Type:
Research Report, Student Research
Link:
Authors:
Zhenqian Xue, Haoming Ma, Zhangxin Chen
Citation:
Xue, Z., Ma, H., Chen, Z. (2023). Numerical Investigation of Energy Production from an Enhanced Geothermal System Associated with CO2 Geological Sequestration. SPE Western Regional Meeting. Anchorage, Alaska.
Abstract:
The development of a geothermal system can supply low-carbon electricity to support the raising energy demand under the energy transition from fossil fuel to renewables. CO2 can substitute for water for energy recovery from geothermal reservoirs owing to its better mobility and higher heat capacity. Additionally, trapping injected CO2 underground can achieve environmental benefits by targeting Greenhouse gas (GHG) mitigation. In this study, different flow schemes are established to assess heat mining and geological CO2 sequestration (CCS) by injecting CO2 for the purpose of an enhanced geothermal system. The Qiabuqia geothermal field in China is selected as a study case to formulate the geothermal reservoir simulation. The results show that a pure CO2 injection into a water-saturated reservoir can provide the best performance in heat mining. Besides, this operational strategy can also provide extra benefits by producing 6.7% CO2 retention. The generated geothermal electricity under a pure CO2 injection into a CO2-saturated formation is the lowest, while its 42.1% of CO2 retention shows a promising CCS performance and the large volume of stored CO2 can supply some profits by carbon credit. Considering the assessment on heat mining and CCS, the pure CO2 injection into a water-saturated reservoir is recommended for the operation of an EGS. Under this flow strategy, well spacing, production pressure difference and fluid injection temperature are dominated in geothermal energy production. Three factors, including well spacing, production pressure difference and fracture conductivity, influence the CO2 storage capacity. In operating an EGS, a larger well spacing, a lower injection temperature and a lower fracture conductivity are suggested. While the optimal production pressure difference should be further determined to balance its effect on geothermal production and CO2 storage since it presents an opposite effect on these two parts. This work demonstrates the feasibility of heat mining associated with CO2 geological permanent storage in an EGS by injecting CO2. The proposed study proves that not only the sufficient and sustainable energy can be supplied but also a significant amount of CO2 emission can be eliminated simultaneously. In addition, the investigation of geothermal energy production and CO2 geological sequestration under different operational parameters can provide profound guidance for the operators.
Keywords:
asia government, saudi arabia government, geologist, eritrea government, sudan government, co2 injection, geology, djibouti government, egypt government, geothermal electricity, Non-Traditional Resources, Geothermal resources