延缓型有机/无机复合交联剂LD-1的研制

CHROMIUM(Ⅵ) SALT/THIOUREA/SODIUM THIOSULFATE REDOX SYSTEM AS DELAYED CROSSLINKER FOR HPAM BASED AQUEOUS GELLING FLUIDS

LD 1是以铬盐 硫脲及铬盐 硫代硫酸钠两种氧化还原体系复合而成的一种延缓型交联剂。实验结果表明 ,单独使用铬盐 硫脲体系或铬盐 硫代硫酸钠体系作为聚丙烯酰胺溶液的交联剂配制堵水调剖剂时 ,均有交联时间难以控制或 48h不交联的问题。由这两种体系复合而成的LD 1用作交联剂时 ,堵水调剖剂成胶时间可调 (10— 30h) ,凝胶强度较高 [(5— 15 )× 10 4 mPa·s],具有明显的延缓交联效果 ,能满足现场施工要求。对LD 1的作用机理进行了探讨 ,认为诱导作用是LD

The crosslinker for HPAM based aqueous gelling fluids used in water shutoff and injection profile modification operations at Daqing Oil Fields is required to create strong bulk gels of viscosity 50—150 Pa·s at the reservoir temperature 45℃ in an adjustible time range of 10—30 hrs. It is shown in this paper that neither chromium(Ⅵ) salt/thiourea(TU) nor chromium(Ⅵ) salt/sodium thiosulfate(STS) redox systems can meet these requirements: the gelation time is difficult to adjust or is longer than 48 hrs. A combination of these two systems, i.e. Cr(Ⅵ)/TU/STS redox system, developed as crosslinker LD 1, can successfully be used in such gelling fluids. The reactions involved in Cr(Ⅲ) relieving are discussed.