抗高温油井水泥缓凝剂的研究进展

概述了近年来抗高温油井水泥缓凝剂的研究现状,主要分为有机膦酸盐、改性羟基羧酸盐、AMPS共聚物、改性木质素、其他新型聚合物以及复配体系六大类,并对国内外相关研究的具体实例进行了对比,总结了两者之间存在的差距,展望了今后该研究领域的研究重点和发展方向。     

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。     

G级高抗硫油井水泥浆性能的影响因素分析

油井水泥作为固井最主要的材料,其性能直接决定着固井质量的好坏。选取了四种常用的G级高抗硫油井水泥,分析了水泥的矿物组成、水泥粒径分布、水化热等性能,并研究了其对水泥浆性能的影响。结果表明：水泥细度和矿物组成是影响水泥浆流变性的主要因素;水泥中铝酸盐矿物含量( C3 A+C4 AF)是影响水泥和外加剂相容性的关键因素;水泥中石膏的种类和含量对稠化时间影响明显。     

磷石膏水泥缓凝剂的研究

磷石膏中的磷酸盐，特别是可容性磷酸盐对水泥有超缓凝作用，是磷石膏过分缓凝的根本原因。磷石膏过分缓凝和喂料困难是磷石膏做缓凝剂应该解决的两个问题。固化磷石膏浸水24h以后有2．0MPa的强度，且可保证喂料和计量的稳定。固化磷石膏磨制的水泥和天然二水石膏磨制水泥相比，二者的凝结时间最接近，强度有一定的提高。     

Working mechanism of a high temperature (200°C) synthetic cement retarder and its interaction with an AMPS®‐based fluid loss polymer in oil well cement

A copolymer comprising of 2‐acrylamido‐2‐methyl propane sulfonic acid (AMPS®) and itaconic acid (molar ratio 1 : 0.32) was synthesized by aqueous free radical polymerization and probed as high temperature retarder for oil well cement. Characteristic properties of the copolymer including molar masses (M_w and M_n), polydispersity index and anionic charge amount were determined. The copolymer possesses a M_w of ～ 2 × 10⁵ g/mol and is highly anionic. HT/HP consistometer tests confirmed effectiveness of the retarder at temperatures up to 200°C. The working mechanism of NaAMPS®‐co‐itaconic acid was found to rely exclusively on its huge calcium binding capacity (5 g calcium/g copolymer). It reduces the amount of freely dissolved, nonbound calcium ions present in cement pore solution and thus hinders the growth of cement hydrates because of lack of calcium. The value for the calcium binding capability is 46 times higher than the stoichiometric amount per ? COO^? functionality. Consequently, calcium also coordinates to other donor atoms present in the retarder. NaAMPS®‐co‐itaconic acid also adsorbs onto cement, as was evidenced by TOC analysis of cement filtrates, zeta potential measurement and decreased rheology of cement pastes. However, adsorption plays no role in the retarding mechanism of this copolymer. Combination of NaAMPS®‐co‐itaconic acid retarder with a common CaAMPS®‐co‐NNDMA fluid loss additive (FLA) revealed that competitive adsorption on cement between these two admixtures occurs. The retarder fills interstitial adsorption sites on cement located between those occupied by the larger FLA molecules. In consequence, fewer amounts of CaAMPS®‐co‐NNDMA can adsorb and its effectiveness is reduced. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

缓凝剂对磷建筑石膏-普通硅酸盐水泥复合体系性能的影响及其机理研究

磷建筑石膏(β-HPG)力学性能差,凝结硬化快,已有研究表明用普通硅酸盐水泥(OPC)替代部分β-HPG可改善其力学性能,但对此复合体系工作性能的调控作用及机理研究尚不明确。本文探讨了三种缓凝剂对β-HPG-OPC复合体系性能的影响,通过测试凝结时间和抗压强度来表征性能变化,通过分析水化热曲线、电导率曲线、XRD谱和SEM照片来讨论作用机理。研究结果表明,三聚磷酸钠(STPP)对复合体系基本无缓凝作用,蛋白质类SC缓凝剂(SC)和柠檬酸(CA)的缓凝作用均较好,其中SC对初凝时间的延缓作用较好,CA对终凝时间的延缓作用更佳。CA使二水石膏晶体的形貌发生改变,导致体系抗压强度显著降低;SC对二水石膏晶体的粗化作用使体系形成相对致密的微观结构体,对抗压强度影响较小。研究结果将为β-HPG-OPC复合体系工程应用提供重要参考,有助于推进β-HPG在工程中的高附加值利用。     

高温缓凝剂AMCT的合成及其性能评价

以甲基丙烯磺酸钠(MAS)、含亲水长链的烯类单体(CL)、丙烯酸(AA)和烯丙基三甲基氯化铵(TMAAC)为原料,合成了一种高温缓凝剂(AMCT)。通过正交实验得到的最佳合成条件为:n(AA)∶n(MAS)∶n(CL)∶n(TMAAC)=4.0∶1.0∶0.15∶0.10,引发剂(NH4)2S2O8加量为单体总质量的4%,单体质量浓度300 g/L,反应温度85℃,反应时间24 h。利用IR和~1HNMR表征了AMCT的结构。采用TGA考察了AMCT的耐温性能。以稠化时间考察了AMCT的温度敏感性和加量敏感性。通过AMCT对水泥浆流变性能的影响说明其分散性和稳定性。通过XRD、EDTA滴定和低场核磁等方法分析了AMCT的缓凝机理。结果表明:AMCT的分解温度为255℃;AMCT的温度敏感性和加量敏感性均符合行业标准要求;AMCT对水泥浆分散性和稳定性无不良影响;AMCT的缓凝机理为自匹配吸附形成包覆层控制水化作用、抑制晶体生长作用和络合作用。     

G级高抗硫酸盐油井水泥的生产实践

介绍了G级高抗硫酸盐油井水泥的熟料烧成、水泥制成及储存发运。按照GB/T 10238《油井水泥》规定的G级高抗硫酸盐油井水泥矿物组成比例,选择生产油井水泥的原燃材料,确定熟料相应的率值及生产要求,严格控制生料质量并做好生产过程中的质量控制。     

国内油井水泥外加剂研究与应用进展

油井水泥外加剂在保证固井质量方面起着关键作用,是重要的油田化学品之一。从降失水剂、缓凝剂、分散剂、早强剂及其他外加剂等方面综述了近5年来国内油井水泥外加剂研制与应用方面取得的进展。     

Synthesis,characterization, and working mechanism of a synthetic high temperature (200°C) fluid loss polymer for oil well cementing containing allyloxy‐2‐hydroxy propane sulfonic (AHPS) acid monomer

A polymer comprising of 2‐acrylamido‐2‐methyl propane sulfonic acid, N, N‐dimethyl acrylamide, allyloxy‐2‐hydroxy propane sulfonic acid (AHPS), acrylic acid, and N, N‐methylene bisacrylamide was synthesized by aqueous free radical copolymerization and tested as high temperature performing fluid loss additive (FLA) in oil well cement. Successful incorporation of AHPS was confirmed and characteristic properties of the copolymer were determined using size exclusion chromatography. The FLA showed excellent water retention in cement at 200°C/70 bar. At this temperature, polymer structure changed from branched to linear and hydrodynamic size decreased by ～50%, thus indicating potential fragmentation, while performance remained unaffected by these alterations. The FLA copolymer does not viscosify cement slurries which is advantageous in high temperature well cementing. The working mechanism of the AHPS‐based copolymer was found to rely on reduction of filtercake permeability which is caused by a voluminous coprecipitate of the FLA with tartaric acid retarder, mediated by Ca²⁺ ions. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

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。     

条件对丙烯酸-丙烯酰胺共聚合成树脂的影响

以丙烯酸、丙烯酰胺为原料，过氧化异丙苯为引发剂，N，N-五甲基二丙烯酰胺为交联剂，制备了吸水树脂，讨论了制备条件的影响。     

水性树脂的制备及对油井水泥防腐性能的提升

以苯乙烯磺酸钠、环氧树脂E54为原料,制备了一种用于提高油井水泥石抗CO₂腐蚀的水性环氧树脂WEP。通过FTIR、¹HNMR及TG分析了其化学结构和热稳定性。将制备的WEP分散到水中形成乳液,测试了乳液的分散性与稳定性。将WEP用于油井水泥石中,在模拟地层高温高压及CO₂酸性环境条件下进行了水泥石腐蚀实验,通过抗压强度、热重分析、SEM以及XRD评价了水泥石的腐蚀程度。结果表明,WEP具有较好的环境应用热稳定性,其热分解温度为295℃。WEP具有良好的自乳化性能,乳液分散均匀,乳液滴粒径较小,且乳液稳定性高,在6000r/min离心分离条件下可稳定30min不分层。WEP可有效提高水泥石抗CO₂腐蚀性能,水泥石在180℃、总压40 MPa、CO₂分压10 MPa条件下,腐蚀90 d后,含WEP的改性水泥石抗压强度衰退率仅为14.7%,CaCO₃质量分数仅为0.25%,均远低于对比水泥石。XRD和SEM结果表明,WEP改性的水泥石腐蚀后,其内部主要成分仍是水...     

水溶液聚合法制备聚丙烯酸盐型高吸水聚合物

以丙烯酸和丙烯酰胺为混合单体,过硫酸铵为引发剂,Ｎ,Ｎ＇－亚甲基双丙烯酰胺为交联剂,开发了一种采用水溶液聚合法制备聚丙烯酸盐型高吸水聚合物的技术。其特点是采用高浓度的混合单体体系,于盘式反应器中进行聚合和交联反应,利用反应放出的热量脱除体系中的水分,无需额外的干燥工序。所得产物吸水率为４００￣７００ｇ／ｇ。     

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     

Effect of different anchor groups on adsorption behavior and effectiveness of poly(N,N‐dimethylacrylamide‐co‐Ca 2‐acrylamido‐2‐methylpropanesulfonate) as cement fluid loss additive in presence of acetone–formaldehyde–sulfite dispersant

The impact of various anchor groups on adsorption behavior of AMPS® copolymers was studied. The anchor groups differ in anionic charge density. Copolymer adsorption and water retention of oil well cement slurries achieved from CaAMPS®‐co‐NNDMA in the presence of an acetone–formaldehyde–sulfite (AFS) dispersant were improved by incorporation of minor amounts (～ 1% by weight of polymer) of acrylic acid (CaAMPS®‐co‐NNDMA‐co‐AA), maleic acid anhydride (CaAMPS®‐co‐NNDMA‐co‐MAA), or vinyl phosphonic acid (CaAMPS®‐co‐NNDMA‐co‐VPA), respectively. Performance of these terpolymers was studied by measuring static filtration properties of oil well cement slurries at 27°C and 70 bar pressure. All fluid loss additives possess comparable molar masses and show the same adsorption behavior and effectiveness when no other admixture is present. In the presence of AFS dispersant, however, adsorption of CaAMPS®‐co‐NNDMA and hence fluid loss control is dramatically reduced, whereas effectiveness of CaAMPS®‐co‐NNDMA‐co‐AA is less influenced because of acrylic acid incorporated as additional anchor group. Even more, CaAMPS®‐co‐NNDMA‐co‐MAA combined with AFS allows simultaneous adsorption of both polymers and thus produces good fluid loss control. CaAMPS®‐co‐NNDMA‐co‐VPA no longer allows adsorption of AFS dispersant. This was also confirmed by rheological measurements. The results show that, in a binary admixture system, adsorption of the anionic polymer with anchor groups possessing higher charge density is preferred. Surface affinity of the anchor groups studied increase in the order ? SO → ? COO^? → vic‐(? COO^?)₂→ ? PO. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Mechanistic study on carboxymethyl hydroxyethyl cellulose as fluid loss control additive in oil well cement

The working mechanism of carboxymethyl hydroxyethyl cellulose (CMHEC, M_w 2.6 × 10⁵ g/mol) as fluid loss control additive (FLA) for oil well cement was investigated. First, characteristic properties of CMHEC such as anionic charge amount, intrinsic viscosity in cement pore solution, and static filtration properties of cement slurries containing CMHEC were determined at 27°C and 70 bar. Effectiveness of the FLA was found to rely on reduction of cement filter cake permeability. Consequently, the working mechanism is ascribed to constriction of cement filter cake pores. Zeta potential measurements confirm that at low CMHEC dosages (0–0.3% by weight of cement, bwoc), adsorption of the polymer onto the surface of hydrating cement occurs. However, at dosages of 0.4% bwoc and higher, an associated polymer network is formed. This was evidenced by a strong increase in hydrodynamic diameter of solved CMHEC molecules, an exponential increase in viscosity and a noticeable reduction of surface tension. Thus, the working mechanism of CMHEC changes with dosage. At low dosages, adsorption presents the predominant mode of action, whereas above a threshold concentration of ～ 10 g/L (the “overlapping concentration”), formation of associated polymer networks is responsible for effectiveness of CMHEC. Addition of anionic polyelectrolytes (e.g., sulfonated melamine formaldehyde polycondensate, M_w 2.0 × 10⁵ g/mol) to cement slurries containing CMHEC greatly improves fluid loss control. Apparently, the presence of such polyelectrolytes causes the formation of colloidal associates from CMHEC to occur at lower dosages. Through this mechanism, effectiveness of CMHEC as cement fluid loss additive is enhanced. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Working mechanism of poly(vinyl alcohol) cement fluid loss additive

The working mechanism of poly(vinyl alcohol) (PVA, M_w ～ 200,000 g mol^?1), a fluid loss control additive (FLA) applied in oil well cementing, was investigated. First, characteristic properties of PVA such as solubility and particle size in cold and hot water, minimum film forming temperature, adsorption on cement, viscosity of cement pore solution and static filtration properties of cement slurries treated with PVA were determined. It was found that the working mechanism of PVA relies on hydrated, but water‐insoluble PVA particles (d₅₀ ～ 2.4 μm). During cement slurry filtration, they coalesce into a polymer film. This film effectively plugs the pores of the cement filter cake. The sample studied here becomes water‐soluble at temperatures > 40°C (d₅₀ decreases to ～50 nm) and looses its effectiveness. Addition of highly anionic dispersants such as ß‐naphthalenesulfonate formaldehyde (BNS) or acetone formaldehyde sulfite (AFS) polycondensate extends the temperature range at which PVA works from 40°C to ～60°C. This effect is ascribed to lower solubility of PVA in the presence of these dispersants. The study reveals that decreased performance of PVA caused by higher temperatures is not the result of thermal degradation of the polymer, but is owed to its increasing water‐solubility. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

提高G级高抗硫酸盐油井水泥物理性能的措施

通过对G级高抗硫酸盐(HSR)油井水泥存在的缺陷与不足的分析,采取相应的工业生产措施,包括合理的配料方案、科学的煅烧方法、有效的磨制措施,得到物理性能优于国家标准的油田固井水泥。