OIL DISPLACEMENT BY POLYMER FLOODING IN THE UZEN FIELD

Abstract

Primary recovery is the production of the hydrocarbons under the natural energy of the reservoir. As the reservoir energy depletes and pressure reduces, production also declines. Secondary recovery methods such as water and gas injection are typically applied after the decline in production has been noticed. When the production of hydrocarbons is not enough, tertiary recovery methods are applied. Chemical flooding is one of the most used techniques to maintain oil production, especially polymer flooding. Polymers are applied to the reservoirs with high water cut since polymers are effective in increasing the sweep efficiency and mobility control. By adding more viscous fluid such as polymer to the water, water becomes more viscous and is able to move more oil from the injection well towards the production one. One of the Kazakhstan fields, where the water cut is very high, is the Uzen field. That is why polymer flooding has been considered for this field. In previous studies, screening of four types of polymers has been completed, after which Polymer 3 solution with a concentration of 2500 ppm was established to be the most suitable for this field. In this paper, Polymer 3 then has been further tested with different kinds of water - Caspian seawater and Alb water (water from Albian age layer) - to study its behavior when injected into the Uzen core sample to displace oil. The results of the oil displacement tests conducted through the Core Flooding System (CFS-700) have shown that polymer prepared with Caspian seawater works better than polymer prepared with Alb water in terms of oil recovery, injectivity, and resistivity factors. The next step of the research is to conduct pilot tests in the field and monitor the polymer behavior in real conditions.