Influence Factors on the Water Sensitivity of the Sand Media

摘要

The influence of water sensitivity on some fields such as petroleum, geotechnical, environmental and chemical engineering has been considered. But it was rarely studied how it affected the permeability of saltwater-freshwater interface. Experiments were conducted to research the effect of flow rate, salinity, pH and Ca2+ ion on water sensitivity of saltwater-freshwater interface. The results of batch and sand-column experiments indicated that: (a) there was an effect of hydrodynamics on the clay particle release from pore surfaces; (b) there was a critical salt concentration, above which, no clay particles would release from pore surfaces; (c) in alkaline solution, the released particles concentration and the total quantity were higher than that at acidic pH values and neutral ones; (d) the Ca2+ ion was less effective for water sensitivity than Na+ ion. The release of particles could result in the permeability reduction of aquifers. Sand-columns’ water shock experiments were conducted to compare with batch experiments in order to identify the results. Two groups’ experiments were conducted to compare each other, and the results with good agreement indicated that the dates of above experiments were reliable and effective.