In the conditions of the digital oil and gas economy, the use of analytical research methods in the field of investment activities of oil companies is becoming increasingly important. The article discusses the mechanisms of economic and cost-effective engineering for the development of oil and gas resources. The Graf information- logical system was created and tested for economic and profitable modeling of oil and gas investment projects both in Russia and abroad. ILS "Graf" controls the correctness of the logical conclusion on the basis of the database and knowledge base of the problem area in order to comprehensively evaluate the options for the development of oil and gas fields on the basis of expert knowledge. The relevance of the study is due to the need to create mechanisms for the economic assessment of oil and gas resources in the dynamic development of the digital oil and gas economy of Russia.