新型低伤害聚合物压裂液的性能研究及评价

Study and Evaluation on the Performance of New Polymer FracturingFluid with Low Damage

针对目前水溶性聚合物压裂液不耐温、剪切稳定性差及植物胶压裂液成本高等问题,研究开发了一种新型的低伤害聚合物压裂液体系。新型低伤害聚合物压裂液体系在40~90℃之间的配方为:WH924聚合物+助排剂JX-D+破乳剂A+交联剂DZ-2,对配方进行性能评价,结果表明:在40℃、 60℃、 80℃、 90℃剪切时间为30~60min,黏度值仍保持在60mPa·s以上。配方中加入一定量的破胶剂B,在40~90℃时破胶效果良好,残渣含量为64~76 mg/L;破胶水化液表面张力在28mN/m以下、界面张力在2mN/m以下。压裂液滤失性能良好,45℃配方岩心伤害率为8%, 90℃配方岩心伤害率为12. 5%,说明新型低伤害聚合物压裂液对储层伤害率小。该聚合物压裂液体系在现场试验26口井,压裂增产效果良好,经过试验确定该压裂液体系适合用于渗透率不大于420mD的储层。新型低伤害聚合物压裂液的成功研制,解决了植物胶压裂液成本高的问题,为大庆低渗透油田储层压裂改造提供了技术支持和保障。

Due to the current water soluble polymer fracturing fluid being not resistant to high temperature,poor shear stability and high cost of vegetable gum fracturing fluid,a new fracturing fluid system with low damage has been developed.The formula of new polymer fluid system that being used between 40℃and 90℃includes WH924 polymer,cleanup additive JX-D,demulsifier A,and crosslinking agent DZ-2.The performance evaluation on its formula showed that the viscosity could be kept above 60mPa·s after shearing for 30 to 60 minutes at temperature 40℃,60℃,80℃,90℃respectively.When a certain amount of gel breaker B was added in the formula,the gel breaking effect was good at 40 to 90℃,and the residue content was 64~76 mg/L.The surface tension of gel breaker solution was less than 28 mN/m,and the interfacial tension was below 2 mN/m.The filtration of fracturing fluid performed very well,e.g.the core damage rate of the formula was 8%at 45℃and 12.5%at 90℃respectively,which means that the new polymer fracturing fluid with low damage has little damage to the reservoir.The polymer fracturing fluid system has been applied to 26 wells with satisfying stimulation effect,which is suitable for the reservoir with permeability less than 420mD.The successful development of the new polymer fracturing fluid with low damage can solve the high cost problem of vegetable gum fracturing fluid,and provide the technical support and guarantee for fracturing stimulation of low permeability oil reservoir in Daqing.