A feature of the modern world is the constantly increasing flow of innovation, which has caused a chain reaction of technological, institutional and social changes in all spheres of activity. Increasingly noted examples of this are the ‘green’ trend, the ecologisation of innovation processes and enterprises following modern trends in sustainable development. In this study, the authors developed an original methodology to risk-assess (probability of success) green innovations based on a decision tree. The authors’ solution facilitates making an optimal decision on the expediency of launching projects to implement green innovations in the oil and gas sector, such as carrying out entire innovation programs, launching a pilot projects or suspending current programs, based on the expected income. In this paper, the methodological approach is tested using conditional data. The results obtained form the foundation for developing a framework for innovation activities at oil and gas complex enterprises, providing a new (green) view on solving the problems of oil and gas innovations and taking a systemic approach to the analysis of green innovations in the oil and gas sector in the Russian Federation. The findings can be used in strategic planning by oil and gas enterprises, in particular, when deciding on the expediency of initiating green innovation programmes.