The article considers the problem of risk management in hydrocarbon field development. The approach to risk assessment and mitigation, based on the application of probabilistic reasoning models, is proposed. A special kind of Bayesian networks – influence diagrams, and associated probabilistic decision trees were proposed as models. An example of its application to the task of assessing and reducing the risk of non-execution of the project document due to unconfirmed reserves is given. As part of the example, the task of assessing the feasibility of drilling an exploration well is considered.