Importance of Stratabound Fracture Networks for Seismic Hazard Assessment of Hydraulic Fracturing
Abstract
Hydraulic fracturing, a powerful completion technique used to enhance oil or gas production from impermeable strata, may trigger unintended earthquake activity. The primary basis for assessment of triggered and natural seismic hazard is the classic Gutenberg-Richter (G-R) relation, which expresses scale-independent behavior of earthquake magnitudes. Using a stochastic approach to simulate microseismicity from three monitoring programs in North America, we show that magnitude-distance trends for microearthquakes induced by hydraulic fracturing may deviate significantly from the G-R relation. This apparent breakdown in the power-law scaling paradigm, coupled with unusually high values for the b-parameter (slope) of the G-R relation, can be explained by a new model based on activation of stratabound fracture networks in which fracture height growth is limited by mechanical bed thickness. For the three areas considered, mechanical bed thickness is well represented by a lognormal distribution, which leads asymptotically to a Gaussian decay for induced magnitudes that fits the observations remarkably well. This new relationship has profound implications for understanding the scaling behavior of induced microearthquakes, as well as for forecasting the probability of larger earthquakes triggered by hydraulic fracturing in oil and gas development.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFMNG13A..08E
- Keywords:
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- 7200 SEISMOLOGY;
- 4400 NONLINEAR GEOPHYSICS;
- 4329 NATURAL HAZARDS Sustainable development