压裂液对宝浪低孔低渗储层伤害因素的研究

实验考察了压裂液对岩心膨胀及润湿吸附性的影响、压裂液浸泡对岩心的影响、压裂液矿化度和pH值以及压裂液破胶液粘度对储层伤害率的影响,结果表明,造成储层伤害的主要因素为：储层毛管阻力高,对水的润湿吸附严重,造成水锁伤害;压裂液在储层滞留时间长,岩心浸泡后粘土微粒运移对孔道伤害;压裂液破胶不彻底,当压裂液的破胶液粘度大于7 mPa·s时会造成储层的渗透率明显降低。不适当的压裂液矿化度和pH值也会对储层造成较大伤害,则压裂液KCl加量应大于2%,压裂液的破胶液和滤液pH值应小于11。

Research on Injury Factors of Fracturing Fluid to Low Porosity Low Permeability Reservoir in Baolang Oilfield

The effects of fracturing fluid on expansibility and wetting absorbability of rock cores, the effect of fracturing fluid immersion on rock cores, and the effects of salinity and pH value of fracturing fluid and viscosity of gel breaking fluid on reservoir injury were investigated. The result showed that the major injury factors to reservoir included water- locking damage due to high resistance of reservoir capillary tube and severe water wetting absorption, pore damage due to clay particle migration after fracturing fluid was retained in reservoir and rock core was immersed for a long time, and reservoir permeability reduction due to incomplete gel breaking of fracturing fluid when viscosity of gel breaking fluid of fracturing fluid was higher than 7 mPa. s. Improper salinity and pH value of fracturing fluid also damaged reservoir obviously, so adding amount of KCI in fracturing fluid should be greater than 2% and pH value of gel breaking fluid and filtrate of fracturing fluid should be less than 11.