非离子微乳液制备及其对钻井液堵塞的解除作用

Preparation of Nonionic Micro Emulsion and Its Application in Removing Mud Solids Blocking

针对钻井过程中存在的固相堵塞、水锁、粗乳液、近井壁地带润湿性等伤害严重问题,基于乙二醇辛基苯基醚的非离子微乳液,对微乳液的性能进行了表征,并考察了微乳液对钻井液堵塞的解除作用。研究表明,研制的微乳液具有界面张力小于0.1 m N/m、可快速增溶高黏原油,pH值、离子类型、矿化度和温度对其增溶能力影响小等特点。实验结果表明,微乳液可有效清除乳液堵塞,清除泥饼中的原油分子,使孔隙的润湿性发生反转,从而恢复储层渗透率;微乳液解堵效率高,泥饼清除效率大于90%,渗透率恢复值在95%以上。

Formation damages existed in drilling operations include particle blocking, water blocking, coarse emulsion, wettability in the near-wellbore area. A non-ionic micro emulsion formulated with glycol ethylene octylphenyl ether has been studied on its efficiency in removing blocking caused by mud solids particles. The micro emulsion has interface tension less than 0.1 mN/m, and can fast solubilize highly viscous crude oils. The pH value, ionic type and salinity of the micro emulsion as well as temperature have little effect on the solubilizing power of the micro emulsion. Laboratory experiments show that this micro emulsion can remove emulsion blocking in the formations and crude oil in mud cakes effectively. It helps restore the permeability of reservoir formations by wettability reversal. 90% of mud cakes can be removed by this emulsion, and the rate of permeability recovery can be as high as 95%.