Microfibers are specially manufactured, acid soluble mineral fibers. The mineral fibers are long and flexible and will interlock to form a strong, dense filter cake. Microfibers are recommended for bridging and plugging voids and fractures. They are also the preferred choice to treat lost circulation in wells with high bottomhole temperatures. Microfibers are thermally stable in excess of 500°F and are compatible with fresh water, completion brines, and diesel oil based muds.