IMPROVEMENT OF HYDROCHLORIC ACID FORMATION TREATMENT FOR VOLGO-URALS CARBONATES

Abstract

Background. At the present stage of development of the oil and gas industry, the structure of oil reserves in the Republic of Bashkortostan is deteriorating. The share of hard-to-recover oil reserves, including those associated with carbonate reservoirs, is increasing. More than 2 0 % of residual and hard-to-recover oil reserves of Bashkortostan are found in carbonate reservoirs. Productive deposits containing oil deposits have a complex geological structure. The development of these reserves will allow maintaining the current level of hydrocarbon production for a long time. The use of hydrochloric acid carbonate reservoirs treatment allows to increase the efficiency of exploitation of these deposits. However, oil deposits in carbonate reservoirs are often operated with an ineffective water flooding system or on a natural regime, which leads to a decrease in reservoir pressure in the bottomhole zone of producing wells. The use of standard hydrochloric acid treatment of production wells under these conditions proves ineffective. In this regard, studies have been conducted aimed at increasing the effectiveness of measures to intensify oil production, which, of course, is an urgent task. Aims and Objectives. Improvement of the hydrochloric acid treatment for Volga-Ural carbonate reservoirs in conditions of low reservoir pressure to increase the efficiency of the method of stimulation of the inflow to the wells. Metods. The mechanism of action of the acid solution on the productive reservoir is based on analytical methods of research. Determination of the rate of reaction of acid solutions with carbonate rock using reaction moderators and reagents is based on a generalization of the results of laboratory studies. Commercial types of research were used in experimental-industrial tests of the proposed method of hydrochloric acid exposure. The results of field work on the intensification of the inflow to production wells were processed using analytical and mathematical methods. Rezults. Based on the concept of the mechanism of the process of oil displacement from weakly permeable carbonate reservoirs, methods for treating the bottomhole zone of producing wells, including those for low reservoir pressure, are proposed. The results of the implementation of the proposed method made it possible to increase the production rate by more than 2 times in comparison with the treatment performed by traditional technology, and the duration of the effect from treatment was much larger. Conclusion. The application of the proposed methods of hydrochloric acid treatment during the intensification of the influx from the carbonate layers of the Bashkir and Vereiskian, Tournaisian stages, including for the conditions of low reservoir pressure in the Republic of Bashkortostan oil fields, will significantly improve the efficiency of the work.