Paper: Field Evaluation of Gelled Acid For Carbonate Formations

A new gelled acid was evaluated in the West Texas, Southeast New Mexico and Oklahoma areas. The purpose of this evaluation was to determine how successful a gelled acid, prepared from xanthan polymer, would be in the following formations: Ellenburger, Blinebry, San Andres, Clearfork, Canyon Lime, Strawn Lime, Grayburg, Devonian, Drinkard Dolomite, Viola and Chester. Treatment depths vary from 4,000 to 22,000 ft. Treatment temperatures vary from 70_ to 310_F. Treatments were performed on both oil and gas wells. The age of the wells stimulated varies from new to 30 yr old. The concentration of gelled acid remained constant at 15% HCl. The concentration of gelling agent remained constant at 60 lb/1000 gal. The size of the treatments varied from 5,000 to 80,000 gal of gelled acid. More than 20 treatments are summarized. Several types of acidizing techniques were employed using gelled acid. These treatments vary from one to nine stages with and without diverting agents and with and without leakoff control additives. These treatments vary from 2 to 15 BPM. Some of these treatments contained 20/40 Sand, N2 and/or radioactive tracers. Production figures for the wells treated are discussed, as well as pertinent related information.