The Physical Reasons to Have Underdamped or Oscillating Variable-Head (Slug) Tests: A Review and a Clarification

Variable-head permeability tests are performed in monitoring wells (MWs) or open holes between packers to assess the local value of hydraulic conductivity, K, of gravel, sand, and fractured rock. This article examines physical reasons for having an oscillating water level in the riser pipe, called underdamped (UD) response. The UD solutions are incomplete because they solve one half of the problem—for the water in the pipe—and ignore the second...