Study of fracture monitoring and heat extraction evaluation in geothermal reservoir modified by abandoned well pattern: Numerical models and case studies

Abstract

The abandoned well pattern for transforming geothermal reservoirs aligns seamlessly with the prevailing shift towards low carbon and enhanced energy efficiency. The effect of anomalous fractures on the effectiveness of heat production is not clear. In this study, we introduce the modified pressure build-up (MPBU) technology tailored for monitoring fracture behavior in geothermal extraction reservoirs. We construct numerical models for geothermal extraction, accounting for dynamic and irregular fractures. Results indicate that the MPBU technology substantially improves the precision of fracture model selection and parameter matching. The interpreted parameters are incorporated into the heat transfer model to assess reservoir heat distribution after 5000 days of extraction. The heat extraction effect of hydraulic fractures is similar to that of irregular fractures. Dynamic fractures have the worst heat extraction effect. Non Sorting Genetic Algorithm II is used to evaluate optimal monitoring and reservoir modification schemes. The innovative technology, numerical models, and optimal solutions will result in an economic improvement of $723,000 per well per year. In conclusion, the integrated monitoring and simulation approach proposed in this paper facilitates efficient and cost-effective differentiation of fracture states, thermal energy extraction evaluation, and optimization of the best extraction strategies to maximize economic benefits for engineers.