关键词: 酸性堵水剂,    , 凝胶,    , 封堵性,    , 长庆油田

Abstract: Based on the acidizing principle of variable-viscosity acid,a acid blocking agent(DQ-3) was prepared with acid densifier as major raw materials,and with crosslinker and inhibitor as additives,to achieve combination of near-wellbore unblocking and far-wellbore blocking.The formula of acid blocking agent (DQ-3)is optimized:10% HCl,0.7% densifier,0.4% crosslinker and 0.05%inhibitor.Various performances of DQ-3 were evaluated by gel test (bottle test method) and core flow test.The results show that when residual acid concentration of DQ-3 system was less than 0.1% (pH=2~3),gel is formed under system reaction,and viscosity is more than 100 000mPa·s;DQ-3 system can resist temperature of 40~90℃,and is insensitive to salinity(above 10g/L);the core water blocking rate of DQ-3 is over 95%,whereas oil blocking rate is below 45%.

Key words: Acidic plugging agent,    , Gel,    , Plugging performance,    , Changqing oil fields