Disclosed are acid fracturing methods for subterranean siliceous formations employing a viscous dissolving fluid to create a permeable conduit that bypasses the near wellbore damage. The viscous dissolving fluids used according to the invention are acid-fracturing treatment fluids containing a dissolving agent viscosified with a material such as a viscoelastic surfactant, and the fluid is injected into a sandstone formation at a pressure sufficient to create a hydraulic fracture. Also, the viscous dissolving fluid leaks off into the faces of the fracture thus "stimulating" the formation. Hence when the hydraulic fracture has closed there is a part of the formation that has been effectively stimulated, creating a pathway for fluids to preferentially flow to the wellbore. The formation may then be flowed back to produce a substantial volume of the treatment fluid.