影响锆冻胶成冻因素的研究

Studies on Influencing Factors for Formation of Aqueous Polyacrylamide/Zirconium Gel

本文研究的锆冻胶是聚丙烯酰胺 (PAM)由氧氯化锆 (ZrOCl2 )形成的锆的多核羟桥络离子交联而成的。研究了PAM溶液的 pH值、ZrOCl2 的质量分数、PAM的质量分数、温度、水解度、相对分子质量、矿化度等因素对锆冻胶的成冻时间和冻胶强度的影响。成冻时间和冻胶强度分别由转子旋转法和突破真空度法测定。研究结果表明 :在实验条件范围内 ,温度越高 ,PAM和ZrOCl2 的质量分数越大 ,水解度越低 ,相对分子质量越高 ,则锆冻胶的成冻时间均越短 ;而对于 pH值及矿化度 ,则存在最佳成冻范围 ,即pH值为 4— 6,矿化度为 8× 1 0 3— 4× 1 0 4mgL- 1时成冻时间最短。研究还证实 ,锆冻胶的成冻时间与冻胶强度的关系符合一般冻胶所遵循的规律 ,即成冻时间越短 ,冻胶的强度越高。锆冻胶在调剖堵水、酸化压裂、防砂等方面有重要的应用。

The aqueous polymer/zirconium gel, or shortly zirconium gel, studied in this work is formed through crosslinking aqueous solution of polyacrylamide(PAM) by multinuclear olation complex ion of zirconium originated from ZrOCl 2. The factors influencing on gelation time and gel strength dealed with are as follows: pH value and massfraction of PAM and ZrOCl 2 in the gelation system, temperature of gelation, degree of hydrolysis and relative molecular mass of the PAM used, and salinity of the system. The gelation time is determined by a revolving magneton method and the gel strength-through breakthrough vacuum measurements. IT is shown that within the limit of the experimental conditions the gelation time of the system becomes shorter when the temperature is getting higher, the massfraction of PAM and ZrOCl 2 taken increases, the degree of hydrolysis of PAM is getting lower or the ralative molecular mass of PAM is getting higher; the shortest gelation time is observed when the pH value is 4-6 and the salinity is in range 8×10 3-4×10 4 mg/L. To the Zr gel a general rule is appliable,too, i.e. the shorter the gelation time the higher the gel strength is. Zr gels can be used for injectivity profile modification and water shutoff, in reservoir acidizing and fracturing and for sand control.