An Assessment Of A Geothermal Resource In East China With Improved Process Design
As great substitution of traditional energy resources with nearly zero greenhouse gas emission, geothermal energy has been studied for decades. However, due to the lack of understanding of geothermal geology and limitation of exploration technology, this kind of lower emissive energy resource was under slow development years ago. Recently, geothermal energy resource is drawing attention again for its potential in worldwide as a result of climate change and the growing public demand for environmental protection and sustainability. Lower temperature hydrothermal geothermal resources present challenges especially from the perspective of maximizing energy recovery over meaningful time frames. Here, we examine the case of a sandstone, relatively low-temperature, high porosity and permeability dominated geothermal resource in Eastern China. From detailed geological modelling and thermal reservoir simulation, we demonstrate that well spacing and operating strategy affect the useful life of the geothermal resource. The results show that use of the geothermal resource could offset the consumption of over 330 million tonnes of coal over the life of the operation. The results show that the well operating strategy has to be balanced with the heat rate through the understrata to the geothermal resource as well as the flow (permeability) and heat storage (heat capacity and porosity) properties of the geothermal resource. This is especially that case for controlling the thermal breakthrough time, the time at which the injected fluid reaches the production wells at a threshold low temperature at which heat recovery makes the energy extraction process infeasible. Thermal breakthrough time is a key characteristic amongst several parameters which can predict the economic and energy supply lifetime of a geothermal reservoir. Temperature loss from the reservoir to the ground surface through production is essential for commercial exploration of a geothermal reservoir. So in this case, a designed model from the ground surface to the geothermal reservoir along wells is also incorporated and simulated. The design basis for a commercial geothermal operation is described.
AAPG Datapages/Search and Discovery Article #90346 ©2019 AAPG European Region, 3rd Hydrocarbon Geothermal Cross Over Technology Workshop, Geneva, Switzerland, April 9-10, 2019