Leptokaropoulos, Konstantinos Michail and Staszek, Monika and Lasocki, Stanislaw and Kwiatek, Grzegorz and Martinez-Garzon, Patricia (2017) Space-Time Evolution of Seismicity in North-Western Geysers Geothermal Field and its Connection to Stimulation Processes. In: EGU General Assembly 2017, 23–28 April 2017, Vienna, Austria.
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Leptokaropoulos_et_al_2017_Space-Time_Evolution_of_Seismicity_in_NW_Geysers_Geothermal_Field_and_its_Connection_to_Stimulation_Processes_Poster.pdf - Submitted Version Download (2MB) | Preview |
Abstract
The rising needs for energy along with the recent requirements for more efficient usage and exploitation of the deep underground have resulted to a growing scientific and public concern on related environmental impacts. Hydraulic fracturing that has been carried out during the last decades is occasionally connected with triggered and induced seismicity worldwide. Data from geothermal fields can be used as a proxy for shale gas exploitation associated seismicity since they are both tightly connected to hydraulic fracturing. For that reason we utilize ‘The Geysers’ data from the compiled SHEER (Shale Gas Exploration and Exploitation Induced Risks) database. The Geysers (California, USA) is the largest producing geothermal field in the world and has been sufficiently monitored and studied since the last decades. Seismic and technological data gathered during the past ∼40 years indicate a connection of seismic activity with the fluctuations of the injected fluid volume. In this study we verify and quantify this correlation by analyzing the data associated with 2 injection wells (Prati-9 and Prati-29) which covers a time period of approximately 7 years (from November 2007 to August 2014). The correlation between spatio-temporal seismicity evolution and variation of the injection data is performed by elaboration of original and smoothed time-series through specified statistical tools (cross correlation, binomial test to investigate significant rate changes, b-value variation). Our analysis indicate a short time delay of seismicity occurrence at distances larger than 200m from the injection well, whereas no evidence of significant correlation between injection rates and b-values was discovered. The obtained results are expected to contribute to a better comprehension of the role of hydraulic fracturing and the physical processes controlling seismogenesis in fluid injection sites. Acknowledgements: This work was supported within SHEER: "Shale Gas Exploration and Exploitation Induced Risks" project funded from Horizon 2020 – R&I Framework Programme, call H2020-LCE-2014-1 and within statutory activities No3841/E-41/S/2016 of Ministry of Science and Higher Education of Poland.
| Item Type: | Conference or Workshop Item (Poster) |
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| Subjects: | Methodology > Method and procesing > Collective properties of seismicity Region > USA > California > Geysers Inducing technology > Geothermal energy production |
| Project: | SHEER project > THE GEYSERS: geothermal energy production |