Energy extraction from low-temperature geothermal resources in hydrocarbon fields of Taranaki region

Hydrocarbon fields host several unused wells with temperatures suitable for low to medium-temperature geothermal energy extraction. The number of these wells increases every year with the depletion of petroleum reserves. Plug and abandonment of a well is a cost-intensive process, and these wells will sit idle after abandonment. However, an opportunity exists to use these drilled holes for geothermal extraction and extend their operational lifetime. This way, the cost of drilling new wells for geothermal exploration and development may be avoided. Also, it is environmentally beneficial and avoids any potential hazards from accidental spillage. To realize this motivation, the energy output from unused wells found in the Taranaki region, New Zealand will be evaluated in a Ph.D. programme. This is a major oil and gas producing region in the country and has many unused wells in place. These wells reach up to 5064m depth and up to 172 °C bottomhole temperatures are found in them. Due to fundamental differences between typical geothermal fields and hydrocarbon fields, it is important to study the thermal and hydraulic performance of these wells. Results obtained in the preliminary work for Ph.D. proposal discussing the potential of geothermal energy extraction will be presented. We will also describe the influence of the reservoir and fluid parameters on the thermal and hydraulic performance. Finally, we address some of the unique challenges and recommendations during energy extraction from these fields.