Abstract: A method of minimizing the weight loss of mass of the drilling pipe and wellbore casing while drilling a subterranean well with an oil-based drilling fluid comprising adding to the oil-based drilling fluid an anti-wear additive based on sulfated, sulfonated or sulfited natural oils or fats of vegetable or animal origin.

Abstract: Method for inhibiting the hydration of clays and shales during drilling operations comprising the use of a water base drilling fluid, which contains from 0.2 to 5% by weight of the condensation product of a dicarboxylic acid having 4 to 10 carbon atoms with alkanolamines, diamines or polyalkyleneamines of formula R??R?N—R?—XH, where X is O or NR0; R0 is hydrogen or a linear or branched alkyl group having from 1 to 6 carbon atoms, R? is a linear or branched, aliphatic or cicloaliphatic alkylene group having from 2 to 10 carbon atoms or R? is R??(NH—R??)n where R?? is ethylene or CH(CH3)CH2, n is a number from 1 to 6 and X is NR0; R? and R?? can be equal or different from one another and are hydrogen or a linear or branched alkyl group having from 1 to 6 carbon atoms, optionally substituted with a hydroxyl group, the condensation product being in neutral form or in the form of salt.