Analysis of the Acid Compositions Application in High-Temperature Carbonate Reservoirs

The use of hydrochloric acid treatment goes back a century. For the first time the company “Ohio Oil” applied acid for formation stimulation in 1895, and the patent for acidizing limestone was obtained by the company "Standard Oil". However, with a significant increase in production volumes, it turned out that acid solutions caused very strong corrosion of downhole equipment. Therefore, the hydrochloric acid treatment method had not been used for 30 years. The discovery by John Grib of “Dow Chemical” in 1931 – slowing down the effect of hydrochloric acid on the metal with arsenic – made it possible to return to this method, and three years later “Halliburton Oil Well Cementing” began to practice acidizing on an industrial scale. As the analysis of the field material has shown, there are many technologies with the use of modified acids intended for acidizing, which are characterized by a high degree of success. Nevertheless, according to the estimates of different authors, the treatments success varies in the range from 60 to 80%, and for repeated treatments – less than 50 %. The urgency degree of the problems associated with acid treatment of the bottomhole formation zone and the tendencies of its development was investigated. Analysis of patent information according to the International Patent Classification for 17 years (from 1997 to 2013 inclusive) for Russian patents and for 15 years (from 1999 to 2013 inclusive) – for American ones showed stable activity of Russian organizations, while foreign organizations showed in this respect a significant growth of interests and achievements. Foreign experts mainly investigated the modeling of acid treatment [6–11], while Russian specialists were more inclined towards service support of acid treatment. It was revealed that there were no methods for calculating the risks of falling out of heavy oil components during acid treatment, depending on the geological and physical conditions of the target.