用于水窜通道堵水的超细水泥浆体系

Ultra-Fine Cement Slurry System for Plugging Water Channelling

利用超细水泥浆实现水窜通道深部堵水,需解决堵剂的深部注入性问题,而注入性能与堵剂的悬浮性和分散性密切相关。选用钠基膨润土(NT)水化胶体溶液作为堵剂的基础悬浮液,并考察了钠土水化规律。实验发现,钠土加量、水化时间、碱性环境、水泥外加剂对钠土水化胶体体系的影响显著,预水化5%单一钠土悬浮液30min以上,即可获得悬浮性能稳定的堵剂基础悬浮液。在基础悬浮液中加入30%超细水泥(XC),考察分散剂(CF)、降失水剂(CG)和改性乳胶(BCT)对堵剂分散性能的影响,配合中温缓凝剂(CH),得到可深部注入的超细水泥浆堵剂配方(初凝时间5 h):30%XC+5%NT+0.75%CF+2%CG+5%BCT+0.5%CH。模拟试验中的平均注入压力为0.289 MPa,表明该配方可用于水窜通道深部堵水。

Ultra-fine cement slurry was used to plug water channeling deeply.The injection performance and system performance of suspension and dispersion were closely related.Sodium bentonite（NT） hydration colloidal solution was chosen as the foundation of suspension and its hydration law was studied.The results showed that the hydration solution of NT was affected remarkably by the concentration of NT,hydration time,alkaline environment and cement additives.A base solution with stable suspension was obtained by prehydration 5% NT solution over 30 min.30% ultra-fine cement（XC） was added to the base solution and the influence of dispersant（CF）,fluid loss control agent（CG） and modified latex（BCT） on the dispersion was researched.The best formula of the fine cement slurry deep plugging agent was： 30% XC＋5% NT＋0.75% CF＋2% CG＋5% BCT＋0.5% temperature retarder（CH）,and the initial setting time was of 5 hrs.The average injection pressure in plugging water channeling simulation experiment was of 0.289 MPa,which indicated the feasibility of the system formula.