E
FIXED CONSTRUCTIONS
E
FIXED CONSTRUCTIONS
E21
EARTH OR ROCK DRILLING; MINING
E21
EARTH OR ROCK DRILLING; MINING
E21B
EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
E21B
EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
E21B43/00
Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
E21B43/00
Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
E21B43/11
Perforators; Permeators
E21B43/11
Perforators; Permeators
E21B43/112
Perforators with extendable perforating members, e.g. actuated by fluid means
E21B43/112
Perforators with extendable perforating members, e.g. actuated by fluid means