Relevance. This paper discusses the optimization of multi-reservoir field development at the Uzen oilfield using geochemistry and an innovative method for inflow distribution across productive layers. Aim. To minimize the negative impact of reservoir property heterogeneity in hydrocarbon fields, a comprehensive approach is proposed. It includes geochemical analysis of oil and the development of specialized downhole equipment for oil-water separation. This approach is aimed at reducing capital investments and operational costs, improving production control, and enhancing the economic efficiency of field development. Methods. The application of downhole injection and separation systems equipped with electrically driven centrifugal pumps opens new opportunities for the oil production sector. This technology significantly increases the efficiency and cost-effectiveness of oil extraction by boosting oil flow rates from existing production wells through the inclusion of new reservoir intervals and reducing lifting and pumping costs via in-well separation and simultaneous water reinjection into the formation. Even without a complete economic analysis, the advantages of implementing this new method in the Parsumurun Dome of the Uzen field are evident, promising significant benefits compared to traditional approaches. Reduced operating expenses and capital investments, combined with the potential for increased oil production revenues, ensure high economic efficiency for the proposed solutions. These factors make investment in this method particularly attractive, offering substantial improvements in the financial performance of field development. Results and conclusions. Pilot testing at the Parsumurun Dome, which contains only 2% of the Uzen field geological oil reserves, provides a unique opportunity to evaluate the effectiveness of the proposed method. Positive results from the pilot trials could justify full-scale implementation across the entire field, offering considerable technological and economic benefits.