CPC Subgroup
E21B 33/1204 Full Title
Sealing or packing boreholes or wells > in the borehole > Packers; Plugs (used for cementing E21B33/134, E21B33/16)
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E21B 33/1204 Sealing or packing boreholes or wells > in the borehole > Packers; Plugs (used for cementing E21B33/134, E21B33/16)