Aquifer Porous and permeable rock unit or unconsolidated layer in the subsurface in which all the pores and voids are filled with water. Water supply for wells comes from aquifers.

Basalt Dark grey fine grained volcanic rock composed of plagioclase, pyroxene and olivine, with relatively low silica (45-52 wt %). The composition reflects an upper mantle origin. Basalt...

BHA Refers to Bottom Hole Assembly, which is the system of tools at the bottom of the drill string that is used for drilling directional wells. The BHA includes the drill bit, mud motor,...