气体钻井后井筒预处理井壁稳定技术

气体钻井技术在提高川东北地区陆相地层钻速、有效防止地层漏失等方面作用显著，但实践过程中存在气体钻井后气液转化过程中的井壁失稳等问题。分析了川东北地区气体钻井后井壁垮塌的原因，探讨了疏水性处理剂对地层岩石表面润湿特性的改变机理，进行了润湿反转剂配方优选和室内试验研究。在川东北地区的多口井进行现场应用后，井壁稳定性明显好转，气液转换时间缩短，初步形成了适合川东北陆相地层地质特点的气液转换井壁稳定技术。试验表明，井筒预处理技术可以提高气液转换施工过程中的井壁稳定性，有效避免泥页岩地层快速吸水失稳垮塌后井下复杂情况发生。

Hole stability technologies for bore hole pretreatment after gas drilling

The cause of wall collapse after gas drilling in the northeastern area of Sichuan is analyzed, the vibration mechanism of the wettability properties of surface of rock in the formation affected by hydrophobic treatment agent is discussed, the optimization and lab experimental study of wettability reversing agents are conducted. After applying the agents to multiple wells in the northeastern area of Sichuan, the hole gets more stable, and the time of gas-liquid conversion is shortened. And the gas-liquid conversion well stability technology appropriate for the geological characteristics of the terrestrial formation of northeastern Sichuan is primarily developed. Test shows that the bore hole pretreatment technology can improve the hole stability during the process of gas-liquid conversion, preventing the complicated downhole conditions caused by collapse of mud shale formations caused by rapid water absorption.