| Title | Numerical Study on Effects of Hydraulic Fracture Geometries on Heat Extraction Performance of a Multilateral-well Enhanced Geothermal System |
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| Authors | Yu SHI, Xianzhi SONG, Gaosheng WANG, Jiacheng LI, Feixue YULONG |
| Year | 2019 |
| Conference | Stanford Geothermal Workshop |
| Keywords | geothermal energy; enhanced geothermal system; hydraulic fracture; heat extraction performance; multilateral wells |
| Abstract | Our previous study (Song et al, 2018) proposed a novel enhanced geothermal system (EGS) with multilateral wells and demonstrated that it had greater heat extraction performance than double-well EGS. However, hydraulic fracturing plays an extremely important role in improving the heat extraction performance of multilateral-well EGS. Therefore, it is significant to investigate effects of hydraulic fracture geometries on the multilateral-well EGS performance. In this study, we use a thermal-hydraulic-mechanical (THM) coupling model to find that which kind of fracture network geometry is suitable for improving multilateral-well EGS performance. Based on the model, effects of hydraulic fracture stages and hydraulic fracture complexities on the multilateral-well EGS performance are investigated. The results indicate that the increase of the hydraulic fracture stages could reduce the injection pressure and facilitate the thermal breakthrough. The hydraulic fractures with longer fractures and without too many direct connections between lateral wells and fractures is beneficial for the improvement of multilateral-well EGS performance. The results of this study provide significant suggestions for the fracturing operation of multilateral-well EGS. |