The PDF file of this paper is in Russian.
Expected events can be predicted with varying accuracy depending on the nature of the events: probabilistic or uncertain. To understand the nature of risk, the relationship between risk and return is of primary importance. You can choose a solution that contains less risk, but at the same time it will be less income, and at the highest risk, the income has the highest value. An entrepreneur, an investor may partially transfer the risk to other subjects of the economy, but it cannot be completely avoided. The article discusses the concepts of "risk" and "uncertainty" from the point of view of solving applied problems in the oil and gas economy, management decision-making environments, methods for evaluating their effectiveness, investor behavior, etc. There are three main areas of conditions (three decision-making environments) in which investors make decisions: a certainty environment - the possible outcomes are precisely known, the probability is equal to one; risk environment - there are many possible outcomes, each of which is characterized by a specific probability of its occurrence; environment of uncertainty - there are many possible outcomes, the probabilities of which are unknown. The various areas of uncertainty and risk taken into account when making investment decisions allow identifying three types of investor behavior: risk appetite, indifference, and risk aversion. Practice shows that most investors are not risk averse. These approaches are considered on examples of some applied problems of the oil and gas economy, in the solution of which the authors were directly involved. It was noted that the use of a matrix of gains or risks from the point of view of several criteria followed by a numerical analysis of the situation can be useful in making a final decision and reduces the likelihood of failure. The approaches considered in the article can also be used to solve other applied problems of the oil and gas economy.