Geothermal Development Opportunity and Risk of Using Abandoned Oil-Gas Wells and Mines with MRI tests

Much work in geothermal is focused on technologies that make deeper drilling more economical, no matter what types of geothermal power plants are. The most important of these problems are well drilling investment cost and energy conversion efficiency, and geological earthquakes problems that can be induced by using enhanced geothermal systems (EGS). The drilling cost and energy efficiency of geothermal are caused by drilling depth. So, finding solution to reduce drilling depth and risk are essential for geothermal development. In this study, we analyze one possible geothermal power plant development method recycling abandoned coal mines which could saving well drilling cost and reducing geology surveying risk, the geothermal wells will be drilled at the bottom of the abandoned coal mines. Then we summarize present project recycling abandoned gas-oil wells for geothermal power plant development. Based on Paris agreement and IPCC special report on 1.5°C, we analyze the situation of renewable and conventional energy to provide the reason why we have many abandoned coal mines and abandoned gas-oil wells to recycle, then we calculate geothermal power plant capacity using abandoned coal mines and using abandoned gas-oil wells. In the second part of this study, we analyze the geothermal risk using EGS, as long as the reservoir rock using hydraulic fracturing, the geothermal risk is the induced earthquake which is caused by fracture propagation of the reservoir rock mass, the MRI (magnetic resonance image) experiments were conducted to obtain morphology of fracture propagation process of rock samples under uniaxial load stress to simulate reservoir rock failure process and measure rock fracture propagation velocity. The results show MRI could provide high quality image of rock fracture propagation process, rock fracture propagation velocity will start from low speed to high speed when approaching the maximum stress of rock.