Field study of sandstone acidizing

This study was made to determine what factors most influence sandstone acidizing success and production response in field treatments. A statistical analysis of 222 treatments in both oil and gas wells in fields along the Gulf Coast and west coast show that the most critical factors to successful stimulation are mud acid volume and treating pressure. The optimum response was obtained with mud acid volumes in the range of 125 to 200 gal/ft of perforated interval and the poorest treatment response occurred when acid was injected at pressures in excess of fracturing pressure. Treatments employing certain surfactants appeared to stimulate water preferentially while those employing a mutual solvent without a surfactant preferentially stimulated oil or did not change watercut. In areas containing highly asphaltic crudes, an aromatic solvent was found to be beneficial.