Research and Application of Gas-lift Reverse Circulation Drilling Technology to Geothermal Well Construction in Dalian Jiaoliu Island

This paper describes the principle of air-lift reverse circulation drilling, and its process feature, equipment selection, drilling assembly, drilling parameters and technical measures. Using the air-lift reverse circulation drilling, combined with geothermal well construction project in Dalian, a good solution was presented to the hole wall's stability problem that cannot be resolved by the conventional normal circulation and technology casing in that complex formation where are water bursting in the upper formation and collapse and falling in the lower strata.