A water-bearing rock strata. In a water-drive field the aquifer is the water zone of a reservoir, underlying the oil zone. When wells are drilled in the reservoir, the water pushes the oil toward the wells boreholes. If the wells are produced at an excessive rate the water may bypass the oil and break into the well bore, leaving much of the oil behind. See Channeling, also Water Coning. aquifer 1. a rock that contains water. 2. the part of a water-drive reservoir that contains the water.
