ANALYSIS OF THE EFFICIENCY OF CARBON DIOXIDE INJECTION INTO CARBONATE FORMATIONS

Abstract

This article raises the issue of development of deposits whose formations are composed of carbonate rocks. The low porosity and permeability of carbonate strata result in low oil production from these reservoirs. Therefore, these fields need to use enhanced recovery methods. A number of methods that have been relevant in the past do not achieve the desired result, so it is necessary to study in more detail new methods for increasing oil recovery. This paper discusses one of these methods for optimizing production, namely injection of carbon dioxide into the formation in order to increase the oil production of the formations. As you know, when injecting gas into the formation, in particular carbon dioxide, there are two main modes of oil displacement: the immiscible displacement mode, in which the gas is in a gaseous form and acts as a displacing agent, and the mixed displacement mode, in which the gas dissolves in oil, changes its properties, contributing to improving the conditions of its displacement. In the course of the work, a comparison of mixed and unmixed injection of carbon dioxide into the formation was made. The dissolution of the gas in the oil occurs at a certain pressure, which is called the miscibility pressure. During the work, the main factors affecting the mixing pressure were identified. The analysis of the effectiveness of the method was carried out by using a digital model. It was found that with mixed carbon dioxide injection, the recovery factor is greater. Shows the impact of carbon dioxide on the reservoir and reservoir fluid during injection. It has been established that carbon dioxide is capable of chemical reactions with rock. These chemical reactions have both positive and negative effects, increasing or decreasing porosity and permeability factors of the formations. The most optimal method of carbon dioxide injection has been determined. The dependence was obtained to determine the efficiency factor of oil production during carbon dioxide injection.