- Volume 19 Issue 3
DOI QR Code
Development of Efficient Monitoring Algorithm at EGS Site by Using Microseismic Data
미소진동 자료를 이용한 EGS 사이트에서의 효율적인 모니터링 알고리듬 개발
- Lee, Sangmin (Dept. of Earth Resources and Environmental Engineering, Hanyang Univ.) ;
- Byun, Joongmoo (Dept. of Earth Resources and Environmental Engineering, Hanyang Univ.)
- Received : 2016.07.05
- Accepted : 2016.08.16
- Published : 2016.08.31
In order to enhance the connectivity of fracture network as fluid path in enhanced/engineered geothermal system (EGS), the exact locating of hydraulic fractured zone is very important. Hydraulic fractures can be tracked by locating of microseismic events which are occurred during hydraulic fracture stimulation at each stage. However, since the subsurface velocity is changed due to hydraulic fracturing at each stage, in order to find out the exact location of microseismic events, we have to consider the velocity change due to hydraulic fracturing at previous stage when we perform the mapping of microseimic events at the next stage. In this study, we have modified 3D locating algorithm of microseismic data which was developed by Kim et al. (2015) and have developed 3D velocity update algorithm using occurred microseismic data. Eikonal equation which can efficiently calculate traveltime for complex velocity model at anywhere without shadow zone is used as forward engine in our inversion. Computational cost is dramatically reduced by using Fresnel volume approach to construct Jacobian matrix in velocity inversion. Through the numerical test which simulates the geothermal survey geometry, we demonstrated that the initial velocity model was updated by using microseismic data. In addition, we confirmed that relocation results of microseismic events by using updated velocity model became closer to true locations.
Supported by : 한국에너지기술평가원(KETEP)
- Abdulaziz, A. M., 2014, Evaluation of Microseismicity Related to Hydraulic Fracking Operations of Petroleum Reservoirs and Its Possible Environmental Repercussions, Open Journal of Earthquake Research, 3, 43-54. https://doi.org/10.4236/ojer.2014.32006
- Bai, C., Li, X., Huang, G., and Greenhalgh, S., 2014, Simultaneous inversion for velocity and reflector geometry using multi-phase Fresnel volume rays, Pure Appl. Geophys., 171, 1089-1105. https://doi.org/10.1007/s00024-013-0686-6
- Brisco, C. and Van der Baan, M., 2016, A review of seismic velocity response to variations in pore pressure, poresaturating fluid and confining stress, Geoconvention 2016, Calgary, Canada, March 2016.
- Castellanos, F. and Van der Baan, M., 2013, Microseismic event locations using the double-difference algorithm, CSEG RECORDER, 38, 26-38.
- Cerveny, V. and Soares, J. E. P., 1992, Fresnel volume ray tracing, Geophysics, 57, 902-915. https://doi.org/10.1190/1.1443303
- Font, F., Kao, H., Lallemand, S., Liu, C. S., and Chiao, L. Y., 2004, Hypocentre determination offshore of eastern Taiwan using the maximum intersection method, Geophysics, 158, 655-675.
- Geiger, L., 1912, Probability method for the determination of earthquake epicenters from the arrival time only, Bulletin of St. Louis University, 8, 56-71.
- Jiang, H., Chen, Z., Zeng, X., Lv, H., and Liu, X., 2016, Velocity calibration for microseismic event location using surface data, Petroleum Science, 13, 225-236. https://doi.org/10.1007/s12182-016-0092-7
- Jordi, C., Schmelzbach, C., and Greenhalgh, S., 2015, On the value of frequency-dependent traveltime tomography for surface-seismic data, Geophysical Research Abstracts, 17, EGU2015-1606.
- Kim, D., Kim, M., Byun, J., and Seol, S. J., 2015, Locating microseismic events using a single vertical well data, Jigu-Mulli-wa-Mulli-Tamsa, 18, 63-73.
- Kim, H. J., Song, Y., and Lee, K. H., 1999, Inequality constraint in least squares inversion of geophysical data, Earth Planets Space, 51, 255-259. https://doi.org/10.1186/BF03352229
- Pavlis, G. L., 1986, Appraising earthquake hypocenter location error: a complete, practical approach for single-event locations, Bull. Seism. Soc. Am., 76, 1699-1717.
- Podvin, P. and Lecomte, I., 1991, Finite difference computation of traveltimes in very contrasted velocity models: a massively parallel approach and its associated tools, Geophysical Journal International, 105, 271-284. https://doi.org/10.1111/j.1365-246X.1991.tb03461.x
- Rawlinson, N., Hauser, J., and Sambridge, M., 2008, Seismic ray tracing and wavefront tracking in laterally heterogeneous media, Advances in Geophysics, 49, 203. https://doi.org/10.1016/S0065-2687(07)49003-3
- Vlastos, S., Liu, E., Main, I. G., Schoenberg, M., Narteau, C., Li, X. Y., and Maillot, B., 2006, Dual simulations of fluid flow and seismic wave propagation in a fractured network: effects of pore pressure on seismic signature, Geophysical Journal International, 166, 825-838. https://doi.org/10.1111/j.1365-246X.2006.03060.x
- Watanabe, T., Toshifumi, M., and Yuzuru, A., 1999, Seismic traveltime tomography using Fresnel volume approach: 69th Annual Meeting, SEG Expanded Abstracts.