PROCEDE ET AGENTS POUR LE CONTROLE DU GONFLEMENT DES ARGILES EN PRESENCE D'EAU DE MER ET BOUES A BASE D'ARGILE

Process for controlling the swelling of clays of bentonite type clays in the presence of salt-water in the preparation of drilling fluids, comprising the steps of selecting at least one compound from the group of salifiable active compounds comprising cyanamide, hexamethylenetetramine, guanidine and aminoguanidine, those having the formula: NH3-n[(CH2)m-OH]n (I) in which m is equal to 2, 3 or 4 and n to 1, 2 or 3 with the possibility, when m is equal to 3 or 4, of having a branched chain, those having the formula: NH2[(CH2)m-NH]n(CH2)m-NH2 (II) in which m is equal to 2, 3, 4, 5 or 6 and n is a whole number from 0 to 10, derivatives of formula (I) and (II), preparing a concentrated mixture, also called premix, of bentonite and soft water, diluting the premix with salt water up to the concentration desired for the drilling fluid, introducing in the premix or in the soft water used for its preparation, or in the premix diluted with salt water, or in the salt water used for diluting the premix, an effective amount of the said a least one active compound without satisfying the same, or introducing the at least one active compound after salification either in the salt water used for dilution of the premix or into the final diluted mixture or in the premix diluted with soft water.