During APR testing, pipe string would be stuck because of wellbore quality,
downhole tools, construction technology and other factors. When the attempt of releasing stuck of pipe string was unsuccessful, it was preferable
to select the RTTS safety joint above RTTS packer for releasing stuck and put forward the pipe string above the safety joint, so as to minimize
the string tools left in the wellbore for subsequent treatment. Combining with working principle and field case, the operation procedure of RTTS
safety joint release operation was improved. According to this operation procedure, two wells in the field realized the release of RTTS safety
joint, and the construction success rate was 100%. It provided technical reference for releasing stuck of APR test string.