关键词: 钻井液, 自乳化, 乳油, 纳米粒子, 稳定性, 润滑性

Abstract:

To solve the emulsion stability problem of paraffin emulsion in drilling fluid, which is easy to demulsification and agglomeration, a paraffin emulsifiable concentrate (EC) with an effective component of 100% was prepared by using compound emulsifiers under certain conditions. In order to improve the lubricity of paraffin EC, nano silica microspheres were preprocessed by kneading drying process and dispersed to the EC system with special dispersant and stabilizer. The stability test showed that the fully suspended nano silica microspheres had good thermal stability and mechanical stability. Compared with the traditional paraffin emulsion, paraffin EC has higher storage stability and ease of use. It can be mixed with water at any ratio to form O/W paraffin emulsion. Performance tests showed that: when 1% paraffin EC was added to the fresh polysulfonate drilling fluid system. the API filtrate loss decreased by 33.8% and the lubricating coefficient decreased by 28.6%. Added 5% salt water polysulfonate drilling fluid system, the API filtrate loss decreased by 26.7%, and the lubricating coefficient reduction rate was 23.4%. Paraffin EC has good compatibility with polysulfonate drilling fluid system and can completely replace traditional paraffin emulsion. Paraffin EC has been tested in the well Bei8 of Songliao Basin. The results showed that the wellbore of Bei8 was stable, the lubricity of drilling fluid was improved obviously, achieved the experimental goals.

Key words: drilling fluid, self-emulsification, emulsifiable concentrate, nanoparticles, stability, lubricity