油品流动减阻剂的研制 Ⅰ.EP 型减阻剂

在油品管输中添加油相减阻剂能增输节能,具有重大的经济意义。研制了高分子量的乙烯-丙烯无规共聚物作为油相减阻剂,在煤油、柴油为流体介质时,添加30ppm,减阻效率可达60%以上(Re=1×10~4,管内径3.88毫米)。同时设计合成了不同分子量、不同丙烯含量、不同分子量分布的系列试样,研究了结构参数与减阻效率之间的关系。发现丙烯组成在40±5%的范围内时,分子量越高减阻效果越好。并且减阻效率也随着减阻剂添加量的增加而增加,但在一定流动条件下有一饱和值。     

减阻率室内环道测定及其影响因素

减阻剂的减阻效果主要表现为加入减阻剂后，流体流动的摩阻压降减小和流动速度加快。因此减阻剂的减阻效果可以用减阻率和增输率来衡量。但国内外普遍采用减阻率来描述。减阻率的计算公式如下：     

原油输送中减阻剂聚合物的特性对减阻率的影响

本文讨论了减阻剂聚合物的分子量、分子量分布、分子结构以及不同物性的原油对减阻率的影响。讨论了聚合物降解的情况及对减阻的影响。     

高聚物型减阻剂减阻性能的研究

对高聚物减阻剂的减阻性能进行研究,考察了高聚物减阻剂的相对分子质量、起始点的管壁切应力τw*、减阻剂添加量、雷诺数及高聚物减阻剂的降解对减阻效果的影响。根据高聚物减阻剂的摩阻系数与雷诺数关系曲线,拟合得到高聚物减阻剂的斜率增量δ。结果表明,减阻剂的减阻率随相对分子质量的增大而提高;减阻剂的均方回转半径Rg越大,减阻起始点要求的管壁切应力τw*值越小,减阻效果越好;减阻剂的减阻率随添加量的增加而增大;减阻剂的斜率增量δ越大,减阻效果越好;高聚物减阻剂在一定剪切力下都会发生一定程度的降解,使减阻率下降。     

油品管道减阻剂

中国石油管道分公司研制的威普牌EP系列减阻剂是世界著名的减阻剂品牌之一,拥有先进的α-烯烃系列减阻剂工业生产线,年产量可达5000m2。自主研发的EP—W、EP—A、EP—O、EP—P、EP—S系列油品减阻剂,可在15。30mg／L的添加量下,使原油管道增输15％～35％,成品油管道增输30％～50％。产品的生产采用先进的本体聚合催化工艺,合成的超高分子量减阻聚合物相对分子质量可达千万级,     

减阻剂减阻效果的评价与分析

针对临邑-濮阳管道添加HG减阻剂的输油工况,建立并运用旋转圆盘装置进行了管输原油加剂模拟实验。对临濮线加HG减阻剂的减阻效果和影响因素进行了分析,确定了减阻率与雷诺数;减阻率与剪切强度;减阻率与加剂浓度;减阻率与输油温度等关系,为减阻剂减阻效果的评价和研究提供了一种新的方法。     

页岩储层压裂减阻剂减阻机理研究

选择6种不同类型的减阻剂,通过研究不同浓度减阻剂的黏度和减阻效果,分析了减阻剂类型、分子量、分子结构、离子性能和浓度对其减阻性能的影响,并对减阻剂减阻机理进行了探索性研究。结果表明,减阻剂水溶液属于幂率流体,在一定流量范围内减阻率随着浓度的提高而提高;其水溶液黏度、离子特征和减阻率没有明显的联系,分子量在100万以上的减阻率在相同浓度下,减阻率趋于一致;影响减阻剂减阻性能的主要因素是减阻剂的分子结构。得出低分子量的长链结构的减阻剂和具有支链的长链结构的减阻剂以及具有柔顺、螺旋型分子链结构的减阻剂减阻性能更稳定;带支链的长链结构的减阻剂,在水中速溶,在较广泛的雷诺数范围内可得到理想的减阻率,具有较小的分子量,容易分解,对储层伤害小,此类减阻剂适合作页岩气储层大规模滑溜水压裂液的添加剂。     

聚长链α-烯烃减阻性能的影响因素研究

利用室内环道评价装置考察了聚长链α-烯烃减阻剂的溶解时间、雷诺数、加剂浓度、黏均相对分子质量和高聚物的抗剪切能力对减阻性能的影响。结果表明：聚合物的减阻率随溶解时间的延长而增大,达到一定值后趋于稳定;聚合物的凝聚状态以及颗粒的分散程度对减阻剂的溶解能力影响较大;加剂浓度在15 mg/L时减阻率达到最大值,加剂浓度与减阻率的关系基本符合Virk经验公式;存在最佳雷诺数,雷诺数大于或小于最佳雷诺数时,减阻能力减弱,直至无效;在一定的相对分子质量范围内,黏均相对分子质量与减阻率呈线性关系,相对分子质量越大,减阻率越好;聚合物经过齿轮泵剪切后会使减阻率急剧下降,经过管壁的初次剪切也会使减阻率下降40%左右。     

洪荆管线常温添加减阻剂输油试验

为了研究不同浓度减阻剂对沿程摩阻、管输量和管输效益的影响规律,在洪荆线采用常温添加减阻剂输送工艺进行输油试验。研究表明:洪荆线可采用常温加剂方式输送原油;添加减阻剂可减小洪湖站与新沟站之间的压降损耗,增加管输量;减阻剂浓度越大,两站之间的压降损耗越小,管输量越大;当减阻剂浓度继续增大时,增输和减阻效果减缓;添加减阻剂运行,可增加洪荆线管输收益;随着减阻剂浓度的增加,管输效益先增大后减小;减阻剂的添加浓度为30 mg/L时,可获得最大的经济效益。     

姬惠原油管道添加减阻剂的现场试验研究

介绍了FLO-MAX减阻剂的原理以及在姬惠原油管道上的现场试验的过程,通过进行不同加剂浓度下的减阻试验,验证了FLO-MAX减阻剂对姬惠原油管道减阻、增输的有效性,研究了管道减阻剂不同的注入浓度与减阻率、增输率的关系,分析了合理的注入浓度范围,结果表明在15 mg/L的浓度下,能达到最佳的增输效果,为今后使用减阻剂提供了依据。     

TiCl_4／Al(i-Bu)_3催化α-烯烃合成原油减阻剂

研究了TiCl4含量不同的两种TiCl4／Al(i-Bu)3催化剂的配比、起始反应温度、后续反应温度对聚合物性能的影响。采用凝胶渗透色谱(GPC)和核磁共振(1H NMR)法对聚合物进行了表征,结合实验室内模拟环道评价装置测定了聚合物的减阻率、抗剪切性能。实验结果表明,在TiCl4含量不同的两种TiCl4／Al(i-Bu)3催化剂的质量比为1:1、起始反应温度为3℃、后续反应温度为10-20℃的条件下合成的聚合物,经GPC测定,其重均相对分子质量达到4．54×106,相对分子质量分布宽度指数接近 2．9;1H NMR测定结果表明该聚合物是典型的聚烯烃类化合物,纯度达到98％以上。该聚合物在柴油中有良好的溶解性,减阻率达到28．9％,经一次高强度机械剪切后其减阻率减少20％-30％,经5次高强度机械剪切后剩余减阻率为8％,可用于工业原油的输送。     

石油减阻聚合物相对分子质量及其分布对其性能的影响

实验采用复配Cp2ZrCl2/Ziegler-Natta催化剂,以本体聚合法制备了系列具有超高相对分子质量的油溶性聚合物。采用凝胶渗透色谱表征聚合物相对分子质量及其分布,并考察了其对聚合物溶液特性粘度的影响。结果表明,当减阻聚合物的相对分子质量达到某一定值时,聚合物的多分散指数对其减阻效果有明显影响;仅通过提高聚合物的相对分子质量来改善其减阻性能,也许并不是行之有效的方法。研究初步认为,高效的减阻聚合物不仅要具备超高相对分子质量,还应有超高的相对分子质量分布。     

降阻剂聚集形态与降阻性能研究

为明确滑溜水压裂液降阻剂宏观降阻性能的微观控制机制,利用环境扫描电镜对不同类型的聚合物降阻剂形成的聚集体结构进行大量微观表征,结合体系降阻性能测试,从聚合物分子聚集态层次揭示浓度对不同降阻剂体系降阻性能作用的微观机理。研究发现,滑溜水降阻剂在极低浓度下聚集形成丝状结构,随着降阻剂浓度的不断提高,这些丝线状结构逐渐缠结连接形成骨架,最终围成多层次的“蛛网状”聚集体网络结构。同时不同类型的滑溜水降阻剂所形成的网络结构又具有各自的特点,其中以乳液型和悬浮液型降阻剂网络结构最为完整,而粉剂型降阻剂由于溶解速度较慢,形成聚集体网络结构分布不均,网络强度普遍不高。降阻剂浓度对降阻剂聚集状态影响极大,在低浓度条件下,3种降阻剂形成的网络结构平均骨架厚度约为0.1～0.3μm。随着降阻剂浓度的增大,体系网眼形状由不规则逐渐转变为多边形,部分降阻剂可形成强度较高、稳定性较好的圆形网络支撑结构,网眼尺寸减小,骨架厚度增加。当降阻剂浓度增加为0.05%时,骨架厚度可达0.3～0.9μm,网络结构强度显著提高。滑溜水降阻剂形成的聚集体网络结构会对体系降阻性能产生重要影响,降阻剂加量与体系降阻性能之间并非表现出...     

Curtailing water production in oil wells: A case for anionic polymers

The influence of anionic polymers for reducing water production in oil wells under induced polymer adsorption is investigated. Cationic polymers are frequently used for polymer injection due to their positive ionic character and the negatively charged silica surface of most porous media. Results obtained for the anionic polymer used in this study, show that polymer adsorption is unaffected by the ionic character of polymers, provided the polymer is hydrophilic. Equally, previous studies on polymer adsorption in porous media have shown that static adsorption regime exists at low shear rate of injection. This results in thin polymer layer whose capability to reduce water permeability is marginal. However, polymer injection at increasing shear rates has revealed an increase in the adsorbed polymer layer and consequently, improved water permeability reduction.In this work, experimental results from sandpacks are presented to show that there is improvement in the adsorbed polymer layer with increased shear rates. This phenomenon is known as “flow-induced adsorption”. The experiments indicate that above a critical shear rate, there is a shift in permeability-reduction mechanism from static adsorption to flow-induced adsorption, resulting in a sharp increase in adsorbed polymer layer. Various scenarios were studied to investigate the effect of polymer residence time and increasing rate of brine flush after polymer injection. For comparison with the above experimental results, similar experiments were performed at increased polymer concentration and in Berea sandstone core. Results indicate that the permeability-reduction mechanism is constrained by increased polymer concentration and low-permeability porous media.     

高分子减阻剂共聚物的合成与表征

采用本体聚合法,以TiCl4／MgCl2-Al(i-Bu)3 为催化剂对1-辛烯/1-十二烯的长链α-烯烃进行共聚,考察不同的聚合条件对减阻率的影响,来提高二元聚合物的减阻率,最终确定最佳工艺条件。聚合物环道减阻测试的结果表明,当1-辛烯在反应物中体积分数为33%左右时,减阻率高达52.3%,通过凝胶色谱、1H-NMR、IR等方法对聚合物进行表征,证明用该方法可以制得重均相对分子质量为6.58×106 ,数均相对分子质量为2.41×106,相对分子质量分布宽度指数为2.73的原油用聚合物减阻剂,聚合较完全。     

Friction pressure correlations for turbulent flow of drag reducing polymer solutions in straight and coiled tubing

Accurate determination of friction pressure losses of dilute drag reducing polymer solutions remains to be a challenge in many practical applications. These include a wide variety of hydraulic operations performed on a daily basis in the oil and gas industry. Most drilling, completions, and stimulation jobs require pumping fluids at high flow rates, which in turn generates high frictional pressure losses, enhanced by the use of small diameter tubing or coiled tubing. Curvature in this latter is believed to generate secondary flows and thus extra flow resistance. Therefore, good drag reduction characteristics of fluids are desirable.In this study, energy dissipation by eddies in turbulent flow of viscoelastic fluids is assumed to be the mechanism causing drag reduction. Various concentrations of Nalco ASP-700 and Nalco ASP-820 dilute polymer solutions are tested at ambient temperature in laboratory-scale and full-scale flow loops installed with straight and coiled tubing sections exhibiting different values of diameter, curvature ratio and pipe roughness. In addition, flow tests are conducted at 100 °F and 130 °F using the laboratory-scale flow loop.Effects of concentration, temperature, curvature ratio, and pipe roughness on drag reduction are discussed in light of Fanning friction factor versus solvent Reynolds number plots. Results show that drag reduction in coiled tubing is lower than in straight tubing. As curvature ratio increases, drag reduction decreases. The effect of increasing temperature is to decrease drag reduction in straight tubing and increase it in coiled tubing. In turn, the effect of increasing pipe roughness is to slightly decrease drag reduction in straight tubing up to a certain Reynolds number value and then it starts to increase. For coiled tubing, the effect of increasing pipe roughness is to decrease drag reduction.In this study, generalized correlations for the prediction of drag reduction in dilute polymer solutions flowing in straight and coiled tubing are developed on the basis of the energy dissipation of eddies in turbulent flow field and a shear rate dependent relaxation time. In addition, correlations are validated using experimental data for a low concentration guar fluid flowing through full-scale flow loop.     

Drag reduction and shear resistance properties of ionomer and hydrogen bond systems based on lauryl methacrylate

Based on molecular dynamics simulation results,a lauryl methacrylate polymer with drag reduction and shear resistance properties was designed,and synthesized by emulsion polymerization using 2-vinyl pyridine and methyl methacrylate as the polar polymerization monomer.After ionization of lauryl methacrylate polymer,an ion-dipole interaction based drag reduction agent (DRA) was obtained.The existence of ion-dipole interaction was proven through characterization of the drag-reducing agent from its infrared (IR) spectrum.The pilot-scale reaction yield of the DRA under optimum conditions was investigated,and the drag reduction and shear resistance properties were measured.The results show that:1) The ion-dipole or hydrogen bonding interaction can form ladder-shaped chains,therefore the synthesized DRA has shear resistance properties;2) The larger the molecular weight (MW) and more concentrated the distribution of MW,the better the drag reduction efficiency and the performance of the ionomer system was superior to that of the hydrogen bonding system;3) With increasing shear frequency,the drag-reduction rates of both the DRAs decreased,and the drag reduction rate of the ionomer system decreased more slowly than of the corresponding hydrogen bonding system.From the point of view of drag reduction rate and shear resistance property,the ionomer system is more promising than the hydrogen bonding system     

Drag reduction behavior of hydrolyzed polyacrylamide/xanthan gum mixed polymer solutions

Partially hydrolyzed polyacrylamide (HPAM) as the main component of slickwater fracturing fluid is a shear-sensitive polymer, which suffers from mechanical degradation at turbulent flow rates. Five different concentrations of HPAM as well as mixtures of polyacrylamide/ xanthan gum were prepared to investigate the possibility of improving shear stability of HPAM. Drag reduction (DR) measurements were performed in a closed flow loop. For HPAM solutions, the extent of DR increased from 30% to 67% with increasing HPAM concentration from 100 to 1000 wppm. All the HPAM solutions suffered from mechanical degradation and loss of DR efficiency over the shearing period. Results indicated that the resistance to shear degradation increased with increasing polymer concentration. DR efficiency of 600 wppm xanthan gum (XG) was 38%, indicating that XG was not as good a drag reducer as HPAM. But with only 6% DR decline, XG solution exhibited a better shear stability compared to HPAM solutions. Mixed HPAM/XG solutions initially exhibited greater DR (40% and 55%) compared to XG, but due to shear degradation, DR% dropped for HPAM/XG solutions. Compared to 200 wppm HPAM solution, addition of XG did not improve the drag reduction efficiency of HPAM/XG mixed solutions though XG slightly improved the resistance against mechanical degradation in HPAM/ XG mixed polymer solutions.     

水性低伤害悬浮降阻剂体系的研究与应用

为了解决聚合物降阻剂粉末在现场应用中存在的水化时间长、溶解效果差等问题,同时避免现有现场用油性悬浮体系环保性差的缺陷,研发了一种以有机醇为溶剂的新型水性低伤害悬浮降阻剂体系,并对滑溜水体系的综合性能进行了室内和现场应用评价。结果表明,聚乙二醇200为最佳悬浮溶剂,当触变剂PR与CQ2720用量分别为1.5%时,体系具有最好的悬浮稳定性,在悬浮体系稳定中两者存在协同增效作用。增加0.5%助分散剂MR312后悬浮降阻剂体系常温静置30 d无沉降,体系黏度稳定在177 mPa·s。悬浮降阻剂体系遇水均匀分散,所配制滑溜水澄清透明,表观黏度可控,降阻率大于70%。在阳101H1-1井的压裂施工中降阻剂分散均匀无结块、起黏迅速,返排液易处理,环境伤害小,环保效果显著。