摘要 |
A well cleaning tool adapted for connection to a drill string for removing debris and residues from the inner wall of a well casing, comprises an elongate generally cylindrical member (1) having a plurality of scratching elements (2) in the outer surface thereof. First and second helical channels or grooves (3 and 4) are defined in the outer surface of the cylindrical member (1) between the scratching elements (2), the second helical channel or groove (4) running in the counter direction to the first helical channel or groove (3).
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