Full-Field Polymer Flooding Project – Principles and Challenges at the Kalamkas Oilfield

Abstract

Abstract The Kalamkas oilfield is one of the largest brownfields in Kazakhstan and has a 45-year development history. With a 27% recovery factor, it still has the potential to make a valuable contribution to Kazakhstan’s oil production. Polymer flooding (PF) is supposed to be the most effective technique to reveal this potential since the first pilot projects in 80’s conducted. Nowadays, when new explorations are expensive, the application and expansion of such technologies are critical to field development. This article presents the main features of modern polymer flooding implementations. Features such as mobile polymer flooding units and their complex reservoir-oriented injections help to create cost-effective staged full-field planning. Strong selection criteria consisting of basic geological and production characteristics were developed to target the "sweet spots" of the reservoir. An analytical method for oil production forecasting was applied to evaluate the feasibility of each selected area. The consistency and duration of polymer flooding areas were identified based on the forecasting results. Moreover, this pragmatic approach is time-saving and allows fast decision-making compared to simulation studies. 26 new polymer areas involving 80 injection wells (~15% of Kalamkas injectors) and over 600 offset producers were selected for polymer flooding. New areas were ranked in terms of their predicted efficiency and considered to be covered by polymer flooding step-by-step for the next 20 years. With the availability of mobile polymer flooding units, it is possible to switch units from completed areas to new involving areas, significantly improving the project’s cost-effectiveness. Another feature of our case is that polymer flooding areas can be grouped by geographical principles and their technical reasons for using the same type of polymer. Thus, polymer flooding units handle multiple formations located at different depths even with different rock and fluid properties. It is also observed that most PF areas are expected to be economically feasible with up to 70% pore volume injection; this parameter can be increased even further if local polymer price is optimized. In conclusion, the developed full-field polymer flooding project is expected to provide 7.5% incremental oil recovery. The current experience of PF pilot projects and lessons learned provide a strong foundation for future extension strategy. Full-field polymer flooding project at the Kalamkas oilfield is expected to be one of the largest chemical EOR projects in the Commonwealth of Independent States (CIS) despite harsh water conditions (~130 g/l salinity) compared to other projects such as Daqing, Mangala, Marmul, and Pelican Lake.