a mixture of clays and chemicals and water; pumped down the drill pipe to lubricate and cool the drilling bit and to flush out the cuttings and to strengthen the sides of the hole
mestura de arxilas e produtos químicos e auga; prodúcese durante o bombeo do tubo de perforación para lubrificar e arrefriar a broca da perforación e para eliminar os cortes e reforzar as laterais do burato