塔河油田成垢机理分析及复合除垢剂研究

摘要

通过对塔河油田成垢机理分析发现,塔河油田在注水开发过程中易形成垢物,主要为难溶性的钡锶硫酸盐和少量有机垢.以自制多羟基聚合物渗透分散防垢剂(PTMAS)为除垢辅剂,以己二胺四乙酸(EDTA)为螯合主剂,通过与适量KOH进行三元复配制,制备了复合除垢剂SS-1.其具体配比(质量分数)为PTMAS∶EDTA∶KOH∶H2O=1∶25∶21∶53.室内实验结果表明:在除垢液温度达到80℃时,SS-1可溶蚀近80％的垢物,温度达到120℃,除垢率接近100％;溶垢时间超过20 h后,除垢率超过80％,溶垢时间为36 h时,垢物几乎全部溶解;除垢率随pH值增大而上升,当pH=10时,除垢率为86.3％,pH=14时,除垢率更接近100％;NaCl和KCl对除垢率影响有限,当NaCl和KCl的质量分数均达到10％时,溶垢率未显著下降.配伍性实验结果证明,SS-1与现场常用处理剂实现良好配伍,可成功解决塔河油田井筒结垢的问题.%The analysis of mechanism of scale formation shows that sulfate scale is easy to form in water flooding process in the Tarim River Oilfield and the main components are sulfates of barium and strontium and organic scale.The compound descaling agent SS-1 is prepared;its composition is self-made polyhydroxy polymer scale inhibitor (PTMAS) as adjuvant,edetic acid (EDTA) as main agent,and KOH.The specific ratio (wt/wt) PTMAS∶EDTA∶KOH∶H2O is 1∶25∶21∶53.The results of the indoor experiment show that SS-1 could dissolve nearly 80％ of the scale when the temperature of the descaling liquid reaches 80 ℃.When the temperature of the descaling fluid reaches 120 ℃,the descaling rate is close to 100％.When the elution time exceeds 20 hours,the descaling rate is more than 80％ and the time 36 hours,the fouling is almost completely dissolved;the descaling rate increases with the increase of pH,with pH=10,the descaling rate is 86.3％.When pH=14,the descaling rate is closer to 100％.NaCl and KCl have limited effect on the decontamination rate,and when NaCl and KCl concentrations reach 10％,no significant decrease of descaling rate is observed.Compatibility experiment proves the compatibility of SS-1 and other agents used in the oilfield are excellent,which solves the scaling problem in the Tarim River Oilfield.