Mud ring wrapping means that rock dust (chips) adheres to the surface of the drilling tool or the borehole wall to form a mud ring and wrap the drilling tool when the water well drilling rig works. After the mud ring is formed, the annular space becomes smaller and the debris is not smoothly removed and continues to gather at the mud ring to form mud packs, which can completely block the wellbore in severe cases, causing sticking and buried drilling accidents.
Stratigraphic factors: micro water gushing and moist formations. The micro water gushing in the formation forms a liquid film on the well wall and makes the rock dust wet. The liquid film and the rock dust on the well wall bond to each other to form a cuttings group. The cuttings group cannot be completely carried out of the wellbore by air. The mud ring is formed by the adhesion and accumulation of the shaft wall and the hammer head, and the phenomenon of the adhesion and aggregation of the mud mass into the mud ring is particularly serious.
Process factors: insufficient equipment configuration; unreasonable drilling tool selection and combination; improper drilling technology; improper operation.
(1) Replace the drilling process. When the formation is wet with a small amount of water seepage, the limestone, dolomite and other rock formations are drilled by atomization (water injection dilution).
(2) Frequent chip removal. Every 0.5~1m of drilling, the drilling tool is lifted away from the bottom of the well for slagging.
(3) Increase the air compressor. Increase the air supply, increase the return air speed, and enhance the sand discharge effect.
(4) Reasonably configure drilling tools. Use reasonable drill collars and drill pipes.
(5)Short-distance tripping to mark the well wall. Prevent the formation and thickening of the mud ring on the shaft wall.