Shale hydration inhibitors and subterranean treatment fluids containing them

A method for inhibiting the swelling and/or the dispersion of shales during the treatment of subterranean shale formations comprising the steps of:

• a) providing a subterranean treatment fluid comprising from 0.001 to 10% by weight (wt %) of a polyester obtained by reacting a dicarboxylic acid having from 2 to 8 carbon atoms with an alkoxylated diamine of Formula (I)
• wherein:
• R1 and R2 are equal or different and are saturated or unsaturated aliphatic C1-C4 alkyl chains;
• n is an integer number comprised between 1 and 5;
• EO is CH2CH2O;
• PO is CH2CH(CH3)O;
• o, p, q and r are integer numbers comprised between 0 and 10, with the proviso that:
• i) the sum of o, p, q and r is at least 2
• ii) o and p cannot be both equal to 0
• iii) q and r cannot be both equal to 0;
• b) introducing said treatment fluid into a wellbore at a pressure sufficient to treat the subterranean shale formations.