Abstract: The drilling operations in Yun’an-1 well was interrupted because of confrontation of massive overthrust faults. In order to achieve the designed exploration purpose, a side track operation was conducted with cable measurement instrument and single shot instrument starting from the depth of 4,000 m to the final depth of 5,810 m. The target point designed was accurately shot. This was the deepest horizontal well in the Eastern area of Sichuan Basin. A better than before technical-economical results and social effects were obtained in this well.