pH值对羟丙基胍胶压裂液性能的影响

Effect of pH Value on Performance of Hydroxypropyl Guar Gum Fracturing Fluid

唐洪彪 王世彬 郭建春

TANG Hongbiao， WANG Shibin，GUO Jianchun

为了弄清压裂液的 pH值在水力压裂施工不同阶段所起的作用， 开展了 pH值对羟丙基胍胶溶胀、 交联、 携砂、 破胶性能的影响研究。结果表明， pH=7～ 10时， 羟丙基胍胶在 20 min内完全溶胀； pH=11～14时， 羟丙基胍胶至少需要 50 min才能完成溶胀。Ostwald-Dewaele方程 能描述冻胶黏度随剪切速率变化关系， pH=7～12时的稠度系数较大， 大于16744 mPa· sn； pH=13～14时的稠度系数明显减小， 小于3130 mPa· sn。静态沉降实验表明， pH=9～12时的静态沉降速度较小， 为 1.31～5.94 mm/h； pH=7、 8、 13时的静态沉降速度较大， 大于 10.64 mm/h； pH=14时， 支撑剂 20 s内完成沉降。破胶实验研究发现， 冻胶在 pH=7～10时的破胶速度大于 pH=1～14时的破胶速度； pH=7～12时， 残渣含量较小， 为 400 mg/L左右。满足各施工阶段的 pH值范围为9～10。图5表2参12

pH was an important factor affecting the performance of hydraulic fracturing. The effect of pH on the swelling performance of hydroxypropyl guar gum，crosslinking properties，proppant settlement，guar gum degradation was studied. The results showed that，at the pH value of 7—10，the swelling time of hydroxypropyl guar gum was less than 20 min，while at the pH value of 11 —14 ，the swelling time was larger than 50 min ，the swelling rate at the pH value of 7 —10 was relatively higher than that at the pH value of 11 —14. The relationship between gel viscosity and shear rate could be described by the Ostwald-Dewaele equation，and at the pH value of 7—12，the consistency coefficient of hydroxypropyl guar gum solution was larger than 16744 mPa·sn，while the consistency coefficient at the pH value of pH 13—14 was less than 3130 mPa·sn. The proppant settlement experiments showed that，at the pH value of 9—12，the settling rate of proppant was relatively low，being of 1.31—5.94 mm/h；at the pH value of 7，8，13，the settling rate increased and the value was larger than 10.64 mm/h；and at the pH value of 14，the proppant settlement completed in 20 seconds. The hydroxypropyl guar gum degradation experiments showed that，the degradation rate at the pH value of 7—10 was larger than that at the pH value of 11—14. At the pH value of 7—12，the residue was relatively low， which was 400 mg/L. In summary，the best pH range was 9—10 for the entire construction process.

10.19346/j.cnki.1000-4092.2016.06.007