压裂用疏水缔合聚合物溶液性质及减阻性能

以功能性疏水单体甲基丙烯酸长链酯与丙烯酰胺(AM)、丙烯酸(AA)和2-丙烯酰胺-2-甲基丙磺酸(AMPS)为原料,合成了疏水缔合聚合物HAWP-18。采用流变仪考察了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,临界缔合质量浓度为2.31 g/L,随着剪切速率增加,HAWP-18的表观黏度缓慢下降后不变,剪切速率降低后,表观黏度可再度恢复,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。采用稳态剪切测试考察了不同质量浓度HAWP-18的剪切应力与剪切速率的关系,结果表明: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-18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。     

疏水缔合聚合物/表面活性剂压裂液的性能

考察了疏水缔合聚合物HAWP-18溶液的稳态流变性能及十二烷基硫酸钠(SDS)和烷基酚聚氧乙烯醚(OP-10)对HAWP-18溶液的影响。并以HAWP-18和十二烷基硫酸钠(SDS)制备了一种压裂液HAWP-18M,评价了其相关性质。结果表明:HAWP-18溶液的表观黏度随着剪切速率的增加而下降,随后基本保持不变。HAWP-18M压裂液具有较好的耐温耐剪切性能,在90℃、170 s-1的条件下连续剪切90 min,黏度仍能保持在50m Pa·s以上。HAWP-18M压裂液的储能模量(G')和损耗模量(G″)基本不受应力变化影响,并且G'>G″,说明HAWP-18M压裂液具有黏弹性并且以弹性行为为主。HAWP-18M压裂液触变性优于羟丙基胍胶(HPG)压裂液。HAWP-18M压裂液静态悬砂性能较好,在砂比(砂占压裂液的体积分数,下同)40%条件下,砂子的沉降速率为8.2×10-4mm/s。在HAWP-18M压裂液中加入过硫酸铵破胶剂,80℃下,1 h内即可破胶,破胶液黏度在5m Pa·s以下,表面张力为25.14 m N/m,与航空煤油的界面张力为0.56 m N/m。     

丙烯酰胺/丁基苯乙烯衍生物疏水缔合共聚物的溶液性能

采用自由基胶束聚合法合成了丙烯酰胺（AM）/丁基苯乙烯（BS）疏水缔合水溶性共聚物(PSAM).凝胶渗透色谱（GPC）测试结果显示,PSAM的重均分子量为1.6868×10⁵,环境扫描电镜（ESEM）照片显示,PSAM在水溶液中形成了疏水缔合网络结构,结果表明,PSAM的增黏能力主要依赖于疏水结构单元的分子间疏水缔合作用.PSAM溶液性能的研究结果表明,溶液质量浓度超过0.1 g·dl^-1时,共聚物具有优良的增黏、耐盐及耐温性能,在80℃时显示良好的抗老化性能;PSAM亚浓溶液为假塑性流体,具有良好的触变性,低剪切速率下在最初一段时间内呈现剪切增稠性质.     

耐温疏水缔合聚合高分子制备及流变性能研究

以丙烯酰胺（AM）?2-丙烯酰胺-2-甲基丙磺酸（AMPS）为原料,引入长链疏水单体DAB和刚性疏水单体Ars,采用自由基水溶液聚合得到耐温型疏水缔合聚合高分子PAS,使用红外光谱仪和扫描电镜表征PAS分子结构并观察分子链的聚集状态,使用热重仪测试聚合高分子的耐热性,RS6000流变仪测试PAS的流变性能并与常规疏水缔合聚合物对比。结果表明：PAS干粉372℃失重50%,具有良好耐热性;聚合高分子PAS具有复杂空间网络结构并观察到疏水侧链的缔合微区,经流变仪频率扫描与应力扫描,聚合高分子PAS表现出良好的触变性和黏弹性,聚合高分子PAS在170 s-1条件下耐温达150℃可保持121 mPa·s,在100℃条件下剪切1.5h,黏度为198mPa·s,经过不同速率剪切后黏度恢复率为78.5%,与常规的疏水缔合型聚合物相比具有更好的耐温性和抗剪切性能。     

疏水缔合聚合物的静态悬砂性能研究

本文考察了部分水解聚丙烯酰胺BRQ-0和疏水缔合聚合物BRQ-5的黏度-剪切速率和黏弹性，并对不同黏度下的聚合物水溶液进行了静态悬砂性能研究。结果表明：通过黏度-剪切速率曲线，拟合出剪切速率170 s^-1下黏度区间10～30 mPa·s对应的聚合物浓度，为后续的黏弹性和静态悬砂性能研究做准备；在黏度区间10～30 mPa·s内，疏水缔合聚合物的弹性模量G′更大；在黏度区间10～30 mPa·s内，疏水缔合聚合物的静态携砂性能比部分水解聚丙烯酰胺要好，规律与聚合物的黏弹性相符合。     

疏水缔合减阻剂的分子模拟

采用分子模拟软件Materials Studio2017R2分别构建非离子型疏水改性聚丙烯酰胺(HM-PAM)、部分水解水溶性疏水缔合聚丙烯酰胺(HAWSP)、部分水解阴离子型聚丙烯酰胺(HPAM)溶液模型,通过分子动力学模拟的方法来计算HPAM、HAWSP与HM-PAM类聚合物在不同Na Cl浓度下的回旋半径(Rg)、均方位移(MSD)。从模拟结果来看,HAWSP与HMPAM、HPAM相比具有更大的回旋半径、更大的特性黏数、更大的流体力学尺寸,会产生更好的减阻效果。在室内采用流体流动阻力测试仪测定HPAM、HAWSP与HM-PAM减阻聚合物在不同Na Cl浓度、不同剪切条件下的减阻性能。实验结果表明,HAWSP型聚合物减阻效果良好,与HM-PAM、HPAM相比具有更好的耐盐性、抗剪切性,与模拟结果一致。     

反相乳液制备缔合型耐盐聚合物及流变性能评价

摘要：以丙烯酰胺（AM）、2-丙烯酰胺-十二烷基磺酸钠（AMC12S）、疏水单体GTE-10为原料,通过反相乳液聚合法制备了一种缔合型耐盐聚合物p(AM/AMC12S/GTE-10)。通过FTIR、1HNMR、SEM、TEM及激光粒度分析仪对其结构和形貌进行表征,并对其流变性能进行评价。结果表明,疏水单体GTE-10成功引入聚合物中,聚合完成后的乳液粒径分布集中且均一,盐的加入使得p(AM/AMC12S/GTE-10)分子聚集态更紧密,形成的空间网络结构更稳定。质量分数为0.7%的p(AM/AMC12S/GTE-10)聚合物水溶液在140 ℃时表现出较好的耐温性能;在120 ℃,170 s-1条件下剪切1 h,在质量浓度为20000 mg/L的NaCl和CaCl2水溶液中分别配制质量分数0.7%的聚合物溶液,其黏度分别为64.7和54.2 mPa·s;触变性能测试表明,聚合物具有较好的剪切恢复性能;黏弹性测试结果表明,盐水条件下储能模量（G′）>损耗模量（G″）,金属离子与苯氧乙烯基发生络合反应,使分子间作用力增强,形成的空间结构更稳定且难被破坏,黏弹性更高。     

一种疏水缔合聚丙烯酰胺作为压裂液减阻剂的性能研究

利用丙烯酰胺、丙烯酸、抗盐单体和疏水单体并通过溶液聚合得到疏水缔合聚合物ACS210,应用流变仪表征其溶液的流变性能,通过管路摩阻测试系统研究了ACS210在不同应用条件下的降阻性能。实验表明,不同质量分数的聚合物溶液的黏度随着剪切时间的延长而下降,长时间剪切后黏度保留率较高。聚合物溶液的黏度与剪切速率曲线符合幂律模型。在质量分数为0.1%时,ACS210溶液的储能模量G'均小于损耗模量G″,溶液表现为黏性行为;随着聚合物质量分数的提高,大分子链的缔合作用增强,G'大于G″。合成的聚合物具有良好的减阻效果。不同质量分数聚合物溶液的摩擦系数随雷诺数的增大均呈减小趋势,而减阻率随着聚合物质量分数的增加先增大后减小。疏水缔合作用对提高减阻率具有促进作用。     

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。     

水包水型疏水缔合聚丙烯酰胺增稠剂的合成及在压裂中的应用

以丙烯酰胺、2-丙烯酰胺-2-甲基丙磺酸和芥酸酰胺羟丙基磺基甜菜碱为原料,采用水分散聚合方式合成出水包水型疏水缔合聚丙烯酰胺增稠剂,通过FTIR和TG对增稠剂的结构及热解质量进行了测试。分析了OWPAM乳液增稠剂的基本性能及水溶液的微观和宏观性能,结果表明,在单体芥酸CAB用量为4.0%时,乳液的产率、平均粒径、表观黏度和稳定性达到最优,黏均分子量为2.43×10~6g/mol;OWPAM乳液的临界胶束缔合浓度(CAC)值为0.32%,当浓度大于CAC值后水溶液体系内的缔合形式以分子间缔合为主,OWPAM乳液在0.1%、流速10m/s时减阻率为72%。助黏剂TR-1质量分数为1.0%时可将0.5%水溶液黏度增加至160mPa·s,复配成的压裂液具有较好耐温耐剪切性、黏弹性和悬砂性,在APS质量分数为0.05%时,测试时间为2h压裂液可以完全破胶,能够达到压裂液的使用标准。     

Study on properties of hydrophobic associating polymer as drag reduction agent for fracturing fluid

In the paper, the hydrophobic associating polymer ACS-210 was prepared by solution polymerization of acrylamide, acrylic acid, salt-resisting monomer and hydrophobic monomer. Chemical structure and properties of the polymer was characterized by FTIR, TGA and XRD. The rheological property of ACS-210 solution was investigated by rheometer. The frictional resistance of the ACS-210 solutions at different application condition was examined using friction testing system. Results showed that the thermal stability of polymer ACS-210 increases and crystallinity of ACS-210 declines after incorporating of hydrophobic monomer. The viscosity of ACS-210 solution of different concentration decreased with prolonging the shearing time and the retention rate of viscosity is relatively high after long shearing time. The relation curve between the viscosity of polymer solution and shear rate followed the power law model. When the concentration of ACS-210 aqueous solution was less than the critical associating concentrations, storage modulus G’ is less than loss modulus G”, the association was weaker between the molecular chains, and the effective spatial structure did not form. After increasing the concentration of the polymer solution, G’ is more than G”, the degree of association of polymer is stronger. The synthesized polymer has favorable drag reduction effect. The molecular weight is not the only factor to determine drag reduction efficiency. The hydrophobic association can also improve the drag reduction efficiency.     

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。     

有机锆交联AM/DMAM/AMPS三元聚合物流变动力学

以乳酸/丙三醇有机锆为交联剂,聚合物[一种耐高温的丙烯酰胺(AM)/N,N-二甲基丙烯酰胺(DMAM)/2-丙烯酰胺基-2-甲基丙磺酸(AMPS)三元聚合物]为稠化剂,获得了耐高温聚合物凝胶.研究了聚合物凝胶的流变学特性(黏弹性、触变性)及其交联流变动力学,获得了聚合物交联过程中黏度、黏弹性模量随时间的变化关系,并考察了剪切速率和温度对凝胶形成的影响,建立了交联流变动力学模型.结果表明,交联聚合物凝胶具有明显的黏弹性和触变性;在180℃、170 s^-1下剪切120 min后,黏度达176.8 mPa·s,获得了耐高温达180℃的凝胶;一级交联流变动力学模型可拟合聚合物的交联流变动力学过程,拟合的模型参数物理意义明确合理.     

减阻剂乳液的合成与性能评价

采用水分散聚合法制备了一种应用于滑溜水中的水溶性减阻剂乳液,对减阻剂溶液的粘弹性、耐温耐剪切性和降阻率进行了测试.结果表明,该减阻剂溶液具有明显的粘弹性特征,耐温耐剪切性能良好,0.2％的减阻剂水溶液的最大降阻率超过70％,表现出了良好的降阻特性,能够作为滑溜水用减阻剂使用.     

黏弹性流体基纳米流体流变学特性

黏弹性流体基纳米流体（viscoelastic fluid based nanofluid,VFBN）是一种具有湍流减阻和对流换热相对强化特性的新型换热工质,其湍流减阻机理与流变学特性关系密切。通过对以2.5×10^-3、5×10^-3、1×10^-2三种质量分数的十六烷基三甲基氯化铵/水杨酸钠水溶液为基液,粒子体积分数为0.1%、0.25%、0.5%、1.0%的铜纳米流体的剪切黏度、零剪切黏度以及松弛时间的测量,实验结果表明VFBN有明显的剪切稀变特性,同时纳米粒子的添加增大了基液的零剪切黏度,并导致基液黏弹性增强。以Giesekus本构模型为理论基础,利用实验参数得到了描述VFBN剪切黏度的实验关联式。     

含蜡原油的黏弹-触变模型

在胶凝温度以下,因蜡的结晶析出并形成三维空间网络结构,含蜡原油表现出复杂的非牛顿流体特性,如黏弹性、屈服应力和触变性等。目前,含蜡原油的触变性模型均为黏塑性模型,没有考虑屈服点附近及之前物料所具有的黏弹特性。为此,提出了一个包含状态方程和速率方程、共10个未知参数的黏弹-触变模型。模型的剪应力由弹性应力和黏性应力构成,弹性应力为剪切模量与剪应变的乘积,剪切模量正比于结构参数和损耗函数。描述结构参数随时间变化的速率方程,假设结构破坏项与能量耗散率相关,克服了以往速率方程中结构破坏项与剪切率相关这一假设的不足。模型可描述含蜡原油所具有黏弹-触变特性,并且所预测的剪应力能够从以黏弹性为主的阶段平滑过渡到以触变性为主的阶段。利用大庆原油剪切率阶跃和滞回环的实验数据对模型进行验证。结果表明:两种测试的模型拟合值与实测值的平均相对偏差分别在2.0%和5.0%以内;利用由剪切率阶跃测试数据拟合得到的模型参数对滞回环测试进行预测,预测的平均相对偏差约为16%。     

Rheology on novel viscoelastic trimeric octadecyl zwitterionic surfactant micelle solutions

In this work, a novel trimeric octadecyl zwitterionic surfactant (TOCC) was successfully synthesized. TOCC was compounded with sodium salicylate (NaSal) for an optimized formulation to form viscoelastic micelles. The effects of NaSal concentration, pH, and temperature on the rheological properties of TOCC and TOCC/NaSal micelle solutions were investigated. The flow curves for both TOCC and TOCC/NaSal micelle solutions can be fitted with the Carreau–Yasuda model. Zero shear viscosity of TOCC/NaSal micelle solution increased and then decreased with increasing NaSal concentration, and the same trend was observed for viscoelasticity. Some micelle solutions exhibited significant thixotropy with stress overshoot. The optimal composition of the TOCC/NaSal micelle solution obtained was 5.0/0.5 wt%. Frequency sweep in the form of Cole–Cole plots indicated that the viscoelastic modulus of the TOCC/NaSal micelle solution fitted the Maxwell model at low and medium frequencies. With increasing pH, 5.0 wt% TOCC micelle solution had the maximum zero shear viscosity at pH = 6.9. The steady-state viscosities of different concentrations of TOCC micelle solutions reached their maximum at neutral conditions (pH = 6.5 ~ 7.0). Viscoelastic modulus of 5.0 wt% TOCC and TOCC/NaSal (5.0/0.5 wt%) micelle solutions decreased with increasing temperature, and thermal thixotropy was observed in both micelle solutions. The novel TOCC and TOCC/NaSal micelle solutions enrich the variety of trimeric surfactants and viscoelastic micelle solutions. This study provides a rheological reference for the applications of viscoelastic trimeric surfactants in smart materials and oil fields.     

Viscoelasticity of concentrated polyacrylonitrile solutions: effects of solution composition and temperature

The effects of solution composition and temperature on the viscoelasticity of concentrated polyacrylonitrile (PAN) solutions were studied using a variety of rheological measurements, such as steady‐state shearing, dynamic stress sweep and transient rheological tests. The first normal stress difference N₁ and the shear stress τ were found to increase with decreasing temperature and increasing PAN concentration and water content in the solutions. The crossover point of N₁ and τ, denoting the equal contribution of viscosity and elasticity to the viscoelasticity of the solutions, moved to lower shear rates at lower temperature, higher PAN concentration and higher water content. The values of the relaxation time (λ) were larger at 70 °C than at 40 °C. In addition, the changes of λ with PAN concentration and water content were different at the two temperatures, ascribed to the different states of the solutions. The PAN solutions were in the linear viscoelastic regime in the temperature range 40–70 °C when the shear stress was below 300 Pa. The creep compliance recovery rate decreased with increasing temperature, but increased with increasing PAN concentration and water content. Thixotropic tests showed that the thixotropy of the solutions was also affected by the solution composition and temperature. Gelation was found to influence the way the solution composition and temperature affected the viscoelastic properties of the PAN solutions. Copyright © 2011 Society of Chemical Industry     

Preparation and evaluation of acryloyl morpholine modified emulsion fracturing fluid thickener with high temperature resistance and salt resistance

To prepare the thickener of fracturing fluid with temperature resistance, salt resistance and quick dissolution, an emulsion thickener (ASC) was synthesized by acrylamide, acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid, and acryloyl morpholine. The dissolution, salt resistance and drag reduction of ASC, and the viscoelasticity, temperature resistance and shear resistance and gel breaking properties of fracturing fluid formed by ASC and zirconium crosslinker were investigated. The results showed that the sticky time of ASC was less than 60 s and the drag reduction rate was 72.5% in 100,000 mg/L brine, showing that ASC had thickening ability in high salinity brine and satisfied the requirements of continuous fluid preparation on the fracturing process. The viscosity of ASC fracturing fluid was 98 mPa s after shearing at 200°C and 170 s⁻¹ for 150 min when the salinity was 100,000 mg/L. When the ammonium persulfate concentration was 400 mg/L, the viscosity of the broken fluid was 4.0 mPa s. The temperature resistance, salt resistance and shear resistance of ASC emulsion fracturing fluid could be significantly improved by the introduction of acryloyl morpholine, ASC fracturing fluid had the characteristics of high elasticity and low viscosity, which could meet the application requirements under ultra-high temperature reservoirs.     

The Effect of Viscoelasticity of Polymeric Adhesives on Shear Stress Distribution in a Single-Lap Joint

In this paper, the effect of viscoelasticity of adhesives on shear stress distribution in the adhesive layer of a single-lap joint under shear load is studied. The joint comprises two elastic single isotropic adherend layers joined by a viscoelastic adhesive polymer. A three-parameter viscoelastic solid model is used to deduce the governing differential equation in the Laplace domain, which is solved using residue theorem. Results show that for an impulse load of 100 N, the maximum shear stress in the adhesive layer is reduced to 39% of its initial value. Also, the ratio of viscous modulus of the adhesive to its shear modulus has an adverse effect on the peak shear stress. An increase in the thickness of the adhesive layer reduced the induced peak shear stress in the joint. Moreover, the shear strain in the adhesive layer reached its steady value after 1000 seconds.