The article is devoted to the development and testing of a comprehensive methodology for assessing the economic efficiency of digital environmental monitoring projects at oil and gas production sites, taking into account the structure of payments for negative environmental impact and regional measures of state support. This is driven by the industry's significant contribution to environmental impact and the growing regulatory requirements for corporate environmental responsibility. The research aims to demonstrate how incorporating the dynamics of environmental payment rates, the effects of preventive control, and state support tools changes the investment profile of projects and enables informed decisions on the digitalization of environmental control. The empirical base includes federal and regional regulatory acts, statistics from Rosstat, the Ministry of Natural Resources, and Rosprirodnadzor for 2018–2023, as well as non-public financial and technical reports from pilot implementations that provided detailed CAPEX/OPEX data and payment breakdowns by type of impact. Methodologically, a DCF model was applied with the calculation of NPV, IRR, DPP, and PI, along with a comparative analysis of traditional and digital monitoring schemes, scenario analysis of support mechanisms, sensitivity analysis of key risk factors, and Monte Carlo simulation. The transition to a digital system is accompanied by an increase in CAPEX by about 700% (up to 145.72 million rubles) while annual OPEX decreases from 42.18 to 21.35 million rubles due to automation and changes in labor structure. The preventive nature of monitoring reduces environmental payments by 42.74 million rubles per year, over 65% of which results from a decrease in excess and emergency payments, forming, together with OPEX savings, a total effect of 63.57 million rubles per year. In the baseline scenario without support, the project remains marginally attractive (NPV 38.47 million rubles; IRR 19.82%; DPP 6.88 years), whereas a 50% investment tax deduction for CAPEX increases NPV to 102.11 million rubles and reduces DPP to 4.51 years. A direct subsidy of 30% of CAPEX yields NPV of 104.98 million rubles, IRR of 31.17%, and DPP of 4.12 years, demonstrating high elasticity of integrated indicators to the level of support. NPV sensitivity is highest to the actual reduction in accident rates and the growth rate of environmental tariffs, while a 20% increase in CAPEX still keeps NPV positive (75.84 million rubles), highlighting the dominant role of operating cash flows. According to Monte Carlo results, the probability of negative NPV with a subsidy of ≥25% CAPEX and achievement of ≥85% of the planned accident reduction does not exceed 5%, indicating high financial stability of the solutions. The conclusions emphasize the synergistic nature of the effect: OPEX savings, environmental payment reductions, and state support together transform digital monitoring from a cost-driven initiative into an investment-attractive project and create a practical tool for companies and regulators.