NHC环保型清洁压裂液性能评价及现场应用

Performance Evaluation and Field Application of NHC Environment-friendly Clean Fracturing Fluid

为解决常规压裂返液不易回收利用的问题,制备了一种NHC压裂液。NHC压裂液稠化剂为一种低分子多糖表面活性剂,具有多糖自交联及表面活性剂卷曲、缠绕的双重作用。当稠化剂BHC-2用量为0.4%~0.8%时,NHC压裂液耐温抗剪切能力在70~90℃,在其返排液中加入0.3%~0.7%BHC-2后,可再次形成压裂液。现场试验表明:在清水中加入0.4%BHC-2所形成的压裂液在施工过程中压力较平稳,在返排液中加入0.3%BHC-2时即可形成交联液,实现携砂压裂。NHC压裂液配液及回收工艺较简捷,在长庆华池油田某井压裂施工7段,回收返排液1 435 m^(3),返排液回收利率为95.67%,较好的利用了返排中的有效成分,减少了水资源的浪费,具有良好的环保效应。后期数据分析表明:使用NHC压裂液改造后储层产油量比胍胶压裂液提高7.55%以上,表明该压裂液对储层伤害较小,有利于维持储层的原始动态平衡。

In order to solve the problem that conventional fracturing fluid is not easy to be recycled,an NHC fracturing fluid was prepared.NHC fracturing fluid thickener was a kind of low molecular polysaccharide surface active agent,which had the dual function of the polysaccharide self-crosslinking and surfactant curling and winding.When the dosage of thickener agent BHC-2 was 0.4%-0.8%,the temperature and shear resistance of NHC fracturing fluid was 70-90℃.And the fracturing fluid could be obtained again by adding 0.3%to 0.7%BHC-2 in flowback fluid.Field tests showed that the pressure of fracturing fluid formed by adding 0.4%BHC-2 in clean water was stable during the construction.The crosslinked liquid formed again by adding 0.3%BHC-2 in flowback fluid could realize sand carrying fracturing.NHC fracturing fluid mix and recovery process was simple.In the fracturing section 7 of a well in Changqing Huachi oilfield,1435 m^(3) of the flowback fluid was recovered,and the recovery rate of the flowback fluid was 95.67%.The effective components in the flowback were well utilized,and the waste of water resources was reduced,which had good environmental protection effect.The later data analysis showed that the oil production of the reservoir increased by more than 7.55%after using NHC fracturing fluid compared with that of guanidine gum fracturing fluid,which indicated that the fracturing fluid had less damage to the reservoir and it was beneficial to maintain the original dynamic balance of the reservoir.