Abstract: An injection process to treat sandstone or limestone subterranean formations using carboxylic acids, dicarboxylic acids and/or aminocarboxylic acids (e.g. glutamic acid N,N-diacetic acid (GLDA); methylglycine N,N-diacetic acid (MGDA); diethylene triamine pentaacetic acid (DTPA), etc.), further involves at least a two step injection process which may include, in one non-limiting embodiment, injecting a relatively higher concentration of organic acid to create wormholes accompanied by a relatively lower concentration of the same or different organic acid to enhance the permeability of the formation.

Abstract: A subterranean formation is treated to inhibit adsorption of asphaltenes by injecting a treatment fluid containing a sacrificial compound, such as a lignosulfonate. The lignosulfonate may be adsorbed onto formation surfaces in such a way as to act to inhibit the adsorption of asphaltenes. A pretreatment fluid for removing asphaltenes may be injected into the formation before the treatment fluid. The pretreatment fluid may contain an organic solvent, such as terpene.