大温差两性离子缓凝剂的制备及在低密度水泥浆中的应用

发布时间：2018-05-31 20:23

本文选题：大温差 + 两性离子缓凝剂　；参考：《西南石油大学》2017年博士论文

【摘要】：随着油气田勘探开发向深井、超深井发展,目的层地质条件的复杂性给固井工程带来了许多困难和挑战,尤其是长封固段低压易漏井固井,不仅要求水泥浆密度低,而且要求水泥浆缓凝剂具有优异的耐高温能力和适应大温差的能力。然而,现有的缓凝剂耐高温和适应大温差能力较差,为此,本文以大温差固井对缓凝剂的要求为出发点,重点开展了大温差两性离子缓凝剂的研究,并将此缓凝剂应用于低密度水泥浆中,形成了大温差低密度水泥浆体系,取得的研究成果如下：(1)以2-甲基-2-丙烯酰胺基-丙磺酸(AMPS)、衣康酸(IA)、甲基丙烯酰氧乙基三甲基氯化铵(DMC)、甲基丙烯醇聚氧乙烯醚(HEPG)为单体,过硫酸钾(K2S208)为引发剂,采用水溶液自由基聚合法制备了大温差两性离子缓凝剂PAID、在单因素实验基础上,采用响应面法分析法优化出最佳合成反应工艺条件为：单体摩尔比AMPS:IA:DMC:HPEG为50：25：10：0.02,K2S208加量1.2%,单体浓度31%,反应时间5h,聚合温度66℃,体系pH为8。采用FTIR、NMR、TG-DSC、GPC、SEM等测试手段对PAID进行表征。结果表明,PAID按设计单体配比进行共聚反应,分子结构中含有预期设计的功能基团；GPC测得PAID的重均分子量为Mw=4.45×105,数均分子量Mn=1.91×105,分子量分布指数PDI为2.3,分子量分布较宽；热分析结果表明PAID热稳定性良好；SEM实验表明,PAID溶液微观形貌呈现树枝状结构。(2)考察了PAID在水泥浆中的综合性能。结果表明,PAID对大温差固井具有良好的适应性,可满足高温条件下水泥浆的安全泵送,又可保证低温井段水泥石抗压强度的发展；PAID具有良好的抗温性及缓凝性,对温度,加量敏感性小,稠化时间与缓凝剂加量呈线性关系,满足90～180℃的固井要求；PAID具有一定分散作用,有利于改善水泥浆的流动性；与降失水剂配伍性良好。(3)合成了不同阳离子含量的两性离子缓凝剂。研究了两性离子缓凝剂在水泥颗粒表面的吸附行为；通过低场核磁T2弛豫时间研究了两性离子缓凝剂对水泥水化初期浆体中水存在状态的影响；采用XRD研究了两性离子缓凝剂对水泥水化产物的影响。基于以上实验,推测两性离子缓凝剂延缓水泥水化的机理主要是吸附机理和络合机理。两性离子缓凝剂适应大温差条件的原因为：1)在水泥颗粒表面的吸附强度小,形成的吸附层疏松,容易解吸附,在不断的“吸附—解吸附”过程中实现其缓凝作用与水泥水化反应的继续进行,有效防止水泥浆的长期不凝现象；2)高低温度下吸附量不同,通过缓凝剂分子对温度的可逆响应特性,缓凝剂在高温下吸附量大,缓凝作用强,低温下吸附量小,缓凝效果弱。以此解决了水泥浆高温稠化时间长与低温强度发展缓慢的矛盾；3)高低温度下对钙离子的络合能力不同,由于缓凝剂分子的温度伸缩性,低温下分子链蜷缩,使部分羧基被包埋,螫合作用减弱,缓凝能力降低。高温下分子链舒展,螯合能力增强,缓凝作用加剧。以此来实现其高温缓凝低温早强的特性。(4)制备了活性减轻材料ESC-25。采用FTIR,EDS,SEM,TG-DSC等手段对ESC-25进行了表征。红外光谱和能谱分析结果表明,矿渣与有机树脂基体成功复合；润湿实验结果表明活性填料改善了有机树脂基体的表面性能,使其表面亲水性增强；SEM实验结果间接表明活性减轻材料具有良好的剪切力学性能。热重结果表明,矿渣的加入,改善了减轻材料的热稳定性。ESC-25具有良好的抗剪切抗压性能,有利于深井固井中保证水泥浆的密度稳定性；XRD和TG-DSC实验证明,ESC-25的活性机理为,在水泥浆的碱性环境中,Ca(OH)2作为碱激发剂,激活矿渣发生火山灰反应,生成对水泥石抗压强度有利的水化硅酸钙凝胶。(5)以PAID和ESC-25为基础,通过筛选及组配外掺料和外加剂,设计了适用于115～135℃,密度为1.3-1.5g/cm3的大温差实心低密度水泥浆体系。实验结果表明,体系综合性能良好,在保证高温稠化时间的条件下水泥石顶部抗压强度强度发展快,对于长封固段低压易漏井固井具有良好的应用前景。
[Abstract]:With the development of oil and gas field exploration and development to deep wells and ultra - deep wells , the complexity of the geological conditions of the destination floor has brought many difficulties and challenges to cementing engineering , especially the low - pressure easy - to - drain well cementing of long - seal section . The results are as follows : ( 1 ) The temperature difference of two - sex ionic retarder is optimized by using the method of response surface method . The results show that the PAID is prepared by copolymerization of 2 - methyl - 2 - acrylamide - propanesulfonic acid ( AMPS ) , itaconic acid ( IA ) , methacryloxyethyl trimethyl ammonium chloride ( DMC ) , GPC and SEM . The results show that PAID is a functional group which is expected to be designed in the molecular structure .
The weight average molecular weight of PAID measured by GPC was Mw = 4.45 脳 105 , number average molecular weight Mn = 1.91 脳 105 , molecular weight distribution index PDI was 2.3 , molecular weight distribution was wider ;
The results of thermal analysis showed that the thermal stability of PAID was good .
SEM experiments show that the microscopic appearance of PAID solution presents dendritic structure . ( 2 ) The comprehensive performance of PAID in cement slurry is studied . The results show that PAID has good adaptability to large temperature difference cementing , and can meet the safe pumping of cement slurry under high temperature conditions , and can guarantee the development of cement stone compressive strength at low temperature .
The PAID has good temperature resistance and retarding property , and has a linear relation to the temperature , the addition amount sensitivity , the thickening time and the adding amount of the retarder , so that the cementing requirement of 90 - 180 DEG C is satisfied ;
PAID has a certain dispersing effect , which is beneficial to improving the fluidity of cement slurry ;
( 3 ) The adsorption behavior of zwitterionic retarder on the surface of cement particles was studied .
The effect of zwitterionic retarder on the presence of water in the initial slurry of cement by low field nuclear magnetic T2 relaxation time was studied .
Based on the above experiments , it is speculated that the mechanism of retarding the hydration of cement by zwitterionic retarder is mainly adsorption mechanism and complexation mechanism .
2 ) the adsorption quantity is different at high and low temperatures , and the reversible response characteristic of the retarder molecule to the temperature is adopted , the absorption quantity of the retarder is large under the high temperature , the inhibition effect is strong , the adsorption quantity at low temperature is small , and the retarding effect is weak , thereby solving the contradiction of slow development of high temperature thickening time and low temperature strength of the cement slurry ;
3 ) Under high temperature and low temperature , the complexing ability of the calcium ions is different . Because of the temperature expansion of the retarder molecules , the molecular chains are curled up at low temperature , so that some carboxyl groups are embedded , the chelating ability is enhanced , and the retarding action is increased .
The wetting experiment results show that the active filler improves the surface property of the organic resin matrix , so that the surface hydrophilicity is enhanced ;
The results of SEM show that the active material has good shear mechanical properties . The results show that the addition of slag improves the thermal stability of the material . The ESC - 25 has good shear compression resistance , which is beneficial to the density stability of cement slurry in deep well cementing .
XRD and TG - DSC experiments show that the activity mechanism of ESC - 25 is that Ca ( OH ) 2 is used as alkali activator in the alkaline environment of cement slurry to activate slag to react with ash to generate hydrated calcium silicate gel with favorable compressive strength .
【学位授予单位】：西南石油大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TE256.6

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