Abstract: Described herein are aqueous composition(s) containing water; a viscoelastic surfactant; an acid; and a water-soluble acid retarding agent. Further described are methods of making and using such compositions.

Abstract: Matrix acidizing treatment are designed and performed in a manner that takes into account radial acid flow into the formation. Subterranean well characteristics are determined (e.g., mineralogical and petrophysical characteristics). One of more candidate acids is selected. A linear pore volume of acid to breakthrough (PVBT) curve is generated for each candidate acid. The linear PVBT curves are modified to account for radial acid flow. The optimal acid is selected by considering wormhole development and cost. An initial acid pumping schedule is generated for the formation to be acidized, including the optimal acid, the treatment volume and the injection rate. Computer software is used to consider the subterranean well characteristics, simulate the initial acid pumping schedule and compare results with the radial PVBT curve. The initial schedule is modified until the results are consistent with the radial PVBT curve. An acidizing treatment is then performed.

Abstract: Matrix acidizing treatment are designed and performed in a manner that takes into account radial acid flow into the formation. Subterranean well characteristics are determined (e.g., mineralogical and petrophysical characteristics). One of more candidate acids is selected. A linear pore volume of acid to breakthrough (PVBT) curve is generated for each candidate acid. The linear PVBT curves are modified to account for radial acid flow. The optimal acid is selected by considering wormhole development and cost. An initial acid pumping schedule is generated for the formation to be acidized, including the optimal acid, the treatment volume and the injection rate. Computer software is used to consider the subterranean well characteristics, simulate the initial acid pumping schedule and compare results with the radial PVBT curve. The initial schedule is modified until the results are consistent with the radial PVBT curve. An acidizing treatment is then performed.

Abstract: Methods of treating a subterranean formation penetrated by a well bore, by diverting treatment fluid stages from zones of higher permeability to zones of lower permeability with an acid precursor material and fibers. The acid precursor material has an average particle size less than 1000 microns.

Abstract: Described herein are aqueous composition(s) containing water; a viscoelastic surfactant; an acid; and a water-soluble acid retarding agent. Further described are methods of making and using such compositions.

Abstract: Methods of treating a subterranean formation penetrated by a well bore, by diverting treatment fluid stages from zones of higher permeability to zones of lower permeability with an acid precursor material and fibers. The acid precursor material has an average particle size less than 1000 microns.