低伤害小分子瓜尔胶压裂液性能研究

华北油田致密储层属于低孔低渗储层,需要压裂改造才能投产,但储层厚度小,孔吼半径小,在压裂过程中应特别关注入井流体对储层的伤害问题。提出采用分子量为常规瓜尔胶一半的小分子瓜尔胶作为压裂液的稠化剂的方法,以降低压裂液高分子稠化剂对储层孔吼的堵塞的伤害,提高改造效果。优选了与小分子瓜尔胶匹配的分散剂、助排剂、黏土稳定剂,形成了适应华北油田致密储层的低伤害小分子瓜尔胶压裂液体系。该压裂液体系可以在5 min内完全溶胀;该压裂液体系在130℃温度下剪切2 h后,黏度保持在80 m Pa·s以上,满足携砂的要求;压裂液体系在90℃可在90 min内完全破胶,破胶液粒径小于10μm;对华北油田致密岩心伤害率小于16%,残渣含量小于10%,对支撑剂导流带的伤害小于15%。可满足华北油田致密储层的压裂要求。

Research the properties of the low damage of low molecular weight guar gum

According to the characteristics of pore of the tight reservoir in Huabei Oilfield, try to use low molecular weight guar gum whose molecular weight is half of the regular guar gum as thicker of the fracturing fluids. Depend on the low molecular weight of guar gum, the damage rate which effects the reservoir is decreased and the stimulating efficiency are remarkabl. The dispersion agent, cleanup additive and clay stabilizer were confirmed based on the test results. The formulation of the fracturing fluids was obtained finally. This fracturing fluids is fit to stimulate the tight reservoir in Huabei Oilfield. After the fracturing fluid system was sheared for 2h in the 1300C, the viscosity of the system was maintained over 80mPa?s. The damage rate of the fracturing fluid to the tight rock is less than 16%, and the residue content is less than 10%.