酸性条件下瓜尔胶交联体系研究

Research on Guar Gum Crosslinking System in Acidic Condition

张宗勋 朱倘仟 侯吉瑞

ZHANG Zongxun ZHU Changqian HOU Jirui

实施注二氧化碳气驱的低渗透油藏在多次压裂的过程中会出现地层酸化， 导致瓜尔胶压裂液无法交联。针对这一问题， 以羟丙基瓜尔胶 HPG为主剂、 HPAM为辅剂， 采用甲醛预处理聚合物， 在模拟酸性条件下对交联体系的交联剂种类进行了优选， 通过研究交联剂、 稠化剂用量、 反应时间等因素对体系交联效果的影响研发了一种酸性条件下的交联体系， 并考察了该交联体系的成胶性能和携砂性能。研究结果表明， 在酸性（pH=3～ 5）条件下， 交联体系的最佳配方为： HPG用量 1.6%、 HPAM 用量 0.2%、 甲醛用量 0.3%、 间苯二酚 0.5 g/L， 甲醛预处理时间为 3～5 h； 该体系交联前的黏度为 100 mPa·s， 流动性好， 在 65℃条件下交联反应 5 h 后的黏度高达 2000mPa·s， 成胶性能良好； 该体系具有良好的携砂性能， 在 65℃下支撑剂在交联前体系中的沉降速率是在交联后体系中的 31倍。图 3表 3参 12

Multiple-time hydraulic fracturing is generally required in low permeability reservoirs with the implementation of CO2 flooding，and the formation presents weakly acidic condition，which leads to the poor guar gum crosslinking effect. In order to solve this problem，hydroxypropyl guar gum （HPG） was selected as the main crosslinking agent，preprocessed partially hydrolyzed polyacrylamide（HPAM）by methanol as the assisted agent，and then different types of crosslinker were screened under the simulated acidic condition. Furtherly，the influence of the dosage ratio of crosslinker and thickener，reaction time and reaction temperature on the crosslinking effect was studied. In this way，the novel method was developed to prepare guar gum crosslinking system under the acidic condition，and the gel-forming property and sand-carrying capability of the system was investigated. The optimizing formula under acidic condition（pH=3—5）was as follows：1.6% HPG+0.2%HPAM+0.3%methanol+0.5g/L resorcinol， and the methanol-preprocessed time was 3—5 h. Gelling property of the systerm was excellent，the viscosity of the system before and after crosslinking for 5 h at the temperature of 65℃ was 100 mPa·s and 2000 mPa·s，respectively，and the sedimentation rate of proppant in the former was 31 times as long as that in the latter，which indicated that the system possessed good proppant transportation performance.

10.19346/j.cnki.1000-4092.2017.02.010