空气钻井地层出水处理技术

利用空气钻含水地层,地层水会流入井眼,干燥的岩屑吸水很容易黏糊成团并附着在井壁和钻具上形成泥环,从而造成卡钻现象。基于低表面张力快速渗透分散破坏泥团原理,采用静态表面张力测定、润湿角测定、定时面积法、圆片帆布法、滚动回收率测定以及粒度分布测定等评价方法对9种表面活性剂的渗透性、分散性进行评价。可以看出,它们都有一定的润湿效果;结构中含有带支链的疏水基且亲水基小的表面活性剂渗透性强;阴离子表面活性剂的分散原理是双电层理论,非离子表面活性剂的分散原理是空间位阻效应,高分子分散剂比普通表面活性剂分散效果好。实验结果表明,加入CJY后的柴油溶液具有强渗透性和强分散性,碎解、破坏黏土泥团效率比油基解卡剂JKZ高,且温度越高,破坏程度越高,碎解效果越明显,对于解决空气钻井地层出水问题提供了依据。 

Treatment of Formation Water Invasion in Air Drilling

A serious concern in air drilling is the invasion of formation water into the hole, viscosifying the dry cuttings into viscous lumps which are adhered at the surface of the drill string and borehole wall, resulting in pipe sticking. Based on the mechanism that fluid with low surface tension can penetrate fast into and break the lumps, 9 surfactants was selected for the evaluation of their osmosis, and dispersing performance using static measurement of surface tension, wetting angle measurement, timing-area method, area measurement in specific time span, round fabric method, hot rolling test method and particle size distribution measurement. The 9 surfactants tested all had wetting ability. Surfactants with smaller hydrophobic groups in their molecular structures had strong osmosis. The dispersity of anionic surfactants is governed by the electric double layer theory, while the dispersity of nonionic surfactants is governed by steric effect. High molecular weight polymers have better dispersity than common surfactants. Laboratory experimental results showed that diesel oil treated with CJY had strong osmosis and dispersity, making it a better chemical in disintegrating mud lumps than oil based pipe sticking agent JKZ. Diesel oil treated with CJY performed better at elevated temperatures. This study provides a method for the solution of formation water cut during air drilling.