Existing approaches to the analysis of countries economic integration processes in international practice are investigated in the paper. Evaluating methodology of the long-term integration processes in the electric power sector is offered for the EAEU countries in three scenarios: High, low and medium, based on the synergy of various economic and mathematical methods. The actual methodology is formed in accordance with special macroeconomic scenario conditions and includes the final energy consumption forecast with division by the types of energy sources in the context of consumers categories of the EAEU countries based on generated scenario conditions using econometric methods (growth curves, Cobb-Douglas production function, regression analysis, simulation methods), as well as the development forecast of electric power industry concerning the EAEU countries reasoning from perspective dynamics of generating capacities of these countries. Project growth of electric power sector development founded on suggested method was made for the EAEU countries for the period of 2018-2040, specifically, electricity consumption projection, electricity consumption increasing, as well as capacity increasing of NPGS, HEP and RER in these countries. The necessity of further efforts to develop the common electric power market in the EAEU countries in order to obtain possible long-term integration effects are emphasized.

In the presented paper, it is proved that a new objective trend appears in the current conditions of Eurasian region development. It will strengthen mutual cooperation between the countries of Eurasia and it will enrich regionalization process in the context of world energy markets restructuring, intensification of competition, deglobalization tendencies and other challenges of the world economy. At the same time, fuel and energy complex (FEC) is becoming the main driving force for the countries of Eurasian region and their further development. The concept of regional energy integration of the Eurasian Economic Union (EAEU) countries is offered in the paper. It's based on the strategic advantages of economic integration in relation to the fuel and energy complex. Energy potential analysis of the EAEU member countries is performed. The issues of common energy markets formation in the region are considered. The main problems and a number of uncoordinated tasks between the countries participating in integrational process in this area are highlighted in terms of common gas, oil and oil products market formation, although it is noted that development and approval stage of the Programs for such formation is mostly completed. It is expected that these markets will be fully formed by 2025. It was emphasized that energy integration is one of the most important areas for the EAEU countries development, which is expected to bring significant economic benefits in the long-term period.

Portfolio models can serve as an assessment tool for the optimal assignment of capital between the potential investment projects in the various conditions for upstream companies. This process is crucial for any company if it wants to balance the short-term goals and seeks to maximize longterm value of the company. The paper aims to present a practical model of forming oil upstream company's portfolio. The unique feature of this model is an individual approach to investment plan forming in a context of three types of projects: Exploration, oil production and infrastructure projects. This is due to the individual approach which is used for comparison of all projects by using of universal set of indicators. Suggested model uses the multi-criteria selection mechanism by means of aggregating the key estimating indicators into the final project rank score. In that way the task of forming investment project's portfolio of upstream company is a linear programming problem that is solved by simplex method. In the paper the model forms consolidated investment portfolio that takes into account decision makers' preferences in setting of limits for resources.