改性羟丙基瓜尔胶/表面活性剂复合压裂液

Modified hydroxypropyl guar/surfactant based fracturing fluid

摘要:

以溴代十四烷对羟丙基瓜尔胶进行了疏水改性，对改性产物进行了红外和热重分析。用质量分数0.15%疏水改性羟丙基瓜尔胶和质量分数0.8%阳离子双子表面活性剂1,3-N-双（3-十二烷基丙酰胺）-1,1,3,3-N-四甲基异丙醇-1,3-二溴化铵制备了复合压裂液，并对复合压裂液的耐温耐剪切性、流变性、动态携砂性、破胶液界面性质、储层伤害性进行了系统评价。结果表明，羟丙基瓜尔胶成功接入了疏水碳链，且热稳定性良好；所制备的复合压裂液在90℃下黏度高于109 mPa·s；该体系表现为典型的黏弹性流体，动态携砂性良好；破胶液油/水界面张力为0.9 mN/m，且可显著增强储层岩石亲水性；储层基质油相渗透率损害率和裂缝导流能力损害率分别仅为9.1%和5.3%。

Abstract:

Hydroxypropyl guar was hydrophobically modified by1-bromotetradecane. The modified product was characterized by FTIR and thermogravimetric analysis. Then, a composite fracturing fluid composed of mass fraction of 0.15%modified hydroxypropyl guar and mass fraction of 0.8% Gemini surfactant, 1,3-N-bis(3-dodecylpropanamide)-1,1,3, 3-N-tetramethyl isopropanol-1,3-ammonium dibromide was prepared. The heat and shear resistance, rheological property, dynamic proppant transport capacity, interfacial property, and formation damage of the composite fracturing fluid were investigated. The results showed that the hydrophobic carbon chains were connected to hydroxypropyl guar successfully. The composite fracturing fluid exhibited good thermal stability with a viscosity of over 109 mPa·s at 90 ℃ and typical viscoelasticity and favorable dynamic proppant transport. The oil/water interfacial tension of the broken fracturing fluid was 0.9 mN/m, which could significantly enhance the hydrophilicity of reservoir rocks. The loss rates of matrix permeability for the oil phase and crack conductivity were only 9.1% and 5.3% respectively.