高温条件下AMPS类缓凝剂缓凝作用效果分析

缓凝剂的选配是高温水泥浆体系设计最关键的因素之一。为了合理地优选和适用缓凝剂,选用AMPS-IA共聚缓凝剂与大连G级油井水泥作用,通过高温高压稠化仪、X射线衍射仪、扫描电子显微镜和能谱仪等对水泥稠化性能、水化硬化产物的物质组成和微观结构特征进行检测,对其适用性进行分析。结果表明：AMPS类缓凝剂作为高温缓凝剂具有良好的缓凝效果,稠化线形好且稠化时间长。但是重复实验评价缓凝剂稳定性过程中有一定概率出现缓凝剂失效,稠化曲线出现波动,造成水泥浆异常胶凝。产生胶凝的原因是缓凝剂聚合物分子对阳离子产生螯合-吸附作用,在物理搅拌作用下使得大量聚合物分子与水泥熟料成胶联状聚集在搅拌轴外部。     

HJH-1型高温油井水泥缓凝剂的合成及其性能评价

以MA、AMPS、AM为原料合成一种高温油井水泥缓凝剂HJH-1,通过正交实验确定最佳合成条件为:m(MA)∶m(AMPS)∶m(AM)=21∶9∶8、引发剂加量8%(以单体总质量计)、反应温度90℃和反应时间6 h,并对其应用性能进行评价。结果表明,HJH-1型缓凝剂在140℃的高温环境下仍具有很好的缓凝效果,4%加量时稠化时间为300 min,初始稠度低于30 Bc,稠化线形良好,直角稠化时间小于20 min;稠化时间可调性好,温度和加量敏感性低,综合性能满足固井施工安全要求;此外,将低场核磁共振分析技术应用于塑性水泥浆的研究,测试水泥浆体初凝前的横向弛豫时间T2分布,进一步分析了在初始水化阶段水泥浆体中水的存在状态及该缓凝剂对水泥浆初始阶段水化过程的影响。     

高温缓凝剂LY的合成及在低密度水泥浆中的应用

随着石油勘探开发向深部油气层发展,固井长度增加,井底温度升高,需要提高缓凝剂的抗温能力并降低其温敏性。本文首先以AMPS和IA(衣康酸)这两种单体为原料合成共聚物,通过单因素实验法优化合成条件,得出最优合成条件为n(AMPS):n(IA)=50:20,反应温度60℃,引发剂加量1%。再将AMPS/IA共聚物与一种多羟基羧酸盐复配得到新型高温缓凝剂LY,并将该缓凝剂LY应用于低密度水泥浆体系中,通过中、高温条件下的稠化时间对比说明缓凝剂LY对温度的敏感性,实验证实LY的温敏性较小;并通过缓凝剂LY对水泥浆流变性的影响说明缓凝剂的分散性及稳定性,结果证明缓凝剂LY的稳定性较好,并可改善水泥浆的流变性;通过125℃下的高温稠化曲线可知该缓凝剂可抗温度达到125℃,具备高温缓凝剂特性,能够满足固井的要求。再通过XRD谱图分析缓凝剂对低密度水泥石的影响,并最终探讨缓凝机理。     

一种适合于超高温油井水泥缓凝剂的研制

通过优选含有羟基、羧基和磷的单体进行水溶液聚合,合成了耐高温的油井水泥缓凝剂。讨论了单体的优选及合成的最佳条件;测试了超高温缓凝剂的抗高温性能、抗压性能及与其他外加剂的配伍性等。实验表明,该缓凝剂适用温度范围广(110℃~200℃);加量不敏感,与稠化时间具有良好的线性关系,有利于现场施工;在高温下48h强度发展迅速,对水泥石强度无影响;与其他水泥外加剂具有良好的配伍性,对水泥浆体系无不良影响,综合性能能满足固井现场的施工要求。     

超高温油井水泥缓凝剂的合成及评价

通过优选含有羟基、羧基和磷的单体进行水溶液聚合,合成了耐高温的油井水泥缓凝剂。讨论了单体的优选及合成的最佳条件;测试了超高温缓凝剂的抗高温性能、抗压性能及与其他外加剂的配伍性等。实验表明,该缓凝剂适用温度范围广(110℃²00℃);加量不敏感,与稠化时间具有良好的线性关系,有利于现场施工;在高温下48h强度发展迅速,对水泥石强度无影响;与其他水泥外加剂具有良好的配伍性,对水泥浆体系无不良影响,综合性能能满足固井现场的施工要求。     

缓凝剂对氯氧镁水泥水化历程的影响

为了拓展氯氧镁水泥(MOC)的使用范围,研究了缓凝剂(柠檬酸、硼酸、葡萄糖酸钠)对氯氧镁水泥凝结时间、抗压强度、电阻率、水化热和耐水性的影响,同时采用X射线衍射仪分析了氯氧镁水泥改性后的水化产物。结果表明,掺入缓凝剂会延长氯氧镁水泥的凝结时间,当缓凝剂掺量达到0.75%(质量分数,下同)时,各组试样的28 d抗压强度较空白组分别下降了19.3%、16.7%和20.2%。缓凝剂的掺入降低了水泥浆体电阻率速率曲线和内部温度曲线的峰值,推迟了水化放热速率曲线第二峰值出现时间,即降低了氯氧镁水泥的水化速率,改善了氯氧镁水泥放热集中的现象。缓凝剂能提高氯氧镁水泥的耐水性,当硼酸掺量为0.75%时,软化系数可达到0.79。     

高温缓凝剂AMPS-IA的性能及作用机理解释

针对深井固井高温环境下水泥浆稠化时间和抗温性能难以满足现场施工的问题,研制了一种抗高温缓凝剂AMPS-IA,并考察了高温缓凝性能、抗盐性能及它对水泥石抗压强度的影响。通过红外光谱分析,聚合物络合物中最明显的特征在于1405cm-1处吸收峰的出现。在溶液吸收光谱分析中,聚合物络合物中的最大吸收波长的变化代表了-C=O基团上发生了跃迁,-C=O基团的电子云密度降低。根据红外光谱及溶液吸收光谱分析,证实了缓凝剂中的配位体与水泥中的钙离子形成了金属螯合物,通过测试手段证实了AMPS-IA缓凝剂的作用机理。     

高温高压井固井水泥浆体系研究

高温高压环境易对固井水泥浆性能产生较大的影响,引起水泥石强度衰退、添加剂失效等问题。针对高温固井对水泥浆的要求,研究了水泥浆关键添加剂材料,构建了抗高温固井水泥浆体系,并对水泥浆性能进行评价。实验结果表明,研究的高温降失水剂、缓凝剂、分散剂、加重剂能有效降低水泥浆的失水量,调节水泥浆的稠化时间和流变性,提高水泥浆的密度...     

缓凝剂SN-3的制备及其对水泥浆横向弛豫时间T2分布的影响

首先合成了一种新型两性聚合物缓凝剂SN-3,然后采用红外光谱和元素分析等测试手段对其进行结构表征。其次,对其应用性能作了进一步研究,主要包括稠化时间、加量和温度敏感性等,实验结果表明应用性能满足现场施工要求。利用低场核磁共振测试技术重点研究了缓凝剂SN-3对油井水泥浆水化过程中横向弛豫时间T₂分布的影响,在相同的水灰比、温度和水化时间下,对纯水泥浆C和掺有缓凝剂SN-3的水泥浆CHN的横向弛豫时间进行测试和分析,借助迁移速率和峰形指数两个参数表征水泥浆T₂分布曲线的变化过程。最后,结合X衍射和扫描电镜（SEM）进一步探讨缓凝剂SN-3的缓凝作用原理。实验结果表明,缓凝剂使水泥浆中填充于絮凝结构之间的水的受缚程度减小,存在时间变长,转化为化学结合水所经历时间变长;缓凝剂SN-3主要通过沉淀和络合作用达到缓凝效果的。     

适用于大温差固井用一种新型耐温耐盐缓凝剂(PMC-180)的合成及性能评价

针对深井超深井长封固段固井时水泥浆柱顶部强度发展缓慢、缓凝甚至超缓凝的问题,笔者采用溶液聚合原位插层法,以2-丙烯酰胺基-2-甲基丙磺酸(AMPS)、丙烯酸(AA)、二烯丙基二甲基氯化铵(DMDAAC)为单体,以改性蒙脱土为活性聚合填料,合成了一种新型有机-无机复合型大温差缓凝剂(PMC-180),采用红外光谱、X射线衍射及热重分析等方法分别表征了其结构和热稳定性能,并对其相关应用性能进行了评价,探讨了其在水泥浆中的缓凝作用机理。结果表明,所合成共聚产物(PMC-180)为目标产物且具有插层剥离复合结构,初始热解温度为267.27℃,具有良好的耐热稳定性。含PMC-180的水泥浆具有良好高温缓凝性能和抗盐性能,淡水基和盐水基水泥浆均可通过调整其加量调节水泥浆的稠化时间,且稠化曲线平稳无“鼓包”等异常现象;含PMC-180的水泥浆在顶部低温下强度发展良好,可应用于长封固段大温差固井且有效缓解了顶部水泥浆超缓凝的问题;与不同水泥浆体系及外加剂具有良好的配伍性,综合性能良好,易于调整和控制。通过化学分析、X射线衍射、电镜扫描等表征手段,讨论了缓凝剂PMC-180的缓凝机理及大温差适应机理,认为缓凝现象的发生,是因为PMC-180吸附于水泥颗粒表面形成水化吸附层及与Ca2 络合抑制了Ca(OH)2晶核、晶体的正常生长,进而达到缓凝效果;温度的变化控制PMC-180中片层间距变化实现有效缓凝基团的束缚释放,同时分子结构中的阴阳两性离子产生竞争吸附,从而达到高温下具有较强缓凝效果,低温下具有部分缓凝效果,使得PMC-180具有良好的大温差适应性。     

SDJ2油井水泥降失水剂的室内研究

选用合适平均分子量的水溶性天然高分子改性产物羟乙基纤维素(HEC)合成一种油井水泥降失水剂SDJ2,并对添加SDJ2的水泥浆的性能进行了室内评价。这些性能包括水泥浆的流变性能、稳定性、稠化时间、失水量和水泥石的抗压强度等,并且将SDJ2与自制缓凝剂SDH-2进行了配方试验。结果表明,SDJ2对水泥浆有显著的降失水作用,流变性能和稳定性良好,与缓凝剂SDH-2有很好的相容性,稠化时间可调,水泥石抗压强度符合要求。     

油井水泥降失水剂(HCW-1)的合成及性能评价

研究了2-丙烯酰胺-2-甲基丙磺酸(AMPS）、丙烯酸(AA)和一种功能型单体(简称为SM)三元共聚物(HCW-1)的合成方法及在油井水泥浆中的降失水作用,并探讨了其降失水机理。实验结果表明,HCW-1对水泥浆稠化时间和水泥石抗压强度无不良影响,是一种良好的降失水剂。     

Adsorption behavior and effectiveness of poly(N,N‐dimethylacrylamide‐co‐Ca 2‐acrylamido‐2‐methylpropanesulfonate) as cement fluid loss additive in the presence of acetone‐formaldehyde‐sulfite dispersant

A copolymer of N,N‐dimethylacrylamide and Calcium 2‐acrylamido‐2‐methylpropanesulfonate was synthesized by free‐radical copolymerization. Its performance as anionic fluid loss additive (FLA) was studied by measuring static filtration properties of oil well cement slurries at 27°C and 70 bar pressure, respectively. It was found that cement filter cake permeability and API fluid loss decrease with increasing FLA dosage. Filtrate analysis revealed a linear correlation between fluid loss and the amount of FLA adsorbed on the cement surface. FLA adsorption on cement was determined by total organic carbon (TOC) analysis in cement filtrate and confirmed by ζ‐potential measurement. According to environmental scanning electron microscopy (ESEM) investigations, FLA does not alter the filter cake structure. In the presence of an anionic acetone–formaldehyde–sulfite (AFS) polycondensate dispersant, fluid loss control from FLA decreased and cement filter cake permeability increased because AFS reduces the amount of FLA adsorbed. In comparison to FLA, AFS shows stronger adsorption on the cement surface and succeeds in the competition with FLA. The different adsorption behavior of the two polymers is the reason for limited compatibility of this admixture com bination. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4341–4347, 2006     

Competitive adsorption between an AMPS®‐based fluid loss polymer and Welan gum biopolymer in oil well cement

Water‐soluble 2‐acrylamido‐2‐methylpropane sulfonic acid (AMPS®)‐based copolymers are commonly used to provide water retention (fluid loss control) for oil well cement slurries. Here, the fluid loss performance of a CaAMPS®‐N,N‐dimethylacrylamide copolymer (CaAMPS®‐co‐NNDMA) in the presence of Welan gum, an anionic microbial biopolymer produced by anaerobic fermentation using Alcaligenes ATCC 31555 bacteria was investigated at 80°C. Welan gum is used to control unwanted free water development at the surface of the cement slurry. The effectiveness of CaAMPS®‐co‐NNDMA fluid loss additive (FLA) solely relies on its high adsorption onto the positively charged surfaces of cement hydrates. Adsorption of the FLA is, however, perturbed by Welan gum. This anionic polysaccharide competes with CaAMPS®‐co‐NNDMA for adsorption sites on the cement surface. This effect is surprising because in cement pore solution, Welan gum exhibits a much lower specific anionic charge amount than CaAMPS®‐co‐NNDMA. The reason is that Welan gum possesses carboxylate functionalities, which are much stronger anchor groups than the sulfonate groups present in CaAMPS®‐co‐NNDMA. The superiority of the carboxylate groups regarding their affinity to the mineral surface, which possesses insufficiently coordinated Ca atoms is confirmed by a higher calcium binding capability for Welan gum than for the FLA. Thus, Welan gum can reduce effectiveness of CaAMPS®‐co‐NNDMA as fluid loss agent by preventing its adsorption or through displacement of already adsorbed FLA molecules from the surface of cement. In multiadmixture systems, which are commonly used in oil well cement, concrete or mortars, competitive adsorption between different additives for surface sites can negatively impact the performance of these additives. Understanding the reasons behind can help to develop more effective admixture systems. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of high temperature and the role of sulfate on adsorption behavior and effectiveness of AMPS®‐based cement fluid loss polymers

The fluid loss control performance of 2‐acrylamido‐2‐methylpropane sulfonic acid (AMPS®)‐based copolymers added to cement slurries was studied at 27 and 100°C, respectively. It was found that effectiveness of these fluid loss additives solely relies on achievement of a high adsorbed amount on the surface of cement. At elevated temperature (100°C), CaAMPS®‐N,N‐dimethyl acrylamide copolymer (CaAMPS®‐co‐NNDMA) exhibits reduced adsorption and hence decreased fluid loss control of the cement slurry. The reason behind this behavior is poor calcium binding capability of the sulfonate anchor groups, which coordinate with calcium atoms present on the mineral surface. Whereas, an increase in the sulfate concentration present in cement pore solution instigates partial coiling of CaAMPS®‐co‐NNDMA and causes only a slight influence on the performance of this copolymer. The elevated sulfate content results from thermal degradation of ettringite, a cement hydrate mineral produced during the early stages of cement hydration. Incorporation of minor amounts (～ 1.3 mol %) of maleic anhydride into this copolymer produces a terpolymer, which exhibits higher and more stable adsorption, even at high temperature. This effect is owed to the presence of homopolymer blocks of polycarboxylates distributed along the polymer trunk. On mineral surfaces, they present much stronger anchor groups than sulfonate functionalities, as evidenced by their higher calcium binding capability. Consequently, fluid loss performance of CaAMPS®‐co‐NNDMA‐co‐MA is little affected by temperature. Understanding the influence of temperature on the physicochemical interactions occurring between additives and the mineral surface can help to design more effective admixtures suitable for high temperature applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

海上稠油热采井水泥浆体系研究

海上稠油热采井与陆地热采井对水泥浆性能要求基本相同,都要求水泥环在生产中要长期满足经受反复高温考验后仍具有稳定性的特点。针对海上平台作业条件,参照硅酸盐水泥浆体系耐高温特点和纤维材料的增韧效果,优化添加剂组合,配制出一套密度在1.50~1.90 g/cm~3、温度区间为40~90℃的新型水泥浆体系。室内试验结果表明:该水泥浆体系失水量小于50 mL,稠化时间在120~400 min范围内可控,水泥石高温养护24 h的抗压强度最高可达24.8 MPa,在经350℃高温条件下养护28 d,水泥石仍有32.9 MPa的抗压强度。表明该体系可以满足海上热采井固井的施工要求。     

水滑石插层降失水剂的制备和性能研究

随着石油开发逐渐转向陆地深层、超深层,固井工程对油井水泥降失水剂的要求越来越高,降失水剂在高温高盐地层依然需要具备良好的控水特性.为了满足油井水泥降失水剂耐高温的性能,将有机聚合物降失水剂与新型无机材料水滑石结合起来,研制出一种耐高温耐盐的新型油井水泥降失水剂.选择2-丙酰胺基-2-甲基丙磺酸(AMPS)、对苯乙烯磺酸...     

Preparation and property of 2‐acrylamide‐2‐methylpropanesulfonic acid/acrylamide/sodium styrene sulfonate as fluid loss agent for oil well cement

A novel terpolymer 2‐acrylamide‐2‐methylpropanesulfonic acid/acrylamide/sodium styrene sulfonate (AMPS/AM/SSS), used as fluid loss agent for oil well cement under high temperature, was prepared with initiator of azobisisobutryamide chloride. The optimum reaction conditions of polymerization were obtained from the orthogonal experiments, reaction temperature 40°C, initiator 0.1 wt%, molar ratio of monomers AMPS/AM/SSS 20/5/1. The structure and performance of terpolymer was characterized with Fourier transform infrared spectrometer, nuclear magnetic resonance hydrogen spectrum, thermogravimetric and simultaneous differential thermal analysis, high‐temperature and high‐pressure water loss meter, and rotational viscometer, indicating that the terpolymer was perfectly synthesized and started to decompose at 350°C and showed good performance of fluid loss control up to 160°C. The ζ‐potential instrument and scanning electron microscopy were used to investigate the mechanisms of fluid loss control, indicating that the terpolymer can prevent the generation of flocculated structure in the cement and reduce the porosity of the filter cake. These results have important referential value for developing new high‐temperature‐resisting fluid loss agents. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

松南地区低密度水泥浆体系的研究与应用

松南地区地层破裂压力梯度较低,井底循环温度较低,油气层分布十分广泛,注水泥后易造成漏失,发生环空气窜等问题,给固井施工带来了很大的困难,严重影响了固井质量。为解决这些问题,研究并应用了漂珠一微硅低密度水泥浆体系,该体系具有低失水、流变性能好、稠化过渡时间短、抗压强度高等优点,能够满足松南地区固井要求。     

抗高温堵漏隔离液的研制与评价

针对地层埋深大,温度高(＞150℃)的地区,实际固井生产中存在不同程度的漏失,严重影响固井质量等问题,开发出了一种流变性好、稳定性强、密度范围宽、实现封堵的抗高温防漏型隔离液,通过在隔离液中添加核桃壳刚性架桥材料,并复配以木质素纤维和聚合物可变形胶束,用以在隔离水泥和钻井液时对地层裂缝实现有效封堵。采用自由基水溶液聚合方法,用2-丙酰胺基-2-甲基丙磺酸(AMPS)和丙烯酰胺(AM)及其衍生物,合成了适用于隔离液的聚合物堵漏剂,通过红外光谱分析,各单体成功参与反应。对复合堵漏剂的配比加量进行了优选,当复配堵漏剂配比为1%木质素纤维+2%聚合物+1% 18目核桃壳时,隔离液能达到160℃下5 MPa的堵漏承压能力。通过对隔离液的综合性能的评价,包括隔离液的高温稳定性、流变性能、与水泥浆的流变相容性,证明得到的隔离液的高温稳定性和流变性能优良,在160℃时上下密度差为0.01 g·cm^-3,与水泥浆的流变相容性、稠化相容性和失水相容性较好,不会影响水泥浆的泵送且不会缩短胶凝时间。