The PIC team calls on over 4 decades of experience in matrix stimulation to have successfully treated over 10,000 wells in 72 countries. This broad experience base has been paramount in maintaining over 90% success rate while the industry has fallen to less than 25% success. Matrix acidizing offers a treatment which removes acid soluble scale deposits, plugging fines and even reservoir rock to restore well productivity. The acid treatment is typically carried out at low pump rates so as not to exceed formation fracture pressure. The type and strength of acid or acids used is determined by the mineral composition of the scale, fines or rock to be removed. In the case of the "brown field" wells on the shelf in the Gulf of Mexico, hydrochloric acid (HCl) is often used for scale deposits. However, in a majority of cases, these wells are damaged with mobile fines of paraffin/asphaltene scales. Effective removal of this damaged is accomplished with hydrofluoric acid (HF). To improve the efficiency of these fluids, diverter stages are pumped ahead of a buffered HF stage. The strength of the HF is adjusted to just remove fines and not the reservoir rock. In addition to the optimized fluid stages, an engineered design is employed to determine pump rate and volumes so that only the near wellbore area is treated, reducing the risk of unwanted water.