一种聚合物压裂液稠化剂的性能研究及应用

以分子间的静电作用为理论基础,研制出一种适用于中高温地层的阳离子型中高分子量的压裂液用聚合物稠化剂,通过红外光谱谱图以及核磁共振谱图分析聚合物结构,利用扫描电镜观察加入电吸引诱导剂后聚合物溶液空间结构的变化,并对该聚合物压裂液稠化剂进行性能测试,发现该压裂液聚合物稠化剂在加入电吸引诱导剂后可形成较强的空间网状结构,增黏效果很好,并且在110℃、130℃、170 s-1下剪切1 h后黏度保持在40~55 m Pa s,在90℃条件下破胶时间为71.5 min,破胶后无残渣,岩心伤害率低,为12.07%。该压裂液表现出较强的黏弹性,携砂性能好,沉砂速率为1.96×10-4 m/min,且在砂比为60%时,常温下1 h后悬砂状态良好。该聚合物压裂液稠化剂满足现场压裂施工的要求,加之合成原料易得、价格较低,其现场应用前景广泛,通过在苏里格气田苏20-23-X井盒8下段的现场压裂施工测试中可以看出,其施工效果显著。

Study on and Application of a Polymeric Thickening Agent for Fracturing Fluid

A cationic polymeric thickening agent used in fracturing fluid was developed for use in formations of middle or high temperature. Analyses of the thickening agent using IR spectrum, NMR and SEM showed that a spatial network was formed by the molecules of the polymer after reacting with an electric-attraction inducer, rendering the polymer very good thickening capacity. This polymer has viscosity between 40-55 mPa·s after shearing at 170 s-1 at 110℃ and 130℃ for 1 hour. Time for gel breaking was 71.5 minutes at 90℃. No residue was left after gel breaking, meaning that reservoir damage caused by this polymer would be very low (12.7% in an experiment.) Fracturing fluid formulated with this polymer showed very good viscoelasticity, and sand carrying capacity, rate of sand sedimentation being 1.96×10-4 m/min. At normal temperature, fracturing fluid containing 60% sands still showed good suspension stability after standing for 1 hour. As a cost-effective material, it satisfied the need for field fracturing operation, as shown in the fracturing of the lower segment of HE-8 in Well Su20-23-X, Sulige gas field.