Watermelon string mill shoes downhole tools
Watermelon string shoe is one of the milling tools in sidetracking operation. It is used for repairing casing, reaming and opening channels. It is usually used immediately after opening windows. The milling edge (working area) of the watermelon mill contacts the borehole wall, and the end of each edge is designed as a cone. When the window is being opened, the watermelon stubg mill ccan lengthen the window from the top and remove the scaling and burrs left on 
the pipe wall during the initial cutting.
Tab.4 Watermelon string mill parameter
Borehole Dia. | Screw Thread | Working Area OD (mm/in) | Working Area Length | Totul Length |
139.7 (5-1/2) | 2 7/8 REG (NC 26) | 112 (4-7/16) | 600 (23-5/8) | 1130 (44) |
139.7 (5-1/2) | 2 7/8 REG (NC 26) | 116 (4-9/16) | 600 (23-5/8) | 1130 (44) |
139.7 (5-1/2) | 2 7/8 REG (NC 26) | 118 (4-5/8) | 600 (23-5/8) | 1130 (44) |
139.7 (5-1/2) | NC 31 | 120 (4-3/4) | 600 (23-5/8) | 1280 (50) |
146.0 (5-3/4) | NC 31 | 124 (4-7/8) | 600 (23-5/8) | 1280 (50) |
168.3 (6-5/8) | 3 1/2 REG (NC 31) | 142 (5-9/16) | 600 (23-5/8) | 1280 (50) |
177.8 (7) | 3 1/2 REG (NC 31) | 151 (5-15/16) | 600 (23-5/8) | 1280 (50) |