An Interpretation of Microseismic Spatial Anomalies, b-values, and Magnitude Analyses To Identify Activated Fracture Networks in Horn River Basin
- Abdolnaser Yousefzadeh (University of Calgary) | Qi Li (University of Calgary) | Claudio Virués (CNOOC-Nexen) | Roberto Aguilera (University of Calgary)
- Document ID
- Society of Petroleum Engineers
- SPE Production & Operations
- Publication Date
- November 2018
- Document Type
- Journal Paper
- 679 - 696
- 2018.Society of Petroleum Engineers
- Reservoir characterization, Fault identification, Horn River Basin, Microseismic b-value, Microseismic interpretation
- 1 in the last 30 days
- 130 since 2007
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We analyzed microseismic spatial and temporal distribution, magnitudes, b-values, and treatment data to interpret and explain the observed anomalies in microseismic events recorded during exploitation of shale gas reservoirs in the Horn River Basin of Canada. The b-value shows the relationship between the number of seismic events in a certain area and their magnitudes in a semilogarithmic scale. The b-value is important because small changes in b-value represent large changes in the predicted number of seismic events. In this study, b-value is considered as an indicator of the mechanism of observed microseismicity during hydraulic-fracturing treatments.
We estimated the directional diffusivity to define the microseismicity front curve for each stage of hydraulic fracturing. On the basis of our definition of an average front curve, we managed to separate most of the microseismic events that are related to natural-fracture activation from hydraulic-fracturing microseismic events. We analyzed b-values for microseismic events of each stage before and after separating fracture-activation microseismic events from original data, and created a map of b-values in the study area. This allowed us to approximately locate activated fractures mostly in the northeastern part of the study wellpad. The b-value map agrees with our assumption of activated-fracture locations and high ratio of seismic activities. The dominant direction of the suggested activated natural fractures agrees with the general trend of the Trout Lake fault zone located approximately 20 km west of the study area.
Suggested fracture direction also agrees with anomalous-events density, energy distribution, and treatment data. We are proposing intermediate b-values for calculation of the stimulated reservoir volume (SRV) in areas with both hydraulically fractured events and events related to natural-fracture-network activation in those instances in which it is not viable to separate events based on their origin.
|File Size||11 MB||Number of Pages||18|
Aguilera, R. 1980. Naturally Fractured Reservoirs, first edition. Tulsa: PennWell Books.
Aguilera, R. 2003. Geologic and Engineering Aspects of Naturally Fractured Reservoirs. Canadian Society of Exploration Geophysicists, Recorder 28 (2): 44–49.
Aki, K. 1965. Maximum Likelihood Estimate of B in the Formula Logn=A - Bm and Its Confidence Limits. Bull. Earthquake Res. Inst. 43: 237–239.
Aki, K. 1987. Magnitude-Frequency Relation for Small Earthquakes: A Clue to the Origin of F-Max of Large Earthquakes. Journal of Geophysical Research 92 (B2): 1349–1355. https://doi.org/10.1029/JB092iB02p01349.
Ashtari Jafari, M. 2008. The Distribution of b-Value in Different Seismic Provinces of Iran. Presented at the 14th World Conference on Earthquake Engineering, Beijing, 12–17 October. International Association for Earthquake Engineering (IAEE).
BC Oil & Gas Commission. 2012. Investigation of Observed Seismicity in the Horn River Basin. BC Oil & Gas Commission Publications.
BC Oil & Gas Commission. 2014. Horn River Basin Unconventional Shale Gas Play Atlas. BC Oil & Gas Commission Publications.
Cipolla, C. L., Warpinski, N. R., Mayerhofer, M. J. et al. 2008. The Relationship Between Fracture Complexity, Reservoir Properties, and Fracture Treatment Design. Presented at the SPE Annual Technical Conference and Exhibition, Denver, 21–24 September. SPE-115769-PA. https://doi.org/10.2118/115769-PA.
Eaton, D. W., Davidsen, J., Pedersen, P. K. et al. 2014. Breakdown of the Gutenberg-Richter Relation for Microearthquakes Induced by Hydraulic Fracturing: Influence of Stratabound Fractures. Geophysical Prospecting 62: 806–818. https://doi.org/10.1111/1365-2478.12128.
Godano, C., Lippiello, E., and de-Arcangelis, L. 2014. Variability of the b-Value in the Gutenberg-Richter Distribution. Geophysical Journal International 199 (3): 1765–1771. https://doi.org/10.1093/gji/ggu359.
Gutenberg, B. and Richter, C. F. 1944. Frequency of Earthquakes in California. Bulletin of the Seismological Society of America 34 (4): 185–188.
Hanks, T. C. and Kanamori, H. 1979. A Moment Magnitude Scale. Journal of Geophysical Research 84 (B5): 2348–2350. https://doi.org/10.1029/JB084iB05p02348.
Ishimoto, M. and Iida K. 1939. Observations Sur Les Seismes Enregistres Par Le Microsismographe Construit Dernierement. Bull. Earthquake Res. Inst. Univ. Tokyo 17: 443–478.
Kanamori, H. 1978. Quantification of Earthquakes. Nature 271: 411–414. https://doi.org/10.1038/271411a0.
Kijko, A. and Smit, A. 2012. Extension of the Aki-Utsu b-Value Estimator for Incomplete Catalogs. Bulletin of the Seismological Society of America 102 (3): 1283–1287. https://doi.org/10.1785/0120110226.
Maxwell, S. C., Jones, M., Parker, R. et al. 2009. Fault Activation During Hydraulic Fracturing. In 79th Annual International Meeting, Society of Exploration Geophysicists, Expanded Abstracts, 1552–1556. https://doi.org/10.1190/1.3255145.
Maxwell, S. C. and Cipolla, C. 2011. What Does Microseismicity Tell Us About Hydraulic Fracturing? Presented at the SPE Annual Technical Conference and Exhibition, Denver, 30 October–2 November. SPE-146932-MS. https://doi.org/10.2118/146932-MS.
Maxwell, S. C. and Norton, M. 2012. Enhancing Shale Gas Reservoir Characterization Using Hydraulic Fracture Microseismic Data. First Break 30 (2): 95–101.
Maxwell, S. C. 2014. Microseismic Imaging of Hydraulic Fracturing: Improved Engineering of Unconventional Shale Reservoirs. Distinguished Instructor Short Course, Distinguished Instructor Series, No. 17, first edition. USA. Society of Exploration Geophysicists.
Segall, P. and Lu, S. 2015. Injection-Induced Seismicity: Poroelastic and Earthquake Nucleation Effects. Journal of Geophysical Research: Solid Earth 120: 5082–5103. https://doi.org/10.1002/2015jb012060.
Shapiro, S. A., Huenges, E., and Borm, G. 1997. Estimating the Crust Permeability From Fluid-Injection-Induced Seismic Emission at the KTB Site. Geophysical Journal International 131 (2): F15–F18. https://doi.org/10.1111/j.1365-246X.1997.tb01215.x.
Shapiro, S. A. and Dinske, C. 2009. Fluid-Induced Seismicity: Pressure Diffusion and Hydraulic Fracturing. Geophysical Prospecting 57 (2): 301–310. https://doi.org/10.1111/j.1365-2478.2008.00770.x.
Urbancic, T. I., Shumila, V., Rutledge, J. T. et al. 1999. Determining Hydraulic Fracture Behavior Using Microseismicity. Presented at the Vail Rocks 1999 37th US Symposium on Rock Mechanics (USRMS), Vail, Colorado, 7–9 June. ARMA-99-0991.
Utsu, T. 1965. A Method for Determining the Value of b in a Formula Logn¼A - Bm Showing the Magnitude-Frequency Relation for Earthquakes. Geophys. Bull. Hokkaido Univ. 13: 99–103.
Warpinski, N. R. 2014. Microseismic Monitoring—The Key Is Integration. The Leading Edge 33 (10): 1098–1100. https://doi.org/10.1190/tle33101098.1.
Yousefzadeh, A., Li Q., and Aguilera, R. 2015. Microseismic 101: Monitoring and Evaluating Hydraulic Fracturing To Improve the Efficiency of Oil and Gas Recovery From Unconventional Reservoirs. Presented at the SPE Latin American and Caribbean Petroleum Engineering Conference (LACPEC), Quito, Ecuador, 18–20 November. SPE-177277-MS. https://doi.org/10.2118/177277-MS.
Yousefzadeh, A., Li, Q., Virues, C. et al. 2016. Toward Interpretation of Intermediate Microseismic b-Values. Presented at the Geoconvention 2016, Calgary, 7–11 March.
Yu, G. and Aguilera, R. 2012. 3D Analytical Modeling of Hydraulic Fracturing Stimulated Reservoir Volume. Presented at the SPE Latin American and Caribbean Petroleum Engineering Conference, Mexico City, 16–18 April. SPE-153486-PP. https://doi.org/10.2118/153486-MS.