the technical name for a suspension of clay in water, used as a flushing liquid in well drilling.
Clay mortar is prepared in a special device either from powdered clay or from lumps of clay. Sometimes, it is made in the drill hole from clay previously drilled up. The properties of clay mortar differ under the influence of drilled rock, temperature, and so on. To achieve the desired properties, various chemical reagents and heavy mineral powders (such as weighting compounds, petroleum, or other agents) are added. The clay mortar is pumped into the drill hole through the boring tube, adheres to drilled rock particles, and brings them to the surface. After the clay mortar is cleaned of rock particles, it is pumped back into the drill hole. In flux, clay mortar has the properties of a liquid; in rest, of a solid body. By being filtered to a fluid state through the porous walls of the drill hole, the clay mortar forms a thin low-permeable shield that hinders the formation of gas, oil, and water flows, prevents collapse of the wall of the drill hole and jamming of the drilling pipe, turns the face motor-turbobore, cools the bit, and allows more intense drilling.
S. IU. ZHUKHOVITSKII