Expandable convoluted tubing technology has been applied in the field of petroleum drilling both in China and abroad, but the research on small diameter expandable convoluted tubing in the field of geological drilling has little effect. In this case, mall diameter expandable convoluted tubing technology for geological drilling industry is researched and developed, which has been successfully applied in sealing up the leaky stratum in ZK3-1 drilling in Sichuan coal survey, then drilling to the final depth. This application is a new field for the accident treatment in geological drilling industry, which fills the gap in the field of small diameter expandable convoluted tubing in China.