Flocculation
Flocculation is the process where clays, polymers, or other charged particles become attached and form a fragile structure. After the clay is depressed in the mud system, the platelets arrange themselves according to their electrical surface charges. Positively charged edge to negatively charged face and floc together.
Flocculation is not desirable, since it results in a high yield point and high gel strength. Common causes of flocculation are high ionic strength, a high concentration of shale in the mud and high temperature, or contamination with an influx from the formations. Deflocculants are used for neutralizing the charges on the clay surfaces.