缓交联铬冻胶体系影响因素分析

缓交联铬冻胶体系由部分水解聚丙烯酰胺、重铬酸钠与有机还原剂硫脲组成。由于硫脲的还原能力弱 ,因此该体系成冻时间较长 ,其终冻时间长达 8～ 10d ,可用于油藏的深部调剖。分析了铬冻胶的形成过程 ,通过测定成冻时间 (包括初冻时间及终冻时间 )和突破真空度评价了各种因素的影响。研究结果表明 ,随着交联剂质量分数的减少、pH值的升高 ,铬冻胶体系的成冻时间延长 ,强度增大 ;随着部分水解聚丙烯酰胺质量分数的增大 ,成冻时间缩短 ,强度增大 ;随着温度的升高 ,成冻时间缩短 ,强度变化不大

Influencing factors on chromium gel system of retarded crosslinking

A kind of chromium gel system of retarded crosslinking made of partially hydrolyzed polyacrylamide(HPAM), sodium bichromate and organic reductant sulfocarbamide was investigated. Because of the weak reduction ability of sulfocarbamide,the gelation time of the system is longer. Especially the final gelation time may be from eight days to ten days,thus this system is fit the deep profile control. The formation process of chromium gel was analyzed, and its various influent factors were evaluated by determining the gelation time (including initial gelation time and final gelation time) and breakthrough vacuum value. It is shown that gelation time is getting longer along with the mass fraction of crosslinking agent getting smaller and pH value getting bigger, and the system strength is getting stronger (that is also because the breakthrough vacuum value is getting bigger). The gelation time is getting shorter,and the strength is getting stronger with the mass fraction of HPAM getting bigger. The gelation time is getting shorter, and the strength has a little change with the temperature rising.