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.
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张宗勋 , 朱倘仟 , 侯吉瑞 .酸性条件下瓜尔胶交联体系研究[J].油田化学,2017,34(2):241-244. ZHANG Zongxun, ZHU Changqian, HOU Jirui. Research on Guar Gum Crosslinking System in Acidic Condition[J]. OILFIELD CHEMISTRY,2017,34(2):241-244.