新型疏水缔合聚合物压裂液破胶性能研究

性能良好的压裂液不仅要求具有良好的流变性能和悬砂性能等,还必须具有良好的破胶水化性能,以提高压裂液的返排率,减少对储层的伤害。该研究以过硫酸铵(APS)作为破胶剂,探讨了疏水缔合聚合物压裂液(SRFG)破胶液粘度随破胶温度、破胶时间和破胶剂浓度的变化规律;研究了破胶液的表面张力随破胶温度和破胶剂浓度的变化规律;最后比较了三种不同聚合物压裂液的破胶性能。结果表明:单一使用过硫酸铵,保持其浓度0.05%和破胶时间0.5~2h不变,SRFG压裂液最低破胶温度为60℃;随着过硫酸铵浓度和破胶温度增加,破胶变得更加彻底,更有利于降低破胶液表面张力;SRFG压裂液与市售A和B聚合物压裂液的破胶性能相当,SRFG压裂液返排效果优于A、B聚合物压裂液。     

压裂用疏水缔合聚合物溶液性质及减阻性能研究

摘要：以一种功能性疏水单体与丙烯酰胺（AM）、丙烯酸（AA）和2-丙烯酰胺-2-甲基丙磺酸（AMPS）为原料,合成了一种疏水缔合聚合物HAWP-18。采用流变仪考察了疏水缔合聚合物HAWP-18的耐剪切性能、黏弹性及触变性,结果表明,HAWP-18属于假塑性流体,临界缔合浓度为2.31g/L,表现出较强的耐剪切性能;黏弹性测试表明,HAWP-18是典型的黏弹性结构流体,具有较宽的线性黏弹区,该体系的储能模量G''大于损耗模量G'',并且黏度越大,弹性特征越强;采用稳态剪切测试研究了不同质量浓度HAWP-18的剪切应力与剪切速率的关系,HAWP-18具有触变性,并且触变性随质量浓度增大而增强;使用自制摩阻测试仪测定了不同质量浓度HAWP-1的减阻性能,结果表明,HAWP-18减阻率随质量浓度的增加先上升后降低。HAWP-18的耐剪切性及其良好的黏弹性、触变性和减阻性能为其应用于压裂液提供了实验支撑。     

疏水缔合聚合物增稠性能研究

在不同条件下 ,进行了疏水缔合聚合物增稠性能研究 ,结果表明疏水缔合聚合物在蒸馏水中 ,基本上看不到疏水缔合效果 ;疏水缔合聚合物的氯化钠溶液或氯化钙溶液 ,在缔合临界矿化度之前 ,随着溶液矿化度的增大 ,溶液粘度逐渐降低 ;在缔合临界矿化度之后 ,随着溶液矿化度的增大 ,溶液粘度迅速升高 ,达到极大值后又逐渐下降 ;油田采出污水中均存在较高含量的钙、镁等高价离子 ,疏水缔合聚合物在油田采出污水中 ,随着矿化度和温度的升高 ,疏水缔合增稠效果越差。认为目前把疏水缔合聚合物作为油田三次采油用耐温抗盐聚合物研制的主攻方向是不合适的     

疏水缔合聚合物溶液的性能

疏水缔合水溶性聚合物指在常规水溶性聚合物主链上引入极少量疏水基团所形成的一类新型聚合物。与部分水解聚丙烯酰胺(HPAM)相比,这类聚合物的分子量不高,但具有独特的溶液性能。本文综述了疏水缔合聚合物的增黏、耐温、抗盐、抗剪切的溶液性能。     

疏水缔合水溶性聚合物的分子结构对疏水缔合的影响

疏水缔合水溶性聚合物是水溶性聚合物中含有少量疏水基团,在水溶液中疏水基团由于范德华力聚集在一起,使水溶液具有良好的增粘作用和抗盐耐温性。对该类聚合物的分子结构对疏水缔合的影响作了综述。     

十二烷基苯磺酸钠对疏水缔合两性聚合物的性能影响

使用激光光散射仪、流变仪研究了十二烷基苯磺酸钠（SDBS）对疏水缔合两性聚合物的溶液性能影响.结果表明,盐浓度较低时,溶液粘度随表面活性剂浓度的增加出现先增加后下降的过程;盐浓度过高时,表面活性剂在盐水中析出.表面活性剂对聚合物溶液的弹性模量具有较大的影响,对粘性模量的影响较小.表面活性剂对聚合物的流体力学半径＜Rh＞和聚合物的表观重均分子量Mw均有较大影响.     

疏水缔合聚合物减阻剂的合成及流变性能研究

采用疏水单体FW-12(物质的量比2∶1的丙烯酸十八酯与甲基丙烯酸十六烷基酯混合物)与丙烯酰胺(AM)、丙烯酸(AA)、2-丙烯酰胺基-2-甲基丙磺酸(AMPS)聚合得到水溶性疏水缔合聚合物减阻剂FHAPAM。考察了聚合过程放热特点,找出含疏水基团时聚合反应热量变化基本规律,用流变仪测定了FHAPAM水溶液的流变性能;芘探针实验探究了溶液的极性及变化规律;室内减阻实验测试其减阻性能。结果表明:FHAPAM聚合温度受疏水单体摩尔分数影响较大,存在明显的平台区,FHAPAM水溶液受剪切作用表现出强触变性;溶液极性随疏水单体摩尔分数的增加而降低,且第一振动带与第三振动带强度比值I1/I3的比值存在突变点;FHAPAM耐温性强于普通聚丙烯酰胺(PAM);疏水单体摩尔分数不同,储能模量(G')、损耗模量(G″)均表现出特殊性。FHAPAM低浓度时,减阻性能优良,其展现出作为滑溜水压裂液良好的应用前景。     

疏水缔合聚合物破胶性能研究

压裂液能否彻底破胶返排是决定压裂施工是否成功的关键因素之一。本文主要研究了以过硫酸铵(APS)作为破胶剂,疏水缔合聚合物压裂液(BCG)破胶液粘度随破胶温度、破胶剂浓度的变化情况,以及表界面张力、残渣和伤害等。     

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。     

疏水缔合聚合物的合成、表征及其溶液性能研究

采用自由基胶束聚合法,合成了一种疏水缔合型丙烯酰胺-烷基丙烯酸酯共聚物。用1HNMR谱和TEM对该共聚物进行了表征。用旋转黏度计测定了不同疏水基含量的聚合物的溶液性能,考察了温度对聚合物溶液性能的影响,同时研究了外加盐对聚合物溶液形貌的影响。     

Rheological properties of hydrophobically modified polyelectrolyte systems: Concentration effects

The behavior of hydrophobically modified alkali‐soluble associative polymer (HASE) at various polymer concentrations was investigated. The results showed that the formation of network structure, which enhances the rheological behavior, depends on two critical polymer concentrations, namely the critical cluster overlapping concentration (C*) and the established network concentration (C**). C* is defined as the critical concentration for the transformation of individual cluster to a transient network structure. C** represents the critical concentration in the semidilute regime where the formation of transient network is completely established. Experimental results demonstrated that the polymer solutions transformed from a predominantly viscous behavior below C* to one with dominant elastic properties above C**. Because of the formation of larger aggregation number above C**, the relaxation times of the polymer systems shift to longer times. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5166–5173, 2006     

Synthesis in inverse emulsion and associating behavior of hydrophobically modified polyacrylamides

An inverse free‐radical emulsion polymerization technique was used to prepare copolymers of acrylamide and two different hydrophobic comonomers: N,N‐dihexylacrylamide (diC6) or N,N‐diphenylacrylamide (diPh). The products of the reaction were high molecular weight hydrophobically modified water‐soluble polymers (HMWSPs) encapsulated within water droplets dispersed in an organic medium. A comparison of the copolymer compositions prepared under different experimental conditions showed that the level of incorporation of diPh in the final copolymer depended strongly on its localization in the emulsion (aqueous or oil phase) and on the nature of the redox initiator pair (water‐soluble or oil‐soluble). The rheological properties of the HMWSPs in aqueous solution were investigated as a function of the comonomer content and the nature of the initiator, using steady‐flow experiments. The thickening properties were found to be directly correlated to the conditions of synthesis and were optimal when the initiator and the hydrophobic comonomer were located in two distinct phases. An examination of the viscosity as a function of shear rate showed that these solutions exhibit typical characteristics of hydrophobically associative polymers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 916–924, 2004     

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。     

Surfactant co-thickening in model associative polymers

Associative thickeners act to thicken aqueous systems through the formation of non-specific hydrophobe associations. The formation of these ‘pseudomicellar’ units is driven by the exclusion of the thickener hydrophobes from the aqueous phase, a phenomenon greatly enhanced by the presence of the appropriate level and type of non-ionic surfactant. This enhancement of hydrophobic association is accompanied by a dramatic increase in solution viscosity, commonly referred to as surfactant co-thickening. The selection of an ‘appropriate’ surfactant is dictated by the solubility of the surfactant in the system which is in turn controlled by temperature, the nature of the surfactant hydrophobe, the degree of ethoxylation and the presence of co-solvents.     

Synthesis, structure and properties of hydrophobically associating polymers

Hydrophobically modified water-soluble polymers have recently become the subject of extensive research because of their use as aqueous viscosity modifiers in oil recovery and latex paint systems. In this study, poly(acrylamide) samples modified with small amounts of a hydrophobic monomer (ethylphenylacrylamide) have been prepared by free radical copolymerization using an aqueous micellar process in which the use of a surfactant ensures the solubilization of the hydrophobe. The copolymers exhibit improved thickening properties with respect to homopoly(acrylamide) analogs due to intennolecular hydrophobic associations. The aqueous solution-copolymer properties strongly depend on the amount of surfactant used in the synthesis. The differences observed between the samples are directly related to the copolymer microstructure, that is to a more or less block distribution of the hydrophobic units. The interactions in aqueous solution of a surfactant (sodium dodecylsulfate (SDS)) with these copolymers have been examined. A strong increase in viscosity is observed upon the addition of SDS below its critical micelle concentration, owing to the formation of mixed micelles of SDS and hydrophobic monomers. The complex rheological behavior observed is explained in terms of the balance between inter and intrachain liaisons. The effects of hydrolysis on the hydrophobic interactions are also discussed.     

Enhancing rheological properties of hydrophobically associative polyacrylamide aqueous solutions by hybriding with silica nanoparticles

Organic/inorganic hybrid aqueous solutions were prepared by mixing silica nanoparticle suspension and hydrophobically associating polyacrylamide (HAPAM) solution, and their rheological behaviors were examined in both pure water and brine in comparison with HAPAM. It was found that HAPAM/silica hybrid exhibits viscosity enhancement in aqueous solution and better heat‐ and salt‐ tolerances than HAPAM. Meanwhile, their long‐term thermal stability is also improved. Cryo‐TEM observation reveals that a reinforced three‐dimensional network structure of HAPAM/silica hybrid is formed. These improved properties are attributed to the formed hydrogen bond between carbonyl groups in HAPAM skeleton and silanol functionalities in silica nanoparticles in the hybrid system, and the silica nanoparticles in the hybrid act as physical crosslinkers between macromolecules. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40876.     

低毒性有机交联聚合物凝胶的研制

将水杨酸钠作为苯酚和间苯二酚的替代品,形成了水杨酸钠/乌洛托品低毒性的有机交联体系。选用疏水改性聚丙烯酰胺与水杨酸钠/乌洛托品交联剂的水凝胶体系,研究了其成胶条件及性能。实验表明,该体系成胶时间、强度可控,能够将物理缔合与化学交联形成协同作用,同时该体系适用范围广,在高速剪切破坏下成胶强度仍能保持较大的比例。     

Rheological and mechanical properties of dynamic covalent polymers based on imine bond

Dynamic covalent polymers based on imine bond (FPIs), which are capable of reorganizing their constitution on the molecular level, are prepared from bio-based dimer fatty acids. The irregular structure of carbon chains in dimer fatty acids leads to the amorphous nature of FPIs. The effect of imine bond on the glass transition temperature of FPIs is studied by differential scanning calorimetry. The linear viscoelasticity of FPIs is investigated by small amplitude oscillatory shear tests and analyzed by using the Likhtman-McLeish theory. It is found that the rheological behavior of FPIs is similar with that of static, linear entangled polymers predicted by Likhtman-McLeish theory, when the dynamic chain arrangements caused by imine-bond exchange is not active enough. For FPIs, the temperature variation of viscosity is still following the Arrhenius law with an activation energy of ~50 kJ mol⁻¹. Owing to the thermal adaptability, FPIs demonstrate great malleability, self-healing capability and processing stability at elevated temperatures.     

Synthesis in inverse emulsion and properties of water‐soluble associating polymers

An inverse, free‐radical emulsion polymerization technique was designed for the preparation of copolymers of acrylamide and sodium acrylate modified with low amounts (<0.5 mol %) of a series of amphiphilic comonomers, the isooctylphenoxy–poly(oxyethylene)(n) methacrylates (1 ≤ n ≤ 12). The products of the reaction were hydrophobically modified water‐soluble polymers (HMWSPs) of high molecular weight encapsulated within water droplets dispersed in an organic medium. Kinetic studies showed that the full‐conversion samples were rather homogeneous in composition because of the specificity of the process. A mechanistic scheme is proposed that accounts for the incorporation level of the amphiphilic comonomer as a function of its hydrophile–lipophile balance and the nature of the redox initiator (hydrophilic or lipophilic). The rheological properties of the HMWSPs in aqueous solutions were investigated as a function of the comonomer content and the nature of the initiator with steady‐flow experiments. The thickening properties were directly correlated to the conditions of synthesis and were optimal when the initiator and the amphiphilic comonomer were located in two distinct phases. A maximum in viscosity was observed for a hydrophobe content of about 0.3 mol %. An examination of the viscosity as a function of the shear rate and time showed that these solutions had all the characteristics of associating polymers. The complex rheological behavior was the result of the balance between interchain and intrachain hydrophobic liaisons and the kinetics of disorganization and reorganization of the network structure. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1418–1430, 2002; DOI 10.1002/app.10337     

Rheological evaluation of synthesized template‐hydrophobically modified acrylamide based copolymers in brine

The newly hydrophobically modified associating acrylamide‐based copolymers were prepared by the inverse miniemulsion polymerization method in order to investigate the copolymers rheological and associating properties in water and brine solutions. Dimethyldodecane (2‐acrylamidopropyl) ammonium bromide (DDPAB) was synthesized and used as a hydrophobic monomer and was later copolymerized with acrylamide in the presence of poly(acrylic acid‐co‐maleic acid) and various molecular weights of poly(acrylic acid) as templates. The chemical compositions and functional groups of the resulting hydrophobic monomer and copolymers were characterized using the ¹H nuclear magnetic resonance and Fourier transform‐infrared spectroscopy. According to the studies on the solutions viscosity behavior, incorporation of small amount of hydrophobic monomer improved the thickening properties due to the intermolecular hydrophobic association. The apparent viscosity of the copolymers with a template was much greater than those prepared without a template. The molecular weight of the template strongly influenced the thickening behaviors of the copolymers. A template copolymer with 1 mol % of a hydrophobic monomer was the one most efficient. The addition of electrolyte saline improved the polarization of the solutions and enhanced the thickening ability. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43588.