~(3+)的界面性质

利用滴体积法研究了La~(3+)/HNO_3/N,N,N',N'-四辛基-3-氧戊二酰胺(TODGA)/稀释剂体系的界面性质,考察了TODGA浓度、液滴形成时间、稀释剂种类、La~(3+)浓度、体系温度、离子强度和溶液酸度等因素对体系界面性质的影响.实验结果表明,体系达到界面饱和吸附时间约为120 s,可认为体系达到萃取平衡;TODGA浓度不同时,界面张力也不同,进而判定界面饱和吸附物种亦不相同;极性较小的稀释剂体系的界面张力降低较大,按照正辛烷环己烷苯甲苯次序降低;HNO_3对TODGA的质子化作用使其表面活性显著增强,故硝酸浓度增大导致界面张力降低;Na NO_3的存在降低了界面上游离萃取剂分子的浓度,致使界面张力增大.     

Triton X-100/甲苯/水三元体系界面张力的耗散颗粒动力学模拟

采用耗散颗粒动力学方法在介观层次上模拟了非离子表面活性剂Triton X-100 在油/水界面上的分布行为, 并把用于油/水二元体系界面张力的计算方法拓展到含表面活性剂的三元体系. 利用该方法可以得到与实验数值吻合的界面张力数据. 另外, 模拟结果直观展示了表面活性剂界面张力与界面密度的关系, 为表面活性剂复配增效理论提供了依据. 该模拟方法给出的微观信息可以为驱油体系配方筛选和表面活性剂有效应用提供指导.     

PU/PSt型复合乳液粒子热力学平衡形态预测

以水性聚氨酯分散液为种子采用无皂乳液聚合新技术合成出了具有核壳结构的聚氨酯 聚苯乙烯(PU PSt)型复合聚合物乳液 .采用界面张力简化计算方法 ,通过界面自由能变化最小的热力学判据对合成的复合乳液粒子的热力学平衡形态进行了预测 .并利用透射电子显微镜和接触角法测定的膜的表面极性对其进行了证实 .结果表明 ,界面自由能变化的最小判据可以推广到PU PSt体系 ,文中给出的界面张力的简化计算方法是可行的 .     

聚丙烯/硫酸钡复合体系的界面相互作用与流变性质和结晶行为的关系

制备了一系列具有不同界面状态的聚丙烯 (PP) 硫酸钡 (BaSO4)复合体 .PP BaSO4的界面分别用硅烷、硬脂酸、马来酸酐接枝聚丙烯 (PP g MAH)改性 .研究表明 ,填充体系的熔体粘度和熔体弹性均高于基体 .以硅烷和PP g MAH进行界面改性后 ,PP BaSO4的界面相互作用加强 ,导致复合体系中的熔体粘度和熔体弹性进一步提高 ,同时BaSO4对PP的成核活性提高 .填料用硬脂酸处理后 ,硬脂酸能够在填料粒子表面上形成一个包覆层 ,使粒子与PP的亲和性改善 .同时该包覆层具有润滑作用 ,使得复合体系的熔体粘度和熔体弹性下降 ,并使得该体系中BaSO4的成核活性低于硅烷和处理的体系 .本文探讨了由复合体系的熔体粘度定量比较填充复合体系中聚合物 填料界面相互作用的方法 ,讨论了界面改性对复合体系流变性质和结晶行为影响的机理     

Effect of metal ions on the viscosity of polyacrylamide solution and the mechanism of viscosity degradation

聚丙烯酰胺( HPAM)是油田常用的驱油聚合物,用油田污水配制HPAM溶液易导致其黏度明显降低,影响驱油效果.依据埕东油田污水实测的各种金属阳离子含量来配制HPAM溶液,测得各金属阳离子对其黏度影响由大到小的顺序为:Na+ ＞Fe2+ ＞Ca2+ ＞K+＞ Mg2+;通过红外光谱和扫描电镜分析金属阳离子导致HPAM溶液降黏的机理,Na+、K+、Ca2+、Mg2+主要是通过与HPAM链上的羧酸根阴离子静电引力相互作用,降低HPAM分子表面原有的电荷密度,造成分子链卷曲,同时减弱了极性基团的溶剂化能力,释放大量的“束缚水”,从而使黏度显著降低;Fe2+离子主要是与水中溶解氧共同作用,引发自由基反应,导致HPAM骨架水解断裂,致使黏度显著降低.     

核壳型聚丙烯酸丁酯/聚(苯乙烯-甲丙烯酸甲酯)乳胶粒子形态设计及模拟

在简化及限制的实验条件下，提出了一套界面张力的简化推算方法，通过计算证实了采用该简化算法所得界面张力可较为准确地预测丙苯体系复合乳胶粒子的热力学平衡形态．并且根据性能要求，通过界面自由能变化最小的热力学判据对核壳型聚丙烯酸丁酯／ 聚（ 苯乙烯 甲基丙烯酸甲酯） 复合乳胶粒子进行形态设计，采用种子半连续乳液聚合法制备复合乳胶，利用电镜对设计粒子的最终核壳形态进行了证实．     

电感耦合等离子体原子光谱法间接测定油田污水中硫离子

油田水驱采出污水中硫元素的含量较高,各区块中的还原性物质硫化物是曝氧工艺除去的主要元素,其对聚合物粘度的影响较大,直接影响原油采收率,是油田水驱污水处理和配聚用水处理的主要对象。本研究建立了电感耦合等离子体原子发射光谱法(ICP-AES)测定Fe2 间接测定水驱污水中S2-的方法。通过加入过量Fe2 ,使S2-生成FeS沉淀,用脱脂棉过滤,以ICP-AES测定滤液中剩余的Fe2 ,差减法间接测定污水中S2-的含量。本法简便、准确快速,线性范围宽,回收率在96.9%~98.7%之间,相对标准偏差为2.15%。并对南阳油田实际污水中还原性硫离子进行了测定。     

Degradation Action of the Anaerobic Bacteria and Oxygen to the Polymer

Oxygen could prohibit anaerobic bacterium in the produced water and degrade the polymer molecular chains. Aiming at problems making up aerobic polymer solution by the produced water in Daqing Oil Field, some evaluations were done on the viscosity characteristics of polymer solution and bactericide in anaerobic and aerobic environments. Reasonable aerobic concentration of the produced water was obtained. The experimental results indicate that the viscosity of polymer solution confected by the produced water in the aerobic environment is higher than that of the polymer solution confected by the produced water in the anaerobic environment, and the reasonable aerobic concentration is about 6 mg•L^－1. The bactericide has sterilization ability in anaerobic and aerobic environments, but the sterilization effect is better in the aerobic environment.     

Effect of Oxygen and Bacteria on the Property of Polymer Gel

The viscosity property of Cr~(3 ),Al~(3 ),and compound ion cross-linked polymer gel solution in the anaerobic and aerobic environment was investigated aiming at meeting the practical demand of the oil field.The viscosity reserving effect after adding the biocide and the gelation in the anaerobic and aerobic environments was also studied in the paper.The results indicate that the viscosity of the cross-linked polymer gel solution caused by the water produced in aerobic environment is higher than that in anaerobic environment,and that the viscosity value of the cross-linked polymer gel solutions after adding biocides has improved to some extent and polymer gel has gelated well in anaerobic environment.     

Characterization and demulsification of produced liquid from weak base ASP flooding

Weak base alkali-surfactant-polymer (ASP) flooding technology has been applied in Daqing oilfield to enhance oil recovery. The effects of ASP on the characteristics of oil droplets in produced liquid were investigated. Surfactant can decrease interfacial tension (IFT) and zeta potential, making main contribution to the stability of oil droplets. Weak alkali (Na₂CO₃) can decrease IFT and polymer can decrease zeta potential, resulting in stable oil droplets in produced liquid. The produced liquid from weak base ASP flooding is easier to treat than that from strong base ASP flooding. A mixed demulsifier GFD410-8 was prepared and used to enhance oil–water separation in produced liquid. When the demulsifier dose of 50 mg/kg was used to demulsify the simulated produced liquid with the concentrations of alkali 2000 mg/kg, surfactant 600 mg/kg and polymer 600 mg/kg, water volume and water content after 30 min settling were less than 30% and 1000 mg/L, respectively. The demulsifier also greatly decreased water content in oil phase and oil concentration in water phase for actual produced liquid from oil well. The demulsification mechanism was also investigated in terms of IFT and zeta potential.     

INTERACTION OP POLYVINYL ALCOHOL WITH LECITHIN AT THE AIR/WATER AND OIL/WATER INTERFACES AND ITS EFFECT ON EMULSION STABILITY

The interaction of polyvinyl alcohol (PVA) with lecithin films at the air/water and xylene/water interfaces was studied at pH 3, the isoelectric point of lecithin. Surface and interfacial tension measurements and electro-phoretie mobility data showed that PVA either replaces the lecithin molecules or becomes coadsorbed with it at the interface. This mixed film has no elasticity and very low interfacial viscosity. However, coalescence rate measurements showed that the emulsion formed by the polymer* lecithin is more stable than that formed with either polymer or lecithin alone. The enhanced stability by the PVA-lecithin mixed film was attributed to steric interaction produced by the adsorbed polymer.     

ASP复合驱油体系瞬时界面张力的研究

以胜利油田孤岛试验区原油为油相,用正交试验筛选了碱/天然混合羧酸盐/聚合物驱油体系,讨论了各组分对ASP复合驱油体系油水瞬时界面张力的影响,并探讨了各组分间的相互作用机理及其在油水界面的吸附机理。     

Effect of Cross Linking Agent on Alkali/Surfactant/Polymer

Alkali/surfactant/polymer (ASP) multisystem flooding technique, which has an expansive application prospect, is one of the enhancing oil recovery (EOR) methods. By adding the organic chromium to the ASP, the molecular structure of polymer was made to change, and the capability of controlling mobility coefficient of ASP was improved. The results showed that multisystem could still keep ultra‐low interfacial tension between the multisystem and crude oil after addition of Cr³⁺. The resistance factor and residual resistance factor, the indicator which describes the capability of controlling mobility, upgraded strikingly. However its storage modulus and loss modulus, the indicator which describes viscoelasticity, increased. The results of physical simulation experiment indicated that this type of improved ASP could increase the recovery ratio by 4.3% compared to common ASP multisystem.     

What is the Criterion for Selecting Alkaline/Surfactaint/Polymer Flooding Formulation: Phase Behavior or Interfacial Tension

An experimental study on determination of alkaline, surfactant, polymer (ASP) flooding systems using natural mixed carboxylate was conducted to examine the decisive factor for ASP flooding, phase behavior or interfacial tension. The volume and color of middle phase liquid were observed, the transient interfacial tension at different salt and alkaline concentrations were measured and, finally, coreflood test in laboratory were made. The results showed the flooding system with larger volume and brown color of middle phase emulsion sometimes not to obtain better oil recovery efficiency. The primary and more important phenomenon affecting the oil recovery is a lower or ultralow minimum interfacial tension value at the crude oil/soluble phase interface.     

Interaction between polymer and anionic/nonionic surfactants and its mechanism of enhanced oil recovery

Various experimental methods were used to investigate interaction between polymer and anionic/nonionic surfactants and mechanisms of enhanced oil recovery by anionic/nonionic surfactants in the present paper. The complex surfactant molecules are adsorbed in the mixed micelles or aggregates formed by the hydrophobic association of hydrophobic groups of polymers, making the surfactant molecules at oil-water interface reduce and the value of interfacial tension between oil and water increase. A dense spatial network structure is formed by the interaction between the mixed aggregates and hydrophobic groups of the polymer molecular chains, making the hydrodynamic volume of the aggregates and the viscosity of the polymer solution increase. Because of the formation of the mixed adsorption layer at oil and water interface by synergistic effect, ultra-low interfacial tension (～2.0?×?10^?3 mN/m) can be achieved between the novel surfactant system and the oil samples in this paper. Because of hydrophobic interaction, wettability alteration of oil-wet surface was induced by the adsorption of the surfactant system on the solid surface. Moreover, the studied surfactant system had a certain degree of spontaneous emulsification ability (D50?=?25.04?µm) and was well emulsified with crude oil after the mechanical oscillation (D50?=?4.27?µm).     

三元复合驱碱/表面活性剂/聚合物模拟原油乳状液稳定动力学特性

基于两相分离的乳状液稳定模型,研究了三元复合驱模拟原油乳状液稳定动力学特性;通过液膜强度和油水界面张力探讨了碱/表面活性剂/聚合物对模拟原油乳状液稳定动力学特性的影响机理。 结果表明,乳状液稳定模型可以很好的评价乳状液的稳定性,并得到乳状液的稳定动力学特性;碱浓度小于900 mg/L有利于乳状液的稳定,碱浓度大于900 mg/L不利于乳状液的稳定;表面活性剂和聚合物浓度的增加使得形成的模拟原油乳状液更加稳定;模拟原油乳状液的稳定作用主要是通过碱、表面活性剂降低油水界面张力并增加油水界面膜强度,聚合物通过提高界面膜强度实现的,三者存在协同效应。     

纳米SiO2/HPAM/NaCl分散体系的稳定性、流变性及驱油性能研究

利用纳米粒度及Zeta电位分析仪、流变仪和悬滴法对纳米SiO_2/HPAM/NaCl体系60℃的稳定性、流变性及油水界面张力进行了研究。结果表明,HPAM的加入使SiO_2悬浮液的Zeta电位更负、粒径明显增加,静置10 d无明显浑浊现象。加入纳米SiO_2后,HPAM溶液的黏度增加,耐温、耐盐和耐剪切性能得到改善。对于质量分数为0.18%的HPAM溶液,SiO_2质量分数小于0.5%时,随SiO_2质量分数的增加,体系的黏度、储能模量和损耗模量增加,临界线性应变减小,蠕变回复能力增强;SiO_2质量分数大于0.5%时,出现了相反的现象;这是因为SiO_2质量分数不同时,HPAM在SiO_2表面的吸附量、吸附构型及两者之间形成的网状结构不同。纳米SiO_2的加入同时强化了HPAM降低油水界面张力的性能,加入质量分数为0.2%和0.5%的SiO_2后,HPAM的采收率分别提高了4.5%和6.0%。