低伤害多羟基醇压裂液体系研究

针对长庆油气田超低渗透的储层特点,从减少稠化剂集团在储层中的滞留、降低压裂液对储层的基质渗透率和支撑裂缝的伤害出发,开发出一种新型低伤害、低成本的低聚合多羟基醇水基压裂液体系.该压裂液体系以低聚合多羟基醇为稠化剂,有机硼为交联剂,合成了一种释酸剂作破胶剂.通过室内实验确定了压裂液的最佳配方:低聚合多羟基醇质量分数为2.0%、交联剂质量分数为0.8%、pH值调节剂质量分数为0.16%,并对其性能进行了评价.评价结果表明,该压裂液体系具有很好的流变性和抗剪切性,滤失量小,破胶彻底和残渣低等优良性能,对储层伤害小于常规胍胶压裂液.因此,该压裂液体系具有很好的应用前景.

Development of a polyhydroxy alcohol fracturing fluid system with low reservoir damage

According to the characteristics of the ultra-low permeability reservoirs in Changqing oil and gas fields,in order to reduce the retention of thickener group in the reservoirs and decrease the damage of fracturing fluid to the permeability of the reservoir matrix and the cracks in the reservoirs,a polyhydroxy alcohol water-based fracturing fluid system with low molecular mass,low reservoir damage and low cost is developed.In the system,a polyhydroxy alcohol with low molecular mass is used as thickener,organic boron as crosslinker,and a synthesized acid releaser as gel breaker.The optimal formulation of the fracturing fluid system is determined by laboratory experiments:the mass fractions of polyhydroxy alcohol,the crosslinker and pH regulator are 2.0%,0.8% and 0.16% separately.The performance of the fracturing fluid system is evaluated.The evaluation results show that,the fracturing fluid system is of good temperature stability,shearing resistance and rheological property,and it is also of perfect gel-breaking capacity,less filter loss and lower reservoir damage than conventional guanidine glue fracturing fluid.So the fracturing fluid system has a good application prospects.