Application of sidetracking to obstacle bypassing in hot dry rock Well HDR-1

Abstract:

A sticking incident happened in HDR-1 well at a depth of 3000m in hot dry rock. After various treatments， over 100m long “lost fish” still remained downhole. With the casing-milling method to continue to deal with the fish， it may lead to great difficulty， high risk and long period. After trade-offs of various methods， it is decided to adopt the method of sidetracking to bypass the incident section. Through the comparison of three plans of sidetracking with the deflector inside casing， sidetracking from the open hole cement plug and sidetracking with the open hole deflector， sidetracking from the open hole cement plug was finally adopted. The successful application of sidetracking around the barrier is the first time in hot dry rock drilling in China， which has overcome the technical difficulties of large depth， large diameter，high temperature and high hardness， and applied advanced technology， such as measurement while drilling， complex power drilling technology， high temperature resistant mud， providing new technical support for hot dry rock scientific drilling and deep geothermal resource exploration in China.