| Abstract:A sticking accident occurred in HDR-1 well at a depth of 3,000 M in hot dry rock. After various treatments, bottom of hole still has more than 100m of “Falling fish”. Because of the difficulty, high risk and long period of fish falling in the casing-milling hole, it is decided to give up the casing-milling and adopt the method of sidetracking through the window to bypass the accident section. Through the comparison of three plans of sidetracking by using deflector in casing pipe,sidetracking with open hole cement plug and sidetracking with open hole deflector,
sidetracking with open hole cement plug is finally adopted.The successful application of sidetracking around the barrier is the first time in the construction of hot dry rock in China, and it overcomes the technical difficulties of large depth, large diameter,high temperature and high hardness, the advanced technology, such as measurement while drilling, complex power drilling technology and high temperature resistant mud, is applied to provide new technical support for hot dry rock scientific drilling and deep geothermal resources exploration in China. |