NaCl、NaBr对HPG压裂液性能的影响

Effect of NaCl and NaBr on the Performance of HPG Fracturing Fluid

肖 兵 张高群 陈 波 胡娅娅 曹 凯 武玉东 栾飞

XIAO Bing ZHANG Gao-Qun CHEN Bo HU Ya-Ya CAO Kai WU Yu-Dong LUAN Fei

随着国内外深井、高压井、高应力井储层的压裂改造，压裂液加重已成为降低压裂施工压力的必要措施，常用的加重剂为NaCl、NaBr等无机盐。室内研究了NaCl、NaBr对压裂液性能的影响。结果表明，加重之后压裂液黏度升高，并呈指数上升趋势；压裂液耐温耐剪切能力提高，14% NaCl、14% NaBr加重压裂液在130℃、170 s-1连续剪切120 min后的黏度分别约为200 mPa·s和300 mPa·s，而非加重压裂液剪切70 min后的黏度在100 mPa·s以下；加重压裂液高温滤失降低，黏弹性略有降低。加重后，压裂液破胶相对困难，所需破胶剂量增大。125℃时，30% NaBr压裂液需0.3% APS以上剂量才能达到非加重压裂液加入0.05% APS的效果。低剪切速率下，加重后压裂液的摩擦压降相对偏高；但随剪切速率增大，摩擦压降有低于非加重压裂液的趋势。

With the fracturing treatment of deep wells and high-pressure wells at home and abroad, weighting of fracturing fluid had become the necessary measures of reducing pressure in fracturing operation. And the commonly aggravating materials were inorganic salt, such as NaCl and NaBr. The effect of NaCl and NaBr on the properties of fracturing fluid was studied. The results showed that the viscosity of fracturing fluid increased exponentially after inorganic salt added. The fluid capability of temperature-resisting and shear resistance raised. The viscosity of fracturing fluid contained 14% NaCl and 14% NaBr was 200 mPa·s and 300 mPa·s respectively with 130℃ temperature, 170 s-1 shear rate and 120 min shear time. However, that of non-aggravating fracturing fluid dropped to 100 mPa·s after 70 min. Inorganic salt could reduce the fracturing fluid loss at high temperature, but would lower its viscoelastic. After aggravating, gel breaking became relatively difficult and the gel breaking dose increased. The effect of 30% NaBr fracturing fluid mixing 0.3% APS above could equal to that of the non-aggravating fracturing fluid mixing 0.05% APS at 125℃. In low shear rate, the friction of aggravating fracturing fluid was on the high side relatively. But with increasing shear rate, the friction of aggravating fracturing fluid would lower than that of non-aggravating fracturing fluid.