Piping vs. Plugging as a Result of Clay Dispersion/Swelling in Porous Media

摘要

This text discusses the nature of clay dispersion and addresses two different outcomes which may result: piping and plugging. Two sequential steps of clay particle dispersion are reviewed: (1) detachment of particles from pore walls or surfaces of a seepage conduit; and (2) entrainment and migration of these particles in the seepage stream. The main variables that affect particle detachment and particle migration are examined, including particle/pore size ratio, clay content and mineralogy, and particle release rate. A capillary model is developed to predict the conditions under which piping vs. plugging is likely to occur as a result of clay particle dispersion.