| Title | Dynamic Modelling of Microseismic Activities in a Geothermal Field |
|---|---|
| Authors | Umran SERPEN, Niyazi AKSOY, Zulfu DEMIRKIRAN, Hilal ATES |
| Year | 2020 |
| Conference | World Geothermal Congress |
| Keywords | microseismicity, dynamic modelling, reinjection, production |
| Abstract | Salavatlı geothermal field in Turkey has been developed in the last 15 years, and during this period 5 power plants with a totaling power generation capacity of 72 MWe were installed. In order to monitor the reinjection fluid pathways first tracer testing, then micro-earthquake monitoring were used. First power plant was commissioned in 2006, and the second in 2010 when a 9 station network was deployed around the license area and microseismic activities were started to monitor. Application of high-precision micro-earthquake hypocenter location has continued until today and will proceed. In the last decade observing microseismic events across different networks have also started in three more geothermal fields in Turkey under exploitation, and are currently continuing. Geothermal resources derive their capacity for fluid and heat transport mainly from fracture systems. Microseismicivity occurred on fracture systems might identify large faults and fractures which provide fluid storage and recharge capacity to have a sustainable geothermal reservoir. Large microseismicivity was mainly observed in the exploitation area and 1-3 km depth of the injection and production intervals in Turkey. As for geological structures the activity is observed near fault systems. Important geological features might be elucidated by microseismic monitoring that has indicated activities with the start of field operations in the exploitation areas where seismicivity has not been previously observed. During the eight years of observation microseismic activities occurred in the area delimitated by the low resistivity anomaly where all wells have been drilled were conducted. Reinjection wells are located around the margins of this anomaly. In this study substantial microseismic activities have been recorded over 8 years of monitoring depending upon surface operations conducted, such as new production and reinjection wells added to the exploitation operation around license area, and they are connected to the new power plants. After examination of data obtained some relations between surface operations and subsurface activities are inferred. Large data obtained over 8 years are dynamically 3D modeled and it helped to understand better and evaluate the changes occurring underground. |