Dictionary:Dirty

{{#category_index:D|dirty}} Shaly; containing appreciable amounts of shale dispersed in the interstices. Such shale lowers the permeability and effective porosity and affects the readings of many types of logs. A composite electrolyte system of clay and sand can be responsible for membrane polarization effects. Clay particles in the sand act as selective ion sieves and surface conduction along the clay minerals causes low resistivity.