Well Drilling Rig Wiki Knowledge
Difference between positive circulation and reverse circulation drilling rigs
(1) Positive circulation is to inject circulating mud from the drill pipe, and the drilling ballast floats in the mud due to its lighter specific gravity than the mud, and is discharged to the top of the hole with the mud. With the gradual increase of drilling ballast, the mud concentration is getting bigger and bigger, and because of the drilling residue precipitation and lead to repeated grinding, so the efficiency is low. But thick mud is good for drilling wall protection, not easy to collapse the hole, used for quicksand and other easy to collapse the hole soil layer is adaptable.
(2) Reverse circulation is the drilling rod sucking out the circulating mud with drilling ballast, and the top of the hole to replenish the mud to maintain the liquid level in the hole, so as to ensure the stability of the hole wall. Reverse circulation can greatly reduce the invalid labor of repeated grinding of drilling ballast, and can make drilling efficiency greatly improved. It is more suitable for rock layer, gravel and dense soil layer.
