一种油田驱油用支化聚合物的合成及性能评价

由于目前部分水解支化聚烯酞胺在实际应用于高温和高盐化度的油藏中时,很多聚合物溶液的增黏作用没有发挥出来,并且部分水解支化聚烯酞胺易被剪切降解,所以对部分水解支化聚烯酞胺进行修饰改性,在其中增加疏水单体和极性单体的方法来改善聚合物的耐温抗盐性来满足需求。本实验制备了一种驱油用聚合物,然后首先研究了初始温度对合成的聚合物相对分子质量的影响,接着研究了在聚合物当中导入极性单体以及疏水单体对聚合物在复合盐水溶液中表观黏度的影响,最后又进一步评价了聚合物的耐热性以及抗剪切性。结果表明：当疏水单体和极性单体的质量分数分别在0.55%、5%及初始温度在11℃左右时,该驱油聚合物具有非常好的热稳定性、增黏性与耐剪切性。     

水溶性疏水缔合聚合物单体的合成

水溶性疏水缔合聚合物含有大量的亲水基团和少量的疏水基团,疏水基团间的疏水缔合作用使这种聚合物具有独特的增粘、抗剪切、耐温和耐盐的溶液性能,通常采用亲水单体和疏水单体共聚制备这类聚合物。对常用亲水单体AMPS及各类疏水单体如季铵盐不饱和单体AMPDAC和DAMAB、长链丙烯酸酯,N-烷基丙烯酰胺和N-芳烷基丙烯酰胺的合成进行了综述。     

页岩压裂用疏水缔合聚合物的合成及性能分析

采用表面活性大单体法,在聚丙烯酰胺分子链上引入少量疏水基团,合成AM—AA．DM共聚体系,应用到页岩气压裂液中。考察了引发温度、引发剂用量、疏水单体含量等对聚合物性能的影响。结果表明,聚合的最佳条件为：引发温度40℃,引发剂含量0．1％,单体总浓度25．0％。在此条件下,聚合物的粘均分子量为112万左右,粒度主要分布在0．4—1．0μm之间,合成产物均一性较好;合成产物水溶液具有良好的抗剪切性能。     

PAAD-16酸液稠化剂的合成与性能

以二甲氨基丙基甲基丙烯酰胺和溴代十六烷为原料,丙酮为溶剂,合成了一种疏水单体——二甲基十六烷基(2-甲基丙烯酰胺基丙基)溴化铵(DHAB),并以DHAB、2-甲基-2-丙烯酰胺基丙磺酸(AMPS)和丙烯酰胺(AM)为单体,以自由基水溶液聚合法合成了一种疏水缔合聚合物P(AM-AMPS-DHAB)(PAAD-16),用IR、荧光光谱(FL)和SEM对其进行了结构表征。结果表明:PAAD-16的酸溶时间约为90 min;以该疏水缔合聚合物为主要添加剂配制而成的稠化酸在30℃、170s~(–1)下的表观黏度为59m Pa×s,在60、90℃下的热稳定性(ω)分别为85.0%和66.1%,在该条件下连续剪切120 min后剪切稳定性(ω')为81.4%,具有良好的增黏性、耐温抗剪切性和缓速性能。     

微乳液聚合法AM-SMA疏水缔合聚合物的研究

通过甲基丙烯酸十八酯(SMA)与丙烯酰胺(AM)微乳液聚合合成了疏水缔合聚合物,采用红外光谱(FTIR)表征了疏水缔合聚合物的结构,考察了SMA含量、AM含量、聚合物浓度、NaCl浓度以及剪切速率对疏水缔合聚合物溶液表观粘度的影响。结果表明聚合物水溶液临界缔合浓度为0.6g/dL,疏水缔合聚合物表现出较强的盐增粘效应和抗盐性;12%SMA的疏水缔合聚合物水溶液表现出剪切增粘和假塑性流体行为,FTIR谱图初步证实疏水缔合聚合物的结构。     

疏水缔合水溶性聚合物的合成与表征

综述了疏水缔合型水溶性聚合物合成与表征方法，介绍了在合成过程中提高油溶性单体和水溶性单体混溶性的方法，简述了疏水物质含量的核磁共振、紫外光谱、裂解气相色谱等测定方法。     

聚合法对疏水缔合聚丙烯酰胺粘度的影响

为了增强聚丙烯酰胺的增粘性能,提高其抗剪切、抗温和抗盐性,使用实验室自制的疏水单体、丙烯酰胺和离子型单体,通过3种不同的聚合方法进行自由基共聚合。分析了不同聚合途径下,研究组分、剪切、温度和盐对聚合物溶液表观粘度的影响。结果表明,反相乳液聚合法的产物的临界缔合浓度小于0.4 g/L,85℃下粘度保持60%以上,其表观粘度在受剪切后的恢复率达到100%,抗剪切性能明显。利用一种小分子化合物来抑制Fe2+对聚合物的降解作用,达到保持聚合物溶液粘度目的。     

耐盐型疏水缔合聚合物的制备及流变性能

采用丙烯酰胺(AM)、丙烯酸(AA)、2-丙烯酰胺-2-甲基丙烷磺酸(AMPS)和水溶性阴离子疏水单体S-18制备了新型耐盐疏水缔合聚合物S-18HPAM。聚合放热测试表明:疏水单体含量的增加导致放热时间的延长,更有利于疏水结构的形成。微观结构测试表明:聚合物具有复杂的网状结构,在NaCl溶液中网状结构更为明显。流变测试结果表明:聚合物在盐溶液中具有良好的耐温和抗剪切性能。聚合物质量分数为0.3%(基于溶液总质量),温度90℃,剪切速率170 s–1和NaCl质量浓度20000 mg/L条件下,剪切后表观黏度大于70 mPa·s。在总矿化度20000 mg/L模拟地下水条件下,S-18HPAM质量分数为0.3%,剪切后黏度为70 mPa·s,加入质量分数0.5%表面活性剂十二烷基硫酸钠(SDS)后,黏度增加到170m Pa·s。储能模量G'随着聚合物质量分数的增加而增大,体系弹性增强,同时疏水结构单元数量增加,形成致密的空间网络结构。     

一种疏水缔合聚合物的合成及溶液性能

将十八烷基-二甲基甲代烯丙基氯化铵(C18DMMAAC)作为疏水单体,与丙烯酸(AA)、丙烯酰胺(AM)在水溶液中通过自由基聚合得到疏水缔合聚合物HAPAM-18,通过1HNMR和红外光谱对其结构进行了表征。最佳的聚合反应条件为:n(AM)∶n(AA)∶n(C18DMMAAC)=74.94∶25∶0.06,AA的摩尔中和度为95%,单体总质量分数为20%,引发剂质量分数为0.05%(以单体总质量计),温度45℃,反应时间12 h。研究表明,聚合物溶液的临界缔合质量浓度为2 g/L;聚合物溶液对温度较为敏感,80℃时黏度保留率为70.93%;聚合物溶液仍为剪切变稀的假塑性流体,但表现出良好的抗剪切性能,剪切1 h后黏度保留率达115%;由于设计为含较多阴离子的聚合物,该聚合物的抗盐性较差。     

疏水缔合聚合物PADA的合成与性能评价

以质量分数为33.0%二甲胺水溶液、氯丙烯为原料,合成中间体二甲基烯丙基胺,然后以溴代十六烷与二甲基烯丙基胺为原料,通过季铵化反应合成了一种疏水性季铵盐单体ADMA-16。并以AM、DMC与ADMA-16为反应单体合成了一种三元疏水缔合聚合物PADA。通过测定PADA溶液的表观黏度优化PADA的合成条件,研究PADA的耐温抗盐性能。结果表明,PADA的临界缔合浓度为0.33%。聚合物PADA表现出一定的耐温抗盐性。     

Evaluation of hydrophobically associated polyacrylamide‐containing aqueous fluids and their potential use in petroleum recovery

Acrylamide and tridecyl acrylate copolymers were synthesized by micellar copolymerization to obtain water‐soluble, hydrophobically modified polymers. Rheological properties of the obtained polymer solutions were evaluated and compared to those of solutions of a commercial polyacrylamide currently used in the petroleum industry. The behavior of the copolymer solutions was studied as a function of the variation of hydrophobic monomer content incorporated in the copolymer as well as the salt content of the aqueous medium, for diluted and semi‐diluted regimens. Comparative studies of such effects on the intrinsic viscosity and the critical concentration of those polymers were conducted. The increase in hydrophobic monomer content produced a sudden increase in the bulk and absolute viscosity of the polymeric solutions, a trend that was more intense from a certain concentration typical for each polymer. Salt addition led to lower bulk viscosity caused by a stronger interaction among hydrophobic groups, resulting from minimized exposure of such groups and water. The same effect was observed for the critical concentration. A comparison of the synthesized polymers with industrial polyacrylamide showed that the synthesized polymers were characterized by advantageously high shear strength and high salt resistance. However, in the absence of salts, higher copolymer amounts were needed to prepare solutions whose viscosity was the same as that of commercial polyacrylamide. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3686–3692, 2004     

The characteristics and flocculation performance of hydrophobic association poly-(3-methacryloylamido propyl trimethyl ammonium chloride)

The cationic polymer plays a crucial role in the flocculation process for solid–liquid separation. A hydrophobic-associated cationic polymer was prepared through micellar free-radical polymerization of cationic monomer 3-methyl acrylamide propyl trimethyl ammonium chloride (MAPTAC) and hydrophobic monomer Poly (ethylene glycol) Octadecyl methacrylate (OEMA). The Poly-MAPTAC-OEMA can form network structure through intermolecular hydrophobic association in aqueous solution, which leads to the solution viscosity increase and the salt thickening property. The critical associating concentrations (CACs) of Poly-MAPTAC-OEMA are 5818–6992 mg/L in aqueous solution. For the diatomite suspensions, at the dosage above about 5 mg/L, the Poly-MAPTAC-OEMA can show higher flocculation efficiency compared with Poly-MAPTAC. Specifically, at the dosage of 8 mg/L, the enhancement rate of sedimentation rate can reach 7.27%–32.31%. Meanwhile, the hydrophobic association mainly enhances the bridging ability but has no significant effect on the improvement of the electric neutralization ability of Poly-MAPTAC-OEMA. The flocculation performance-enhanced dosage of Poly-MAPTAC-OEMA is obviously lower than the CAC of Poly-MAPTAC-OEMA; this may be because during the flocculation process, the Poly-MAPTAC-OEMA first absorb and deeply concentrate on the particle surface, and then the hydrophobic association and bridging enhancement of Poly-MAPTAC-OEMA can occur more easily on the particle surface.     

Associating behaviour of polyacrylamide modified with a new hydrophobic zwitterionic monomer

The nucleophilic ring opening of dicyanoketene ethylene acetal by tertiary amino monomers leads to an hydrophobic zwitterionic monomer [(dimethylammonioethoxy)dicyanoethenolate]propylmethacrylamide (DADPMA) characterized by a very high dipole moment. Hydrophobically modified water soluble polymers have been prepared by classical radical polymerization of acrylamide and DADPMA either in homogeneous medium (water/ethanol mixtures) or in micellar solution (water containing sodium dodecylsulphate (SDS)). The copolymers obtained have a high molecular weight (M _w = 2–5 × 10⁶ g mol^?1) and are water soluble for a content of DADPMA lower than 1% mole/mole. The properties of the copolymers in aqueous solution depend on the synthesis conditions, especially on the ratio ethanol:zwitterionic monomer. © 2001 Society of Chemical Industry     

AM/阳离子单体在盐水介质中的分散聚合

水溶性单体在盐水介质中的分散聚合是一种新型绿色合成技术.本研究通过丙烯酰胺(AM)和阳离子单体甲基丙烯酰氧乙基三甲基氯化铵(DMC)在无机盐水溶液中的分散共聚合,制备了稳定的P(AM-DMC)水基分散体.采用扫描电镜、激光粒度仪测定了粒子形貌和粒径.研究了稳定剂结构与用量、共聚单体组成、第三单体盐的种类和浓度对水基分散聚合的影响.     

低渗油田压裂控水用聚电解质复合溶液性能研究

将阴离子聚丙烯酰胺(HPAM)与阳离子聚合物(DP-1)应用溶液共混法,制备了低渗油田压裂控水用聚电解质复合溶液。研究了阴阳离子聚合物稳定共存的条件,评价了复合溶液的耐温抗盐性能、抗剪切耐冲刷性能以及控水性能。结果表明,在一定量外加盐(KCl)的作用下,阴阳离子聚合物可形成稳定的低粘度聚电解质复合溶液,且具有良好的耐温性和抗盐性;随剪切速率的增加,复合溶液粘度先降低后又有增加;在60℃下岩心流动实验中,盐水驱替100 PV时残余阻力系数为2.66,具有良好的耐冲刷性;水相渗透率降低90.53%,油相渗透率降低14.60%,具有明显的不等比例降低油水相渗透率特征,可用于近水或高含水低渗油层控水压裂改造,降低现场施工风险。     

Thermoviscosifying polymer used for enhanced oil recovery: rheological behaviors and core flooding test

Polymer flooding represents one of the most efficient processes to enhance oil recovery, but the poor thermostability and salt tolerance of the currently used water-soluble polymers impeded their use in high temperature and salinity oil reservoirs. Thermoviscosifying polymers (TVPs) whose viscosity increases upon increasing temperature and salinity may overcome the deficiencies of most water-soluble polymers. A novel TVP was studied in comparison with traditional partially hydrolyzed polyacrylamide (HPAM) in synthetic brine regarding their rheological behaviors and core flooding experiments under simulated high temperature and salinity oil reservoir conditions (T: 85 °C, and total salinity: 32,868 mg/L, [Ca²⁺] + [Mg²⁺]: 873 mg/L). It was found that with increasing temperature, both apparent viscosity and elastic modulus of the TVP polymer solution increase, while those of the HPAM solutions decrease. Such a difference is attributed to their microstructures formed in aqueous solution, which were observed by cryogenic transmission electron microscopy. Core flow tests at equal conditions showed an oil recovery factor of 13.5 % for the TVP solution versus only 2.1 % for the HPAM solution.     

疏水型高强度水凝胶的合成与性能

以丙烯酰胺和疏水单体为原料 ,过硫酸钾 -硫酸亚铁为引发剂 ,采用溶液聚合法合成了疏水型高强度水凝胶。研究了单体组成、单体浓度、引发剂用量、交联剂用量、反应温度等因素对产物性能的影响。对比分析了疏水型水凝胶的吸水倍数、吸水速率和强度。疏水型水凝胶的强度大于常规高吸水性树脂 ,最长吸水时间长 ,吸水速度平缓。对疏水型高强度水凝胶强度进行了统计回归分析 ,对吸水速率和最长吸水时间进行了分析描述。     

Solution properties of anionic hydrophobic association polyacrylamide modified with fluorinated acrylate

The anionic hydrophobic association polyacrylamide (AFPAM) modified with fluorinated acrylate have been synthesized of acrylamide (AM), 2-acrylamide-2-methyl propanesulfonic acid (AMPS) and 2-(perfluorooctyl)ethyl acrylate (FEA) by free radical micellar copolymerization in aqueous solution utilizing sodium dodecyl sulfate(SDS) as the surfactant and potassium persulfate(KPS)/sodium bisulfite(SBS) as the redox initiator. The solution properties of these polymers were investigated. The results show that there are strong hydrophobic associations in the AFPAM aqueous solution. The intrinsic viscosity decreases and Huggins constant increases with the increase of hydrophobic FEA content. The addition of NaCl and CaCl₂ results in an increase of solution viscosity which indicate the good salt-resistant performance. The polymers exhibit good temperature tolerance property, shear-thickening and thixotropy behavior. Additionally, the AFPAM has higher surface activity in salt solution than in water.     

Synthesis,characterization, and solution properties of a surface‐active hydrophobically associating polymer

A nonionic surfmer (MAA‐EO₂₃C₁₂) was prepared and reacted with acrylamide, acrylic acid, and a double tailed hydrophobic monomer (BTMAM) to synthesize a surface‐active hydrophobically associating copolymer (SHAP) through photoinitiated free radical copolymerization in aqueous solution. Fourier transform infrared and ¹H‐nuclear magnetic resonance spectroscopy were used to characterize the functional monomer and the SHAP. Several performance evaluations, such as viscosification property, temperature resistance, salt tolerance, and shear resistance, were also conducted. Experiment results demonstrated that the introduced nonionic surfmer and hydrophobic monomer could endow the copolymer with excellent temperature resistance, salt tolerance, and shear resistance capability at low concentration. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46569.     

Synthesis and characterization of a calcium‐ and sodium‐containing acrylamide‐based polymer and its effect on soil strength

Soil degradation is a significant problem throughout the world. One strategy that can be used to improve soil physical properties is the use of soil conditioners, particularly anionic polyacrylamides. Synthetic water‐soluble anionic acrylamide‐based polymers have wide applications in agriculture, such as mulch and agrochemicals, and can also be used as soil modifiers for erosion control, nondesertification, and soil stabilization. In this study, anionic polyacrylamides containing cationic metal ions were prepared by free‐radical polymerization. Anionic polymer with negative charges was produced by the reaction of mono‐ and divalent inorganic salts with acrylamide monomer via solution polymerization. Hydrolysis of the polymer was carried out by using calcium chloride and sodium carbonate in their soluble forms, and the negative charges on the polymer were regulated by variation of the molar ratios of inorganic salts with respect to the acrylamide monomer concentration. The molecular weight and charge density of the anionic charged polymers were improved and manipulated by using these methods. The molecular structure of the polymers was characterized and confirmed by common techniques. The effect of the polymers on soil strength was evaluated, and the results showed that the addition of anionic polymer having a high molecular weight improved the behavior of soil components. J. VINYL ADDIT. TECHNOL., 19:140–146, 2013. © 2013 Society of Plastics Engineers