Article analyses modern tendencies in oil-and-gas sector resources base development. Article shows not only high oil prices influenced growth of the oil-and-gas sector resources base (what gave chance for the transfer of uneconomic resources into profitable reserves), not only widespread of modern oil-and-gas production technologies (like horizontal drilling and hy drof­racturing), but also (especially in US) extremely favorable institutional and organizational conditions. Access to modern technology in combination with skills and experience to use these technologies – are among most important features. All together changes not only organiza tional pattern of the oil-an-gas sector, but also principles and forms of the various companies interactions (especially between national and transnational oil-an-gas companies).