新型抗高温二次交联凝胶堵漏材料的研制

Development of A Novel Two-step Crosslinking Gel with High Temperature Resistance for Plugging Lost Circulation

针对普通凝胶抗温能力较差难以适用于高温地层堵漏作业的问题,通过设计合成抗高温凝胶主剂GN-1并运用二次交联技术,研发了新型抗高温凝胶堵漏材料。优选配方为:淡水+1.5%GN-1+0.15%地面交联剂+1%井下交联剂+0.2%抗氧化剂。通过热滚老化与高温流变测试相结合的手段对凝胶抗温能力进行评价。结果表明,该凝胶材料具有良好的热稳定性,在180℃下老化24 h后,7.34 s-1下剪切粘度>10000 m Pa·s。大幅加重后180℃老化24 h仍能保持较好的粘弹性。此外还考察了不同温度和p H值下的成胶性能以及与聚磺钻井液体系的配伍性,为抗高温凝胶堵漏材料在现场的应用奠定基础。

For plugging lost circulation in high temperature formations, normal gels with lower thermal stability are unable to be applied. To solve the problem, a novel two-step crosslinking gel containing thermal stable polymer GN - 1 was devel- oped, which performed high temperature resistance. The optimized gel system is fresh water ＋ 1.5% GN - 1 ＋ 0. 15% ground crosslinkers ＋ 1% downhole crosslinkers ＋ 0. 2% antioxidant. Thermal stability of the gel was evaluated via hot roll- ing and high temperature rheologieal measurement. After hot rolling at 180℃ for 24h, the shear viscosity of the gel at the rate of 7. 34s^-1 was above 10000mPa·s. The viscoelasticity of the high-density gel system remained good after aging for 24h under 180℃. The results showed that the gel had excellent heat-resisting property. The influence of environmental temperature and pH value to gelling performance and the compatibility with polysulfonate drilling fluid system was also discussed, which was very helpful to operation in future.