Following the advent of acid stimulation of oil wells in the late 19^th century, the field of acidizing has experienced periods of rapid technology and commercial development – followed by extended periods of stagnation – sometimes inexplicably. The industry again finds itself in a period of new technology need and innovation – to address the increasing challenges of stimulating both sandstone and carbonate formations, especially in long vertical and horizontal completions, and under extreme down-hole conditions.

The presentation begins with a brief discussion of carbonate and sandstone stimulation categories and current philosophies, followed by a brief summary of the interesting history acidizing. The principal focus of the presentation is on new matrix and fracture acidizing fluid technologies – their applications and limitations – with a view and emphasis on industry needs and direction for the future.