Field evaluation of acid simulation diverter materials and placement methods in Arab-D injection wells with openhole completions

Hydrochloric acid (HCl) stimulation is a common method of removing shallow damage in carbonate formation completions resulting from drilling and workover operations. Current practice in the Ghawar Field is to bullhead large volumes of acid into the power water injection (PWI) wells to stimulate the long, open hole completions in the Arab-D formation. Small stages of particulate materials in a viscous carrying fluid are normally included in the treatment for diversion. This report describes the field testing and evaluation of three different acid treatment designs; (1) the conventional, bullhead treatment, (2) a coiled tubing placed, nitrogen foam diverted treatment and (3) a coiled tubing placed treatment without diverting materials. The treatment designs utilizing coiled tubing were developed in an effort to improve upon the conventional method by providing better formation damage removal throughout the entire porous interval and to reduce costs. A review of he conventional bullheading technique is presented along with case histories of wells that were stimulated with the two treatment techniques utilizing coiled tubing placement. The data presented indicates that the treatments combining coiled tubing placement and nitrogen foam diversion were more effective in stimulating the Arab-D formation and in improving injectivity than the conventional bullhead jobs.