Application of Sidetracking in Casing in Guizhou Geothermal Drilling

Abstract:

Sticking accident happened at the drilling depth of 907.91m in Jiangxipo geothermal well, back-off was used after releasing failed, the remainded 75.53m drilling tool could not be taken out and the top end of the drilling tool was at the depth of 832.38m. It is necessary to adopt sidetracking to bypass the top end of the drilling tool for continue drilling. In the case of casing cementing completion, sidetracking window from inside casing was carried out with DXQ210/H type deflecting device selected as the deflecting tool and KCXZ216 type taper miller as milling tool. Based on the analysis on the general situation of the accident, the paper introduces the working principle of the deflecting device and the technical scheme of sidetracking window from inside the case and summarizes the attentions in the construction operation. The sidetracking is smoothly completed at the depth of 2364.56m.

Key words:Geothermal drilling; casing window; deflecting device; milling cone; side drill