准饱和盐水基免配缔合交联压裂液的研究及应用

Association Cross-linked Fracturing Fluid with Ultra-high Salt Resistant Suitable for On-line Preparation

玛湖风城组含有大量可溶性碱盐,特殊储层压后压降快、堵塞井筒严重影响试油。为了验证入井压裂液对储层盐矿溶蚀是否会造成影响,基于风城组储层典型碱盐矿组成特点,模拟不同配液水对储层盐矿溶蚀影响,构建了一套耐温(120℃)、抗高盐(30×10^(4)mg/L)免配聚合物交联压裂液体系,并进行现场试验。结果表明:高盐水较自来水对典型模拟盐的抑溶率达到60%以上;以悬浮基疏水缔合聚合物溶液“链间缠结+缔合作用+盐效应”协同作用实现增稠剂速溶、高效增黏,并与多元络合离子为核心的有机硼锆铝缓交联剂以化学交联原理形成了耐温耐高盐的免配交联压裂液体系,最优配方为1.8%稠化剂GAF-TE+0.4%交联剂JL-3+0.3%增效剂GF15B+0.04%破胶剂APS,在120℃、170 s^(-1)下剪切1 h后的黏度大于100 mPa·s,具有良好的悬砂和携砂能力。现场M井压裂施工3层,成功率为100%,压后顺利完成试油,最高日产油4.4 m~3。采用高盐压裂液体系在抑制储层溶蚀减缓地层压降快具有一定效果。

The rapid pressure drop and salt deposit in wellbore after fracturing in the special reservoir containing a large amount of soluble alkali salt in the Mahu Fengcheng Formation,seriously affected the oil testing.In order to verify whether the fracturing fluid entering the well would have an impact on the dissolution of the reservoir salt mineral,the impact of different inflow fluids on the dissolution of the reservoir salt mineral was simulated,the cross-linked fracturing fluid system with on-line preparation,temperature resistance(120℃)and salt 4 resistance(30×10 mg/L)was constructed and field tests was carried out based on the composition characteristics of the typical alkali salt mineral in the Fengcheng Formation reservoir.The results showed that the rate of dissolution high salt water to typical simulated salt was more than 60%compared with that of tap water.The“molecule interchain entanglement+association+salt effect”of suspension based hydrophobically associating polymer solution could be realized,resulting in the rapid dissolution and high viscosity increase of the base solution,and the cross-linked fracturing fluid system with on-line preparation,temperature resistance and salt resistance was formed between the thicken agent and the organic boron-zirconium-aluminum slow crosslinking agent by chemical crosslinking.The optimal formula was as follows,1.8%thickener GAF-TE+0.4%crosslinker JL-3+0.3%synergist GF15B+0.04%gel breaker APS.The shear viscosity of the system was greater than 100 mPa·s after sheared for 1 hour at the temperature of 120℃and at the shear rate of 170 s-1,exhibiting good dynamic and static sand carrying capacity.The well M(three layers)fracturing were successfully constructed on site.the oil test after fracturing was successfully completed,and the maximum daily oil production was 4.4 m3.The high-salt fracturing fluid system had certain positive effect on the reduction of formation pressure drop due to reservoir dissolution.