页岩气井水力压裂用黏土稳定剂LM-1的研制及评价

Development and evaluation of clay stabilizer LM-1 for hydraulic fracturing of shale gas wells

页岩气井水力压裂过程中容易发生黏土水化膨胀和运移,造成储层损害,影响压裂施工的效果。因此,室内合成了一种适合页岩气井水力压裂的季铵盐阳离子黏土稳定剂LM-1,并参照相关标准,对其综合性能进行了评价。实验结果表明,黏土稳定剂LM-1与常规的胍胶压裂液和滑溜水压裂液体系的配伍性较好,不会影响压裂液体系的整体性能;具有良好的耐水洗能力和防膨能力,当LM-1的质量分数为2.0%时,水洗前后钠膨润土的膨胀体积不再变化,其防膨率能够达到90%以上;黏土稳定剂LM-1的泥岩损失率仅为8.6%,远远优于其他常用的黏土稳定剂;另外,经过黏土稳定剂LM-1处理后,页岩储层天然岩心的渗透率变化率较小,起到了良好的黏土稳定作用,能够有效防止压裂过程中黏土遇水膨胀造成的储层损害。

The process of hydraulic fracturing of shale gas wells, clay hydration expansion and migration are easy to occur, resulting in reservoir damage and affecting the effect of fracturing operation. Therefore, a quaternary ammonium cationic clay stabilizer LM-1 suitable for hydraulic fracturing of shale gas wells was synthesized in laboratory, and its comprehensive performance was evaluated with reference to relevant standards. The experimental results show that the compatibility of clay stabilizer LM-1 with conventional guanidine gum fracturing fluid and sliding water fracturing fluid system is good, and it will not affect the overall performance of the fracturing fluid system. It has good water-washing resistance and anti-swelling ability. When the mass fraction of LM-1 is 2.0 %, the expansion volume of sodium bentonite will not change before and after water-washing, and the anti-swelling rate of clay stabilizer LM-1 can reach more than 90 %. The mudstone loss rate of LM-1 is only 8.6 %, which is much better than other commonly used clay stabilizers. In addition, after the treatment of LM-1, the permeability change rate of natural core in shale reservoir is small, which plays a good role in clay stabilization and can effectively prevent the reservoir damage caused by clay swelling in fracturing process.