化学交联聚乙烯醇的交联度和降失水性能的关系  

Correlations between the cross-linking degree of polyvinyl alcohol and its property of fluid loss controlling

作　　者：陈涓[1] 彭朴[1] 汪燮卿[1] 赵艳[2] 周仕明[2] 丁士东[2] 

机构地区：[1]中国石化石油化工科学研究院 [2]中国石化石油勘探开发研究院钻井研究所

出　　处：《钻井液与完井液》2002年第5期22-24,共3页Drilling Fluid & Completion Fluid

摘　　要：作为油井水泥降失水剂,聚乙烯醇(PVA)和共混的无机盐在较低温度下(<40℃)难形成均匀的络合物胶,在较高温度下(>100℃)络合物胶又易分解,因此共混交联PVA的适用温度范围较窄。用化学交联的方法对油井水泥降失水剂PVA进行了改性。室内实验评价了化学交联聚乙烯醇的交联度(交联度与分子量成正比,试验用分子量来表征交联度)与其降失水性能的关系以及添加化学交联PVA的水泥浆的综合性能。结果表明,控制交联度使化学交联PVA的平均分子量在350000～650000之间,加有化学交联PVA的水泥浆的API失水量可以控制在50 mL以下,抗温可达120℃,抗盐(NaCl)可达8％;化学交联PVA使水泥浆的稠化时间稍有延长,抗压强度不降低,抗析水能力增强,与分散剂USZ复合使用,水泥浆的流变性能良好;化学交联PVA能提高水泥浆的防气窜能力.When used as the fluid loss agent for oil well cement, it is difficult for polyvinyl alcohol (PVA) to form even complex gel with the mixing inorganic salt in temperature lower than 40 ℃ ; while in higher temperature,(>100 ℃), the complex gel is easily decomposable, thus the range of cross-linked PVA is relatively narrow. PVA is modified by the method of chemically cross-linking, and the correlations between the cross-linking degree of polyvinyl alcohol (the molecular weight is used for the cross-linking degree of polyvinyl alcohol, as it is proportional to the cross-linking degree) and its fluid loss controlling property are evaluated, as well as the synthetical performances of the cement slurry with chemically cross-linked PVA. The results show that by controlling the cross-linking degree, the average molecular weight of PVA is maintained between 350,000 to 650,000, and API fluid loss of the cement slurry with chemically cross-linked PVA is controlled within 50 mL, while its temperature tolerance is up to 120 ℃ and salt (NaCl) resistance is 8%. The thickening time of cement slurry is slightly extended, yet its compressing strength is not decreased and its water precipitation resistance also improved; when used with the dispersing agent USZ, the cement slurry achieved better rheological property, and in addition, the chemically cross-linked PVA can also improve the anti-gas migration of the cement slurry.

关 键 词：化学交联 聚乙烯醇 交联度 降失水性能 油井水泥 降失水剂 改性 

分 类 号：TE256.6[石油与天然气工程—油气井工程]