In most cases of Tapered Bit accidents, the hard disk has not been dropped into the rock formation, or the orifice is not well fixed. So how to prevent casing accidents from happening?
1. Before running the casing, the slag in the hole should be washed clean;
- The casing must be lowered on the hard disk of the rock formation. Use a reducing drill to drill small holes first, and after the casing is installed, the bottom and the hole must be tightly sealed;
- For the casing in the hole, check whether the pipe and the thread are in good condition one by one. Excessive wear, large bending, etc. shall not be run into the hole;
- The threaded connection part of the casing should be sealed with adhesive to reduce the resistance when the casing is pulled out;
- For pinholes with cracks and karst caves, if the length of the karst cave is greater than the length of a single casing, a double-layer Drill pipe should be run.