When assessing economic feasibility using the NPV indicator, of some importance is the order of commissioning well clusters – the earlier a prospective well cluster is commissioned, the higher the NPV. This being said, creation of an optimal well commissioning schedule is directly conducive to maximizing the project's total efficiency. Traditionally, Rosneft uses a ‘geological’ drilling rating system when making up well cluster drilling schedules; this approach is based on initial production rates. This system ignores capital expenditures, the bulk of which goes to well drilling and the associated surface construction; but quite often well clusters with high initial production rates prove less profitable owing to outweighing capital costs.
With the purpose of increase NPV of the project, it is proposed to exercise drilling of well clusters according to their economic efficiency. The initial step in field development is constructing the basic common objects. For a quick payback, it is necessary to first commission well clusters having the greatest economic efficiency. The calculation of the technical/economic rating is performed iteratively in several steps, each of which picks up a well cluster with the maximum NPV. The amount of surface facilities for each well cluster remains variable across the iterations. This approach is implemented in the company's proprietary software package.