滑溜水压裂液用聚合物减阻剂性能

用反相乳液聚合法制备了一种用于滑溜水压裂液的水溶性减阻剂(WDRA-M),分子链中由于引入自制长链疏水单体(丙烯酸长链酯,WLHM)提高了WDRA-M分子链的柔顺性。通过激光散射仪、滑溜水摩阻测试仪和动态流变仪分别对WDRA-M的粒径大小及分布、减阻性能和流变性能进行了测试。结果表明:WDRA-M粒径为76.95 nm,PDI为0.108,粒径呈单峰分布,且分布均匀。WDRA-M的最佳质量浓度为0.7 g/L,减阻率达62%。流变实验结果表明:WDRA-M为非牛顿流体,储能模量G'(0.783 Pa)大于损耗模量G″(0.354 Pa),具有较强的弹性,能够减小滑溜水压裂液与管道之间的摩阻;在25℃、剪切速率为170 s-1的条件下,剪切30 min,表观黏度由43.46 m Pa·s降为38.66 m Pa·s,表观黏度保留率达89.0%,表明WDRA-M具有较好的耐剪切性能。现场应用结果表明:在3.5 m3/min压裂液排量下,WDRA-M减阻率比胍胶高42.5%,比国外同类产品高12.5%。     

分子结构对水解AM/DMDAAC聚合物流变性能的影响

为研究分子结构对两性离子聚合物流变性能的影响方式,以丙烯酰胺（AM）和二甲基二烯丙基氯化铵（DMDAAC）为单体,进行自由基共聚,随后对共聚产物进行水解,制得了9个具有不同特性黏数、阴离子度和阳离子度的两性离子聚合物-部分水解聚AM/DMDAAC（HPAD-1,HPAD-2,HPAD-3,HPAD-4,HPAD-5,HPAD-6,HPAD-7,HPAD-8,HPAD-9）。通过IR、1HNMR、滴定法和乌氏黏度计表征了聚合物的结构参数。用旋转黏度计和流变仪分别考察了HPAD溶液表观黏度和剪切稀释行为。实验结果表明：HPAD的特性黏数与溶液表观黏度、剪切稀释性正相关。随着特性黏数由182.03 mL/g升至555.08 mL/g,质量分数0.75%的HPAD溶液表观黏度由12.1 mPa•s（HPAD-9）增至766.5 mPa•s （HPAD-7）。HPAD的阴离子度和阳离子度与溶液表观黏度负相关,对剪切稀释性影响较小。当阴离子度从29.98 mol%增至51.75 mol%,质量分数0.2%的HPAD溶液表观黏度从111.1 mPa•s（HPAD-1）降至21.5 mPa•s（HPAD-4）。阳离子度为10.31 mol%的HPAD-2和阳离子度为6.88 mol%的HPAD-8在5 s-1至100 s-1范围内的剪切稀释曲线几乎重合。     

页岩气压裂用滑溜水胶液一体化稠化剂研究

为了提高页岩气现场配液施工效率,降低不同压裂液间配伍性对压裂液性能的影响,利用AM、DMC、DMDB为原料,采用混合胶束水溶液聚合,合成一种滑溜水胶液一体化用稠化剂。用管路摩阻仪和高温流变仪对滑溜水体系降阻性能和组装压裂液体系耐温耐剪切性能进行评价。结果表明,该疏水缔合聚合物溶解时间小于2 min,0. 1%的滑溜水黏度达到10 m Pa·s,降阻率为65. 7%,组装压裂液在90℃,170 s^(-1)条件下剪切2 h,表观黏度大于50 m Pa·s。滑溜水和胶液具有良好的降阻效果及耐温耐剪切性,能够满足滑溜水和压裂液在线混配的要求,可以实现滑溜水胶液一体化。     

页岩气压裂用滑溜水胶液一体化稠化剂研究

为了提高页岩气现场配液施工效率,降低不同压裂液间配伍性对压裂液性能的影响,利用AM、DMC、DMDB为原料,采用混合胶束水溶液聚合,合成一种滑溜水胶液一体化用稠化剂。用管路摩阻仪和高温流变仪对滑溜水体系降阻性能和组装压裂液体系耐温耐剪切性能进行评价。结果表明,该疏水缔合聚合物溶解时间小于2 min,0. 1%的滑溜水黏度达到10 m Pa·s,降阻率为65. 7%,组装压裂液在90℃,170 s~(-1)条件下剪切2 h,表观黏度大于50 m Pa·s。滑溜水和胶液具有良好的降阻效果及耐温耐剪切性,能够满足滑溜水和压裂液在线混配的要求,可以实现滑溜水胶液一体化。     

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。     

聚硅氧烷侧链高分子液晶电流变液体的性能研究

研究聚硅氧烷侧链高分子液晶配制成电流变液体的电流变效应 ,以获得高性能的电流变液体 ,应用德国RV2 0电流变仪测试性能。结果表明 ,该电流变液体 5 2℃ ,电场强度由零增至DC 2 0 0 0V/mm ,剪切速率为 30 0s-1时 ,剪切应力由 2 0 0Pa增至 5 4 0 0Pa ,表观黏度由 2 0 0mPa·s增至 10 0 0 0mPa·s;剪切速率为 4 0 0s-1时 ,剪切应力由 2 0 0Pa增至 6 30 0Pa,表观黏度由 2 0 0 0mPa·s增至 76 0 0mPa·s ;剪切速率为 5 0 0s-1时 ,剪切应力由 2 75Pa增至 6 80 0Pa,表观黏度由5 0 0mPa·s增至 90 0 0mPa·s。 77℃时 ,同样条件下 ,剪切速率为 5 0 0s-1时 ,剪切应力达 80 0 0Pa,具有更高的剪切应力 ,说明温度适应性较强。     

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。     

超稠油复合降粘剂SDG-3的研究和应用

针对塔河油田超稠油开采难度大、常规油溶性和水溶性降黏剂存在较大局限性的问题,采用脂肪醇聚氧乙烯醚、NaOH、氯乙酸、醇类和混合芳烃为原料,制备了一种高效复合降黏剂SDG-3。考察了其分散原油重组分能力、界面活性、乳化性能、降黏性能、耐温耐盐性和破乳性能。结果表明：SDG-3能分散超稠油中重组分,质量分数1%的SDG-3在不含水条件下使原油黏度从181 000 mPa•s降低至81 989mPa•s,降低了54.7% ; 使地层水（矿化度2.2×105mg/L）-超稠油(1.81×105mPa•s)界面张力由27mN/m降低至0.32mN/m,对超稠油乳化效果优于常规水溶性降黏剂,形成的O/W乳状液平均粒径为2.5μm,对委内瑞拉、中海油、塔河超稠油降黏率均达到99%以上,优于常规油溶性降黏剂降黏率的72.6%,耐盐度达2.2×105mg/L,耐高温达140℃,与油田破乳剂配伍性好。在塔河油田进行现场实验期间,日平均节约稀油率66.6 %,平均提高稠油采收率为14.4 %。     

硼钛复合交联剂的制备及其在葫芦巴胶压裂体系中的应用

以四硼酸钠、钛酸丁酯、三乙醇胺、甘油、乙二醇为原料,合成了有机硼钛交联剂,制备了葫芦巴胶压裂液。研究了主剂及配体物料比,反应温度与反应时间对交联剂成胶性能的影响。结果表明,m（四硼酸钠）：m（钛酸丁酯）=1:4,m（三乙醇胺）：m（甘油）=1:2,反应温度70℃,反应时间3h的条件下,合成的交联剂性能最优。考察了w（葫芦巴胶溶液）=0.4%,m（葫芦巴胶溶液）：m（硼钛交联剂）=100:（0.4~0.6）时,葫芦巴胶压裂液的性能,交联延时150s,耐温耐剪切性能良好;常温下,携砂比V（压裂液）：V（石英砂）=70：30时,沉降速度0.009mm•s-1;体系易破胶,破胶液黏度低于5mPa•s,对储层伤害小。     

疏水缔合聚丙烯酰胺作为滑溜水压裂液减阻剂的应用性能研究

以丙烯酰胺、丙烯酸和2-丙烯酰胺基-2-甲基丙烷磺酸作为亲水单体,再引入疏水单体R-8,使用水溶液聚合,获得了低摩阻、高粘弹性的疏水性缔合聚合物DR-8,用FTIR表征结构,分别通过管路摩阻测试系统和流变仪测试了DR-8在不同条件下的减阻性能及流变性能。结果表明,合成的聚合物与预期产品结构一致,当流速为3 m/s、浓度为1.2 g/L时,DR-8的减阻率为75.5%,具有良好的减阻性能,同时具有良好的黏弹性,能够满足非常规油气藏体积压裂、大排量施工、降低摩阻的要求,而且在载砂量方面明显优于常规滑溜水压裂液。     

溶液聚合合成减阻剂及其特征对减阻的影响

油相减阻剂的合成方法主要分为本体聚合法和溶液聚合法.对溶液聚合法合成的α-烯烃聚合物进行室内模拟环道评价装置、凝胶渗透色谱、核磁共振及红外光谱测试,分析结果表明,溶液聚合转化率高达97.92%,产物为超高分子质量聚合物,减阻率达到56.45%接近于美国固体产品的减阻率.     

Degradation of surfactant solutions by age and by a flow singularity

Four different surfactants were investigated in a closed hydraulic loop in order to find the influence of age of the solution on drag reducing effectiveness and on decrease of critical shear stress. It shows that aging of a particular surfactant is dependent on its concentration. Different sensitivity of solutions to flow disturbances is also shown.     

CHAR GASIFICATION: PARTICLE MODEL COMPARISON IN A STIRRED TANK REACTOR

A simple well mixed model is developed to study the effect of single particle models for the gasification of char in a reactor. Two models, a lumped model and a distributed model, are used to describe the processes in the particle. The model consists of the conservation equations along with the residence time distributions and population balance equations. It is found that neglecting the conversion distribution function in the bed causes considerable differences at high temperatures and large particle sizes. The lumped model is rather insensitive to the mean residence time of the particles and the pressure, compared to the dependence observed in the distributed system. The difference in the design parameters predicted by the models is large and further, the particle size influences these parameters to a greater extent in the distributed system, the lumped system being almost independent of the particle size.     

Review on the applications and developments of drag reducing polymer in turbulent pipe flow

Drag reduction phenomenon in pipelines has received lots of attention during the past decades due to its potential engineering applications, especially in fluid transporting industries. Various methods to enhance drag reduction have been developed throughout the years and divided into two categories;non-additives method and additives method. Both categories have different types of methods, with different formulations and applications which will generally be discussed in this review. Among all the methods discussed, drag reduction using polymer additive is as one of the most enticing and desirable methods. It has been the subject of research in this field and has been studied extensively for quite some time. It is due to its ability to reduce drag up to 80% when added in minute concentrations. Reducing drag in the pipe will require less pumping power thus offering economic relieves to the industries. So, this paper will be focusing more on the use of polymer additives as drag reducing agent, the general formulations of the additives, major issues involving the use of drag reducing polymers, and the potential applications of it. However, despite the extensive works of drag reduction polymer, there are still no models that accurately explain the mechanism of drag reduction. More studies needed to be done to have a better understanding of the phenomenon. Therefore, future research areas and potential approaches are proposed for future work.     

THE EFFECT OF HETEROGENEOUS DRAG REDUCING SURFACTANT IN DRAG AND HEAT TRANSFER REDUCTION IN CRUDE OIL SYSTEMS

Pilot scale experiments have been performed to study the effect of a heterogeneous surfactant into the drag and heat transfer coefficient in crude oil pipelines. The effects of surfactant concentration, pipe diameter, Reynolds number and temperature were studied in this research program.

An extensive set of data was obtained for heat transfer and friction coefficients for a heterogeneous surfactant known as MDR-2000. A wide range of Reynolds numbers were covered and experiments were conducted for many different Prandtl numbers. All drag and heat transfer reduction experiments were performed in the same installation using the same measurement techniques which facilitates the assessment of the trends caused by the various parameters studied.

Typical results showed that the friction coefficient was reduced by half at the optimum concentration. While, the heat transfer coefficient was reduced even more dramatically.     

An experimental study of drag reduction by nanofluids through horizontal pipe turbulent flow of a Newtonian liquid

This study investigates the effect of nanofluid injection as a drag reducing agent into horizontal pipes under turbulent flow conditions of water. An experimental apparatus was set up. The test section of the apparatus consisted of a smooth unique pipe and four galvanized iron pipes with the same length. Nanofluids were injected through pipes. Results showed that drag reduction in rough pipes was more than that in smooth pipes at the same flow conditions and it increased as the relative roughness increased. Also, drag reduction rose with increasing the nanofluid concentration up to about 24% in some tests.     

Laminar Drag Reduction in Hydrophobic Microchannels

The apparent slip effects of laminar water flow in smooth hydrophobic microchannels and patterned hydrophobic microchannels were investigated. A series of experiments were performed to demonstrate the drag reductions for laminar water flow in hydrophobic microchannels. These microchannels were fabricated from silicon wafers using photolithography and were coated with hydrophobic octadecyltrichlorosilane (OTS). To generate a larger drag reduction, the patterned hydrophobic microchannels were fabricated to allow the liquid to flow over a region of trapped air in the cavity between the microridges. With the geometrical dimensions used, pressure drop reductions ranging from 10 to 30 % were found in the smooth microchannels and patterned microchannels. The pressure drop reduction was shown to increase with increasing microridge spacing and decreasing microchannel width. Using micro‐particle image velocimetry (PIV), we measured an apparent slip velocity at the wall of approximately 8 % of the centerline velocity, yielding a slip length of approximately 2 μm in the smooth hydrophobic microchannel. Theoretically, the analytical solution derived for three‐dimensional flow in a rectangular duct is presented to predict the slip velocity and slip length at the wall based on the pressure drop measurement. These results are in agreement with the experimental data obtained using micro‐PIV.     

A mechanistic model of turbulent drag reduction by additives

The phenomenon of drag reduction in walled turbulent flows of polymer solutions is theoretically modeled. A new mechanistic model of a polymer molecule in a turbulent flow field is suggested. It is argued that the dominant forces on a polymer fiber in the turbulent flow field are elastic and centrifugal. According to this model, an additional route of dissipation exists, in which eddy kinetic energy is converted to polymer elastic energy by the centrifugal elongation of the rotated polymer, which in turn is viscously damped by the surroundings, when the polymer relaxes. A novel approach is then illustrated, where it is shown that this mechanistic model can be accounted for as a turbulent scale alteration, instead of addition, which enables the classical dimensional analysis of a turbulent boundary layer to apply. Using this dimensional analysis with the equivalent altered scale yields remarkable results. Correct-form velocity profiles are obtained, and Virk's asymptote and slope are predicted with no empirical constants. Drag-flow rate curves are also calculated, and compared favorably with Virk's experiments. The onset of drag reduction phenomenon is also explained by this model, and calculations of it are also compared with Virk's data. The parametric dependencies of the onset point agree well with Virk's conclusions.     

Bio-polymers for improving liquid flow in pipelines—A review and future work opportunities

Several decades following Tom's discoveries on polymeric drag reducing agents (DRA) continue to see research efforts to produce robust and shear-stable DRA. Most efforts revolve around established artificial polymers, but questions have been raised recently about their environmental impact and safety. As such, a large number of researchers are looking into natural materials especially bio-polymers as substitutes. Several bio-polymers are found to exhibit drag reducing capabilities in aqueous media. All these factors suggest that bio-polymers would make a suitable alternative to artificial DRAs. This paper aims to present several works to-date on bio-polymer DRAs, and expose new possibilities.