METHODOLOGICAL ASPECTS OF THE STUDY OF THE RATE CONSTANT OF THE REACTION OF HYDROCHLORIC ACID WITH CARBONATE FORMATION ROCK

Hydrochloric acid treatments are most widely used to intensify oil production from carbonate reservoirs. But despite a wealth of experience in the use of hydrochloric acid treatments, the results of treatments often do not reach the planned values of oil production growth. Efficiency of acid exposure depends on the depth of penetration of the hydrochloric acid solution into the thickness of the productive reservoir, which, in turn, is conditioned by the degree of reactive activity of the acid composition. It is important to achieve the creation of filtration channels in the zone remote from the borehole, which will lead to an improvement in the filtration characteristics of the bottomhole formation zone to the proper extent. Therefore, in order to achieve the best result when planning acid exposure, it is important to consider the geological and physical properties of the object to be treated and select the appropriate formulation of the acid composition. The reaction rate constant is a parameter that allows you to take into account the compatibility of the acid composition and the geological and physical conditions of the productive reservoir. This parameter characterizes the rate of reaction between substances. However, a generally accepted method for studying the kinetic parameters of the reaction of acid compositions with carbonate formation rock has not yet been developed, which leads to low reproducibility of experimental results. The purpose of the research presented in the article is to develop a methodology for studying the kinetics of the reaction of hydrochloric acid with carbonate rock and to create a unified approach to determining the reaction rate constant, characterized by the greatest reproducibility of the results. The experimental part of the work was carried out in several stages, including the preparation of core material, the preparation of hydrochloric acid solution and its thermostating, and the further conducting of four series of studies at the PIK-OSG volumetric setup to determine the optimal acid-rock ratio, identify the optimal weight of the core material and establish the optimal coarseness of its grinding. The obtained results of experiments on the study of methodological aspects of the study of the rate constant of the reaction of hydrochloric acid with carbonate rock showed that the experiments should be conducted in conditions of an excess of rock relative to acid, in this case the mass of the core sample and the coarseness of the grinding of the core material will not affect the error in determining the reaction rate constant.