Prevention of drilling hole collapse

Prevention of drilling hole collapse

The preventive measures for hole collapse should first meet two conditions: mud liquid column pressure = technological pore pressure; Minimize water infiltration into the rock and soil or water seepage around the hole wall.

Preventive measures for hole collapse caused by geological factors include:

(1) Increase the mud density and increase the mud liquid column pressure to balance the formation pressure;

(2) Use a larger ratio of mud to plastic to protect the hole.

Preventive measures for hole collapse caused by physical factors include:

(1) Start the pump too fast and keep the drill pipe working under constant tension as far as possible to avoid the sudden increase of liquid column pressure and the violent impact of drilling tools on the hole wall;

(2) According to the distribution of underground obstacles, the drilling track design and reaming procedure shall be well done to avoid the rotary extrusion of the drilling tool on the hole wall caused by the excessive curvature of the guide hole;

(3) Reasonably control the mud density and geological properties, make the mud have a certain liquid column pressure, and maintain the low return velocity of the mud