Peculiarities of late-stage development of oil fields in Ukraine and ways of increasing oil production

The relevance of the study lies in identifying typical stages of oil field development and determining the beginning of the late-stage period based on the actual values of annual and accumulated oil production and water cut of well products. The purpose of the research was to identify the main features of the late stage of development and to develop technical and economic directions and measures to stabilise and increase oil and gas production. The paper analysed the possibilities of increasing domestic oil production in Ukraine by using the resource potential of fields whose reserves are classified as hard-to-recover. The authors formulated the criteria by which individual deposits and fields contain hard-to-recover reserves and determined the structure of such reserves, taking into account the elements of residual oil saturation of the pore space. The peculiarities of late-stage field development in terms of the dynamics of changes in development indicators were determined. The geological, industrial, economic, social and environmental problems accompanying the development of fields at a late stage were considered. Using the example of the development of the oil industry in Ukraine, the article analysed typical stages of field development and oil and gas production. The structure of oil reserves classified into active reserves, which are extracted mainly through natural reservoir energy, and hard-to-recover reserves, which require the use of targeted artificial stimulation of the reservoir system using various targeted methods and technologies, was presented. A procedure for determining the beginning of the late stage of field development based on the curves of actual accumulated oil production and water cut of well products was proposed and demonstrated using real actual data. The location of the residual hard-to-recover reserves in the oil-saturated pore space was identified. Based on the available average statistical information, the defining features of the late stage of development were comprehensively disclosed, which are grouped into geological, technological, organisational, economic, financial, social and environmental. The main areas of activity of research and development and oil and gas companies to address the problem of stabilising and increasing oil production at the late stages of field development were identified