The present invention provides a method of stimulating a subterranean
formation penetrated by a well. The formation has a water-bearing section
and a hydrocarbon-bearing section. The method includes the steps of: (a)
introducing into the formation an aqueous treatment fluid containing a
hydrophobically-modified relative permeability modifier, and (b)
introducing an acidizing treatment fluid into the formation. The
hydrophobically-modified RPM can be formed and introduced into the
formation in several ways. For example, the hydrophobically-modified RPM
can be the reaction product of a hydrophilic polymer and a hydrophobic
compound that are capable of reacting with each other. The hydrophilic
polymer is a polymer containing reactive amino groups in the polymer
backbone or as pendant groups, which are capable of reacting with a
hydrophobic alkyl halide compound. The hydrophobically-modified RPM can
include, for example, a polymer of DMAEMA quaternized with an alkyl
halide, wherein the alkyl halide has an alkyl chain length of 6 to 22
carbons.